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Mixed Metal Acetylide Complexes PRADEEP MATHUR, SAURAV CHATTERJEE AND VIDYA D. AVASARE
Chemistry Department
Indian Institute of Technology-Bombay
Powai, Bombay 400 076, India
Published in Advances in Organometallic Chemistry ,Volume 55, 2007, Pages 201-277
http://dx.doi.org/10.1016/S0065-3055(07)55004-5
2
I. Introduction 3
II. Mixed Group 8 Metal Acetylide Complexes 4
III. Mixed Group 10 Metal Acetylide Complexes 13
IV. Mixed Group 11 Metal Acetylide Complexes 15
V. Mixed Group 6 - 9 Metal Acetylide Complexes 19
VI. Mixed Group 10 -12 Metal Acetylide Complexes 71
VII. Other Mixed Metal Acetylide Complexes 79
VIII. Abbreviations 99
References
3
I INTRODUCTION
Complexes containing C2 hydrocarbyl ligands occupy a very important position in
the development of di-, tri- and polynuclear organometallic chemistry. Recognition that
monovalent anions of alk-1-ynes, [RC≡C]¯ are isoelectronic to cyanide ion and CO
prompted the first preparation of metal alkynyl complexes in 1953.1,2 Since then, a
number of synthetic strategies have been developed and chemistry of metal acetylide
complexes has grown tremendously.3-12 Ability of the alkynyl part (-C≡CR) of the metal
acetylides to bind to metal centres in a variety of bonding modes enables a large number
of acetylide – bridged polynuclear complexes to be synthesised.13-26 The presence of
metal and electron - rich C≡C moiety in acetylide complexes facilitates cluster growth
reactions, and frequently, coupling of acetylide moieties to form polycarbon chains on
cluster frameworks is observed.27-30
In this review, focus is given on mixed – metal acetylide complexes which have
been prepared from metal – acetylide precursor complexes. Particular emphasis is given
on aspects of variation of acetylide bonding on mixed – metal polynuclear frameworks
and on reactivity of the polycoordinated acetylide ligand. Since, we recently reviewed
oxo - incorporated metal acetylide complexes,31 these are excluded from the present
review. A large majority of the acetylide – bridged mixed metal complexes contains
metals of the same group of the Periodic Table and, therefore, we have subdivided the
review based on different groups. Although, several examples exist of mixed – metal
acetylide complexes containing metals from groups 6, 7, 9 and 12, quite surprisingly, we
4
could not find any example of mixed – metal acetylide complexes containing metals only
from one of these groups.
II MIXED GROUP 8 METAL ACETYLIDE COMPLEXES
Most of the mixed metal acetylide complexes of this particular group are those
associated with Cp, Cp* and carbonyl ligands. A number of synthetic studies have been
carried out for polynuclear C2 complexes derived from ethynyl and diethynediyl iron
complexes. Reaction of the ethynyliron complexes [{(η5-C5R5)Fe(CO)2}-C≡C-H] (R =
H, 1; R = Me, 2) with [Ru3(CO)12] in refluxing benzene affords triruthenium μ-η1,η2,η2-
acetylide cluster compounds [Ru3(CO)9(μ-H) (μ3-η1:η2:η2-C≡C-{(η5-C5R5)Fe(CO)2})]
(R = H, 4; R = Me, 5) (Scheme 1).32 On the other hand, the reaction of the
ethynediyldiiron complex, [{(η5-C5Me5)Fe(CO)2}-C≡C-{(η5-C5Me5)Fe(CO)2}] (3) with
[Ru3(CO)12], gives a complicated mixture of products, from which [Cp*2Fe2Ru2(μ4-
C2)(CO)10] (6) and [Cp*2Fe2Ru6(μ6-C2)(CO)17] (7) have been isolated and characterized
by X-ray crystallography as permetalated ethene and permetalated ethane complexes
respectively (Scheme 2).32 The four metal atoms in 6 form an open-rectangular array
embedded in which is a C2 ligand. Compound 7 is an octanuclear compound with two C2
units above and below a Ru4 plane arranged perpendicular to each other. Two of the
edges of the central Ru4 plane are bridged by Ru(CO)3 groups and the other two by
FeCp* moieties.
5
Ru3(CO)12
Fe
Ru
Ru
CC
Ru
H
(CO)3
(CO)3
(CO)3
1; R = H 2; R = Me
C CFe H(CO)2
(CO)2
(η5-C5R5)
(η5-C5R5)
4; R = H 5; R = Me
C6H6, 80ºC
Scheme 1.
Ru3(CO)12
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
O(CO)3 (CO)3
CC
CRu C
Ru
RuRuRu
Ru
FeCp*
FeCp*
CO
COCO(CO)3
(CO)3
Ru = Ru(CO)2
+
6 7
C CFe Fe(CO)2(η5-C5Me5) (CO)2(η5-C5Me5)
Benzene60 ºC
3
Scheme 2.
On reflux of a THF solution of a mixture of [Fe2(CO)9] and 6, iron-substituted
derivative of 5, complex [Ru2Fe(μ-H)(CO)9(μ3-C≡C-{(η5-C5Me5)Fe(CO)2})] (8) is
formed. Treatment of 6 with CF3SO3H, HBF4.OEt2 or CF3COOH forms an unstable
cationic species 9,which has been characterised solely by spectroscopy, as it readily
converts to [{(η5-C5Me5)Fe(CO)]+ X- (Scheme 3).32
6
Fe2(CO)9
(CO)3
(CO)3 (CO)3
8
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
H
O(CO)2 (CO)2
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
O(CO)3 (CO)3
HX
+ +
9a; X = CF3SO39b; X = BF49c; X = CF3COO
+
X
[ Cp*(CO)Fe ] X+
6
Cp*Cp*
OC
FeC
Ru RuC
COC
FeOC
O
(CO)3 (CO)3
(η5-C5Me5)(CO)2
CC
Ru
Ru
Fe
H
Fe
X
Scheme 3.
Thermolysis of the mixed-metal tetranuclear cluster [(μ3-C≡C-{(η5-
C5H5)Fe(CO)2})Ru3(μ-H)(CO)9] (4) affords two products: [CpFeRu6(μ5-C2)(μ5-
C2H)(CO)16] (10) and [Cp2Fe2Ru6(μ6-C2)2(CO)17] (11) (Scheme 4).33 The anion [(μ3-
C≡C-{(η5-C5H5)Fe(CO)2})Ru3(CO)9]- (12) derived from 4 undergoes coupling of the
{(C2)FeRu3} core to give compound 11 and a heptanuclear cluster [Cp2Fe2Ru5(μ5-
C2)2(CO)17] (14), a coordinatively saturated compound with 112 cluster valence electrons
bearing two six-electron donating C2 ligands.
7
PPh4
[Cp2Fe]PF6 CH2Cl2
KOHPPh4Br
12
Toluene
110 ºC
4
(CO)3
(CO)3
(CO)3
Fe
RuRu
CC
Ru
H
+
(CO)3
(CO)3
(CO)3
Fe
RuRu
CC
Ru
H
(η5-C5H5)(CO)2
(η5-C5H5)(CO)2
(CO)3
(CO)3
C C
Ru Ru
Ru
Ru
Fe
CCC
CpH
Ru
RuO
(CO)310
+ 11
(CO)2
11
+ Fe FeRuRu
Ru
Ru Ru
OC CO
C C
C
C
C
O14
C C
CRuC
Ru
RuRuRuRu
FeCp
FeCp
CO
COCO(CO)3
(CO)3
(CO)2 (CO)2
Ru = Ru(CO)2
Cp Cp
Scheme 4.
Treatment of 6 with R-chloropropionic acid results in an addition reaction
yielding a μ-hydrido μ-carboxylato derivative, [(μ4-C=C)(μ-H)(μ-κ1,κ1-
CH3CHClCOO)Fe2Ru2Cp*2(CO)8] (15). On irradiation of a THF solution of 6, in
presence of diphosphines, [Ph2P(CH2)nPPh2] (n= 1, 2), the substituted products [(μ4-
C=C)Fe2Ru2Cp*2(CO)8{μ-Ph2P(CH2)nPPh2}] (n = 1, 16a; n = 2, 16b) are formed.
Treatment of 16 with HBF4.OEt2 results in protonation at the C=C unit to give the
cationic μ4-C2H complex, [(μ4-C=CH)Fe2Ru2Cp*2(CO)12(dppm)]BF4 (17) which on
reduction with [NEt4] BH4 results in elimination of one of the iron fragments to afford a
8
trinuclear acetylide cluster, [(μ3-C≡CH)FeRu2Cp*(CO)5(dppm)] (18a). On the other
hand, treatment of 17 with H2SiPh2 leads to hydrogen addition to give the trinuclear μ3-
HC=CH complex [(μ3-HC=CH)(μ-H)FeRu2Cp*(CO)5(dppm)] (18b). Thus, the μ3-
HC=CH ligand in 18b arises from formal hydrogenation of the μ4-C=C ligand in 16a and
the ligand transformations are realized by the flexible coordination capability of the C2
ligand. Cluster expansion of 16a with [Co2(CO)8] gives
[(μ3-C≡CFe(CO)2Cp*)FeRu2CoCp*(CO)12(dppm)] (19) (Scheme 5).34a
9
6
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
O
(CO)3 (CO)3
CH3CH(Cl)COOH
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
O O
CHCH3
H
O(CO)2 (CO)2
Cl15
16a
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
P PPh2
O(CO)2 (CO)2
Ph2
Co2(CO)8
16b
Cp* Cp*
OC
FeC
Ru RuC
COC
FeOC
P PPh2
O(CO)2 (CO)2
Ph2
Ph2P(CH2)xPPh2
x = 1, 2THF, hν
+
(CO)2
P
Ru(CO)2
FeCp*
CP
Ru
C
Co COC
(CO)2
(CO)
Ph2
Ph2
O
+Cp*FeCo(CO)5
1916a
Cp*Cp*
ORu
Fe
C
C
RuC
COC Fe
P PPh2
H
O(CO)2 (CO)2
Ph2
+ BF4
17
HBF4.OEt2
Cp*O
(CO)2 (CO)2
C FeC
Ru Ru
C
P PPh2
H
Ph2
18a
Cp*
O(CO)2
(CO)2
Ph2
18b
H2SiPh2 THF
Et4NBH4
CH
C
Fe
RuRu
C
P PPh2
H
H
CH2Cl2
C6H6, 70ºC
CH2Cl2
THF
Scheme 5.
Thermal reaction of a THF solution of ethynediyl complex [{Cp2Ru(CO)2}2(μ-
C≡C)] (20) with diiron nonacarbonyl gives [Cp2Fe2Ru2(μ4-C≡C)(μ-CO)(CO)8)] (21)
(Figure 1).34b
10
CC
Fe
Fe
Ru
C
Ru(CO)2
Cp
Cp
(CO)3
(CO)3
O
21 Figure 1.
Highly conjugated polycarbon–metal systems, the zwitterionic μ-but-2-yn-1-
ylidene-4-ylidyne complex [Ru3(CO)10(μ3-C–C≡C–μ-C)Fe2Cp*2(CO)3] (23) and the
dimerized product with a cumulenic μ-C8 ligand, [(Cp*Fe)4Ru2(CO)13[μ6-C8–C(=O)]
(24a) have been isolated from the reactions of butadiynediyldimetal complex, [{(η5-
C5Me5)Fe(CO)2}–C≡C–C≡C–Fe(η5-C5Me5)(CO)2] (22a) with [Ru3(CO)12] (Scheme 6).
An isostructural C8 complex 24b is obtained on reaction of the Fe-Ru mixed metal
complex [{(η5-C5Me5)Fe(CO)2}–C≡C–C≡C–Ru(η5-C5Me5)(CO)2] (22b) with
[Ru3(CO)12]. A zwitterionic acetylide cluster-type product {(η5-
C5Me5)Fe(CO)2}+[Cp(CO)2Ru(η2-C≡C)–(μ3-C≡C)Fe3(CO)9]- (25) is formed by the
reaction of butadiynediyldimetal complex, [{(η5-C5Me5)Fe(CO)2}–C≡C–C≡C–Ru(η5-
C5H5)(CO)2] (22c) with [Fe2(CO)9] (Figure 2).35a X-ray crystallography reveals a
pentanuclear structure containing a dinuclear μ-η1,η2-acetylide cationic species and a
trinuclear μ3-acetylide anionic species.
11
Ru3(CO)12
RuC C
RuRu
CFe
Fe
C C CO O
(CO)Cp*
(CO)Cp*
(CO)3
(CO)3 (CO)3
+
(CO)3(CO)3
O
Cp*(CO)
Cp*(CO) CC
CC
Fe
Fe
C C C C
CRu
C
FeCp*(CO)2
FeCp*Ru
O
23
24a
Fe FeC C C CCp* Cp*(CO)2 (CO)222a
(CO)2
Scheme 6.
O
CC
CC
M2
M1
C C C C
CRuC
RuCp*(CO)2
FeCp*Ru
(CO)3(CO)3
O
Cp*(CO)
Cp*(CO)
(CO)2
24b'; M1/M2 = Fe/Ru 24b''; M1/M2 = Ru/Fe
Fe
(CO)3
(CO)3
(CO)3Fe
Fe
C C C
Fe
C RuCp(CO)2
25
Cp* (CO)2+
-
Figure 2.
Thermolytic reaction of a THF solution of [{CpRu(PPh3)2}2{μ-C≡C)n}] (n = 3,
26a; n = 4, 26b) with [Fe2(CO)9] afford the corresponding heterometallic complexes
[Fe3{μ3-CC≡C{Ru(PPh3)Cp}2(CO)9] (27a) and [Fe3{μ3-CC≡C{Ru(PPh3)2Cp}{μ3-
CC≡CC≡C{Ru(PPh3)2Cp}(CO)9] (27b) respectively (Scheme 7).35b
Cp (PPh3)2Ru (C C)n Ru(PPh3)2CpFe2(CO)9
Ru(PPh3)2Cp
C C
(CO)3Fe Fe(CO)3
(C C)n-2CCCp(PPh3)2Ru Fe
(CO)3
26a; n = 326b; n = 4
27a; n = 327b; n = 4
THF, 65 ºC
Scheme 7.
12
The triosmium acetylide cluster, [Os3(μ-H)(μ3-C≡CMe)(CO)9] (28) reacts with
[Ru3(CO)12] in refluxing hexane to give the tetranuclear [RuOs3(μ4-HC2Me)(CO)12] (29)
(Scheme 8).36a
(CO)3Os Os
Os(CO)3
H
CC
Me
(CO)3Ru3(CO)12
Os(CO)3
(CO)3RuOs
C
Os(CO)3
CMeH
28 29
(CO)3
Scheme 8.
Reaction of a dichloromethane solution of cis-[(dppm)2RuCl2] with trans-
[(dppm)2(Cl)Os(C≡C-p-C6H4-C≡CH)] and NaPF6 gives a vinylidene complex, which
converts to trans-[(dppm)2(Cl)Os(C≡C-p-C6H4-C≡C-Ru(Cl)(dppm)2] (30) on addition of
DBU in the reaction mixture (Scheme 9).36b
i) cis-[(dppm)2RuCl2]2NaPF6, CH2Cl2
PPh2Ph2P
Ph2P PPh2
Ru Clii) DBU
30
C CHCCOs
PPh2
Ph2P
Ph2P
PPh2
Cl C6H4 CCOs
PPh2
Ph2P
Ph2P
PPh2
Cl C6H4 C C
Scheme 9.
On reflux of a benzene solution containing [Fe2M(CO)9(μ3-E)2] (M = Ru; E = S,
Se) (31a, b) and [Fe(η5-C5H4E’CH2C≡CH)2] (E’ = S, 32a; Se, 32b) unusual ferrocenyl
containing heterometal clusters [Fe(η5-C5H4E’CH2C≡CH)(η5-C5H4{Fe2M(CO)8(μ-E)(μ3-
E)(E’CHCCH2)})] (M = Ru, E = Se and E’ = Se, 33a; M = Ru, E = S and E’ = Se, 33b)
are formed (Scheme 10).37 The molecular structure of 33b consists of a butterfly FeRuS2
unit attached to a {FeSeC(H)=CCH2} five-membered ring which is bonded via Se atom
to the C5H4 ring of a {(η5-C5H4)(η5-C5H4SeCH2C≡CH)Fe} unit.
13
Fe EM
Fe
E
E' CH2 C CH
Fe
E' CH2 C CH
+
Benzene
(CO)3
(CO)3
(CO)3
C C
E'CH2
Fe
E
EFe M(CO)3
HFe
E' CH2 C CH
(CO)2
(CO)3
33a; M = Ru, E = Se, E' = Se
31a; M= Ru, E = S 31b; M= Ru, E = Se 32a; E' = S
32b; E' = Se
33b; M = Ru, E = S, E' = Se
80ºC
Scheme 10.
III MIXED GROUP 10 METAL ACETYLIDE COMPLEXES
Reaction of trans-bis(tri-n-butylphosphine)diethynylnickel (34) with l-alkynes in
the presence of an amine complex of a copper(I) salt as a catalyst gives quantitatively
alkynyl ligand exchange products. In this synthetic method, complex 34 reacts with
appropriate α,ω-diethynyl compounds to afford high molecular weight linear polymers
(35-38) in good yields.38 This procedure provides a convenient route to heterometallic
nickel-platinum-poly-yne polymers (Scheme 11).
Ni
PBu3
PBu3
CC CHHCn + R CC CHHCn R CC CCNiPBu3
PBu3
( ) n/2 + n HC CH
R = Ni
PBu3
PBu3
CC CC , p-C6H4 , Pt
PBu3
PBu3
CC CC , p-C6H4 Pt
PBu3
PBu3
CC CC p-C6H4
3835 36 37
34
Scheme 11.
14
Formation of heterodinuclear Pt-Pd anionic complexes [(C6F5)2Pt(CCR)2Pd(η3-
C3H5)]- (R = Ph, tBu, SiMe3) (42a-c) and neutral trinuclear complexes [{(η3-
C3H5)Pd}2{Pt(CCR)4}] (R = Ph, tBu, SiMe3) (41a-c) have been reported from the
reactions of anionic substrates 39, [Pt(C≡CR)4]2-or 40, cis-[Pt(C6F5)2(C≡CR)2]2-with
[{Pd (η3-C3H5)Cl}2] complex (Scheme 12).39
40
41a; R = Ph41b; R = tBu
41c; R = SiMe3
39
cis-[Pt(C6F5)2(C CR)2]2 PtF5C6 C CR
C CRF5C6
[{Pd(η3-C3H5)Cl}2]
[{Pd(η3-C3H5)Cl}2]
[Pt(C CR)4]2Pt
RC C C CR
C CRRC C
Pd
Pd
+
+
Pd
42a; R = Ph42b; R = tBu
42c; R = SiMe3
12
Acetone
Acetone
Scheme 12.
The reaction of mononuclear platinum acetylide complexes [cis-Pt(CCR)2L2] (R
= Ph, tBu; L = PPh3) towards cis-[Pd(C6F5)(thf)2] (43) results in the formation of
dimetallic Pt-Pd (R =Ph, 44; R = tBu, 45) complexes (Scheme 13).40
cis-[Pd(C6F5)2(thf)2] cis-[Pt(C CR)2(PPh3)2] PtPh3P C CR
C CRPh3P
44; R = Ph45; R = tBu
+
Pd C6F5F5C6
Acetone
Scheme 13.
