Synthesis and structural characterization of two coordination polymers constructed by bis(4-(1H-imidazol-1-yl)phenyl)methanone and 5-(tert-butyl)isophthalate ligands

Gao-Feng Wang 1 , Shu-Wen Sun 2 , Wei-Bing Wang 2 , Hong Sun 2  and Shao-Fei Song 2
  • 1 Department of Applied Chemistry, Yuncheng University, Yuncheng 044000, P.R. China
  • 2 Department of Applied Chemistry, Yuncheng University, Yuncheng 044000, P.R. China
Gao-Feng Wang
  • Corresponding author
  • Department of Applied Chemistry, Yuncheng University, Yuncheng 044000, P.R. China, wgf1979@126.com
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, Shu-Wen Sun, Wei-Bing Wang, Hong Sun and Shao-Fei Song

Abstract

Two coordination polymers, {[Co(bipmo)(tbip)]·3H2O}n (1) and {[Cd(bipmo)(tbip)]·3H2O}n (2) (bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2tbip=5-tert-butylisophthalic acid), were synthesized by solvothermal methods and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction data indicate that the solid state structures of 1 and 2 consist of metal-aromatic carboxylate layers, which are pillared by weak interactions to generate a three-dimensional network. The topological structures of 1 and 2 are uninodal nets based on 3-connected nodes with the Schläfli symbol of {63}.

1 Introduction

The design of coordination polymers has attracted much interest due to their structural diversity as well as potential applications such as storage and separation of gases, ion exchange, magnetism, fluorescence, and others. To date, many approaches have been applied to assemble these crystalline products [1], [2], [3], [4], [5], [6], [7], [8]. In general, the effective strategy for constructing the desired coordination polymers is to use elaborately designed organic spacers as linkers and metal centers as the nodes. In fact, there are many factors governing the final structure, such as the nature of the metal and of the ligands, the metal-to-ligand ratio, the pH value, and the counter ions. Any subtle alteration of these factors can lead to the formation of new oligonuclear structures or extended frameworks.

Polycarboxylate ligands that usually possess two or more coordination sites can be assembled around metal ions in various arrangements. Furthermore, the structural complexity can be enhanced through ancillary ligands such as imidazole or pyridine derivatives, which can pillar the metal-carboxylate motifs into higher dimensionality to generate an extended structural topology [9], [10], [11], [12], [13].

As part of our research on the assembly of imidazole-based complexes [14], [15], [16], [17], [18], [19], [20], we report here the synthesis and characterization of two complexes, {[Co(bipmo)(tbip)]·3H2O}n (1) and {[Cd(bipmo)(tbip)]·3H2O}n (2), constructed from M(OAc)2, bipmo, and H2tbip (M=Co, Cd), in which the dicarboxylate groups in 1 and 2 present μ1-η1:η0 monodentate and μ1-η1:η1 chelate coordination modes (Scheme 1). The topological structures of 1 and 2 are uninodal nets based on 3-connected nodes with the Schläfli symbol of {63}.

Scheme 1:
Scheme 1:

Molecular formula of the ligand bis(4-(1H-imidazol-1-yl)phenyl)methanone (bipmo) and 5-tert-butylisophthalic acid (H2tbip).

Citation: Zeitschrift für Naturforschung B 74, 3; 10.1515/znb-2018-0197

2 Results and discussion

2.1 Preparation and characterization of the complexes

The two new coordination polymers were synthesized by solvothermal reactions of M(OAc)2 with H2tbip and bipmo in good yields. The complexes were characterized by elemental analyses and FT-IR spectoscopy spectroscopy. The asymmetric stretching vibrations νas(COO–) were observed in the range of 1660–1662 cm−1 and the symmetric stretching vibrations νs(COO–) of 1367–1375 cm−1.

2.2 Molecular structures of 1 and 2 in the crystal

Numerical details of the crystal structure determinations of 1 and 2 are listed in Table 1. Selected bond lengths and angles for 1 and 2 are listed in Table 2. Complex 1, {[Co(bipmo)(tbip)]·3H2O}n, features a porous two-dimensional (2D) structure, with the asymmetric unit comprising one Co2+ center, one tbip2− and one bipmo ligand, and three water molecules. As shown in Fig. 1, the Co1 center is surrounded by three carboxylate O atoms from two tbip2− ligands in which the dicarboxylate groups present μ1-η1:η0 monodentate and μ1-η1:η1 chelate coordination modes, and two imidazole N atoms from two bipmo ligands. The Co–O distances vary from 1.986(3) to 2.043(4) Å, and the O–Co–O angles are in the range from 57.43(15) to 147.99(16)°, whereas the Co–N distances are 2.043(4) (Co1–N4#2) and 2.056(4) (Co1–N1) Å with the N1–Co–N4#2 angle of 104.61(16)° (#2=1 – x, 1 – y, 1 – z).

Table 1:

Summary of crystallographic data for the complexes {[Co(bipmo)(tbip)]·3H2O}n (1) and {[Cd(bipmo)(tbip)]·3H2O}n (2).

