Short Metal-Metal Bond Distances Containing the Indium tris(3,5-dimethyl)-1 Pyrazolylborate Moiety

Brandon AlexanderChemistry Seminar

What’s a Pyrazolylborate?

BH

N N

N N

NN

-S. Trofimenko (DuPont)-Appeared 1966-Tridentate

-Can bind to a metal center with two donor sites like the pincers of a scorpion

-The third donor site reaches over the plane to bind to the final position created by the metal and the other two donor atoms

-Scorpionate Ligand (fac manor)

1-1

What’s a Pyrazolylborate?

-Why a pyrazolylborate?

• SynthesisBH

N N

N N

NN

-1

Types of Pyrazolylborates

• Bis(Pyrazolylborate)

BH

H

N N

N

N

• Tris(Pyrazolylborate)• Tetrakis(Pyrazolylborate)

BH

N N

NN

N

N

B

N

N

N

NN

N

N

N

-1

-1

-1

Synthesis of PyrazolylborateKBH4 + H-pz

3-H2

~180 C

4-H2~220 C

~150 C

2-H2

BH

N

N

NN

N N

-1

(Ex)

“tris” ligandK[HB-pz3]

BH

H

N N

N

N

“bis” ligandK[H2B-pz3]

-1

“Tetrakis” LigandK[B-pz4]

B

N

N

N

NN

N

N

N

-1

Indium tris(3,5-dimethyl)-1Pyrazolylborate• Adding the Metal Center

In

Cl

Cl

BH

N N

N N

NN

THF

3

4

5-R group selection

Adding the Metal CenterSynthesis

KL + InCl3 LInCl2 . THFTHF

+ KClL=tris ligand, [HB(Me2-pz)3]

BH

N

N

N N

N N

-1

Reger, et. al. Organometallics. 1994.

BH

N N

NN

N N In

Cl

Cl

THF

Indium Pyrazolylborate • Now we synthesized an Indium Pyrazolylborate

Now what?-Reactivity

BH

N N

NN

N N In

Cl

Cl

THF

•Can react with• Other pyrazolylborates

• Diethyldithiocarbamate• NaS2CN(C2H5)2

• Maleonitriledithiolate• MNT- (Na2S2C2(CN)2)

• Other R groups

Reacting the In-pz

• Create Metal-Metal bonds with In-pz and Metal Carbonyl(s)

• Metal Carbonyl Anions

(In-pz= Indium Pyrazolylborate)

Metal Carbonyls• Reger, et.al. explored metal-metal bonds with

two metal carbonyl complexes.

• Fe(CO)5

• W(CO)6

Fe

OC

OC

CO

CO

OC

W

OC

OC

CO

CO

OC CO

Synthesizing the Metal Carbonyls into a [2-] Dianion

Fe

OC

OC

CO

CO

OC

Naphthalene

Na (s) +Fe

CO

OCCO

OC

-2

-CO

W

OC

CO

CO

OC CO

-2

W

OC

OC

CO

CO

OC CO Naphthalene

Na (s) +

Synthesizing the Metal Carbonyls into a [2-] Dianion

-CO

Stability of Metal Carbonyl Anions

• Metal Carbonyl Anions are light and extremely heat sensitive.

• React violently with the atmosphere and readily release carbon monoxide.

• Stored under Nitrogen environment

Bringing it all Together• Selected Indium Pyrazolylborate has been

synthesized.• A set of [2-] metal carbonyl anions have been

synthesized

Fe

CO

OCCO

OC

-2

W

OC

CO

CO

OC CO

-2BH

N N

NN

N N In

Cl

Cl

THF

Bringing it all Together• Reactivity of the Indium Pyrazolylborate and the

Metal Carbonyl Anions

• “One pot” reaction

Bringing it all Together“One Pot” Reaction

LInCl2. THF + Na2M(CO)x L-In-M-(CO)x

THF

-2NaCl

L = tris ligand, [HB(Me2-pz)3]

(M-CO)x = any [2- ]metal carbonyl

• Very High Molar Mass

• Not very soluble

Reger, et. al. Organometallics. 1994.

Final ProductShort Metal-Metal Bond

• [(HB(Me2-pz)3]In-Fe(CO) 4

• “Shortest In-Fe bond to date”

2.463(2) Å

2

Final ProductShort Metal-Metal Bond

• [(HB(Me2-pz)3]In-W(CO) 5

• “First In-W bond to be structurally characterized”

2.783(2) Å

2

Measuring the Metal-Metal Bond

• X-Ray Crystallography

ORTEP Drawing of [(HB(Me2-pz)3]In-Fe(CO) 4

Reger, et. al. Organometallics. 1994.