15
IV MIXED GROUP 11 METAL ACETYLIDE COMPLEXES
New aspects of chemistry and bonding have emerged from reactions of the
anionic linear metal acetylide complexes [M(C2Ph)2]- with metal phenylacetylide
polymers [M(C2Ph)]n (M = Cu, Ag, Au). The reactions involve depolymerization,
ethynylation and condensation to form novel clusters. Thus, the homonuclear
[Ag5(C2Ph)6]- and heteronuclear [Au2Cu(C2Ph)4]-, [Au3M2(C2Ph)6]- (M = Cu, Ag),
[Ag6Cu7(C2Ph)14]-, and [AuAg6Cu6(C2Ph)14]- complexes have been obtained. Extension
of ethynylation reactions to neutral complexes resulted in formation of
[Au2Ag2(C2Ph)4(PPh3)2], [Ag2Cu2(C2Ph)4(PPh3)4], [AuAg(C2Ph)2]n, [AuCu(C2Ph)2]n,
and [AgCu(C2Ph)2]n.
Mixed gold-silver and gold-copper phenylacetylide polymers [{AuM(C2Ph)2}n]
(M = Ag, 46; M = Cu, 47) have been made by the reaction of [Au(C2Ph)L] (L = AsPh3,
P(OPh)3) with [{Ag(C2Ph)}n] (48) and [{Cu(C2Ph)}n] (49) respectively. The gold-silver
polymer 46 has also been prepared by the reaction of [AuClPPh3] with [{Ag(C2Ph)}n].41
Another heterometallic gold-silver cluster, [Au2Ag2(C2Ph)4(PPh3)2] (50) has been
prepared by the reaction of [(PPh3)AuC2Ph] and [AgC2Ph]n and also by the reaction of
PPh3 with the polymer [AuAg(C2Ph)2]n (46) (Scheme 14).42 The structure of 50 consists
of a linear arrangement of two phenylacetylide groups about each gold atom, with each
silver atom asymmetrically π-bonded to two triple bonds and one phosphine ligand
(Figure 3).
16
50
C
C
Ph
Ag
Ag
C
C
Au
C
C
Ph
Ph
C
AuC
Ph
P(Ph)3
(Ph3)P
Figure 3.
Ph3PAuC2Ph + AgC2Ph [AuAg(C2Ph)2PPh3]2
PPh3
[AuAg(C2Ph)2]nPh3PAuCl + 2AgC2Ph
50
46 Scheme 14.
Reaction of [Au2(C2Ph)3]- and [AgC2Ph] gives a gold-silver pentanuclear cluster
[Au3Ag2(C2Ph)6]- (51) (Scheme 15).43
[N(PPh3)2][Au2(C2Ph)3][AgC2Ph]
1/2[N(PPh3)2][Au3Ag2(C2Ph)6] + 1/2[N(PPh3)2][Au(C2Ph)2]
51
Scheme 15.
The pentanuclear cluster [Au3Ag2(C2Ph)6]- (51) has also been obtained from the
reaction between [Ag(C2Ph)2]- and the polymer complex [{AuAg(C2Ph)2}n] (46)
(Scheme 16).44
17
51
[Au(C2Ph)2]
[Au2Ag(C2Ph)4]
2[Ag(C2Ph)2][AuAg(C2Ph)2]
[Au3Ag2(C2Ph)6]
[Ag(C2Ph)2] [Au(C2Ph)2]
[AuAg(C2Ph)2]
+
+
unstable
2[Au2Ag(C2Ph)4]
[Au(C2Ph)2]
Scheme 16.
Homonuclear silver complex [Ag5(C2Ph)6]- (52) and heteronuclear silver-copper
complex [Ag4Cu(C2Ph)6]- (53) have been obtained by the reactions of silver
phenylacetylide with the linear complex anions [Ag(C2Ph)2]- and [Cu(C2Ph)2]-,
respectively (Figure 4).43
Ag
C
Ag
C
C
Cu
C
C
Ph
Ph
C
Ag C
C
Ag
C
C
Ph
Ph
C
Ph
CPh
52 53
Ag
C
Ag
C
C
Ag
C
C
Ph
Ph
C
Ag C
C
Ag
C
C
Ph
Ph
C
Ph
CPh
Ag
C
Au
C
C
Au
C
C
Ph
PhC
Ag C
C
Ag
C
C
Ph
Ph
C
Ph
CPh
51 Figure 4.
The reaction of [Cu(C2Ph)2]- and [{AuCu(C2Ph)2}n] (47) affords the cluster
[Au2Cu(C2Ph)4]- (54) or [Au3Cu2(C2Ph)6]- (55) depending on the molar ratio of the
reactants. The pentanuclear cluster [NnBu4][Au3Cu2(C2Ph)6] (55) is also obtained by the
reaction of [NnBu4][Au(C2Ph)2] with a mixture of [AuC2Ph]n and [CuC2Ph]n.45 X-ray
structural data for 55 reveals a trigonal bipyramidal arrangement of metal atoms with two
copper atoms in the apical and three gold atoms in the equilateral positions. Each gold
atom is σ-bonded to two acetylide groups in almost linear co-ordination while each
18
copper atom is asymmetrically π-bonded to three alkyne groups (Figure 5). In contrast,
the reaction of [Cu(C2Ph)2]- and [{AuAg(C2Ph)2}n] (46) gives the expected complex
[Au3Ag2(C2Ph)6]- (51) and the trimetallic [AuAg6Cu6(C2Ph)14]- (56) (Scheme 17).46
2[AuAg(C2Ph)2]
[Au2Ag(C2Ph)4]
[Cu(C2Ph)2]
[AgCu(C2Ph)2]
[Au3Ag2(C2Ph)6]
[Au2Ag2Cu(C2Ph)6]
[AuAg6Cu6(C2Ph)14]
[Au(C2Ph)2]
[Au(C2Ph)2] 6[AgCu(C2Ph)2]+
+
+
+
unstable[Au2Ag2Cu(C2Ph)6]
2[Au2Ag(C2Ph)4]51
56 Scheme 17.
Cu
C
Au
C
C
Au
C
C
Ph
PhC
Cu C
C
Au
C
C
Ph
Ph
C
Ph
CPh
55
Cu
C
C
Au
C
C
Ph
Ph
Au
C
C
C
Ph
CPh
54 Figure 5.
A trimetallic cluster, [Au3AgCu(C2Ph)6]- (57) has been prepared by the reaction
of [Au3Cu2(C2Ph)6]- (55) with a mixture of gold phenylacetylide and silver
phenylacetylide. Complex 57 is also obtained by the addition of [Au3Ag2(C2Ph)6]- (51)
to [{AuCu(C2Ph)2}n] (47) or by the reaction of [Au2Cu(C2Ph)4]- (54) with
[{AuAg(C2Ph)2}n] (46). High nuclearity heterometallic cluster [AuAg6Cu6(C2Ph)14]-
(56) has been synthesized by the reaction of a dichloromethane solution of polymeric
[{Ag(C2Ph)}n], [{Cu(C2Ph)}n] and [Ag(C2Ph)2]-. Other synthetic methods to prepare 56
19
include reaction of [Au3Cu2(C2Ph)6]- (55) or [Au3Ag2(C2Ph)6]- (51) with a mixture of
[{Ag(C2Ph)}n] and [{Cu(C2Ph)}n].48 Room temperature reaction of the linear complex
[Ag(C2Ph)2]- and a mixture of [{Cu(C2Ph)}n] and [{Ag(C2Ph)}n] in dichloromethane
affords the silver-copper heteronuclear cluster [Ag6Cu7(C2Ph)14]-(57). When
[Cu(C2Ph)2]- or halide ions, X- (X = Cl, Br, I) are treated with [{Ag(C2Ph)}n] and
[{Cu(C2Ph)}n], cluster 57 is obtained.47
An X-ray diffraction study of cluster 57 reveals a 13-atom bimetallic anionic
cluster with two types of Cu atoms, one inside the body of the cluster and six on its
surface. The surface atoms form a distorted trigonal bipyramidal geometry whereas the
internal Cu atom linearly coordinates two C2Ph groups in addition to six Cu-Ag bonding
interactions and three tetranuclear [Ag2Cu2(C2Ph)4] subclusters (Figure 6).49
PhPh
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
57
C C
CCAg
Cu Cu
Ag
Ag
Cu
Cu
AgCu
AgAg
Cu
CuCC C
CC C
CC
C C
CC
CC
C CCC
CC
CC
CC
Figure 6.
V MIXED GROUP 6 - 9 METAL ACETYLIDE COMPLEXES
The metal acetylides [Cp(CO)2MC≡CR] (58a, M = Fe, R = Ph and 58b-c, M =
Ru, R = Ph, tBu, Me) react with [Co2(CO)8] to form the acetylide-bridged trinuclear
20
mixed metal complexes [Co2(CO)6-μ-(Cp(CO)2MC≡CR)] (M = Fe and R = Ph, 59;, M =
Ru and R = Ph, tBu, Me, 60a-c) (Figure 7).50
Co(CO)3(CO)3Co
PhC C
Cp(CO)2Fe
Co(CO)3(CO)3Co
RC C
Cp(CO)2Ru
59a60a; R = Ph60b; R = tBu60c; R = Me
Figure 7.
Compounds with a tetrahedral C2Co2 core, [Co2(CO)6(μ-η2,η2-MCCH)] (M =
CpFe(CO)2, 62a; M = Cp*Fe(CO)2, 62b) have been obtained by the interaction of THF
solution of ethynyliron complexes [{CpFe(CO)2}-C≡CH] (61a) and [{Cp*Fe(CO)2}-
C≡CH] (61b) with [Co2(CO)8] respectively. The reaction of the ethynyldiiron complex
[{Cp*Fe(CO)2}-C≡C-{Cp*Fe(CO)2}] (63) with [Co2(CO)8] similarly affords the deep
green adduct [Cp*Fe[Co(CO)2]2(μ-CO)2(μ-η1,η2,η2-CC-Fp*)] (64), which shows
fluxional properties at ambient temperature (Scheme 18).51
HCM C Co2(CO)8
Co Co
62a; M= CpFe(CO)262b; M = Cp*Fe(CO)2
(CO)3 (CO)3
Fe FeCCCo2(CO)8
(CO)2
(CO)2Fe
Co
Co
C C FeCp*
CCO
Cp*
63
64
61a; M= CpFe(CO)261b; M = Cp*Fe(CO)2
(CO)2(CO)2 Cp*Cp*
(CO)2
O
CM C H
THF
THF
Scheme 18.
Photolytic reaction of [(μ-η2,η2-M-C≡C-H)Co2(CO)6] (M = CpFe(CO)2, 62a; M
= Cp*Fe(CO)2, 62b) produces pentanuclear clusters [(η5-C5R5)2Fe2Co3(μ5-CCH)(CO)10]
21
(R = H, 65a; R = Me, 65b), respectively, via an apparent addition reaction of a (η5-
C5R5)FeCo(CO)n fragment to 62. On the other hand, thermolysis of 62a gives the Fe-
free hexacobalt cluster compound [(μ-CH=CH){(μ3-C)Co3(CO)9}2] (66), whereas when
62b is thermolyzed, the Fe-Co dimer without the C2H ligand, [Cp*Fe(CO)(μ-
CO)2Co(CO)3] (67) is obtained, in addition to the photolysis product 65b. Reduction of
62 with hydrosilanes gives 1,2 disilylethylene and the tetranuclear μ-vinylidene cluster
[(C5R5)FeCo3(μ4-C=CH2)(CO)9] (R = H, 68a; R = Me, 68b) by hydrosilylation and
hydrometallation of the C2H ligand, respectively (Scheme 19).52
65a; R = H65b; R = Me
68a; R = H68b; R = Me
(CO)2 (CO)2
FeC
CH
Co Co
H
Co
CC
(CO)2
(CO)2
(CO)
Fe
CC
Fe
CoCo
H
CoC
C
C
(CO)2
(η5-C5R5)
O
O
O
(η5-C5R5)
(CO)3
O
O(η5-C5R5)
hν
H-SiEt3
Co Co(CO)3 (CO)3
(CO)2
62a; R = H62b; R = Me
C(η5-C5R5)Fe C HC6H6
C6H6
Scheme 19.
Interaction of the trinuclear ethynyl complexes [Co2(CO)6[(μ-(η5-
C5R5)Fe(CO)2C≡CH] (R = H, 62a; R = Me, 62b) with [Fe2(CO)9] results in the
formation of a tetranuclear vinylidene intermediate [Co2Fe(CO)9[μ3-C=C(H)Fe(η5-
C5R5)(CO)2] (69) which undergo thermal decarbonylation to produce the tetranuclear
acetylide clusters [(μ4-C2H)[(η5-C5R5)Fe]FeCo2(CO)10] (70 a,b) (Scheme 20).
Similarly, the addition reaction of [(η5-C5R5)Fe(CO)2C≡CH] (61a,b) to the trimetallic
22
species RuCO2(CO)11 affords the ruthenium analogue of the vinylidene complex
[Co2Ru(CO)9[μ3-C=C(H)Fe(η5-C5R5)(CO)2] (71a,b), which decarbonylates to [(μ4-
C2H)[(η5-C5R5)Fe]RuCo2(CO)10] (72a,b) (Scheme 21).53
Co Co(CO)3 (CO)3
(CO)2Fe2(CO)9
(CO)3
(CO)3
(CO)2
FeC
C(η5-C5R5)Fe
CoCo
H
(CO)3
62a; R = H62b; R = Me
(CO)3
(CO)3
(CO)CC(η5-C5R5)Fe H
Fe
Co
CoC
(CO)2
O
69; R = H 70a; R = H70b; R = Me
C(η5-C5R5)Fe C H +C6H6
Scheme 20.
(CO)2(η5-C5R5)FeC CHRuCo2(CO)11
C
CRu Co
Co
H(η5-C5R5)Fe
(CO)3
(CO)3
(CO)3
(CO)2
O(CO)2
(CO)2
C(η5-C5R5)Fe HC
CoRu(CO)3Co
C
C
O(CO)
61a; R = H61b; R = Me
71a; R = H71b; R = Me
72a; R = H72b; R = Me
C6H6, 80ºC
Scheme 21.
A formal replacement of (η5-C5Me4Et)Fe(CO) moiety of a triiron μ3,η1,η2,η2-
acetylide cluster compound 73a by an isolobal Co(CO)3 fragment occurs when cluster
73a reacts with [Co2(CO)8] (Scheme 22).54a
23
(CO)2
(CO)2
(CO)2Fe
Fe
Fe
Fe
CC
C
(η5-C5Me4Et)
O(CO)2
(CO)2
(CO)2Fe
Co
Fe
Fe
CC (η5-C5Me4Et)(η5-C5Me4Et)
(CO)3Co2(CO)8
73a 73b
C6H6
Scheme 22.
The triiron acetylide cluster compound [PPN] [Fe3(CO)9C≡C(OAc)] (74a) [PPN
= (Ph3P)2N+] reacts with [Fe(CO)4]2- at room temperature to produce the metalated
acetylide cluster [PPN]2[Fe3(CO)9C≡CFe(CO)4] (74b). Further metalation of 74b with
excess [Co2(CO)8] produces a hexametallic cluster [PPN] [Fe3Co3(C2)(CO)18] (76). The
reaction proceeds by formation of two intermediate compounds, the dicarbide-containing
cluster compound [PPN]2[Fe4Co2(C2)(CO)18] (75a) and the acetylide [PPN]
[Fe2Co(CO)9CCFe(CO)4] (75b) (Scheme 23).54b
24
THF
(CO)3
(CO)2
(CO)3 (CO)3
(CO)3
(CO)2
FeFeFe
CC
OAc
(CO)3
(CO)3
(CO)3
FeFe
Fe
CC
Fe(CO)4
(CO)3
(CO)3
(CO)3
FeCo
Fe
CC
Fe(CO)4
(CO)3
(CO)3
(CO)3
O O
(CO)3
(CO)2
(CO)3 (CO)3
(CO)3
(CO)2O O
Fe(CO)42-
Co2(CO)8
Fe2(CO)82-
Co2(CO)8
Co2(CO)8
2
74a
74b
76
75a75b
CCo
Fe
FeC
C
Co
Co
Fe
C
C CFe
Fe
FeC Co
Co
Fe
C
2CH2Cl2CH2Cl2
Co2(CO)8
Scheme 23.
A number of iron-cobalt mixed metal cluster compounds have been obtained by
sequential addition of [Co2(CO)8] and [Fe2(CO)9] to [Cp*Fe(CO)2-C≡C-C≡C-H] (77)
(Scheme 24).55 Their formation involves addition of a metal fragment to the C≡C bonds,
reorganization of the cluster framework, transfer of metal fragments, valence
isomerization of the C4(H) linkage and 1,2-H shift of the C4H ligand.
25
Co2(CO)8
C CFe C HC
C C
Fe
Fe
Co
C CFe
C C C CFe H
C C CC HC
Co
CoFeFe
C
Cp*(CO)2
Cp*(CO)2
Cp*(CO)2
Cp*(CO)2
79
80 81
82 83
Co2(CO)8
Co Co(CO)3 (CO)3
Fe2(CO)9
(CO)3(CO)3
(CO)3 Co Co(CO)3 (CO)3
Co Co(CO)3 (CO)3
Fe2(CO)9
(CO)3
(CO)3
(CO)3 (CO)3
Cp*(CO)
O
O
(CO)+ (CO)2
(CO)3
(CO)3
(CO)3
Cp*(CO)
O
O
(CO)3
Fe C C C C H
Co Co
C CC
CoFe
FeC
H
C Co
Co
Co
C
Cp*
Cp*Co
H
FeC
CFe
Co
Co CoCo
CC
C
C
C
C
84
O
O O
O Co = Co(CO)2
77
HCC HC C
CoFeCo(CO)3
(CO)3(CO)3
(CO)3
(CO)3
85
Co Co
THF
THF THF
81
82C6H6
80ºC
C6H6
80ºC
C6H6
Scheme 24.
Sequential addition of [Co2(CO)8] and [Fe2(CO)9] to the butadiynediyl iron
complex (78) results in formation of the mixed Fe/Co complexes 86 and 87 and the C4-
bridged Co6 cluster 88 (Scheme 25).55
26
Cp*(CO)2
86
87
Co2(CO)8
CCFe C FeC
Co Co(CO)3 (CO)3
Fe2(CO)9
(CO)2
(CO)3
CC
CFe
Co
FeCo
CFe
C
C
(CO)3
Co2(CO)8
O
Cp*O
(CO)3 (CO)3
(CO)3
(CO)3
Co
Co
Co
C C C C Co
Co
Co
(CO)3
(CO)3
88
78Fe(CO)2Cp*C CFe C C
Cp*(CO)2 Cp*(CO)2
Cp*(CO)2
THF THF
THF
Scheme 25.
Compound 77 also reacts with [Mo2Cp2(CO)4] at room temperature or with
[CpMoCo(CO)7] at 50 °C to yield mixed metal acetylide complexes 89,
[Cp*Fe(CO)2C4H{Cp2Mo2(CO)4}] and 90, [Cp*Fe(CO)2C4H{CpMoCo(CO)5}]. On
further reaction with [Co2(CO)8], 89 gives 91 (Scheme 26).55
or77
Cp*(CO)2Mo2Cp2(CO)4
CH2Cl2, RT
CpMoCo(CO)7C6H6, 50ºC
CCCFe C H
CpMo MLn(CO)2
89; MLn= MoCp(CO)290; MLn= Co(CO)3
Co2(CO)889
Cp*(CO)
Co
OC
CoFe
C
CCC C H
(CO)2
(CO)2
O
CpMo MoCp(CO)2(CO)2
91
THF
Scheme 26.
