Synthesis and Crystal Structure of Three New Zn(II), Ni(II)and Mn(II) Coordination Polymers Based on AsymmetricDicarboxylate Ligand

Lili Yang

Received: 22 August 2011 / Accepted: 28 October 2011 / Published online: 10 November 2011

� Springer Science+Business Media, LLC 2011

Abstract Three new coordination polymers [Zn(pda)

(H2O)]n (1), [Ni(pda)(bib)1.5]n (2) and [Mn2(pda)2(bimb)]n

(3) [H2pda = 3,40-biphenyl-dicarboxylic acid, bib = 4,40-bis (2-imidazol-1-ylmethyl) biphenyl and bmib = 4,40-bis

(2-methylimidazol-1-ylmethyl)biphenyl] have been syn-

thesized and structurally characterized by elemental

analysis, IR and X-ray diffraction. Single-crystal X-ray

analyses revealed that that pda ligand acts as bridging

ligand, exhibiting rich coordination modes to link metal

ions: monodentate, bidentate chelating, bis-monodentate

and chelating/bridging fashions. Compound 1 and 2 dem-

onstrate a one-dimensional chain. Compound 3 is a two-

dimensional (4,4) layer structure. Furthermore, the solid

state luminescence spectrum of compound 1 is investigated

at room temperature.

Keywords Coordination polymer � Crystal structure �Asymmetric dicarboxylate

1 Introduction

Due to the intriguing variety of architecture and potential

applications in luminescence, gas storage, molecular

magnetism and ion exchange, the construction of metal–

organic frameworks (MOFs) have attracted widespread

interest in recent years [1–12]. Carboxylate ligands have

been employed most often in the design and synthesis for

MOFs because of their versatile linking capability in virtue

of both covalent bonding and supramolecular interaction

[13–18].

We selected the 3,40-biphenyl-dicarboxylic acid for the

following reasons. First, the two carboxylic groups may

have different coordination modes with an ability to gen-

erate metal oxygen chains or clusters. Second, two phenyl

rings are not coplanar which can meet the different coor-

dination requirements of metal centers. In this work, we

also used the bis(imidazole)ligands of bib and bimb as

organic units to construct the hybrid organic–inorganic

compounds. The selection of the two ligands is based on

the following considerations: (i) the bis(imidazole) ligands

have flexibility and conformational freedom, which may

provide different capacities for spatial extension; (ii) these

ligands can act as bridges to construct high dimensional

frameworks. Based on the above mention, we designed and

synthesized three new coordination polymers [Zn(pda)

(H2O)]n (1), [Ni(pda)(bib)1.5]n (2) and [Mn2(pda)2(bimb)]n

(3) based on 3,40-biphenyl-dicarboxylic acid as the primary

ligand.

2 Experimental

2.1 Materials and Physical Measurements

All reagents and solvents employed were commercially

available and were used as received without further puri-

fication. Elemental analysis was carried out on a Carlo

Erba 1106 full-automatic trace organic elemental analyzer.

FT-IR spectra were recorded with a Bruker Equinox 55 FT-

IR spectrometer as a dry KBr pellet in the 400–4000 cm-1

range. Solid-state fluorescence spectra were recorded on a

F-4600 equipped with a xenon lamp and a quartz carrier at

room temperature.

L. Yang (&)

Department of Biology Chemistry Engineering, Weihai

Vocational College, Weihai 264210, Shandong, china

e-mail: liliyang1029@yeah.net

123

J Inorg Organomet Polym (2012) 22:709–716

DOI 10.1007/s10904-011-9626-z

2.2 Synthesis of the Complexes

2.2.1 [Zn(pda)(H2O)]n (1)

The hydrothermal reaction of Zn(OAc)2�2H2O (0.216 g,

1 mmol), H2pda (0.242 g, 1 mmol), NaOH (0.08 g,

2 mmol) and distilled water (18 mL) was heated to 160 �C

for 96 h in a 25 mL stainless steel reactor with a Teflon

liner, followed by slow cooling to room temperature. The

resulting reaction products were colorless block crystals

that were washed with alcohol to give pure samples (Yield:

43% based on Zn). Elemental Anal. Calcd. (%) for

C14H10ZnO5: C, 51.96; H,3.11. Found: C, 51.56; H, 3.15.