Tbp Geometry

Measuring the Metal-Metal Bond

ORTEP Drawing of [(HB(Me2-pz)3]In-W(CO) 5

Reger, et. al. Organometallics. 1994.

Oh Geometry

Expanding the use of In-pz with one (or more) Metal Carbonyl Anions

• Strong, et. al. have developed a potential high yield & high purity synthesis of the [2-] trimer iron carbonyl from its neutral parent .

• Potential bonding with In-pz complex with trimer dianion. (capping)

•Triiron Dodecacarbonyl

3

References1. Trofimenko, S. J. Amer. Chem. Soc. 1967,89, 3170.

2. Reger, Daniel L.; Mason, Scott S.; Rheingold, Arnold L.; Haggerty, Brian S.; Arnold, Frederick P. Syntheses and Solid State Structures of [HB(3,5-Me2pz)3]InFe(CO)4 and [HB(3,5-Me2pz)3]InW(CO)5 (pz = Pyrazolyl Ring). Intermetallic Complexes with Short Metal-Metal Bonds. Organometallics. 1994, 13, 5049-5053.

3. Strong, H.; Krusic, P. J.; San Filippo, J. (1990). Robert J. Angelici. ed.. "Sodium Carbonyl Ferrate, Na2Fe(CO)], Na2[Fe2(CO)8], and Na2[Fe3(CO)11]. Bis[μ-Nitrido-Bis(triphenylphosphorus)(1+] Undecarcarbonyltriferrate(2-), [(Ph3P)2N]2[Fe3(CO)11]". Inorganic Syntheses 28: 1990. 203–207.

4. Bhattacharyaa, N.K. ; Coffy, T.J, Quintana, W; Salupo, T.A.; Bricker, J.C. ; Shay, T.B.; Payne, M. ; Shore, S.G. Syntheses of dinuclear carbonylates of the iron subgroup: [M2(CO)8]2- (M = Ru, Os) and [FeRu(CO)8]2-. Structures of [PPh4]2[FeRu(CO)8] CH3CN and [PPh4]2[Fe2(CO)8] 2CH3CN. Organometallics. 1990, 9, 2368-2374.

5. Ellis, J. E. Metal Carbonyl Anions: from [Fe(CO)4];2- to [Hf(CO)6];2- and Beyond. Organometallics. 2003,22, 3322-3338.

6. Reger, Daniel L.; Mason, Scott S.; Reger, Lance B.; Rheingold, Arnold L.; Ostrander, Robert L. Synthesis and Characterization of Indium(III) Complexes Containing Two Different Chelate Ligands of the Type [Hydrotris(3,5-dimethylpyrazolyl)borate]In[ligand]X. Inorganic Chemistry, 1994,33, 1811-1816.

7. Scheer, Manfred1; Himmel, Daniel2; Johnson, Brian P.1; Kuntz, Christian1; Schiffer, Michael. Ring Expansion of a Cp* Moiety: Formation of a 1,2-Diphosphacyclooctatetraene Ligand. Angew. Chem. Int. Ed. 2007, 46 , 3971.

8. Trofimenko, S. Molybdenum complexes with non-inert-gas configuration. J. Amer. Chem. Soc. ,90,4754, 1968.

References9. Trofimenko, S. The Coordination of Pyrazole-Derived Ligands. Chem. Rev.; 1972; 72(5); 497-509.

10 Kleinberg, Inorganic Synthesis. “Triiron Dodecacarbonyl”. 1963. McGraw-Hill. 8. 193-196.

11. Ramer, G. Inorganic Chemistry. “Organometallic Chemistry”. 2006. 4e. 596-597.

12 Lo, Frederick Yip-Kwai. Giuliano Longoni, Paolo Chini, Loren D. Lower, and Lawrence F. Dahl “Isolation and structural characterization of the triiron undecacarbonyl dianion [Fe3(CO)11]2-: stereochemical interrelationship with triiron dodecacarbonyl and the triiron undecacarbonyl hydride monoanion.” J. Am. Chem. Soc., 1980, 102 (26), 7691-7701

13. Heiber, W., R. Werner. “Uber Vierkernige Carbonyl Ferrate.” Chem. Ber. 1957, 90. (2). 286-296. Translated.

Acknowledgements

Mount Union College Department of Chemistry

Dr. Scott Mason & Dr. Debra Boyd-Kimball

Dr. Yan Sun, Case Western Reserve University

Haowen, Anthony, Sergey, & Brian for practice