27
Reaction of [Co2(CO)8] with the acetylide complexes,
[M(C≡CC≡CR)(CO)3Cp] (M = Mo, W; R = H, Fe(CO)2Cp) (92a-c) afford simple
adducts (93a-c) containing a Co2(CO)6 group attached to the least sterically-hindered
C≡C triple bond (Scheme 27). In contrast, bis-cluster complexes [{Cp(OC)8Co2M(μ3-
C)}C≡C{(μ3-C)Co2M’(CO)8Cp}] (M = M’ = Mo, W; M = Mo, M’ = W) (95a-c) have
been obtained when [M(C≡CC≡CR)(CO)3Cp] (M = Mo, W; R = M(CO)3Cp (M = Mo,
W), Fe(CO)2Cp) (94a-c) are used to react with [Co2(CO)8] (Scheme 28). Reaction
between [Co2(μ-dppm)(CO)6] and [{W(CO)3Cp}2(μ-C4)] affords [Co2(μ-dppm){μ-
[Cp(OC)3W]C2C≡C[W(CO)3Cp](CO)4] (97).56a
Co2(CO)8
92a; M = Mo; R = H92b; M = W; R = H92c; M = W; R = Fe(CO)2Cp
(CO)3Co Co(CO)3
Cp(CO)3MC
CC C
R
C C C C RCp(CO)3M
93a; M = Mo; R = H93b; M = W; R = H93c; M = W; R = Fe(CO)2Cp
Scheme 27.
28
Co2(CO)8
94a; M = M' = Mo94b; M = M' = W94c; M = Mo; M' = W
C CCCp(CO)3M C M'(CO)3Cp
C
Cp(CO)2M
Co
(CO)3Co C C C
M'(CO)2Cp
Co
Co(CO)3
(CO)3
(CO)3
C C M'(CO)3CpC CCp(CO)3M
95a; M = M' = Mo95b; M = M' = W95c; M = Mo; M' = W
Co(CO)3(CO)3Co
(CO)3Co Co(CO)396
Scheme 28.
Reaction of a THF solution of [{W(CO)3Cp}2(μ-C8)] and [Co2CO8] gives mono
and di-adducts, [{W(CO)3Cp}2{μ-C8[Co2(CO)6]}] (98a) and [{W(CO)3Cp}2{μ-C8-
[Co2(CO)6]2}] (98b) (Figure 8). Thermolytic reaction between [{W(CO)3Cp}2(μ-C8)]
and [Co2(μ-dppm)(CO)6] under benzene reflux affords [{W(CO)3Cp}2{μ-C8[Co2(μ-
dppm)(CO)4]}] (99a) and two isomeric products, [{W(CO)3Cp}2{μ-C8[Co2(μ-
dppm)(CO)4]2}] (99b) and [{W(CO)3Cp}2{μ-C8[Co2(μ-dppm)(CO)4]2}] (99c) (Figure
9).56b
29
WC
CC
CC
C
WC
C
Co Co
Cp
Cp(CO)3
(CO)3
(CO)3 (CO)3
Cp(CO)3
Cp(CO)3 CW C
C
Co
Co CC
C Co
Co
WCC
(CO)3
(CO)3
(CO)3
(CO)3
98a 98b Figure 8.
Cp(CO)3
Cp(CO)3 CW C
C
Co
Co CC
C Co
Co
WCC
P
P
P
P (CO)2
(CO)2
(CO)2
(CO)2
99c
Cp
Cp(CO)3
(CO)399b
Ph2
Ph2
Ph2
Ph2
Cp
Cp(CO)3
(CO)3
99aPh2
Ph2 Ph2
Ph2
Ph2
Ph2
WC
CC CCo
Co PP
(OC)2 W
WC
CCCCC C
WC
Co
CoPP
Co
Co PP
(OC)23
(CO)2
Figure 9.
Deprotonation of the alkyne-bridged clusters [RuCo2(CO)9(μ3-RC≡CH)] (100a-
d) with triethylamine and further reaction with the organometallic halides [Cp(CO)2FeCl]
(101), [Cp(CO)2RuCl] (102), [Cp(PPh3)NiCl] (103), and [Cp(CO)3MoCl] (104) in
presence of catalytic amounts of copper(I) iodide results in incorporation of the metal
species as organometallic acetylides MC≡CR into the RuCo2M metal frameworks (105-
111) (Scheme 29). With acids, the resulting acetylide-bridged clusters are reconverted to
the starting materials.57
30
CoRu
HRC C
Co(CO)3(CO)3
(CO)3
100a; R = Me100b; R = Ph
(CO)2(CO)3
(CO)3
CoRu
RC C
Co
MCp(CO)
CO(CO)2(CO)2L
(CO)3
CoRu
RC C
Co
NiCp
CO
(CO)2(CO)3
(CO)3
CoRu
RC C
Co
Mo
CO
(CO)2Cp
105a; M = Fe, R = Me105b; M = Fe, R = Ph106a; M = Fe, R = Me106b; M = Fe, R = Ph
107; R = Me, L = CO108; R = Me, L = PPh3
109; R = Me
(CO)2(CO)3
Cp(CO)2
CoRu
RC C
Mo
Mo
CO
(CO)2Cp
(CO)3(CO)3
Cp(CO)2
CoRu
HC C
Mo
R
110a; R = Me110b; R = Ph
111; R = Me
Cp(CO)2MClM = Fe, RuCp(PPh3)NiCl
Cp(CO)3MoCl
+
Cp(CO)3MoCl
Et3N, CuI, THF
Et3N, CuI, THF
Et3N, CuI, THF
Et3N, CuI, THF
Scheme 29.
A pentanuclear heterometallic acetylide complex [Cp2Mo2Ru3(CO)10(C≡CPh)2]
(113) has been prepared by the thermolysis reaction of a toluene solution of metal
acetylide [CpMo(CO)3(C≡CPh)] with [Ru3(CO)12] (Figure 10).58
Mo Ph
Ru
C
Ru
C
Ru
C Mo
C
CPh
C
(CO)3
Cp
(CO)3
CpO
O
113
Ru = Ru(CO)2
Figure 10.
31
Room temperature reaction of [W(C≡CC≡CH)(CO)3Cp] with the reactive
[Ru3(CO)10(NCMe)2] forms initially [Ru3{μ3-HC2C≡C[W(CO)3Cp]}(μ-CO)(CO)9]
(114), which readily transforms to [Ru3(μ-H){μ3-C2C≡C[W(CO)3Cp]}(CO)9] (115) on
benzene reflux and to 116 on reaction with excess of [W(C≡CC≡CH)(CO)3Cp] (Scheme
30).59 Similarly, reaction with [Ru3(μ-dppm)(CO)10] forms three interconverting isomers
of [Ru3(μ-H){μ3-C2C≡C[W(CO)3Cp]}(μ-dppm)(CO)12] (117-119) (Scheme 31).
[Ru3(CO)10(NCMe)2]
(CO)3
O
H
(CO)3Ru Ru(CO)3
CC
C C
W(CO)3Cp
Ru
C
C6H6
(CO)3
H
C COC
C
OC
Ru Ru(CO)4Ru
W
CCC
C
C(OC)3CpW
(CO)2Cp
H
114
115 116
CH)(CO)3(Cp)][W(C C C
(CO)2
CH)(CO)3(Cp)][W(C C C
80ºC
(CO)3
(CO)3Ru Ru(CO)3
CCC
C W(CO)3Cp
Ru
H
CH2Cl2
CH2Cl2
Scheme 30.
32
(CO)3Ru Ru(CO)3
Ru
CHCC CW
P PPh2 Ph2
(CO)3(CO)3Cp
[Ru3(μ-dppm)(CO)10]
117
118 119
HC C C CW(CO)3Cp
(CO)3Ru Ru(CO)3
Ru
C
H
CC CW
P PPh2 Ph2
(CO)3(CO)3Cp
(CO)3Ru Ru(CO)3
Ru
C HCC CW
P PPh2 Ph2
(CO)3(CO)3Cp
THF, 65ºC
Scheme 31.
Further reaction of [Ru3(μ-H){μ3-C2C≡C[W(CO)3Cp]}(CO)9] (115) with
[Ru3(CO)12] affords [{Ru3(μ-H)(CO)9}(μ3-η2,μ3-η2-C2C2){Ru2W(CO)8Cp}] (120a),
while reaction with [Fe2(CO)9] gives an analogous product 120b,in which three of the
ruthenium sites are partially occupied by a total of one or two iron atoms (Scheme 32).
Treatment of [Ru3(μ-H){μ3-C2C≡C[W(CO)3Cp]}(CO)9] (115) with [Co2(CO)8] forms a
vinylidene cluster [{CoRu2(CO)9}(μ3-η2,μ3-η2-CCHC2){CoRuW(CO)8Cp}] (121) by a
process involving the transfer of cluster-bound hydride to the C4 ligand.59
33
(CO)3
(CO)3
(CO)3
(CO)3
(CO)3
(CO)3Ru Ru(CO)3
CC
CC
W(CO)3Cp
Ru
H115
(CO)2Cp
Ru
RuW M
C
M
C C MC
H(CO)3
120a; M = Ru120b; M=Fe/Ru
Co2(CO)8
Co M
C C
Ru
M
C
Ru
CW
CO
(CO)2Cp
(CO)3
(CO)2
(CO)3H
121; M = Co/Ru
(CO)2
M = M(CO)2
Fe2(CO)9or
Ru3(CO)12 Toluene, 110ºC
Toluene, 110ºC
Scheme 32.
Reaction of a dichloromethane solution of 1,6-bis(trimethylsilyl)hexa-1,3,5-triyne
(122) with [Os3(CO)10(NCMe)2] yields [Os3(CO)9(μ-CO)(μ3-η1,η1,η2-
Me3SiC≡CC2C≡CSiMe3)] (123), which on reflux in heptane with [Ru3(CO)12] gives
[Os3Ru(CO)12(μ4-η1,η2,η1,η2-Me3SiC≡CC2C≡CSiMe3)] (124). However, thermal
reaction between 122 and [Ru3(CO)12] forms a butterfly cluster [Ru4(CO)12(μ4-
η1,η2,η1,η2-Me3SiC≡CC2C≡CSiMe3)] (125a) and the ruthenole complex [Ru2(CO)6{μ-
η2,η5-C(C≡CSiMe3)C(C≡CSiMe3)C(C≡CSiMe3)C(C≡CSiMe3)}] (125b). In the room
temperature reaction between cluster 125a and [Co2(CO)8], a slippage of the butterfly
cluster core along the hexatriyne chain occurs and [{Ru4(CO)12}{Co2(CO)6}(μ4-
η1,η2,η1,η2:μ-η2,η2-Me3SiC2C≡CC2SiMe3)] (126) is obtained (Scheme 33).60
34
Me3Si SiMe3
C C
Os Os
Os
C CC C
C(CO)3 (CO)3
(CO)3
O
Me3Si SiMe3
C C
Os
Os
Os
C CC C
Ru
(CO)3
(CO)3
(CO)3
(CO)3Ru3(CO)12
[Os3(CO)10(NCMe)2]
Ru3(CO)12
(CO)3
(CO)3
Ru Ru
Ru Ru
Me3Si SiMe3
C CC C
C C
(CO)3 (CO)3
(CO)3 (CO)3
(CO)3 (CO)3
(CO)3 (CO)3
Me3Si
Ru Ru
Ru Ru
C CC
CC
Co Co
CSiMe3
(CO)3 (CO)3
Co2(CO)8
+
122
123 124
125b
126
CMe3Si
Me3Si SiMe3
C CC CC C
C CC C
Ru
Ru
SiMe3C
Me3Si (C C)3 SiMe3
125a
Scheme 33.
Reaction of a benzene solution of [{Cp(PPh3)2Ru}2(μ-C≡C)3}] with [Co2(CO)8]
or [Co2(μ-dppm)(CO)6] gives [{Ru(PPh3)2Cp}2{-C≡CC2{Co2(CO)6}(C≡C)}] (127a) and
[{Ru(PPh3)2Cp}2{μ-C≡CC2{Co2(μ-dppm)(CO)4}C≡CC≡C}] (127b), while
[{Ru(PPh3)2Cp}2{μ-C≡CC2{Co2(μ-dppm)(CO)4}C≡CC≡C}] (127c) has been obtained
from a thermal reaction of [{Cp(PPh3)2Ru}2(μ-C≡C)4}] with [Co2(μ-dppm)(CO)6]
(Scheme 34).35b
35
[Co2(CO)6(dppm)2]
Ru(PPh3)2Cp
C C
L(CO)2Co Co(CO)2L
(CC)n-2
CC
Cp(PPh3)2Ru
Cp (PPh3)2Ru (C C)n Ru(PPh3)2Cp
n = 3, 4or Co2(CO)8
127a; n = 3, L = CO127b; n = 3, L2 = dppm127c; n = 4, L2 = dppm
Scheme 34.
A heterometallic CoRu5 cluster, [CoRu5(μ4-PPh)(μ4-C2Ph)(μ-PPh2)(CO)12(η5-
C5H5)] (129) has been isolated from the reaction between [Ru5(μ5-C2PPh2)(μ-
PPh2)(CO)13] (128) and [Co(CO)2(η-C5H5)] (Figure 11).61 Its structure consists of a
square pyramidal Ru5Co unit, and a Ru(Ph)C2-group attached to it through two
ruthenium and one cobalt atoms.
(CO)3Ru
Ru Ru(CO)3P
CC
Co
Ru Ru(CO)2
PPh2
Ph
(CO)2Ph
(CO)2
Cp
129 Figure 11.
The reaction between [Ru3(μ3-η2-PhC2C2Ph)(μ-CO)(CO)9] and [Co2(CO)8]
affords a pentametallic cluster [Co2Ru3(μ5-η2,η2-PhC2C2Ph)(CO)14] (130) in quantitative
yield.62a The X-ray determined molecular structure consists of a Co2Ru3 bow-tie cluster
straddled by the PhC2C2Ph ligand, the two C≡C triple bonds are attached to the five
metal atoms by 2σ(2Ru) and π(Co) bonding modes (Figure 12).
36
Co
CCC
Ru
C
PhPh
Ru Ru
Co CC
C
C
(CO)3 (CO)3
(CO)2 (CO)2O OO
O
130 Figure 12.
A dihydride complex [Cp*Rh(μ2-1,2-S2C6H4)(μ2-H)Ru(H)(PPh3)2] (131) reacts
with excess of p-tolylacetylene at room temperature to afford a mixture of cis and trans
isomers of alkynyl hydride complex, [Cp*Rh(μ2-1,2-S2C6H4)(μ2-H)Ru(C≡CTol-
p)(PPh3)2] (132a). On the other hand, reaction of 131 with trimethylsilylacetylene gives,
exclusively the cis isomer of [Cp*Rh(μ2-1,2-S2C6H4)(μ2-H)Ru(C≡CSiMe3)(PPh3)2]
(132b) (Scheme 35).62b The mechanism involves hydrogen transfer from 131 to the
alkyne, followed by oxidative addition of a second equivalent of the alkyne to the
dinuclear core of [Cp*Rh(μ2-1,2-S2C6H4)Ru(PPh3)2] unit.
H
S
Rh
S
RuHCp*
H
S
Rh
S
Ru C C RCp*2 R C CH(PPh3)2 (PPh3)2
132a; R = p-tolyl (cis:trans = 8:2)132b; R = SiMe3 (cis)
131
Scheme 35.
Thermal reaction of [Fe3(CO)9(μ3-E)2], (E=Se, 133a; Te, 133b) with [(η5-
C5H5)M(CO)3(C≡CPh)] (M =Mo, W) (134a, b) in the presence of trimethylamine-N-
oxide (TMNO), in acetonitrile solvent yield the mixed-metal clusters [(η5-
C5H5)MFe2(μ3-E)2(CO)7(η1-CCPh)] (E = Se and M = Mo, 135; E = Se and M = W, 136;
E = Te and M = Mo, 137; E = Te and M = W, 138) bearing η1-acetylide groups. Further
37
reaction of 135 or 137 with dicobaltoctacarbonyl at room temperature gives the mixed-
metal cluster compound [(η5-C5H5)MoFe2Co2(μ3-E)2(CO)9(η-CCPh)] (139, 140)
(Scheme 36).63
(CO)2
Cp
Cp(CO)3
135; M =Mo, E =Se136; M =W, E =Se137; M =Mo, E =Te138; M = W, E =Te
139; E = Se140; E = Te
Co2(CO)8
+ M C CPh
133a; E = Se133b; E = Te
134a; M = Mo134b; M = W
Me3NO (CO)3Fe EFe(CO)3
M
E
CC
Ph
(CO)3Fe EFe(CO)3
Fe
ECH3CN, 60ºC
(CO)3Cp
(CO)
(CO)2
Mo
E
Co
Fe
E
(CO)2Fe
CC Ph
Co(CO)3
Scheme 36.
When a toluene solution containing [Fe3(CO)9(μ3-E)2] ( E = S, Se or Te ) and
[W(η5-C5Me5)(CO)3(CCPh)] is subjected to reflux, mixed metal clusters [W2Fe3(η5-
C5Me5)2(μ3-E)2{μ4-CC(Ph)C(Ph)C}] (E = S, 141; Se, 142) are formed.64 The molecule
is made up of a Fe3W2 metal core which is enveloped by terminal and bridging carbonyl
ligands and a μ4-{CC(Ph)C(Ph)C} unit. The five metal atoms are arranged in the form of
an open triangular bipyramidal polyhedron wherein the three Fe atoms occupy the basal
plane while the two W centres are at the axial positions (Scheme 37).
38
(CO)3
+
133b; E = Se133c; E = S
(CO)3Fe EFe(CO)3
Fe
E C CPh
OE
W
CC
C C
E
W
Fe
Fe
Fe
OC
Ph Ph
C
CO
OC
OC CO
Cp* Cp*Toluene
110 ºC(CO)3WCp*
141; E = Se142; E = S
Scheme 37.
When a toluene solution of the acetylide complex, [Mo(η5-C5H5)(CO)3(C≡CPh)]
is thermally reacted with [Fe3(CO)9(μ3-E)2] ( E = S, Se ), formation of mixed metal
clusters, [(η5-C5H5)2Mo2Fe3(CO)8(μ3-E)2{μ5-CC(Ph)CC(Ph)}] (E = S, 143; Se, 144),
[(η5-C5H5)2Mo2Fe4 (CO)9(μ3-E)2(μ4-CCPh)2] (E = S, 145; Se, 146) and [(η5-
C5H5)2Mo2Fe3 (CO)7(μ3-E)2{μ5-CC(Ph)C(Ph)C}] (E = S, 147; Se, 148) are observed
featuring head to tail coupling of two acetylide groups, two uncoupled acetylide groups
and a tail to tail coupling of two acetylide groups, respectively, on the chalcogen bridged
Fe/Mo cluster framework (Scheme 38).65 The head-to-tail acetylide -coupled μ5-
{CC(Ph)CC(Ph)} unit of 143/144 acts as an eight electron donor to the cluster core. The
basic cluster geometry of 147/148 consists of a twisted bow-tie type Fe3MoE unit, one of
the faces is capped by a second Mo atom, and the second face is capped by one terminal
carbon atom of an {(CC(Ph)C(Ph)C} unit.
39
(CO)3
133b; E = Se133c; E = S
(CO)3Fe EFe(CO)3
Fe
E
+145; E = Se146; E = S
(CO)3
(OC)2
CCC
Fe
Fe PhPh
C
Mo Fe
EE Mo
Cp
Cp(CO)3
Ph
E
Fe
C
Fe
FeFeC
CC
Mo
MoE
Ph
Cp
(CO)2(CO)3
(OC)2 (CO)2
Cp
(OC)3 (CO)3
E E
Mo MoCpCp
CC
Fe FeC
CC
Fe
PhPh
O
Toluene 90ºC
+
C CPh(CO)3CpMo+
143; E = Se144; E = S
147; E = Se148; E = S Scheme 38.