IR(cm-1): 3310w, 1646s, 1570s, 1409s, 1247w, 1128w,

907m, 855m, 738m.

2.2.2 [Ni(pda)(bib)1.5]n (2)

The hydrothermal reaction of NiCl2�6H2O (0.239 g. 1 mmol),

H2L (0.242 g, 1 mmol), bib (0.314 g; 1 mmol), NaOH

(0.08 g, 2 mmol) and distilled water (15 mL) was heated to

160 �C for 96 h in a 25 mL stainless steel reactor with a

Teflon liner, followed by slow cooling to room temperature.

Green crystals for compound 1were obtained in 41% for 1

(based on Ni). Elemental Anal. Calcd. (%) for C44H35N6NiO4:

C,68.53; H,4.54;N,10.90. Found: C,68.41; H,4.52; N,11.30.

IR: 1611s, 1526s, 1406s, 1256m, 1166m, 1073w, 845w,

734m, 692w.

2.2.3 [Mn2(pda)2(bimb)]n (3)

A mixture of MnCl2�4H2O (0.198 g; 1 mmol), H2L (0.242 g,

1 mmol), bimb (0.342 g; 1 mmol), NaOH (0.08 g, 2 mmol)

and distilled water (15 mL) was heated to 160 �C for 96 h in

a 25 mL stainless steel reactor with a Teflon liner, followed

by slow cooling to room temperature. Yellow crystals for

compound 1were obtained in 58% for 1 (based on Mn).

Elemental Anal. Calcd. (%) for C50H38Mn2N4O8: C,64.33;

H,4.07;N, 6.00. Found: C,64.64; H,4.08; N, 6.17. IR: 1584s,

1432s, 1341m, 1210m, 985m, 838w, 763m, 649w, 535w.

2.3 X-ray Crystallography

X-ray crystal data collection for the three compounds was

performed on a Bruker SMART APEXII CCD diffrac-

tometer equipped with a graphite monochromated Mo-Karadiation (k = 0.71073 A) by using a x-scan mode.

Empirical absorption correction was applied using the

Table 1 Crystallographic data

and structure refinement

summary for complexes 1–3

a R = R(||F0|–|FC||)/R|F0|b wR = [Rw(|F0|2–|FC|2)2/

Rw(F02)]1/2

Empirical formula C14H10O5Zn C44H35N6NiO4 C50H38Mn2N4O8

Formula weight 323.59 770.49 932.72

Crystal system Monoclinic Triclinic Monoclinic

space group P21/c P-1 P21/c

Unit cell dimensions a = 13.6875 (7) A a = 9.601 (5) A a = 14.3606 (12) A

b = 14.7040 (7) A b = 13.798 (5) A b = 13.4455 (11) A

c = 6.0399 (3) A c = 15.061 (5) A c = 22.2071 (18) A

b = 97.103 (1)� b = 89.406 (5)� b = 103.5486 (12)�Volume (A3) 1206.27 (10) 1796.6 (13) 4169 (2)

Z 4 2 4

Calculated density (mg/m3) 1.782 1.424 1.486

Independent reflections 2206 4895 3984

Independent reflections

(I [ 2r(I))

2206 4895 3984

F(000) 656 802 1920

h range for data collection 1.50–26.74 1.50–24.99 2.16–19.59

Data completeness/Rint 0.994/0.017 0.988/0.022 0.994/0.098

Limiting indices -13 B hB17

-18 B kB17

-7 B lB7

-11 B hB11

-16 B kB13

-17 B lB17

-14 B hB18

-15 B kB17

-28 B lB28

Goodness-of-fit on F2 1.049 1.017 0.989

R1a,wR2

b [I [ 2r(I)] R1 = 0.0251

wR2 = 0.0698

R1 = 0.0447

wR2 = 0.0997

R1 = 0.0536

wR2 = 0.0960

R1a,wR2

b (all data) R1 = 0.0309

wR2 = 0.0727

R1 = 0.0615

wR2 = 0.1099

R1 = 0.1280

wR2 = 0.1220

Largest diff. peak and hole (e/A3) 0.330 and -0.194 0.698 and -0.631 0.362 and -0.339

710 J Inorg Organomet Polym (2012) 22:709–716

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SADABS programs [19]. All the structures were solved by

direct methods and refined by full-matrix least-squares

methods on F2 using the program SHEXL 97 [20]. All non-

hydrogen atoms were refined anisotropically. The hydro-

gen atoms were located by geometrically calculations, and

their positions and thermal parameters were fixed during

the structure refinement. The crystallographic data and

experimental details of structural analyses for coordination

polymers are summarized in Table 1. Selected bond and

angle parameters are given in Table 2.