Under similar thermolytic conditions, formation of clusters [(η5-C5H5)2W2Fe3
(CO)7(μ3-E)2(μ3-η2-CCPh)(μ3-η1-CCH2Ph)] (E = S, 149; Se, 150) and [(η5-
C5H5)WFe2(CO)8(μ-CCPh)] (151) has been observed in reactions of [W(η5-
C5H5)(CO)3(C≡CPh)] with [Fe3(CO)9(μ3-E)2] ( E = S, Se) (Scheme 39).65
40
(CO)3
133b; E = Se133c; E = S
(CO)3Fe EFe(CO)3
Fe
E
Toluene 90ºC
C CPh(CO)3CpW+
Cp
Cp (CO)3
(CO)3O
W
Fe FeC
C
Ph
Cp (CO)2
(CO)3(CO)3
CH2
Ph
W
Fe
FeC
CPh
E
WE
FeC
C
+
151
149; E = Se150; E = S
Scheme 39.
When a benzene solution containing [Fe3(CO)9(μ3-S)2], [(η5-
C5R5)Mo(CO)3(C≡CPh)] (R = H, Me), H2O and Et3N are photolysed with continuous
bubbling of argon a rapid formation of cluster [(η5-C5R5)MoFe2(CO)6(μ3-S)(μ-
SCCH2Ph)] ( R = H, 152; R = Me, 153) is observed (Scheme 40).66 The H2O molecule
acts as a source of protons as confirmed by labeling experiment, and Et3N works as a
phase transfer catalyst
(CO)3
133b; E = Se133c; E = S
(CO)3Fe EFe(CO)3
Fe
E C CPh (CO)3MoL
+
152; L = Cp153; L = Cp*
Et3N:H2Ohν
(CO)3Fe Fe(CO)2
S CC S
MoCH2 PhO
L
L=Cp, Cp*
Scheme 40.
41
Photolytic reaction of metal acetylide complexes with simple metal carbonyls has
been used to form heterometallic acetylide bridged complexes. For instance, photolytic
reaction of a benzene solution of [Fe(CO)5] and [(η5-C5R5)Mo(CO)3(C≡CPh)] (R = H,
Me) under continuous bubbling of argon results in a rapid formation of [(η5-
C5R5)Fe2Mo(CO)8(μ3-η1:η2:η2-CCPh)] (R = H, 154; Me, 155) and [(η5-
C5H5)Fe3Mo(CO)11(μ4-η1:η1: η2:η1-CCPh)] (156) (Scheme 41).67 The structure of 154
consists of a MoFe triangle and a μ3-η1,η2,η2 acetylide ligand. The molecular structure
of 156 comprises of an open Fe3Mo butterfly arrangement with a acetylide group bonded
in μ3-η1 mode.
Fe(CO)5 C6H6, hν,
+
156; R = H
Mo C CPh(CO)3
(CO)3
154; R = H 155; R = Me
(CO)3
(η5-C5R5)Fe
Mo Fe(CO)3C
CPh
(η5-C5R5)Ph
FeMo Fe(CO)3
Fe C CC
CO
O
(η5-C5R5)
(CO)2
(CO)2
(CO)3
0ºC
Scheme 41.
However, when a benzene solution containing a mixture of [(η5-
C5Me5)Mo(CO)3(C≡CPh)], [Fe(CO)5] and [PhC≡CH] are photolysed, formation of
alkyne-acetylide coupled mixed metal cluster [(η5-C5Me5)Fe2Mo(CO)7(μ3-
C(H)C(Ph)C(Ph)C)] (157) is obtained in moderate yield (Scheme 42).67 The molecular
structure of 157 consists of a Fe2Mo triangle with a {C(H)=C(Ph)C(Ph)=C} ligand triply
bridging the Fe2Mo face.
Fe(CO)5 hν
Mo C CPh(CO)3
157
HC CPh+Cp*
Ph
CO
Mo Fe
Fe
HC C
CO
C
PhC C
Cp*
O
(CO)(CO)3C6H6, 0ºC
Scheme 42.
42
When a mixed metal cluster [Fe2Ru(CO)9(μ3-E)2] (E = S or Se) has been reacted
with [(η5-C5H5)M(CO)3(C≡CPh)] (M = Mo or W) in toluene reflux condition,
heterometallic clusters [(η5-C5H5)2Fe2RuM2(CO)6(μ3-E)2{μ4-CC(Ph)C(Ph)C}] (M = Mo
and E = S, 158; M = Mo and E = Se, 159; M = W and E = S, 160; M = W and E = Se,
161) and [(η5-C5H5)2Fe2Ru2M2(CO)9(μ3-E)2{μ3-CCPh}2] (M = W and E = S, 162; M =
W and E = Se, 163), have been isolated from the reaction mixtures (Scheme 43).68 The
molecular structure of 158 consists of an open trigonal bipyramidal Fe2RuMo2 metal core
enveloped by terminal and bridging carbonyl ligands and a μ4-{CC(Ph)C(Ph)C} unit.
Structure of 162 can be described as a FeRuW2S distorted square pyramid core, in which
the WRu edge is bridged by a Fe(CO)3S and the RuFe edge by a Ru(CO)3 unit. One
acetylide group caps the W2Ru face in a η1, η2, η2 fashion and another caps the open
FeRuW face in a similar bonding mode.
158; M = Mo, E = S159; M = Mo, E = Se160; M = W, E = S161; M = W, E = Se
Toluene
+
(CO)3Fe
Ru(CO)3
Fe(CO)3
E
E
+ (CO)3Cp M C C Ph
Cp
Cp
Cp
Cp
Ru(CO)3
Ph
MRu
(CO)3FeE
CFeE
MC C C Ph
CO
CO
110 ºC
162; M = W, E = S163; M = W, E = Se
(CO)
EFe
E M C
M C
FeRu
C
OC
C
O
CO C
C Ph
Ph
O
OC
OC
Scheme 43.
When a toluene solution of a Fe/W mixed metal cluster, [Fe2W(CO)10(μ3-S)2] is
heated at 80 ºC with the tungsten acetylide complex [(η5-C5H5)W(CO)3(CCPh)], the
Fe2W3 mixed metal [(η5-C5H5)2W3Fe2S2(CO)12(CCPh)2] (164) was isolated (Scheme
44).69 Its structure consists of a Fe2WS2 trigonal bipyramidal unit in which the W atom
43
is attached to two separate molecules of [(η5-C5H5)W(CO)3(CCPh)] through the
acetylide group.
Toluene80 ºC
+ W C CPhW(CO)3C(CO)3W C
(OC)3Fe
WS S
Fe(CO)3
C
Ph
C
Ph
164
(CO)3
Cp
Cp
Cp(CO)4
(CO)3Fe SFe(CO)3
W
S
Scheme 44.
When [Fe2Mo(CO)10(μ3-S)2] is made to interact with [(η5-
C5Me5)W(CO)3(C≡CPh)] under mild thermolytic condition in argon atmosphere, a mixed
metal acetylide cluster [(η5-C5Me5)MoWFe4(μ3-S)3(μ4-S)(CO)14(CCPh)] (165) is
isolated (Scheme 45).70 Molecular structure of 165 consists of a {Fe2MoS2} distorted
square pyramid unit in which the basal Mo atom is bonded to the two sulphur atoms of an
open {Fe2S2} butterfly unit and a {(η5-C5H5)W(CO)2} group. A single phenylacetylide
ligand bridges the Mo-W bond in μ-η1,η2 fashion.
(OC)3Fe SFe(CO)3
Mo
S + W C CPh (CO)3Cp*Benzene
60 ºC
165
OO
Mo
SS
WC
SFe(CO)3S
Fe(CO)3(CO)3Fe
Fe(CO)3
C C PhC
Cp*
(CO)4
Scheme 45.
Photolysis of a benzene solution of a mixture of [Fe3(CO)9(μ3-S)2], [(η5-
C5Me5)M(CO)3(C≡CPh)] (M = Mo, W) and HC≡CR (R = Ph, n-Bu and Fc) (Fc =
ferrocene) forms two types of clusters depending on the nature of acetylene used. When
44
phenylacetylene or n-butyl acetylene are used, clusters [(η5-C5Me5)MFe3(CO)6(μ3-
S){(μ3-C(H)=C(R)S}(μ3-CCPh)] (166 - 169) are formed (Scheme 46).71 In these
compounds a new C−S bond is formed yielding a {HC=C(R)S} ligand which bridges a
{MFe2} face of the cluster framework. Use of ferrocenylacetylene in the reaction
medium results in the formation of [(η5-C5Me5)MFe3(CO)7(μ3-S){μ3-C(Fc)=C(H)S}(μ3-
CCPh)] (170, 171) in which a formal switching of the α and β carbons of the coordinated
acetylide moiety is observed (Scheme 47). Nature of the sulfido-acetylene coupling may
be an important factor in determining which cluster type is formed, with the bulky
ferrocene group disfavouring the expected S−Csubs coupling. The structure of 166 can be
described as consisting of a {MoFe3} butterfly core in which the hinge is composed of
the Mo and a Fe atom. One {MoFe2} face is capped by μ3-S ligand as well as an unusual
{HC=C(Ph)S} ligand. The second butterfly face is capped by a {η1: η2: η2-CCPh}
group. The wing - tip Fe atoms bear two and three carbonyl groups each and the hinge
Fe atom has one terminal carbonyl bonded to it.
(OC)3Fe SFe(CO)3
Fe(CO)3
S + M C CPh (CO)3Cp*Benzenehν, 25ºC
166; M = Mo, R = Ph167; M = Mo, R = nBu168; M = W, R = Ph169; M = W, R = nBu
RC CH
H R
SFeM
Fe Fe(CO)3
S
C
C
CC
PhCO
CO
CO
Cp*
Scheme 46.
Compound 170 consists of a Fe3 triangle, which is capped by a sulfido ligand.
One of the iron atoms is bonded to a {(η5-C5Me5)W} group, and the Fe−W bond is
bridged by a ferrocenylacetylene group. A second sulfido ligand triply - bridges the
terminal carbon atom of this acetylene with the tungsten and one of the iron atoms. A
{CCPh} group forms an unusual quadruple bridge in which the β - carbon of the
45
acetylide is now η1-bonded to the tungsten atom. Seven terminal carbonyls distributed
on the three iron atoms and on the tungsten atom complete the ligand environment of the
cluster.72
(OC)3Fe SFe(CO)3
Fe(CO)3
S + M C CPh (CO)3Cp*Benzenehν, 25ºC
FcC CH
170 M = Mo171 M = W
H
(CO)3
(CO)2
(CO)Cp*
C C
SFe
Fe
Fe
M
C C
SOC
Fc
Ph
Scheme 47.
Reactions between [Ir(C2Ph)(CO)2(PPh3)2] and iron carbonyls (Fe(CO)5 or
Fe2(CO)9) result in the formation of iron-iridium clusters [Fe2Ir(μ3-C2Ph)(CO)9-n(PPh3)n]
(n =1, 172; 2 ,173) and [FeIr2(μ3-PhC2C2Ph)(CO)12(PPh3)2] (174). The Rh analogue of
172 has been obtained by a similar reaction (Scheme 48). Substitution of the iridium
bound PPh3 by PEt3 and addition of PEt3 to Cα of the acetylide ligand in 172 gives
zwitterionic [Fe2Ir(μ3-PhC2PEt3)(CO)8(PEt3)] (177), which on heating converts to
[Fe2Ir(μ3-C2Ph)(CO)7(PEt3)2] (179) by migration of PEt3 from carbon to iridium
(Scheme 49).73 Analogous complexes containing cluster-bound PMe2Ph and P(OMe)3
have also been obtained by such type of reaction.
46
174
Fe(CO)5Fe2(CO)9
M(C2Ph)(CO)n(PPh3)2M = Ir, n = 2M = Rh, n = 1
C
(Ph3P)(OC)2M
C
Fe(CO)3
Fe
Ph
(CO)2L172; M = Ir, L = CO175; M = Ir, L = PPh3176; M = Rh, L = CO
(CO)3
Ph
CIr
CIr(CO)2(PPh3)
Fe
CCPh
(Ph3P)(CO)2+
orTHF, 70ºC
Scheme 48.
C
IrC
Fe(CO)3
Fe
Ph
(CO)3
(CO)3
CIr
CFe(CO)3
Fe
LPh
(L)(CO)2
(Ph3P)(CO)2
+ C
IrC
Fe(CO)3
Fe
Ph
(CO)2L'
(L)(CO)2
PEt3
172
177; L = PEt3 178; L = PPh3, L' = PEt3179; L = PEt3, L' = PEt3180; L = PEt3, L' = CO
+
(L)(CO)2
(CO)2L'
C
IrC
Fe(CO)3
Fe
Ph
(L)(CO)2
(CO)2L'
C
IrC
Fe(CO)3
Fe
Ph
181; L = PMe2Ph, L' = PMe2Ph 182; L = PPh3, L' = P(OMe)3183; L = P(OMe)3, L' = P(OMe)3
THF
PMe2PhTHF
P(OMe)3THF, 45ºC
Scheme 49.
47
Reaction of Fe2Ir cluster (172) with dihydrogen gives complex 184, whereas,
stepwise addition of H- and H+ results in the formation of 184 and the isomeric hydrido
alkyne derivative 185 (Scheme 50).74
C
IrC
Fe(CO)3
Fe
Ph
(CO)3
(CO)2
H
(CO)3
CIr
CFe(CO)3
Fe
PhH
(CO)2
(CO)3
CIr
CFe(CO)3
Fe
PhH
H
(CO)2
H
C
IrC
Fe(CO)3
Fe
Ph
H
H(CO)3
(CO)2
172
185184
H2, 30 atm
Cyclohexane, 80 ºC
+(Ph3P) (Ph3P)
(Ph3P)
(Ph3P)
+
Scheme 50.
Treatment of the triruthenium imido complex [Ru3(CO)10(μ3-NPh)] (186) with
metal hydride complex [LW(CO)3H] in refluxing toluene produces a trinuclear
heterometallic imido cluster, [LWRu2(CO)8(μ-H)(μ3-NPh)] (L=Cp, 187a; Cp*, 187b),
which on reaction with tungsten acetylide [CpW(CO)3CCPh] produces a tetranuclear
imidoalkyne complex [LCpW2Ru2(CO)6(μ-NPh)(μ-η2-CH=CPh)] (L=Cp, Cp*) (188a,b)
(Scheme 51).75
48
O
N
C Ru
Ru Ru
Ph
(CO)3 (CO)3
(CO)3
LW(CO)3H
L = Cp, Cp*O
N
C W
Ru Ru
Ph
CH
(CO)3 (CO)3
LO
Ru(CO)3
N
Ph C
CpW
Ru(CO)3
W
C H
LPh
CpW(CO)3C CPh
186 187a; L= Cp 187b; L= Cp*
188a; L= Cp 188b; L= Cp*
+
Scheme 51.
Convenient and widely applicable synthetic routes to trinuclear heterometallic
acetylide complexes [LMM’2(CO)8(CCR)] have been developed which involve the
reaction of metal acetylide [LM(CO)3(CCR)] (L = Cp or Cp*; M = W or Mo; R = Ph,
C5H4F, C5H4OMe, tBu and nPr) with [Os3(CO)10(NCMe)] or [Ru3(CO)12]. Thus,
reaction of [CpW(CO)3C≡CR] (R = Ph, tBu) with [Os3(CO)10(CH3CN)2] in refluxing
toluene produces tetranuclear mixed-metal acetylide complexes
[CpWOs3(CO)11(C≡CR)] (R = Ph, 189a; tBu, 189b).76 The molybdenum analogue
[MoOs3(CO)11(C≡CPh)(η-C5H5)] (190) has also been prepared by a similar procedure.
Carbonylation of 189a, b at 120 ºC under pressurized CO induces cluster fragmentation,
giving [CpWOs2(CO)8(C≡CR)] (191a,b) in 80-85 % yield. Hydrogenation of 189b
produces an alkylidyne complex, [CpWOs3(CO)11(μ3-CC5H11)] (192), while treatment of
189a with excess of ditolylacetylene affects the scission of the acetylide ligand to give
[CpWOs3(CO)8(μ3-CPh){μ4-η5-C(C2Tol2)2}] (193) (Scheme 52).77
49
(CO)2Cp
Os Os(CO)3
Os(CO)3
W C
C
R
(CO)3
(CO)2Cp
(CO)3Os Os(CO)3
WC
C
R
191a; R = Ph 191b; R = nBu
(CO)2Cp
Os
Os(CO)3
Os(CO)3
W CCH2R
(CO)3
192
(CO)3
(CO)2(CO)3
Ph
WCp
Os Os
CCCC C
Os
C
Tol
Tol TolTol
193
CO H2
R = nBu 189a; R = Ph 189b; R = nBu
2TolC CTolR = Ph
Scheme 52.
In contrast, treatment of complexes 189 a and b with alkynes containing electron-
withdrawing groups produces the tetranuclear alkyne-acetylide coupling products
[CpWOs3(CO)10{CR'CR'CCR}] (R = Ph and R' = CO2Me, 194a; R = Ph and R' = CO2Et,
194b; R = nBu and R' = CO2Et, 194c) and [CpWOs3(CO)9{CCRCR'CR'}] (R = Ph and R'
= CO2Me, 195a; R = Ph and R' = CO2Et, 195b; R = nBu and R' = CO2Et, 195c) (Figure
13).76
(CO)3
(CO)3(CO)3
WCp
Os Os
CC
C C
Os
R'RR'
CO
(CO)2
(CO)3
(CO)3WCp
Os
Os
CC
CC
Os
RR'R'
OC
195a; R = Ph, R' = CO2Me195b; R = Ph, R' = CO2Et195c; R = nBu, R' = CO2Me
194a; R = Ph, R' = CO2Me194b; R = Ph, R' = CO2Et194c; R = nBu, R' = CO2Me
Figure 13.
50
The cluster acetylide complexes [MOs3(CO)11(C≡CPh)(η-C5H5)] (M = Mo, 190;
M = W, 189a) react with [Mo(CO)3(C≡CPh)(η-C5H5)] to give planar pentanuclear
complexes [MMoOs3(CO)11(CCPhCCPh)(η-C5H5)2] (M = Mo, 196; M = W, 197) which
contain a C4 hydrocarbon fragment derived from head-to-tail coupling between the two
acetylide fragments. Reaction of complex 190 with [W(CO)3(C≡CPh)(η-C5H5)] does not
produce the coupling product but induces C-C bond scission of [W(CO)3(C≡CPh)(η-
C5H5)] giving a novel carbide-alkylidyne complex [MoWOs3(CO)8(μ4-C)(μ3-
CPh)(CCPh)(η-C5H5)2] (198) (Figure 14).78
MoCC
M Os
OsC
Os
CPh
PhOC(CO)3
(CO)2Cp
Cp
(CO)3(CO)2
Os
Os
W Os
C
CMo
CC
Ph
C
C
Ph
OC
O
O
Cp
Cp
(CO)3
(CO)2
198196; M = Mo197; M = W
Figure 14.
Treatment of the acetylide complexes [CpWOs2(CO)8(C≡CR)], (R = Ph, 191a; R
=nBu, 191b) with Me3NO in acetonitrile followed by reaction with various disubstituted
alkynes, C2R’2 in refluxing toluene facilitates acetylide-alkyne coupling and formation of
two isomeric trinuclear complexes, [CpWOs2(CO)12{C(R’)C(R’)CCR}] (R = Ph and R’
= Tol, 199; R = nBu and R’ = Tol, 200; R = Ph and R’ = CO2Et, 201; R = nBu and R’ =
CO2Et, 202; R = Ph and R’ = CF3, 203) (Scheme 53).79
(CO)3
CR W
Os
CC
C
Os
R'
C
R'
R
Os(CO)3W
Os
C
C
Cp
Cp O
(CO)3(CO)3
W
Os Os
CTol
CC C
R
Tol
Cp(CO)
1. Me3NO/MeCN2. C2Tol2 2. C2R'2
1. Me3NO/MeCN
191a; R = Ph191a; R = nBu
201; R = Ph, R' = Co2Et202; R =nBu, R = Co2Et203; R = Ph, R = CF3
199; R = Ph200; R = nBu
(CO)3
(CO)3
(CO)3
Scheme 53.