3 Results and Discussion

3.1 FTIR Spectrum

The spectra of compounds 1–3 display characteristic bands

of the carboxylate anions at *1600 and *1540 cm-1 for

masym(C–O), *1410 cm-1 for msym(C–O). Furthermore, the Dmvalues (masym(C–O) - msym(C–O)) are 237 and 161 cm-1 for

1, 205 and 120 cm-1 for 1, and 152 for 3, respectively. The

splitting of carboxylate groups in compounds 1–3 indicates

that the carboxylate groups function in different coordi-

nation fashions [21], consistent with their solid-state

structural features from the results of the crystal structure

analyses.

Table 2 Selected bond lengths (A) and angles (�) for complexes 1–3

Compound 1

Zn(1)–O(4)i 1.9259 (15)

Zn(1)–O(3)ii 1.9349 (15)

O(4)i–Zn(1)–O(3)ii 116.24 (7)

O(4)i–Zn(1)–O(1) 120.78 (7)

O(3)ii–Zn(1)–O(1) 103.75 (6)

Zn(1)–O(1) 1.9378 (15)

Zn(1)–O(5) 2.0060 (18)

O(4)i–Zn(1)–O(5) 107.96 (8)

O(3)ii–Zn(1)–O(5) 99.95 (8)

O(1)–Zn(1)–O(5) 105.80 (7)

Compound 2

Ni(1)–O(1) 2.031 (2)

Ni(1)–N(4)i 2.057 (3)

Ni(1)–N(5) 2.070 (3)

O(1)–Ni(1)–N(4)i 91.79 (11)

O(1)–Ni(1)–N(5) 108.18 (11)

N(4)i–Ni(1)–N(5) 92.84 (12)

O(1)–Ni(1)–N(1) 87.61 (11)

N(5)–Ni(1)–O(3)ii 93.90 (11)

N(1)–Ni(1)–O(3)ii 86.57 (11)

O(1)–Ni(1)–O(4)ii 97.40 (10)

N(4)i–Ni(1)–O(4)ii 89.56 (11)

Ni(1)–O(3)ii 2.141 (2)

Ni(1)–O(4)ii 2.231 (3)

N(4)i–Ni(1)–N(1) 176.43 (12)

N(5)–Ni(1)–N(1) 90.70 (13)

O(1)–Ni(1)–O(3)ii 157.22 (10)

N(4)i–Ni(1)–O(3)ii 92.66 (11)

N(5)–Ni(1)–O(4)ii 154.21 (11)

N(1)–Ni(1)–O(4)ii 87.03 (11)

O(3)ii–Ni(1)–O(4)ii 60.32 (9)

Compound 3

Mn(1)–O(1) 2.039 (3)

Mn(1)–O(8) 2.098 (2)

Mn(1)–O(6) 2.162 (2)

Mn(1)–N(4)i 2.214 (3)

Mn(1)–O(6A)ii 2.259 (3)

Mn(2)–O(3)ii 2.284 (2)

O(1)–Mn(1)–O(8) 98.10 (10)

O(1)–Mn(1)–O(6) 111.57 (9)

O(8)–Mn(1)–O(6) 149.27 (11)

O(1)–Mn(1)–N(4)i 106.15 (12)

O(8)–Mn(1)–N(4)i 92.54 (11)

O(2)iii–Mn(2)–O(5)iii 112.45 (9)

O(2)iii–Mn(2)–O(4)ii 160.98 (9)

O(5)iii–Mn(2)–O(4)ii 86.25 (9)

O(2)iii–Mn(2)–O(7) 89.36 (10)

O(5)iii–Mn(2)–O(7) 87.02 (10)

Table 2 continued

Compound 1

O(4)ii–Mn(2)–O(7) 95.29 (9)

Mn(2)–O(2)iii 2.107 (2)

Mn(2)–O(5)iii 2.146 (2)

Mn(2)–O(4)ii 2.229 (2)

Mn(2)–O(7) 2.234 (3)

Mn(2)–N(1) 2.273 (4)