51
When [Ru3(CO)12] has been used to react with [CpW(CO)3C≡CPh] in refluxing
toluene, [CpWRu2(CO)8(C≡CPh)] (204) is isolated. In solution the variable temperature
NMR suggests that the acetylide ligand of 204 undergoes a 360º rotation on the face of
the WRu2 triangle.80 With excess of [CpW(CO)3C≡CR], 204 gives two heterometallic
acetylide clusters [Cp2W2Ru2(CO)9(CCRCCR)] (R = Ph, 205a; R = p-C6H4F, 205b),
with C-C bond coupling and [Cp2W2Ru2(CO)6(C≡CR)2] (R = Ph, 206a; R = p-C6H4F,
206b), without C-C bond coupling (Scheme 54). 81
204a;R = Ph 204b;R = C6H4F-p
+
205a;R = Ph 205b;R = C6H4F-p
W(CO)2Cp
C
RuC
W(CO)2Cp
RuC
CR
R
(CO)2(CO)3W
W(CO)Cp
Ru
(CO)2Ru
C C
C
C
C
R R
CpO
(CO)2
CpW(CO)3(CCR)
206a;R = Ph 206b;R = C6H4F-p
R
Ru(CO)3(CO)3Ru
W(CO)2
C
C
Cp
Scheme 54.
In a similar reaction, thermolysis of a mixture of [Ru3(CO)12] and
[CpMo(CO)3C≡CPh] in a molar ratio 2:3 in refluxing toluene gives the trinuclear
acetylide derivative [CpMoRu2(CO)8C≡CPh] (207) and a pentanuclear heterometallic
acetylide complex [Cp2Mo2Ru3(CO)10(C≡CPh)2] (208) (Figure 15).82
Ru
C
Mo
Ru
C
Ru
C C
MoC
PhPh
C
CpCp
(CO)3
(CO)2
(CO)3OO
207 208Ph
Ru(CO)3(CO)2CpMo
Ru(CO)3
C
C
Figure 15.
Condensation of triosmium alkyne complexes [Os3(CO)10(C2R2)] (R = Tol, 209a;
R = Me, 209b) with mononuclear tungsten acetylide complexes [LW(CO)3C≡CR’], (L =
52
Cp, Cp*, R’ = Ph, tBu) generates six WOs3 cluster complexes via 1: 1 combination of the
starting materials. Treatment of [Os3(CO)10(C2Me2)] with [CpW(CO)3C≡CPh] under
refluxing toluene forms two heterometallic complexes
[CpWOs3(CO)9{CC(Ph)C(Me)C(Me)}] (210a) and
[CpWOs3(CO)10{C(Me)C(Me)CC(Ph)}] (211). On the other hand, thermal reaction of
[Os3(CO)10(C2Tol2)] with [CpW(CO)3C≡CPh] gives
[CpWOs3(CO)9{CC(Ph)C(Tol)C(Tol)} (210b) and [CpWOs3(CO)9(CCTolCTol)(μ3-
CPh)] (212b), whereas only one heterometallic cluster,
[LWOs3(CO)9{CC(R’)C(Tol)C(Tol)}] (L = Cp* and R’ = Ph, 210c; L = Cp and R’ = tBu,
210d) is obtained on thermolysis of [Os3(CO)10(C2Tol2)] with [LW(CO)3C≡CR’] (L =
Cp*, R’ = Ph or L = Cp, R’ = tBu). Addition of 1:1 molar equivalent of [Me3NO] to
compound 211, followed by heating under refluxing toluene affords
[CpWOs3(CO)9(CCMeCMe)(μ3-CPh)] (212a). When toluene solution of
[Os3(CO)10(C2Me2)] is thermally reacted with [Cp*W(CO)3C≡CPh], five heterometallic
clusters are formed (210e, 212e, 213, 214 and 215) (Figure 16).83
53
(CO)3
(CO)3(CO)3
WOs Os
CC
C C
Os
RR'R
OC
L
(CO)2
(CO)3
(CO)3W
Os
Os
CCCC
Os
R
(CO)
R
L
R'
211; L = Cp, R = Me, R' = Ph
(CO)3
(CO)3(CO)3W
Os Os
CC
C OsR
R
CR'
L
212a Cp Me Ph 212b Cp Tol Ph 212c Cp* Me Ph
(CO)3
(CO)3(CO)(CO)2
OsC
C
W
Os
C COs
R'
R
R
L
213; L = Cp*, R = Me, R' = Ph
(CO)2
(CO)2 (CO)2L
C
C
Os
Os
Os WR
R
CC
R'
(CO)3
214; L = Cp*, R = Me, R' = Ph
(CO)3
Os
W
Os
OsCC C
CC
O
R'R
C
R(CO)3
L
O
(CO)2
215; L = Cp*, R = Me, R' = Ph
210a Cp Me Ph210b Cp Tol Ph 210c Cp* Tol Ph210d Cp Tol tBu 210e Cp* Me Ph
L R R'
L R R'
Figure 16.
Thermolysis of a toluene solution of complex 212b with ditolylacetylene yields
the planar clusters [CpWOs3(CO)8(μ3-CPh){C(Tol)C(Tol)CC(Tol)C(Tol)}] (216a). On
the other hand, reaction of 212e in refluxing xylene solvent gives [Cp*WOs3(CO)8(μ3-
CPh){C(Tol)C(Tol)CC(Me)C(Me)}] (216b), [WOs3(C5Me5)(CO)12(μ3-
CPh){CMeCMeCC(Tol)C(Tol)}] (217) and 218 (Scheme 55).84
54
(CO)3
(CO)3(CO)3
W
Os Os
CC
C
OsR
R
CR'
L
(CO)3(CO)2(CO)3
C
WOs Os
CCC
OsR
R
CPh
C
Tol
Tol
L(CO)3
(CO)2
(CO)3
LC
WOs Os
CCC
Os
RR
CPh
C
Tol
Tol (CO)2 (CO)2(CO)3
LW
Os OsC
C
OsCC C
C
C
Ph
RTol
Tol
O
Excess C2Tol2
212b; R = Tol, L = Cp212e; R = Me, L = Cp*
216a; R = Tol, L = Cp216b; R = Me, L = Cp*
217; R = Me, L = Cp* 218; R = Me, L = Cp*
+ +
Scheme 55.
Treatment of 211 with Me3NO followed by thermolysis in refluxing toluene
yields the spiked triangular cluster [WOs3Cp(CO)9(μ-H){CMeCMeCC(μ2-η2-C6H4)}]
(219) as a major product, which, on further thermolysis converts to a butterfly cluster
[WOs3Cp(CO)9{CMeCMeCHC(μ2-η2-C6H4)}] (220) and then to a tetrahedral cluster
[WOs3Cp(CO)8{CMeCMeCHC(μ2-η2-C6H4)}] (221) via hydride migration followed by
loss of CO (Scheme 56).85
55
W OsCC
OsC
PhMe
Me
Cp
OC
Os
C
(CO)3(CO)3
(CO)3 H
MeMe
OsC
C
C
C Os
CpW
Os(CO)3 (CO)3(CO)3
(CO)2
(CO)3
HMe
Me
OsW Os
OsC
C
C
C
Cp
(CO)2
(CO)3(CO)3
CO
+ CO
211 219
220221
OCCp
MeMeCCC C
W
OsH
Os
Os
Toluene110ºC
(CO)3
Me3NOToluene
110ºC
Scheme 56.
The tetranuclear clusters 222-225 shown in Scheme 57 are formed in the reaction
of [Cp*W(CO)3C≡CR] (R = Ph, nBu, CH2OMe, CH2Ph) with [Os3(CO)10(NCMe)2].
While 222 is stable in a single isomeric form, cluster 223-225 exist in two interconverting
isomeric forms on heating. When 222 is treated with Me3NO, followed by heating to
reflux in toluene, 226 is obtained. On similar treatment, complex 223 affords two
isomeric vinylidene clusters [Cp*WOs3(μ4-C)(μ-H)(μ-CCHnPr)(CO)9] (227a,b) as an
inseparable mixture, while thermal reaction of 224 a,b with Me3NO forms two methoxy
derivatives [Cp*WOs3(μ4-C)(μ-H)(μ-CCHOMe)(CO)9] (228a,b) (Scheme 58).86
(CO)2Cp*
Os Os(CO)3
Os(CO)3WC
C
R
(CO)3 (CO)2Cp*
Os(CO)3Os
W Os(CO)3
C
C
R
(CO)3
222; R = Ph223a; R = nBu224a; R = CH2OMe225a; R = CH2OPh
223b; R = nBu224b; R = CH2OMe225b; R = CH2OPh
Scheme 57.
56
OC
Os
Os(CO)3
Os(CO)3
WCC
Ph
Cp*
(CO)3
OsOs
Os(CO)2
W CC C R"
R'
H
CO
(CO)3
(CO)3
227; R', R" = nPr, H228; R', R"= H, OMe
223
224or
222
226
Toluene
110ºC
Toluene
110ºC
Cp*
Scheme 58.
Thermal reaction of 227 with CO in toluene leads to regeneration of 223a,b,
while 228 gives 224a,b along with an alkenyl cluster [Cp*WOs3(μ4-C)(μ-
CHCHOMe)(CO)10] (229) (Scheme 59).86
OsOs
Os(CO)2
W CC C R"
R'
H
CO
(CO)3
(CO)3
227; R', R" = nPr, H228; R', R"= H, OMe
223a,bor224a,b
OC
Os
Os
Os(CO)3
W CC C H
H R'Cp*
(CO)3
(CO)3
229; R' = OMe
Me3NO
CO, 110ºC CO, 110ºC Cp*
Scheme 59.
A mixture of two isomers (230 and 231) of a benzofuryl complex [Cp*WOs3(μ4-
C)(μ-H)2(μ-C8H5O)(CO)9] is formed on thermolysis of 225. Clusters 230 and 231 have
also been isolated on thermolysis of a 1:1 mixture of [Cp*W(CO)3C≡CCH2OPh] with
[Os3(CO)10(NCMe)2] in refluxing toluene (Scheme 60).86
57
225a or b110 ºC
(CO)3
(CO)3
Os
Os
Os(CO)2
WC
C C
HH
H
O
Cp*
(CO)3
(CO)3
+
230 231
HOs(CO)2Os
Os
WC
C C
H
HO
Cp*
Toluene
Scheme 60.
Hydrogenation of the CH2OMe derivative, 224 affords four compounds (232-235)
(Scheme 61).86
110ºC
Os
Os
Os(CO)2
WC
C C
H
H
H
HOMe
Cp*OC
(CO)3
(CO)3
235
(CO)3
(CO)3
Os
Os
Os(CO)2
WC C
H
H CH2OMe
Cp*CO
234
224 + H2
(CO)2W Os(CO)3
Os(CO)3OsC
CH
HCp*
CH2OMe
(CO)2
232
(CO)2
OsOs(CO)3
Os(CO)3
W C
CH2CH2OMeCp*
(CO)3
233
+
+ +
Toluene
Scheme 61.
When the carbide cluster complex [Cp*WOs3(μ4-C)(μ-H)(CO)11] (236) is treated
with excess of Me3NO and 4-ethynyltoluene, the formation of an alkylidyne compound
[(C5Me5)WOs3(μ3-CCHCHTol)(CO)11] (237) is observed, while, the corresponding
reaction of 236 with 3-phenyl-1-propyne affords alkenyl carbido cluster
[(C5Me5)WOs3(μ4-C)(CHCHCH2Ph)(CO)10] (238) and an alkylidyne compound
[(C5Me5)WOs3[μ3-CC(CH2Ph)(CH2)](CO)10] (239) (Scheme 62).87
58
W
Os Os
C
Os H(CO)3
(CO)3
(CO)2Cp*
(CO)3TolC CH
W
Os Os
C
Os
C R
(CO)3
(CO)3
(CO) Cp*
(CO)3
O
PhCH2C CH
(CO)Cp*
(CO)3
(CO)3
(CO)3
(CO)2
Cp*
(CO)3
(CO)3
C
CH2PhCW
Os Os
Os
C HH
(CO)2
+
236 237; R = CH=CHTol
238 239
HC
C
W
OsC
OsOsH
CH2Ph
Scheme 62.
On the other hand, coupling of 236 with an electron deficient alkyne, diisopropyl
acetylenedicarboxylate (DPAD) results in the formation of a dimetallaallyl cluster
[Cp*WOs3(CO)10{C3H(CO2iPr)2}] (240), which undergoes C-C metathesis to afford a
second dimetallaallyl cluster (241) (Scheme 63).88 Trace amount of a related vinyl-
alkylidene cluster 242 has been observed in the reaction of 236 with DPAD in refluxing
toluene solution.
59
2. (CO2iPr)C C(CO2
iPr)
Cp*
Os OsOs
CW
H(CO)3
(CO)3
(CO)3
(CO)2
Cp*W
CC
Os
OsC
C
CO
Os
H
iPrO O OiPr
(CO)2
(CO)3(CO)3
(CO)2
Cp*
COOiPr
W
CC
Os
OsC C O
Os
OiPrH
(CO)2
(CO)3(CO)3
(CO)2Os Os
Os
W C C
CH
CO2iPr
CO2iPrCp*
(CO)3
(CO)3
(CO)2
(CO)2
236
242
240
241
2. (CO2iPr)C C(CO2
iPr)110ºC
1. Me3NO
1. Me3NO110ºCToluene
Scheme 63.
Reaction of [CpWOs2(CO)8(C≡CPh)] with 1.2 equiv of Me3NO in a mixture of
dichloromethane-acetonitrile solvent at room temperature followed by in situ reaction
with hydride complexes [LW(CO)3H] (L = Cp and Cp*) in refluxing toluene produces
the acetylide cluster complexes [CpLW2Os2(CO)9(CCPh)(μ-H)] (L = Cp, 243a; L = Cp*,
243b) and vinylidene cluster complexes [CpLW2Os2(CO)9(CCHPh)] (L = Cp, 244a; L =
Cp*, 244b). Heating of the acetylide or vinylidene complex in refluxing toluene induces
a reversible rearrangement giving a mixture of two isomeric complexes (Scheme 64).78
Me3NO
LW(CO)3H
(CO)Cp
W Os(CO)3
Os(CO)3W
C
C
Ph
H
(CO)2L
W
C
C
COs
WOs
C
Ph
H
OO Cp(CO)
L(CO) (CO)2
(CO)3
191a
243a; L = Cp243b; L = Cp*
244a; L = Cp244b; L = Cp*
110ºC
Scheme 64.
60
Molybdenum analogue, [Cp2Mo2Os2(CO)9(CCPh)(μ-H)] (243c) has been
obtained by the addition of Me3NO to dichloromethane-acetonitrile solution of
[CpMoOs2(CO)8(CCPh)], followed by a thermolytic reaction with [CpW(CO)3H].89
Treatment of the carbido cluster [Ru5(μ5-C)(CO)15] with Me3NO followed by
addition of the tungsten acetylide complexes [LW(CO)3(CCPh)] (L=Cp, Cp*) affords the
heterometallic cluster complexes [LWRu5(μ5-C)(CCPh)(CO)15] (L=Cp, 245a; L=Cp*,
245b) and [LWRu5(μ5-C)(CCPh)(CO)13] (L=Cp, 246a; L=Cp*, 246b). Thermolysis of
245 results in an irreversible formation of 246. Hydrogenation of 246b gives two cluster
compounds [(C5Me5)WRu5(μ6-C)(μ-CCH2Ph)(μ-H)2(CO)13] (247) and
[(C5Me5)WRu5(μ4-C)(μ3-CCH2Ph)(μ-H)4(CO)12] (248), via 1,1-addition of H2 to the
ligated acetylide and concurrent formation of two or four bridging hydrides (Scheme
65).90
61
245b; L = Cp*
RuRu
Ru
CRu Ru
(CO)3
(CO)3
(CO)3
(CO)3 (CO)3
+LW(CO)3(C2Ph)
L = Cp, Cp*
(CO)3
(CO)3
(CO)2(CO)3
C
LW
RuRu
Ru
CRu Ru
C
Ph
(CO)2
(CO)2
245a; L = Cp
110º C
Me3NO
H2L=Cp*
246b; L = Cp*246a; L = Cp
(CO)3
(CO)2(CO)2
(CO)2L O
Ru
OC
OC
Ru
OC
CRu
Ru
CW Ru
C
C
Ph
(CO)2(CO)2
(CO)3
(CO)3
Ru
Ru
Ru
Ru
C
WRu
H
H
CH2
Ph
C
H
C
H
O
WRu
Ru
CRu Ru
CCH2Ph
Ru
C
C C
C
H H
(CO)2
(CO)2
(CO) (CO)2O
O O
O
Cp*
(CO)2
+
248247 Scheme 65.
Heterometallic vinylacetylide clusters [Cp*WRe2(CO)9(CCR)] (R = C(Me)=CH2,
249;R = C6H9, 250) have been obtained from the condensation of mononuclear tungsten
acetylide complexes [Cp*W(CO)3(C≡CR)] (R = -C(Me)=CH2, C6H9) and rhenium
carbonyl complex [Re2(CO)8(NCMe)2]. Treatment of the vinylacetylide complex
[Cp*WRe2(CO)9{C=CC(Me)=CH2}] (249) with alcohols, ROH (R = Me, Et, Ph) in
refluxing toluene solution afford complexes [Cp*WRe2(CO)8(μ-OR)(C=C=CMe2)] (R =
Me, 251a; R = Et, 251b; R = Ph, 251c), which contain an unusual μ3-η3-allylidene ligand
and a bridging alkoxide ligand, and show fluxional behavior in solution. When 249 is
heated in the presence of hydrogen, a metallacyclopentadienyl complex
[Cp*WRe2(CO)7(μ-H){CHCHC(Me)CH}] (252a,b) is formed as a mixture of two non
62
interconvertible isomers (Scheme 66).91 On the other hand, hydrogenation of 250 in
toluene under refluxing condition initially produces a dihydride cluster
[Cp*WRe2(CO)8(μ-H)2{C=C(C6H9)}] (253) which on heating in toluene converts to 254
and 255 (Scheme 67).91
110 ºC
249
252b; R1 = Me, R2 = H252a; R1 = H, R2 = Me
251a; R = Me
251c; R = Ph251b; R = Et
Cp*
Re
CH2
C
W ReC
CMe
CO(CO)2
(CO)3
(CO)3ROH Cp*
(CO)2
(CO)3
(CO)3
RRe
CW
Re
C
C Me
O
Me
Cp*(CO)2
(CO)3
(CO)3R
Re
O
CW
Re
C
C
Me
Me
ReC
CW
Re
CC
C
HR1
HR2
HO
Cp*
(CO)3 (CO)3
H2
Toluene
Toluene110ºC
Scheme 66.
63
W Re
CC
Re C
H
Cp*(CO)2
(CO)3
(CO)3
O
H2 W Re
CC
Re H
H
HCp*(CO)2
(CO)3
(CO)3
251b 253
+O
Cp*
Re
W
Re
CH
CC
HH
(CO)3 (CO)3
254
O
Cp*
(CO)3 (CO)3
255
W
Re ReC
HCCHH
Toluene110ºC
Toluene110ºC
Scheme 67.
The acetylide complex [Co2(CO)6{μ-PhC=CRe(CO)5}] (256) (obtained by the
treatment of the binuclear acetylide-hydride carbonyl complex of rhenium [Re2(CO)8(μ-
H)(μ-C≡CPh)]with [Co2(CO)8]) undergoes nondestructive reaction with oxygen resulting
in the net loss of one acetylide carbon atom together with a CO ligand and formation of
the carbyne cluster complex [Co2Re(CO)10(μ3-CPh)] (257) (Scheme 63).92
CC
(CO)4Re
Ph
HRe(CO)4
Co2(CO)8
C
C(CO)5Re Co(CO)3
Co
Ph
(CO)3
Hexane 20Air
ºC
257
(CO)3256
C
Co(CO)3
Co
Ph
(CO)4Re
Scheme 68.