O(6)–Mn(1)–N(4)i 86.94 (10)

O(1)–Mn(1)–O(6A)ii 94.20 (10)

O(8)–Mn(1)–O(6A)ii 94.64 (10)

O(6)–Mn(1)–O(6A)ii 75.93 (9)

N(4)i–Mn(1)–O(6A)ii 157.22 (11)

O(6)–Mn(1)–N(4)i 86.94 (10)

O(2)iii–Mn(2)–N(1) 85.85 (11)

O(5)iii–Mn(2)–N(1) 96.11 (11)

O(4)ii–Mn(2)–N(1) 88.81 (10)

O(7)–Mn(2)–N(1) 175.01 (11)

O(2)iii–Mn(2)–O(3)ii 102.72 (9)

O(5)iii–Mn(2)–O(3)ii 144.72 (9)

Symmetry code for compounds: (1) (i) x ? 1, y, z; (ii) -x?1, -y?2,

-z; (iii) x - 1, y, z(2) (i) x - 1, y ? 1, z; (ii) x, y - 1, z(3) (i) x,

y ? 1, z; (ii) -x?2, -y?2, -z?2; (iii) -x?1, -y?2, -z?2

J Inorg Organomet Polym (2012) 22:709–716 711

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3.2 Description of Crystal Structures

3.2.1 [Zn(pda)(H2O)]n (1)

Single-crystal X-ray diffraction reveals that each Zn(II)

atom is coordinated by three carboxylate oxygen atoms

from different three L ligands [Zn(1)–O(1) = 1.9378

(15) A, Zn(1)–O(3) = 1.9349(15) A and Zn(1)–O(4) =

1.9259(15) A] and one oxygen atom from water molecule

[Zn(1)–O(5) = 2.0060(18) A] to give a tetrahedron

geometry (Fig. 1a). The carboxylic groups of pda ligand

adopt monodentate and bis-monodentate chelate modes

which lead to link Zn(II) centers to form 1D ladder-like

chains running along a axis (Fig. 1b). The dihedral angle of

two phenyl rings in L ligand is 4.98�. The carboxylate

groups are out of the plane of correspondingly linking

phenyl rings with the dihedral angles between them being

10.35� and 6.43�.

In the compound 1, the chains are bound together by

strong intermolecular hydrogen bonds to create a supra-

molecular architecture. The hydrogen bonding system in

compound 1 consists of the uncoordinated carboxylate

oxygen atom O2 with the hydrogen atoms of H(5A) and

H(5B) from the coordinated water molecule, with a

H(5A)…O(2) distance of 1.92(3) A [the angle of 165(3)�,

symmetry code: x, y, 1 ? z] and a H(5B)…O(2) distance

of 1.93(3) A [the angle of 170(3)�, symmetry code: x,1/2-y,

1/2 ? z] Table 3.

Fig. 1 a Coordination

environment of the Zn(II) ion in

compound 1 with thermal

ellipsoids drawn at 50%

probability (all hydrogen atoms

are omitted for clarity); b The

1D chain structure for

compound 1; c The 3D

supramolecular structure

through hydrogen bonding

interactions

712 J Inorg Organomet Polym (2012) 22:709–716

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3.2.2 [Ni(pda)(bib)1.5]n (2)

The fundamental unit of the compound 2 is shown in Fig. 2a,

there is one crystallographically independent Ni(II) ion. The

Ni(II) is five-coordinate with three carboxylate oxygen

atoms from three pda ligands [Ni(1)–O(1) = 2.031(2) A,

Ni(1)–O(3) = 2.141(2) A and Ni(1)–O(4) = 2.231(3) A]

and two nitrogen atoms from two bib ligands [Ni(1)–

N(1) = 2.077(3) A and Ni(1)–N(5) = 2.070(3) A] to give a

square-pyramidal geometry (Fig. 2a). The dihedral angle of

two phenyl rings in pda ligand is 34.68�. The carboxylate

groups are out of the plane of correspondingly linking phenyl

rings with the dihedral angles between them being 7.33� and

5.50�. It is interesting to note that the bib ligand have two

coordinated modes: bidentate and mondetate modes. The

pda and l2-connected bib ligands link Ni(II) ions form 1D

ladder-like chain and the l1-connected bib are filled in the

hole of the 1D chains (Fig. 2b).