A dichloromethane solution of rhenium ethynyl complex [(η5-
C5Me5)Re(NO)(PPh3){(C≡C)nH}] (n = 1-3) (258a-c) and triosmium complex
[Os3(CO)10(NCMe)2] react at room temperature to give [(η5-C5Me5)Re(NO)(PPh3)
(CC)nOs3(H)(CO)10] (n = 1–3) (259a-c) (Scheme 69). Thermal reaction in hexane
64
converts 259b to the nonacarbonyl complex [(η5-
C5Me5)Re(NO)(PPh3)(CCCC)Os3(CO)9(H)] (260) (Scheme 70).93, 94
HC
CC
ReCON PPh3
Cp*
OsOs
Os
N N
(CO)4
(CO)3 (CO)3
CCH3
CCH3
n-1 +
Cp*
n-1
C
CC
ReCON PPh3
Os
Os
OsH
(CO)4
(CO)3 (CO)3
Cp*
n-1
(CO)4
(CO)3 (CO)3Os
Os
OsH
Re
CON PPh3
CC
C
+
258b; n = 2 258c; n = 3
258a; n = 1 259b; n = 2 259c; n = 3
259a; n = 1
Scheme 69.
Cp*
Os
CC
ReC
COs
OsH
ON
PPh3
(CO)3 (CO)3
(CO)3
Cp*
C
CC
ReCON PPh3
Os
Os
OsH
(CO)4
(CO)3 (CO)3
259b
Hexane
Cp*
(CO)3 (CO)3
(CO)3
+Re
C
ON
PPh3
Os
CC
COs
OsH
260
60ºC
Scheme 70.
Addition of HBF4. Et2O (1 equiv.) to compound 259a gives the cationic dihydride
complex [(η5-C5Me5)Re(NO)(PPh3)(CC)Os3(CO)10(H)2]+ BF4- (261 ) (Scheme 71).93
65
Cp*
C
Os
Os
OsH H
ReCON PPh3
(CO)4
(CO)3 (CO)3
HBF4.Et2O
nBuLi
+ BF4Cp*
C
Os
Os
OsH
ReCON PPh3
(CO)4
(CO)3 (CO)3
259a 261 Scheme 71.
Synthesis of a C3OMe complex [(η5-
C5Me5)Re(NO)(PPh3)(C≡CC(OMe))Os3(CO)11] (262) from the reaction of [(η5-
C5Me5)Re(NO)(PPh3)(C≡CLi)] with [Os3(CO)12] and [Me3O+BF4-] has been reported.93
On refluxing in heptane it forms 263 (Scheme 72).
Cp*
C
ReCON PPh3
Li
1. Os3(CO)12
2. Me3O+BF4-
Cp*
C
ReCON PPh3
Os
Os
OsC
OMe
(CO)4
(CO)3 (CO)3
heptanereflux
Cp*
Os
CC
COs
OsO
ReON
PPh3
(CO)3
(CO)3
(CO)3
Me
+
262 263
δδ
Scheme 72.
Products obtained from the reaction between molybdenum dimer [Mo2(CO)4(η-
C5H5)2] and [M(CCR)(CO)2(η-C5H5)] (M = Ru or Fe, R = Me or Ph) depends on the
alkynyl metal used. The ruthenium containing reactant gives the dimolybdenum alkynyl
adducts [Mo2{Ru(μ-CCR)(CO)2(η-C5H5)}(CO)4(η-C5H5)2] (R = Me (264a), Ph (264b))
as the only isolable product. In contrast, the iron alkynyls undergo Fe-C bond cleavage
to give the alkyne adducts [Mo2(μ-η2-HC2R)(CO)4(η-C5H5)2] (R = Me, 265a; R = Ph,
265b) (Scheme 73).95
66
264a; R = Me264b; R = Ph
CpM C CR+M = Ru
R = Me, Ph
M = Fe
CpMo MoCp
C
C
C
R
O
CpRu
CpMo Mo(CO)Cp
C
C
C
R
O
H
+
CpMo MoCp
[{Fe(CO)2(η5 C5H5)}2]
(CO)2
(CO)2
(CO)2
(CO)2
(CO)2(CO)
(CO)2
265a; R = Me265b; R = Ph
Scheme 73.
On the other hand, reaction of [{Ru(CO)2(η-C5H5)}2(μ-C≡C)] with
[Mo2(CO)4(η-C5H5)2] gives [MoRu2(μ2-CO)3[μ3-C≡C{Ru(CO)2(η-C5H5)}](η-C5H5)3]
(266), but not the dimolybdenum ‘alkynyl’ adduct, 264a,b (Scheme 74).96
CpRu C C RuCp+
CpRu
Ru Ru
C
C
MoC
C
CO
CpMo MoCp(CO)2
(CO)2
(CO)2
(CO)2CpCp
CpO
O
(CO)2
266 Scheme 74.
Reaction of [(OC)4Fe(η1-PPh2C≡CPh)] (267) with [Co2(CO)8] at room
temperature affords the heterotrimetallic complex [(OC)4Fe(μ-η1:η2-
PPh2CCPh)Co2(CO)6] (268), in which the alkynic moiety is bound to a Co2(CO)6 unit.
Both the mono- and di-substituted complexes, [(OC)4Fe(μ-η1:η2-
PPh2C≡CPh)Co2(CO)5{P(OMe)3}] (269a) and [(OC)4Fe(μ-η1:η2-
PPh2CCPh)Co2(CO)4{P(OMe)3}2] (269b), have been obtained on reaction of 268 with an
67
excess of trimethylphosphite at elevated temperature. Thermolysis of 269a results in
phosphorus-carbon bond cleavage and iron-cobalt bond formation to yield the acetylide
bound mixed-metal triangular cluster [FeCo2(CO)6{μ3-η2-CCPh}{P(OMe)3}(μ-PPh2)]
(270). Substitution of a Co - bound carbonyl ligand of 270 with triphenylphosphine gives
[FeCo2(CO)5{μ3-η2-CCPh}{P(OMe)3}(PPh3)(μ-PPh2)] (271) (Scheme 75).97
P
PhPh
C CCo
Co
Ph(OC)4Fe
P
PhPh
CC
Co
Co
Ph(OC)4Fe
+
267 268
269b269a
270 271
269a
(CO)4
Hexane 54ºC
C CPhP
FePh
Ph
Co2(CO)8P
PhPh
C CCo(CO)3
Co(CO)3
PhFe
P(OMe)3
(OC)2Co
C C
Fe
CoPPh
Ph
Ph
(CO)3
(CO){P(OMe)3}
PPh3 Hexane 28 ºC
Toluene 68ºC
(CO)4
Ph3P(OC)Co
C C
Fe
CoPPhPh
Ph
(CO)3
(CO){P(OMe)3}
(CO)2{P(OMe)3}
(CO)2 {P(OMe)3}(CO)2
{P(OMe)3}(CO)2
Scheme 75.
Reaction between [CpFe(CO)2(C2Me)] and [Co2(CO8)] which affords a μ-alkyne
complex [CpFe(C2Me)Co2(CO)8] (272a).98 In contrast to the reaction of phenylacetylide
complex [CpFe(CO)2C2Ph] and [Co2(CO8)] forms [(η-C5H5)Fe(C2Ph)Co2(CO)6] (273)
and [(η-C5H5)Fe(C2Ph)Co2(CO)8] (272b) (Figure 17).99
68
Cp
Co
C
FeC R
Co(CO)3(CO)3
(CO)2
Cp
Co
C
Fe
CPh
Co(CO)3
(CO)3272a; R = Me272b; R = Ph
273; R = Ph
Figure 17.
Tungsten-iridium tetrahedral cluster [WIr3(μ-CO)3(CO)8(η-C5R5)] (R5 = H5,
274a; R5 = Me5, 274b; R5 = H4Me, 274c), prepared from the reaction between
[WH(CO)3(η-C5R5)] and [IrCl(CO)2(p-toluidine)] under CO atmosphere, has been used
extensively to synthesise several mixed metal acetylide complexes. Thermal reaction of
[WIr3(μ-CO)3(CO)8(η-C5Me5)] (274b) with [W(C≡CPh)(CO)3(η-C5H5)] results in the
isolation of an edge-bridged tetrahedral cluster [W2Ir3(μ4-η2-C2Ph)(μ-CO)(CO)9(η-
C5H5)(η-C5Me5)] (275a) and an edge-bridged trigonal-bipyramidal cluster [W3Ir3(μ4-η2-
C2Ph)(μ-η2-C=CHPh)(Cl)(CO)8(η-C5Me5)(η-C5H5)2] (275b) (Scheme 76).100 Cluster
275a is formed by the insertion of [W(C≡CPh)(CO)3(η-C5H5)] into Ir-Ir and W-Ir bonds,
and contains a μ4-η2 alkynyl ligand. Cluster 275b also contains an alkynyl ligand
bonded to two iridium atoms and two tungsten atoms in a μ4-η2 fashion and a vinylidene
ligand bridge the W-W bond.
69
274c
275a 275b
PhC(OC)3CpW C
W
IrIr IrC
C
C
CO
(CO)3(CO)2
(CO)2
Cp*O
O
O+
CH2Cl234 ºC
CpC
Ph
HC
C
CIr
W
Ir
WIr W
Ph
Cl
(CO)2
Cp*(CO)2
(CO)2
(CO)2
Cp
C
IrIr
W
Ir
WC
CO
OCPh
C
Cp
Cp*O
(CO)2
(CO)3(CO)2
+
Scheme 76.
A similar reaction of a THF solution of W-Ir cluster, [WIr3(CO)11(η-C5R5)] (R =
H, 274a; R = Me, 274b) with [(η-C5H5)(CO)2Ru(C≡C)Ru(CO)2(η-C5H5)] leads to
cluster compound [Ru2WIr3(μ5-η2-C2)(μ-CO)3(CO)7(η-C5H5)2(η-C5R5)] [R = H, 276a;
R = Me, 276b] containing WIr3 butterfly core capped by Ru atoms. The reaction
involves an insertion of a C2 unit into a W-Ir bond and scission of Ru-C bond of the
diruthenium ethyndiyl precursor (Scheme 77). Another mixed metal cluster with a
butterfly W2Ir2 unit capped by a Ru(η-C5H5) group, [RuW2Ir2{μ4-η2-
(C2C≡C)Ru(CO)2(η-C5H5)}(μ-CO)2(CO)6(η-C5H5)3] (277) has been isolated by the
reaction of [W2Ir2(CO)10(η-C5H5)2] (274d) with the diruthenium ethyndiyl reagent
(Scheme 78). When the reaction between [WIr3(CO)11(η-C5R5)] (R5 = H5, 274a; R5 =
Me5, 274b; R5 = H4Me, 274c) and [(η-C5H5)(CO)3W(C≡CC≡C)W(CO)3(η-C5H5)] is
performed in refluxing toluene solution, metallaethynyl type of clusters [W2Ir3{μ4-η2-
(C2C≡C)W(CO)3(η-C5H5)}(μ-CO)2(CO)2(η-C5H5)(η-C5R5)] (R = H, 278a; R = Me,
278b; R5 = H4Me, 278c) are obtained (Scheme 79).100a
70
RuCp(CO)2C(OC)2CpRu C
W
IrIr Ir
CC
(CO)3(CO)3
(CO)3
+45 ºCTHF
Ir Ru
WCRu
Ir
C
IrC
CO
COCO
Cp
(C5R5)Cp
(CO)2
O
(CO)2
O
(C5R5)
O
Ir = Ir(CO)2
274a; R = H274b; R = Me
276a; R = H276b; R = Me
Scheme 77.
+
Cp
Cp(CO)3
(CO)2
Cp
CpRu C
Ru
WCCIr
COCO
C
Ir
W
CO
RuCp(CO)2C(OC)2CpRu C 45 ºCTHF
Ir = Ir(CO)2
O
Cp
O
(CO)3
(CO)3 (CO)2
W
IrIr W
CC
277
Cp
274d
Scheme 78.
WCp(CO)3C)2(OC)3CpW (C110ºC
Ir = Ir(CO)2
O
(η5-C5R5)
O
(CO)3
(CO)3 (CO)3
W
IrIr Ir
CC
+
274a; R = H274b; R = Me274c; R5 = H4Me
Toluene(CO)3
(CO)3
(η5-C5R5)
Cp
Ir
WCC
IrCO
CO
CC
Ir
WCO
CpW 278a; R = H278b; R = Me278c; R5 = H4Me
Scheme 79.
Mixed group 6-9 transition metal complexes,
[{Cp(OC)3W}C≡CC≡C{M(CO)(PPh3)2}] (M = Ir, 279a; M = Rh, 279b) have been
obtained from the reaction between [W(C≡CC≡CH)(CO)3Cp] and [M(OTf)(CO)(PPh3)2]
(M = Ir, Rh) in presence of diethylamine. Thermal reaction of a THF solution of 279a or
279b with [Fe2(CO)9] gives [{Cp(OC)3W}C≡CC2{Fe2M(CO)8(PPh3)}] (M = Ir, 280a; M
71
= Rh, 280b) and [{Cp(OC)8Fe2W}C2C2{Fe2M(CO)8(PPh3)}] (M = Ir, 281a; M = Rh,
281b) (Scheme 80).100b
W
Fe
Fe
C C C C
Fe
Fe
M
(CO)3
(CO)3(CO)3
(CO)3
(CO)2PPh3(CO)2
Cp
Cp(CO)3 M
PPh3
PPh3
COCCW C C
279a; M = Ir279b; M = Rh
Cp(CO)3
FeCC
WC
M
C
Fe(CO)
PPh3
(CO)3
(CO)3
THF 60 ºC
280a; M = Ir280b; M = Rh
281a; M = Ir281b; M = Rh
+
Scheme 80.
VI MIXED GROUP 10 - 12 METAL ACETYLIDE COMPLEXES
Platinum-acetylide complexes have been used in reactions with copper, silver or
gold salts to form heteropolynuclear Pt-Ag, Pt-Cu or Pt-Au complexes bridged by
alkynyl ligands. A synthetic strategy for heterometallic complexes with bridging alkynyl
ligands have been developed by Fornies and co-workers,102-110 in which alkynyl
substrates containing linear acetylide units are allowed to react with electrophilic metal
centres containing potential leaving groups. Reaction of alkynyl platinate(II) complexes
[NBu4]2[Pt(C≡CR)4].nH2O (R = Ph, n = 0; R = tBu, n = 2) and X2[cis-
Pt(C6F5)2(C≡CR)2] (X = PMePh3, R = Ph; X = NBu4, R = tBu) towards suitable
electrophilic copper, silver and gold complexes has been investigated to obtain a variety
types of heteropolynuclear platinum complexes, the type formed depending on the nature
of the platinum starting material and on the molar ratio of the reactants. Treatment of
[Pt(C≡CR)4]2- (39) (R = Ph (a), tBu (b)) with AgClO4, or with CuCl or [AuCl(tht)] (tht =
72
tetrahydrothiophene) in the presence of NaClO4 in 1:2 molar ratio forms a hexanuclear
complex [Pt2M4(C≡CR)8] (M = Ag, Cu, Au) (R = Ph, nBu) (282a,b-284a,b).102 The Cu
analogue, [Pt2Cu4(C≡CPh)8] has been prepared by the reaction of
[Pt{C5H4Fe(C5H5)}Cl(cod)] with an excess of phenylacetylene and CuI.101 An anionic
tetranuclear complex [Pt2M2(C6F5)4(C≡CR)4]2- (285a,b-286a,b) has been obtained from
the reaction of [cis-Pt(C6F5)2(C≡CR)2]2- (40) with AgClO4, AgCl or CuCl in a 1:1 molar
ratio.103 On treatment of complex 285a,b with AgClO4 (1:2), the Pt-Ag mixed-metal
acetylide complex [{PtAg2(C6F5)2(C≡CR)2}n] (287a,b) is obtained.104 An alternative
reaction of [Pt(C6F5)2(C≡CR)2]2- (40) with two equivalents of AgClO4 also gives
complex 287a,b. X ray diffraction study of 301 (an acetone solvated derivative of 287)
reveals a polymeric nature of the complex (Scheme 82). A trimetallic Pt-Ag complex
[Pt2Ag(C≡CR)4L4]ClO4 (291-293) has been synthesized by the reaction of cis-
[Pt(C≡CR)2L2] (288-290) with AgClO4 (2:1 molar ratio) (Scheme 81).102
73
282a Ag Ph282b Ag nBu283a Cu Ph283b Cu nBu284a Au Ph284b Au nBu
288a PPh3 Ph288b PPh3 nBu289a PEt3 Ph289b PEt3 nBu290a dppe Ph290b dppe nBu
12
[Pt(C CR)4]2
cis-[Pt(C CR)2L2]
PtRC C C CR
C CRRC C
PtRC C C CR
C CRRC C
MM M
MAgClO4 orCuCl or[AuCl(tht)].2NaClO4
Ag
R
PtC
C
C
R
C
L
L
CC
PtC
RC
L
L
R+
AgClO4
39a; R = Ph39b; R = nBu
M R
L R291a PPh3 Ph291b PPh3 nBu292a PEt3 Ph292b PEt3 nBu293a dppe Ph293b dppe nBu
L R
Scheme 81.
74
2
[Pt]RC C
RC C
285a Ag Ph285b Ag nBu286a Cu Ph286b Cu nBu
M
M
[Pt]C CR
C CR
2AgClO4
S = Acetone
cis-[Pt(C6F5)2(C CR)2]2AgClO4,
AgCl or CuCl40
[Pt]C CR
C CR
Ag
Ag
[Pt]RC C
RC C
Ag
Ag
n
AgClO4
[Pt]C CR
C CR
Ag
Ag
[Pt]RC C
RC C
AgSS
AgS S
287a; M = Ag, R = Ph287b; M = Ag, R = nBu [Pt] = Pt (C6F5)2
301a; M = Ag, R = Ph301b; M = Ag, R = nBu
M R
Scheme 82.
Treatment of complex 285a,b with PPh3 or PEt3 (1:2 or 1:4 ratio) or with dppe
results in the formation of anionic complexes 294-295 and dianionic complexes 296
respectively.105 On the other hand, reaction of polymeric complex 287 with phosphines,
tert-butylisocyanide or pyridine in a Ag:L molar ratio of 2:1 produces hexanuclear
complexes [Pt2Ag4(C6F5)4(C≡CR)4L2] (297-300) which are structurally related to
complex 301 (Scheme 76). The X-ray structure of 297a reveals the tridentate behavior of
the two cis-[Pt(C6F5)2(C≡CR)2] fragments towards silver atoms. The alkynyl ligands
exhibit an unsymmetrical μ3-η2 bonding mode. In contrast, trinuclear
[PtAg2(C6F5)2(C≡CR)2L2] (302-305) are isolated when higher proportion of the ligand L
is used with complex 287. The tetranuclear 285 is obtained when 287 is reacted with
NBu4Br (Scheme 83).106,110
75
[Pt] C CRC CR
[Pt]C CR
C CR
Ag
Ag
[Pt]RC C
RC C
AgL
AgL
Ag L
[Pt]C CR
C CR
[Pt]
RC C
RC C
Ag
AgP
P
[{PtAg2(C6F5)2(C CR)2}n]
[PtAg2(C6F5)4(C CR)4]2-
[Pt]C CR
C CR
AgL
dppeL(1:2 or 1:4)
285
Br
287
L 2L
AgL
[Pt] = Pt(C6F5)2
2
294a PPh3 Ph294b PPh3 nBu295a PEt3 Ph295b PEt3 nBu
296a; R = Ph296b; L = nBu
L R
297a PPh3 Ph297b PPh3 nBu298a PEt3 Ph298b PEt3 nBu299a CN tBu Ph299b CN tBu nBu300a Py Ph300b Py nBu
L R302a PPh3 Ph302b PPh3 nBu303a PEt3 Ph303b PEt3 nBu304a CN tBu Ph304b CN tBu nBu305a Py Ph305b Py nBu
L R
Scheme 83.
Two different Pt-M ( M = Ag, Cu) complexes (306-313) have been isolated when
the hexanuclear complexes 282a,b-283a,b are reacted with anionic ligands X- (X = Cl,
Br) or neutral ligands L ( L = tCNBu, pyridine). For instance, the reaction of
76
[Pt2M4(C≡CPh)8] (M = Ag, 282a; M = Cu, 283a) with four equivalents of anionic (X =
Cl, Br) or neutral ligands ( L = CNBut, pyridine) gives the corresponding trinuclear
anionic or neutral complexes (306-310), while, reaction of [Pt2M4(C≡CtBu)8] (M = Ag,
282b; M = Cu, 283b) with the same ligands gives hexanuclear complexes (311-313).
Addition of 8 equivalents of the ligands to 282b or 283b afford the trinuclear complexes
(306-310) (Scheme 84).107
[Pt2M4(C CPh)8] PtRC C C CR
C CRRC C
LM
LM
n
4L282a; M = Ag282b; M = Cu
L = Br, Cl, CN tBu, py
28 NBu4Br
306a 2 Ph Ag Cl306b 2 Ph Ag Br307a 2 Ph Cu Cl307b 2 Ph Cu Br308a 0 Ph Ag CN tBu308b 0 Ph Ag py309a 2 tBu Ag Cl309b 2 tBu Ag Br310a 2 tBu Cu Cl310b 2 tBu Cu Br
4L
PtRC C C CR
C CRRC C
PtRC C C CR
C CRRC C
M
M
ML
ML
L = Br, Cl, py
n
311a 2 Ph Ag Cl311b 2 Ph Ag Br312a 2 Ph Cu Cl312b 2 Ph Cu Br313 0 Ph Ag py
or
n R M L
n R M L
Scheme 84.
The platinum mononuclear complexes [Pt(C≡CR)4]2- (39) and
[Pt(C6F5)2(C≡CR)2]2- (40) have been used to synthesise di- and trinuclear complexes
containing doubly bridged alkynyl systems. Their reactions with mercury halides afford
1:2 adducts (314-316) or 1:1 adducts (317-319) (Scheme 85).108
77
CR)4]2[Pt(C PtC C
C C
C
CC
C
R R
RR
HgX
XHgX
X
2
2HgX2
314a Cl tBu314b Cl SiMe3
315a Br tBu315b Br SiMe3
316a I tBu316b I SiMe3
39
CR)2]2cis-[Pt(C6F5)2(C PtC
C
C
CR
R
F5C6
F5C6
HgX
X
2
HgX2
40
317a Cl tBu317b Cl SiMe3
318a Br tBu318b Br SiMe3
319a I tBu319b I SiMe3
X R
X R
Scheme 85.
The hexanuclear platinum-copper complex [Pt2Cu4(C6F5)4(C≡CtBu)4(acetone)2]
(320) and the polynuclear derivative [PtCu2(C6F5)2(C≡CPh)2]x (321), which crystallizes
in acetone as [Pt2Cu4(C6F5)4(C≡CPh)4(acetone)4] (322), have been prepared from the
reaction of [cis-Pt(C6F5)2(THF)2] with the corresponding copper-acetylide, [Cu(C≡CR)]x
(R = Ph, tBu) (molar ratio 1:2) as starting materials. The Ag-analogues (323-325) have
been synthesized similarly (Scheme 86).104,109
78
2[AgC CPh]x
[Ag Pt(C6F5)2(C CPh)2]x
2[AgC CtBu]x
[Ag Pt(C6F5)2(C CtBu)2]x
4[CuC CPh]x
[PtCu2(C6F5)2(C CPh)2]x
2.5[CuC CtBu]x
[cis Pt(C6F5)2(thf)2]
Acetone
Acetone
AgSS
C CPt
C C tBu
tBuC6F5
C6F5
Ag
Ag
C6F5
CC
tBu
PtC6F5
CCtBu
AgS S
[cis Pt(C6F5)2(thf)2]
S = Acetone
322
321
323324
320
325
PtC6F5F5C6
CC
CPh
CuCu
Cu
CPh
CuC
C
Ph
PtC
F5C6 C6F5
C
S
S
Ph
S
S
CCPt
CtBu tBu
C6F5C6F5
C
SCu
PtC6F5 C6F5
CCCtBuC tBu
Cu Cu
S
Cu
Scheme 86.
79
Addition of four equivalents of 2,2’-bipyridine to a solution of 320 or 321 yields
neutral trinuclear alkynyl bridged complexes [{cis-Pt(C6F5)2(μ-C≡CR)2}{Cu(bipy)}2] (R
= tBu, 326; R = Ph, 327). An analogous trinuclear complex [{cis-Pt(C6F5)2(μ-
C≡CtBu)2}{Cu(dppe)2] (328) has been obtained by the reaction of 320 with four
equivalents of dppe. In contrast, the reaction of 321 with dppe produces mixtures of
mononuclear platinum or copper complexes (Scheme 87). A comparison of the
photoluminescent spectra of 320 and 321 with those of the related platinum-silver species
[PtAg2(C6F5)2(C≡CR)2]x and the monomeric [cis-Pt(C6F5)2(C≡CR)2]2- suggest the
presence of emitting states bearing a large cluster [PtM2]x -to-ligand (alkynide) charge
transfer (CLCT).109
[Pt2Cu4(C6F5)4(C CtBu)4(acetone)2]
[{cis-Pt(C6F5)2(μ-C CtBu)2}{Cu(dppe)2}]
N NCu
CuNN
326; R = tBu 327; R = Ph
4 dppe
4 [2,2'-bipy]
320
328
PtF5C6
F5C6 C
C
C
C R
R
Scheme 87.
VII OTHER MIXED METAL ACETYLIDE COMPLEXES
A variety of acetylide complexes have been reported with mixed early-late
transition metal or mid-late transition metal complexes. The synthetic procedures either
involve reactions of early transition metal acetylide complexes with late transition metal
80
complexes containing labile ligands or vice versa. Mixed early-mid transition metal
acetylide complexes are rather rare.
The reaction of mononuclear [Cp2Ti(C≡CtBu)2] with cis-[M(C6F5)(thf)2] (M = Pt)
results in the formation of dimetallic Pt-Ti acetylide complex [Cp2Ti(μ-η1-
C≡CBut)2Pt(C6F5)2] (329) (Scheme 88).111
cis-[Pt(C6F5)2(thf)2]
329
PtC6F5
C6F5
Ti
C
C
C
C
Cp
Cp
tBu
tBu
[Ti(Cp)2(C CtBu)2]
Scheme 88.
When [Pt(C2H4)(PPh3)2] is added to [Ti(η-C5H5)2(C≡CR)2] (R = But, Ph),
products [Cp2Ti(μ-η1,η1-C≡CBut)(μ-η2,η1-C≡CBut)Pt(PPh3)] (330) and [Cp2Ti(μ-η2,η1-
C≡CPh)2Pt(PPh3)] (331) are obtained (Scheme 89).112
[Pt(C2H4)(PPh3)2]
330; R = tBu
PtTi
C
C
CC
Cp
Cp
R
PPh3
R
[Ti(Cp)2(C CR)2] +
331; R = Ph
Ti
CC
CC
Cp
Cp
R
R
Pt PPh3+
R = Ph, tBu
Scheme 89.
A solution of tetranuclear heteroleptic arylcopper aggregate [Cu4R2Br 2] (R =
C6H3(CH2NMe2)2-2,6) in diethylether reacts at room temperature with the titanium
complex [(η5-C5H4SiMe3)2Ti(C≡CSiMe3)2] (332), in 1:4 molar ratio, to give a 1,1-bis-
metallaalkenyl complex [(η5-C5H4SiMe3)2Ti(C≡CSiMe3){μ-C=C(SiMe3)(R)}Cu] (334)
81
resulting from an intramolecular addition of a Cu-C bond across the alkyne triple bond
(Scheme 90).113 A probable formation of complex 333 as an intermediate has been
proposed.
Ti
SiMe3
SiMe3
R1 Ti
SiMe3
SiMe3
R1 Cu SAr1/2 Cu4R2Br2 LiR
Ti
SiMe3
SiMe3
R1 Cu R
Cu
Ti
SiMe3
SiMe3 NMe2
NMe2
R1
334
333332 335R = C6H3(CH2NMe2)2-2,6 Ar = C6H4CH2NMe2-2
Et2O
R1 = (η5-C5H4SiMe3)2 Scheme 90.
Dinuclear Pt-Rh (336a-c, 339) and Pt-Ir (337a-c, 338) complexes with doubly
alkynyl bridging systems have been isolated from the reactions between platinum alkynyl
complex, 40 and from cyclooctadiene complexes of rhodium and iridium (Scheme 91).114
82
339
12
+
[(Cp*)Ir(PEt3)(Me2CO)2][ClO4]2R = Ph
R = SiMe3
cis-[Pt(C6F5)2(C CR)2]2 MC
CR
40(cod)
338
F5C6
F5C6
Pt
PhC
IrC
CPh
C
PEt3
Cp*
RhC
CSiMe3
PEt3
Cp*
336a Rh Ph336b Rh tBu336c Rh SiMe3 337a Ir Ph337b Ir tBu337c Ir SiMe3
[Rh(cod)(OEt2)2]ClO4
[{IrCl(cod)}2]or
[(Cp*)Rh(PEt3)(Me2CO)2][ClO4]2
F5C6
F5C6
PtC
CR
C
F5C6
F5C6
Pt
SiMe3C
M R
Scheme 91.
The tetranuclear mixed metal cluster [(η5-C5H5)2Ni2Fe2(CO)5(μ-PPh2)(μ4 -η2 -
C≡CPh)] (340) has been synthesised in high yield via condensation of [Fe2(CO)6(μ-
PPh2)(μ2-η2-C≡CPh)] and [(η5-C5H5)2Ni2(CO)2] in benzene reflux.115 X-ray analysis
has revealed a μ4-acetylide complex coordinated on a spiked triangular metal skeleton
(Figure 18).
Fe
CNiC Fe
Ni
Ph2P
PhCp
Cp
(CO)3
(CO)2
340 Figure 18.
83
A triangular Ni-Fe acetylide complex [Cp2NiFe2(CO)6(C2tBu)] (341) has been
obtained when [Cp2Ni2(HC2tBu)] is reacted with [Fe3(CO)12] in refluxing heptane
(Figure 19). 116
But
NiFe
Fe
C
C(CO)3
(CO)3
Cp
341 Figure 19.
A pentanuclear Ni-Ru cluster [NiRu4(CO)9(μ-PPh2)2(μ4-C≡CiPr)2] (342) has
been synthesised by the addition of electron rich [(η-Cp)Ni(CO)]2 to a carbocationic μ3-
acetylide group in [Ru3(CO)9(μ3-C≡CiPr)(PPh2)].117 Its structure consists of a Ru4
butterfly, zipped up by a Ni(CO) group, with the two acetylide groups in μ4-η2-bonding
mode (Figure 20).
(CO)2
(CO)2
(CO)
C
RuRu
Ru
Ru
Ni
Ph2P
C
C
C
PPh2
CHMe Me
CHMeMe
Ru = Ru(CO)2342
Figure 20.
The reaction of the terminal alkyne, [HC≡C-iPr] with [Ru3(CO)12] in boiling
heptane gives [(μ-H)Ru3(CO)9(μ4-η2-C=CHiPr)] (343) which on further reaction with an
octane solution of [(η5-C5H5)Ni(CO)]2 under reflux condition forms the vinylidene
84
cluster [(μ-H)(η5-C5H5Ni)Ru3(CO)9(μ4-η2-C=CHiPr)] (344) (Figure 21).118 Structure of
344 consists of a butterfly arrangement of Ru3Ni moiety, with the vinylidene ligand σ -
bonded to two ruthenium and one nickel atoms and η2- coordinated to the third
ruthenium atom.
Cp
HR
Ru
H
Ni
Ru Ru
C
C
(CO)3(CO)3
(CO)3(CO)3
(CO)3
(CO)3
R
Ru
H
Ru
Ru
CC
343 344 Figure 21.
Reaction of a THF solution of [Ru2(CO)6(μ-PPh2)(μ-η1,η2-C≡C–C≡CR)]
(R= tBu, 345a;R = Ph, 345b) with [Pt(PPh3)2(η-C2H4)] leads to a trimetallic
heteronuclear complex [Ru2Pt(CO)7(PPh3)(μ3-η1,η1,η1-C=C–C≡CR)(μ-PPh2)] (346a,b)
(Scheme 92).119 A THF solution of 345a also reacts under reflux condition with
[Ni(cod)2] or [Ni(CO)4] to give a pentanuclear cluster, [Ru4Ni(CO)12(μ-PPh2)2(μ4-
η1,η1,η2,η4-tBuC≡CC4C≡CtBu)] (347), resulting from stoichiometric coupling of two
moieties of 345a and the incorporation of a nickel atom bonded to two Ru2 units. The
structure of 347 also shows a head-to-head coupling of two butadienyl ligands to form a
C8 chain.
85
RC
CC
CRu Ru
PPh2
(CO)3 (CO)3
345a; R = tBu345b; R = Ph
CNi
C
RuC
Ru
C
Ru Ru
PPh2
tBuC
C
P
C
C
tBu
Ph2
(CO)3 (CO)3
(CO)3
(CO)3
(CO)
[Ni(cod)2]or [Ni(CO)4]
PtC
Ru Ru
PPh2
C
PPh3
RC
COC
(CO)3(CO)3
[Pt(PPh3)2(C2H4)]
347
THF 80ºC
THF
346a; R = tBu346b; R = Ph
Scheme 92.
A triangular triosmium-platinum cluster complex [Os3Pt(μ-H)(μ4-η2-
C≡CPh)(CO)10(PCy3)] (349) has been synthesised by the treatment of the unsaturated
[Os3Pt(μ-H)2(CO)10(PCy3)] (348) with [LiC≡CPh] followed by protonation.120 X-ray
structural analysis reveals a μ4-η2-C≡CPh ligand about the triosmium framework with a
platinum atom coordinated to one of the three osmium atoms in a spiked triangular
arrangement (Figure 22).
PtC C
Os Os
Os
P(Cy3)
H
Ph(CO)
(CO)3 (CO)3
(CO)3
349 Figure 22.
86
To achieve alkyne oligomerization, bis(acetylide) Pt(II) complexes have been
used to facilitate acyclic dimeriztion of alkynyls through head-to-head C-C bond
coupling.121,122 Thermal reaction of a toluene solution of [cis-Pt(C≡CPh)2(dppe)] (350a)
with [Mn2(CO)9(CH3CN)] gives a mixed Mn-Pt compound,
[Mn2Pt(PhCCCCPh)(CO)6(dppe)] (351),121 whereas reaction of 350a with [Ru3(CO)12]
in refluxing toluene forms two isomeric Ru/Pt compounds (352 a,b) (Scheme 93).122
Ru3(CO)12
Ph
Ru
CCRu
CC
Pt
Ph
Ru(CO)4P
P
(CO)3
(CO)3 Ph
Ru
CC Ru
CCRu
Ph
Pt
P P
(CO)3
(CO)3
(CO)(CO)3
+
352a 352b
PtC
C
CPh
CPh
P
P
Mn2(CO)9(CH3CN)
350a
Toluene 110º C
C
C
C CPt Ph
Ph
P
P
Mn
Mn(CO)3
(CO)3
P
P= dppe
351
Toluene 110º C
Scheme 93.
In refluxing toluene, compound 350b reacts with [Ru3(CO)9(PPh3)3] to form the
μ-1,3-diyne compound [Pt(η2-PhCCCCPh)(PPh3)2] (350c). Successive reaction of 350c
with [Fe(CO)5] and [Ru3(CO)12] under benzene reflux lead to the isolation of a
dimetallacyclic compound, [FePt(μ 2-η1:η1: η2-C(O)PhC=CC≡CPh)(CO)3(PPh3)2] (353)
and a triangular cluster, [MPt2(μ3-η1:η1:η2-Ph-CCC≡CPh)(CO)5(PPh3)2] (M= Fe, 354a;
M= Ru, 354b) (Scheme 94).121
87
PtC
C
CPh
CPh
Ph3PPh3P
Ru3(CO)12
[Ru(CO)9(PPh3)3] PhC C C CPh
Pt(Ph3P)2
Fe(CO)5
C C C CPh
CO
Fe
Pt
PhPPh3
PPh3
353354b; M = Ru
354a; M = Fe
350b 350c
350c
(CO)3(CO)3
C C CCPh
PtM
Pt
Ph
PPh3
COOC
Ph3P
Toluene, 110ºC
Toluene, 110ºC
C6H680ºC
C6H6, 80ºC
Scheme 94.
Addition of [(dppm)2RuCl2] to trans-[(PEt3)2Pt(Ph)(C≡C-p-C6H4-C≡CH)]
followed by treatment with DBU forms a heterometallic acetylide complex
[(PEt3)2Pt(C≡C-p-C6H4-C≡C)Ru(Cl)(dppm)2)] (355). Thermal reaction of a methanol
solution of [Cp(PPh3)2RuCl] with trans-[(PEt3)2Pt(Ph)(C≡C-p-C6H4-C≡CH)] results in
the formation of trans-[Cp(PPh3)2Ru(C≡C-p-C6H4-C≡C)Pt(Et3P)2(Ph)] (356) (Scheme
95).36b
PEt3
PEt3
CC CHCPtPh
i) [(dppm)2RuCl2],2NaPF6, CH2Cl2 CC CC
PPh2Ph2P
Ph2P PPh2
Ru Cl
PEt3
PEt3
PtPh
CC CC
PEt3
PEt3
PtPhPPh3Ph3P
Ru Cp[RuCp(PPh3)2Cl],
Na, MeOH
ii) DBU
355
356Scheme 95.
Reduction of 172 with Na/Hg followed by addition of [O{Au(PPh3)}3][BF4] or
[AuCl(PPh3)] gives complexes [AuFe2Ir(μ3-C2HPh)(CO)8(PPh3)2] (357a) and
88
[Au2Fe2Ir(μ4-C2Ph)(CO)7(PPh3)2] (357b) (Scheme 96). Reaction of complex 172 with
K[BH(CHMeEt)3] followed by auration gives a Au3FeIr cluster
[Au3Fe2Ir(C2HPh)(CO)12(PPh3)4] (358). The Rh analogue of 357 has also been prepared
by a similar procedure.123
(CO)3
CIr
CFe(CO)3
Fe
PhH
AuPPh3
(Ph3P)(CO)2
1) Na/Hg2) [O{Au(PPh3)}3][BF4]
(CO)3
C
IrC
Fe(CO)3
Fe
Ph
(Ph3P)(CO)2
(CO)3
C
IrC
Fe(CO)3
Fe
Ph
Au
Au
(Ph3P)(CO)
(PPh3)
(PPh3)+
357a 357b
172
or K[BH(CHMeEt)3 or AuCl(PPh3)
Scheme 96.