Table 3 Hydrogen bond lengths and angles of compound 1

D–H…A D–H H…A D…A hD–H…A

O(5)–H(5A)…O(2)#1 0.80(3) 1.92(3) 2.694(3) 165(3)

O(5)–H(5B)…O(2)#2 0.83(3) 1.93(3) 2.745(2) 170(3)

Symmetry codes: #1: x, y, 1 ? z; #2: x, 1/2-y, 1/2 ? z

Fig. 2 a Local coordination geometry of central Ni(II) with thermal ellipsoids drawn at 50% probability (all hydrogen atoms are omitted for

clarity); b The 1D ladder-like chain for compound 2

J Inorg Organomet Polym (2012) 22:709–716 713

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Fig. 3 a Coordination environment of the Mn(II) ion in compound 1 with thermal ellipsoids drawn at 50% probability (all hydrogen atoms are

omitted for clarity); b The 1D chain formed through L ligands; c The 2D layer (4,4) structure for compound 3

714 J Inorg Organomet Polym (2012) 22:709–716

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3.2.3 [Mn2(pda)2(bmib)]n (3)

The local coordination geometry of polymer [Mn2(pda)2

(bmib)]n with atomic numbering scheme is depicted in

Fig. 3a. It is shown that the asymmetry unit of the molecule

consists of two Mn(II) ions, two coordinated pda ligands

and one bimb ligand. The two Mn(II) ions are in different

coordination environment. Mn1(II) is surrounded by five

coordinated atoms. One coordination sites is occupied

by one nitrogen atoms of bimb ligand [Mn(1)–N(4) =

2.214(3)A] and the others by four carboxylic oxygen

atoms from four different carboxylate ligands [Mn1 (II)–

O(1) = 2.039 A, Mn1 (II)–O(8) = 2.098 (2) A, Mn1(II)–

O(6) = 2.162(2) A and Mn1 (II)–O(6A) = 2.259(3)A].

Mn2(II) is center is coordinated by five oxygen atoms

[Mn2 (II)–O(2) = 2.107 A, Mn2 (II)–O(3) = 2.284 A, Mn2

(II)–O(4) = 2.229 A, Mn2 (II)–O(5) = 2.146 (2) A and

Mn2(II)–O(2) = 2.107 A] from four pda ligands and one

nitrogen atom from bimb ligand [Mn2(II)–N(1) = 2.273(4)

A], showing an octahedral geometry. The pda ligand adopts

two coordination modes: One carboxylate group is bis-

monodentate mode (l2-g1:g1) and the other is bis-mono-

dentate/bridging mode (l2-g1:g2), which bridge adjacent

four Mn(II) ions to form a one-dimensional chain. These

chains are further linked by bridging bimb ligands to

generated a 2D (4,4) grid layer along the ab plane.

3.3 Fluorescent Properties

The solid-state photoluminescence of 3,40-biphenyl-dicar-

boxylic acid ligand exhibits a broad weak fluorescent

emission on 360 nm with an excitation maximum at

314 nm [22]. Compound 1 shows red-shifted fluorescent

emission around 411 nm upon excitation at 350 nm

(Fig. 4). Because Zn(II) ion is difficult to oxidize or reduce,

the fluorescent emission of compound 1 may be assigned to

intraligand (p–p*) fluorescent emission. The enhancement

of luminescence is perhaps a result of the coordination of

carboxylate ligand to a metal center, increasing the asym-

metry and rigidity of the ligand, reducing the non-radiative

decay of the intraligand excited state [23–25].

4 Conclusions

In this paper, we used asymmetry carboxylate and/or

N-donor ligands to construct three new metal–organic

frameworks. X-ray analyses demonstrates that compound 1

and 2 show a one-dimensional structure. Compound 3 is a

two-dimensional (4,4) net. Moreover, the solid state

luminescence demonstrates that compound 1 is a good

candidate for optical material.

5 Supplementary Materials

Crystallographic data for the structural analysis have been

deposited with the Cambridge Crystallographic Data Cen-

ter, CCDC reference numbers: 839301–839303. These data

can be obtained free of charge at: http://www.ccdc.cam.ac.

UK (or Cambridge Crystallographic Data Center, 12 Union

Road, Cambridge CB2 1EZ, UK (fax: ?44-1223-336-033;

e-mail: deposit @ ccdc.cam.ac.uk).

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