Mono-, di- and tri-gold containing ruthenium clusters [Ru3Au(μ3-
C2tBu)(CO)9(PPh3)] (360), [Ru3Au2(μ3-C=CHtBu)(CO)9(PPh3)2] (361) and
[Ru3Au3(C2tBu)(CO)8(PPh3)3] (362) have been isolated by a deprotonation reaction of
[HRu3(CO)9C2tBu] (359) with K[HB(CHMeEt)3], followed by auration with
[O{Au(PPh3)}3][BF4] (Scheme 97).124 Molecular structure of 361 contains a trigonal
pyramidal Ru3Au2 core with the Ru3 face bridged by a vinylidene ligand, σ-bonded to
two ruthenium atoms and η2-coordinated to the third ruthenium atom.
89
C
RuRu
Ru
C
H
But
(CO)3 (CO)3
(CO)3
359
C
RuRu
Ru
C
Au
But
(CO)3 (CO)3
(CO)3
360
(PPh3)
C
RuRu
Ru
C
Au
But
Au
(CO)3 (CO)3
(CO)3
361
(PPh3) (PPh3)
1.2. [O{Au(PPh3)}3][BF4]
+
362
Au
AuRu
Ru
Ru
Au
CC
But
(CO)3
(CO)3
(CO)3
(PPh3)
(PPh3)
(PPh3)
K[BH(CHMeEt)3
+
Scheme 97.
Addition of a THF solution of K[BHsBu3] to a solution of [Ru3(μ-H)(μ3-
C2H)(CO)9] (363) in THF followed by auration with [AuCl(PPh3)] results in the isolation
of [AuRu3(μ-H)(μ3-C2H2)(CO)9(PPh3)] (364) and [Au2Ru3(μ3-C=CH2)(CO)9(PPh3)2]
(365) (Scheme 98).125 Complex 364 crystallises in a dark red form, in which the AuRu3
core forms a tetrahedron (364a), and a yellow form, in which the AuRu3 core has a
butterfly structure (364b). The C2H2 ligand is 2η1,η2 coordinates to the Ru3 face in both
the isomeric forms. In cluster 365 the Au2Ru3 core has a distorted square pyramidal
conformation with the CCH2 ligand attached to the Ru3 face.
90
C
RuRu
Ru
C
H
H
(CO)3(CO)3
(CO)3363
1.K[HBsBu3]
H Ru
C
Ru Ru
CH
Au
C
C
H
(CO)3 (CO)2
364a
O
O(PPh3)
(CO)2
CRu
Ru Ru
CH
AuH
H
(CO)3 (CO)3
(PPh3)
(CO)3
(CO)3 (CO)3
(PPh3)
(CO)3
C
Ru
Ru Ru
H2C
AuAu(PPh3)
364b 365
2. [AuCl(PPh3)]
+ +
Scheme 98.
Thermal reactions of a benzene solution of [RuCl(PPh3)2(C5H5)] and [Cu(C2Ph)]
afford [RuCuCl(C2Ph)(PPh3)2(C5H5)]2 (366) and [RuCuCl(C2Ph)(PPh3)2(C5H5)] (367a),
whereas, similar reaction with [Cu(C2C6H4Me-p)] or [Cu(C2C6H4F-p)] results in the
formation of a halogen free complex [RuCu(C2R)2(PPh3)(C5H5)] (368a,b) (R = p-
MeC6H4 or p-FC6H4) and [RuCuCl(C2C6H4Me-p)(PPh3)2(C5H5)] (367b) (Figure 23).126
The Me-analogue, [RuCuCl(C2Me)(PPh3)2(C5H5)] (367c) has been obtained by a heating
reaction of [Cu(C2Me)] and ruthenium chloride in benzene. On reflux, a benzene
solution of [RuCl(PPh3)2(C5H5)] and [Cu(C2C6F5)] gives a tetranuclear complex
[{RuCu(C2C6F5)2(PPh3)(C5H5)}2] (369). Room temperature reaction of a benzene
solution of [Fe2(CO)9] and 366 gives the trinuclear cluster
[Fe2Ru(C2Ph)(CO)6(PPh3)(C5H5)] (370). Thermal reaction of a mixture of cis-
[ReCl(CO)3(PPh3)2] and Cu(C2Ph) in THF affords [ReCuCl(C2Ph)(CO)3(PPh3)2] (371),
while, thermolysis of [ReCl(CO)3(PPh3)2] and Cu(C2C6F5) in benzene gives
[ReCu(C2C6F5)2(CO)3(PPh3)2] (372) (Figure 24).126
91
366 368a; R= p-MeC6H4368b; R= p-FC6H4
Ph
Ru PPh3Ph3P
C
C
Cp
CuClCl
Cu
PhC
RuC
PPh3Ph3PCp
R
Ru PPh3Ph3P
C
C
Cp
Cu Cl
367a; R = Ph367b; R= p-MeC6H4367c; R = Me
Cu
PPh3
RuC
C
CC
Cp
R R
Figure 23.
RuCC C C
Cp
F5C6 C6F5
CuPh3P Cu PPh3
RuC CC C
Cp
F5C6 C6F5
PhRu
Ph3P
C C
FeFe(CO)3
Cp
(CO)3
CO
CPPh3
OC
OCPPh3
Re
CPh
Cu
Cl PPh3
C6F5
C6F5
O
OC
COC
Ph3PRe
C
CC
C
Cu PPh3
369 370 371 372
Figure 24.
The compounds [Ag3({Ru(CO)2(η-C5H4R)}2(μ-C≡C))3](BF4)3 (R = H, 374a; R =
Me, 374b), have been prepared from [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] (R = H, 373a;
Me, 373b) and AgBF4 (Figure 25), and used in the reaction with [CpRuCl(CO)2] to give
[{Ru(CO)2(η-C5H4R)}3(η1,η1-C≡C)][BF4] (R = H, Me).127
92
CCRu Ru
C
Ag
C
Ru
Ru
C
C
Ag
Ru
Ru
(C5H4R)(CO)2(CO)2
(CO)2
(CO)2 (CO)2
(CO)2
(C5H4R)
(C5H4R)
(C5H4R)
(C5H4R)
(C5H4R)
374a; R = H374b; R = Me
Ag
++
+
Figure 25.
Addition reaction of dichloromethane solution of [Au(C≡CPh)L] (L = PPh3 or
PMe2Ph) and [Os3(CO)10(MeCN)2] gives [Os3(C≡CPh)(AuL)(CO)10] (375a,b) which
contains a butterfly Os3Au metal core and a μ-η2-phenylethynyl ligand bridging two
osmium atoms. Decarbonylation of 375a,b in refluxing heptane gives [Os3(μ3,η2-
C≡CPh)(μ-AuL)(CO)9] (376a,b) (Scheme 99).128
PhC
C
Os Os
OsAu
L
(CO)3
(CO)4
(CO)3 (CO)3
(CO)3
(CO)3
PhC
Os Os
OsAu
C
L375a; L = PPh3 375b; L = PMe2Ph
Heptane
376a; L = PPh3 376b; L = PMe2Ph
96 ºC
Scheme 99.
Numerous examples exist of reactions between [M(C2R)(PR’3)] (M = Au, Ag,
Cu; R = Ph, C6F5; R’ = Me, Ph) and [Os3(μ-H)2(CO)10], which might be expected to
proceed by oxidative addition of [RC2M(PR’3)] and addition of the cluster-bound
hydrogen to the acetylide moiety. In toluene at –ll ºC, a rapid reaction occurs between
[Os3(μ-H)2(CO)10] and [M(C2C6F5)(PPh3)] (M=Au, Ag, Cu) to give [Os3M(μ-
CH=CHC6F5)(CO)10(PPh3)] (377a-c) in quantitative yield,129 while the reaction between
93
[H2Os3(CO)10] and [M(C2Ph)(PR3)] (M = Cu, Ag, Au;R= Me or Ph) affords
[HOs3M(CO)10(PR3)] (M = Au, R = Me, Ph; M = Ag, Cu, R = Ph), [Os3M(μ-
CH=CHPh)(CO)10(PR3)] (M = Au and R = Me, 378a; M = Au and R = Ph, 378b; M =
Ag and R = Ph, 378c; M = Cu and R = Ph, 378d), [Os3M(μ-CH=CHPh)(CO)9(PR3)] (M
= Au and R = Me, 379a; M = Au and R = Ph, 379b; M = Ag, R = Ph, 379c), [HOs3M(μ3-
HCCPh)(CO)8] (M = Au, 380a; M = Ag, 380b; M = Cu, 380c) and [Os3M(η-
CH=CHPh)(CO)9(PR3)2] (M = Au and R = Me, 381a; M = Au and R = Ph, 381b; M =
Ag and R = Ph, 381c; M = Cu and R = Ph, 381d) (Figure 26).129 X-ray crystallography
of compounds 377a and 378b reveals the presence of a butterfly metal core and a μ-
η1,η2-vinyl ligand which is bonded to two osmium atoms of the Os3Au core.
COs Os
OsM
C6F5CH H
(CO)4
(CO)3
(CO)3
(PPh3)
377a; M = Au 377b; M = Ag 377c; M = Cu
COs Os
OsM
PhCH H
(CO)4
(CO)3
(CO)3
(PR3)
COs Os
OsM
PhCH H
(CO)4
(R3P)(CO)2
(CO)3
(PR3)
378a Au Me378b Au Ph378c Ag Ph378d Cu Ph
M R
381a Au Me381b Au Ph381c Ag Ph381d Cu Ph
M R
Figure 26.
Thermal reaction of a THF solution of [AgC2Ph] and [RhCl(PPh3)3] results in the
formation of a hexanuclear cluster compound [Rh2Ag4(C2Ph)8(PPh3)2] (382a).130 The
analogous Ir2Ag4 compound, [Ir2Ag4(C2Ph)8(PPh3)2] (383a) has been obtained from
AgC2Ph and [trans-IrCl(CO)(PPh3)2] on toluene reflux. Thermolysis of a solution of
[RhCl(PPh3)3] and [AgC2C6F5] in 1,2-dimethoxyethane yields three compounds:
[Rh2Ag4(C2C6F5)8(PPh3)2] (382b), [Ag(PPh3)]+[Rh(C2C6F5)4(PPh3)2]- (384a) and
{[Ag(PPh3)]2+[Rh(C2C6F5)5(PPh3)]2-} (385). The analogous iridium compound
[Ir2Ag4(C2C6F5)8(PPh3)2] (383b) and [Ag(PPh3)]+[Ir(C2C6F5)4(PPh3)2]- (384b) are
94
obtained when a toluene solution of [trans-IrCl(CO)(PPh3)2] and AgC2C6F5 are heated to
reflux (Figure 27).
PPh3
MC
CAr
CC
Ar
C C ArCC
Ag Ag
Ag AgMC
CAr
C CArC
CAr
CC
Ar
Ar
PPh3
382a; M = Rh, Ar = Ph382b; M = Rh, Ar = C6F5383a; M = Ir, Ar = Ph383b; M = Ir, Ar = C6F5
M
PPh3
C
C
C
C
C
C
C
C
F5C6
C6F5
C6F5
F5C6
PPh3
AgPPh3
384a; M = Rh384b; M = Ir
Ag
PPh3
385
Ag
Ph3P
Rh
PPh3
C CC CF5C6 C6F5
F5C6 C
CC6F5
CC C C C6F5
Figure 27.
Thermolytic reaction between [(η-C5H5)Fe(CO)2Cl] and [CuC2Ph] affords a
mixed metal complex [(η-C5H5)Fe(CO)2(C2Ph)CuCl]2 (386) (Figure 28).131 Complex
386 contains a planar Cu2Cl2 ring, and each copper atom is symmetrically bonded to a C2
unit of the phenylethynyl group.
Cu
Cu FeC
CPh
Cl
Cl
C
Fe
CPh
CpCp
(CO)2
(CO)2
386 Figure 28.
95
In toluene solution [trans-Pt(C≡CH)2(PMe2Ph)2] and [W2(OtBu)6] reacts at 30 ºC
to give [trans-Pt(C≡CH)[C2W2(OtBu)5](PMe2Ph)2] (387) and [trans-
Pt{C2W2(OtBu)5}2(PMe2Ph)2] (388) (Figure 29).132,133a
PtC
C
W
W
C
C
W
W
(OtBu)3
(OtBu)2
(OtBu)3
(OtBu)2
(PMe2Ph)2 PtC
C
C
W
W
CH
(OtBu)3
(OtBu)2
(PMe2Ph)2
388 387 Figure 29.
Reaction of a THF solution of [Cp(CO)(NO)W(C≡CR)]- (R = C6H5, 390a; R =
C6H4CH3, 390b; R = C(CH3)3, 390c) with [(C6H5)3PAuCl] results in the formation of a
tungsten-gold acetylide complex, [CpW(NO)(μ-CO)(μ-C≡CR)Au(P(C6H5)3)] (391)
(Scheme 100).133b Reaction of a THF solution of [Cp(CO)(NO)W(C≡CR)]- (R = C6H5,
390a; R = C6H4CH3, 390b; R = C(CH3)3, 390c; R = SiMe3, 390d) with
[Cp(CO)2Fe(THF)]BF4 as electrophile gives a bimetallic complex [{Cp(CO)(NO)W} η2-
{Cp(CO)2FeC≡CR}] (392a-d). Photolytic decarbonylation of complexes 392a-d gives
diastereomeric mixtures of heterometallic acetylides [{Cp(CO)(NO)W}η2-
{Cp(CO)FeC≡CR}] (393a-d/394a-d) (Scheme 100).133c
96
nBuLiWCp C C
R
HNOOCWCp C C R
NOOC
Li+
W
Cp
C C R
NO
OC
Au
PPh3
Ph3PAuCl389a; R = tBu389b; R = Ph389c; R = p-Tol
[CpFe(CO)2THF] BF4
CCp(CO)2Fe C R
392a; R = tBu392b; R = Ph392c; R = p-Tol392d; R = SiMe3
391a; R = tBu391b; R = Ph391c; R = p-Tol
WOC NOCp
CFe CR
WCNO
Cp
Cp
OC
O
CFe CR
WC NO
Cp
OC
Cp
O
+hν
393a; R = tBu393b; R = Ph393c; R = p-Tol393d; R = SiMe3
394a; R = tBu394b; R = Ph394c; R = p-Tol394d; R = SiMe3
THF
THF
390a; R = tBu390b; R = Ph390c; R = p-Tol390d; R = SiMe3
C6H6392a-d
Scheme 100.
Reaction of fac-[Mn(CCR)(CO)3(dppe)] (R = CH2OMe, 395a; R = tBu, 395b; R
= Ph, 395c) with a suspension of CuCl in dichloromethane affords [MnCuCl(μ-
CCR)(CO)3(dppe)] (396a-c). On the other hand, the reaction of 395a and 395b with
[Au(C6F5)(tht)] (tht = tetrahydrothiophene) gives [MnAu(C6F5)(μ-CCR(CO)3(dppe)] (R
= CH2OMe, 397a; R = But, 397b). Cationic mixed metal complexes [Mn2Cu(μ-
CCR)2(CO)6(dppe)2]PF6 (R = CH2OMe, 398a; R = But, 398b) have been isolated from a
dichloromethane solution of compound 396a or 396b on addition of TlPF6 in presence of
395a or 395b respectively. The silver and gold complexes, [Mn2M(μ-
CCtBu)2(CO)6(dppe)2]PF6 (M = Ag, 399; Au, 400) are formed when [AgBF4] or
[AuCl(tht)] are reacted with TlPF6 and two fold excess of 395b. Addition of TlPF6 to
97
complex 396b in presence of [P(C6H4Me-2)3] gives a cationic mixed metal complex
[MnCu(μ-CCtBu)(CO)3(dppe){P(C6H4Me-2)3}]PF6 (401) (Figure 30).133d
Mn C C R(CO)3(dppe)
Cu
Cl
Mn C C R(CO)3(dppe)
Au(C6F5)
Mn C C R(CO)3(dppe)
M
Mn C C R(CO)3(dppe)
+Mn C C R(CO)3(dppe)
+
MP(C6H4Me-2)3
396a; R = CH2OMe396b; R = tBu396c; R = Ph
397a; R = CH2OMe397b; R = tBu
398a Cu CH2OMe398b Cu tBu399 Ag tBu400 Au tBu
M R401; M = Cu, tBu
Figure 30.
Like organic alkynes or some monometalated acetylides (LnMC≡CR), the
dirhenioethyne [(OC)5ReC≡CRe(CO)5] (402) has been found to behave as an η2-ligand
towards CuI, AgI, and AuI. Thus, when a THF solution of 402 reacts with CuCl, complex
[{(η2-C≡C{Re(CO)5}2)Cu(μ-Cl)}2] (404) is isolated (Scheme 101).134
2 (CO)5Re C C Re(CO)52CuCl
Re(CO)5
Re(CO)5
(CO)5Re
(CO)5Re
CuCuCl
Cl
404
402
Scheme 101.
Reaction of 402 with [Cu(NCMe)4]PF6, [Ag(NCMe)4]BF4, [AgSbF6] or
[AgO2SOCF3] gives cationic bis- (alkyne) complexes [(η2-C≡C{Re(CO)5}2)2M]+X- (M
98
= Cu, Ag; X = PF6, BF4, SbF6 or CF3SO2) (405a-d) and a cationic dimetallic tetrahedron
[(μ-η2,η2-C≡C{Re(CO)5}2)Cu2(NCMe)4]2+ (406) (Figure 31).134
Re(CO)5(CO)5Re
Re(CO)5(CO)5Re
M X
405a; M = Cu, X = PF6405b; M = Ag, X = BF4405c; M = Ag, X = SbF6405d; M = Ag, X = CF3SO3
2 (PF6 )2(CO)5Re Re(CO)5
Cu
NCCH3
NCCH3CuH3CCN
H3CCN
406
+
+
Figure 31.
On the other hand, a dichloromethane solution of [(OC)5ReC≡CSiMe3] (403) on
reaction with [Cu(NCMe)4]PF6 yields the cationic complex [(η2-
C≡CRe(CO)5SiMe3)2Cu]+ (407). Hydrolysis of [(μ-η2:η2-
C≡C{Re(CO)5}2)Cu2(NCMe)4](PF6)2 (406) or treatment of 403 with [Cu(MeCN)4]PF6 in
moist CH2Cl2 affords the difluorphosphate-bridged complexes [{μ-η2:η2-
[(OC)5ReC≡CR]}2Cu4(μ2-O2PF2)4] (R = Re(CO)5, 410; R = SiMe3, 411) (Scheme 102).
The gold complex [(η2-C≡C{Re(CO)5}2)AuPPh3]SbF6 (408) obtained from the reaction
of [Au(PPh3)SbF6] with 402, exists in equilibrium in solution with [Au(PPh3)2SbF6] and
[(η2-C≡C{Re(CO)5}2)2Au]SbF6 (409) (Scheme 103).134
99
Re(CO)5Me3Si
SiMe3(CO)5Re
Cu
PF6+
407
CuOOP
F F
CuO
OP
F F
Cu
OO PF F
Cu
O OP
F F
R
Re(CO)5
(CO)5Re
R
410; R = Re(CO)5411; R = SiMe3
403[Cu(NCMe4)PF6
[Cu(NCMe4)PF6
H2OCH2Cl2 \
H2OCH2Cl2 \
403406
Scheme 102.
Re(CO)5(CO)5Re
Re(CO)5(CO)5Re
Au
+Re(CO)5(CO)5Re
AuPPh3
SbF6+
2 [Au(PPh3)2]SbF6 +
409408
SbF6
Scheme 103.
VIII ABBREVIATIONS
Cp = (η5-C5H5)
Cp* = (η5-C5Me5)
dppe = Diphenylphosphinoethane
dppm = Diphenylphosphinomethane
DPAD = Diisopropylacetylenedicarboxylate
DBU = 1,5-Diazabicyclo(5.4.0)undec-5-en
100
Fc = Ferrocene
PPN = Bis(triphenylphosphine)nitrogen(l+), [(Ph3P)2N+]
tht = Tetrahydrothiophene
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