Compound12
Empirical formulaCo(C19H14N4O)(C12H12O4)·3H2OCd(C19H14N4O)(C12H12O4)·3H2O
Formula weight647.54701.02
T, K293(2)293(2)
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/c
a, Å10.8565(8)10.9429(4)
b, Å17.9500(13)17.7582(7)
c, Å17.5496(13)17.8685(6)
β, deg113.173(5)113.701(3)
V, Å−33144.0(4)3179.4(2)
Z44
Dcalcd., g cm−31.371.46
μ, mm−10.60.7
F(000), e13481432
θ range, deg2.98–25.352.99–25.35
hmin, hmax–13, 12–13, 12
kmin, kmax–21, 21–21, 21
lmin, lmax–12, 21–21, 20
Refl. collected/unique14,082/573712,977/5816
Rint0.04520.0390
Data/restraints/ref. param.5737/6/4005816/27/400
Goodness-of-fit on F21.0521.082
R1/R2 [I>2σ(I)]0.0666/0.16930.0418/0.0822
R1/R2 (all data)0.1071/0.20000.0634/0.0936
Largest peak/hole, e Å−30.77/–0.430.45/–0.46
Table 2:

Selected bond lengths (Å) and bond angles (deg) for complexes 1 and 2.a

12
Co(1)–O(4)#11.986(3)Cd(1)–N(1)2.238(3)
Co(1)–O(2)2.035(3)Cd(1)–O(2)2.251(2)
Co(1)–N(4)#22.043(4)Cd(1)–N(4)#12.277(3)
Co(1)–N(1)2.056(4)Cd(1)–O(4)#22.350(3)
Co(1)–O(3)2.043(4)Cd(1)–O(5)#22.408(2)
Cd(1)–O(3)2.490(3)
O(4)#1–Co(1)–O(2)100.20(15)N(1)–Cd(1)–O(2)134.97(11)
O(4)#1–Co(1)–N(4)#2125.07(19)N(1)–Cd(1)–N(4)#1105.26(12)
O(2)–Co(1)–N(4)#2107.49(15)N(1)–Cd(1)–O(4)#2105.62(11)
O(4)#1–Co(1)–N(1)91.37(16)N(4)#1–Cd(1)–O(4)#2133.90(12)
O(2)–Co(1)–N(1)129.96(16)O(2)–Cd(1)–O(5)#2135.56(11)
N(4)#2–Co(1)–N(1)104.61(16)N(4)#1–Cd(1)–O(3)129.55(10)
O(4)#1–Co(1)–O(3)147.99(16)O(5)#2–Cd(1)–O(3)136.82(9)
O(2)–Co(1)–O(3)57.43(15)

aFor 1, symmetry operations: #1x, 1/2 – y, –1/2 + z; #2 1 – x, 1 – y, 1 – z; for 2, symmetry operations: #1 3 – x, 1 – y, 1 – z; #2x, 1/2 – y, 1/2 + z.

Fig. 1:
Fig. 1:

Coordination environments of complex 1. The hydrogen atoms and water molecules are omitted for clarity. Symmetry codes: #1x, 1/2 – y, –1/2 + z; #2 1 – x, 1 – y, 1 – z.

Citation: Zeitschrift für Naturforschung B 74, 3; 10.1515/znb-2018-0197

To better understand the complicated framework, the network topology of the complex was analyzed by the freely available computer program Topos [21]. As depicted in Fig. 2a, each Co1 center acts as a 3-connected node to connect two tbip2− ligands and two bipmo ligands. Each tbip2− and bipmo unit serves as a bridging linker for the Co2+ ions. From a topological point of view, the framework of 1 can be classified as a 3-connected 2D network with the Schläfli symbol of {63} (Fig. 3b).

Fig. 2:
Fig. 2:

View of the layer in complex 1. (a) Simplified 3-connected node in complex 1. (b) Schematic representation of the simplified 2D 3-coordinated net with {63} topology.

Citation: Zeitschrift für Naturforschung B 74, 3; 10.1515/znb-2018-0197

Fig. 3:
Fig. 3:

Coordination environments of complex 2. The hydrogen atoms are omitted for clarity. Symmetry codes: #1 3 – x, 1 – y, 1 – z; #2x, 1/2 – y, 1/2 + z.

Citation: Zeitschrift für Naturforschung B 74, 3; 10.1515/znb-2018-0197

As shown in Fig. 3, the asymmetric unit 2 consists of one Cd2+ cation, one tbip2− and one bipmo ligand, and three water molecules. The Cd1 center is six-coordinated by two imidazolate N atoms from two bipmo ligands, and four carboxylate O atoms from two tbip2− ligands, showing a distorted octahedral coordination geometry. The Cd–N bond lengths are 2.238(3) and 2.277(3) Å [Cd(1)–N(1)=2.238(3), Cd(1)–N(4)#1=2.277(3) Å; #1=3 – x, 1 – y, 1 – z], whereas the Cd–O bond lengths lie in the range of 2.251(2)–2.490(3) Å [Cd(1)–O(2)=2.251(2), Cd(1)–O(4)#2=2.350(3), Cd(1)–O(5)#2=2.408(2), Cd(1)–O(3)=2.490(3) Å; #2=x, 1/2 – y, 1/2 + z]. The two bipmo ligands link adjacent Cd(II) cations with the Cd···Cd separation of 15.45 Å, whereas each tbip2− anion acts as a μ2-bridge to link two adjacent Cd(II) centers with its two carboxylate groups in μ1-η1:η1 modes with the Cd···Cd separation of 9.60 Å (Figs. 3 and 4a), generating a waved chain (Fig. 4b). The waved chains are further linked to each other by these two bipmo ligands to form a layer (Fig. 4b).

Fig. 4:
Fig. 4:

View of the layer in complex 2. (a) Simplified 3-connected node in complex 1. (b) Schematic representations of the simplified 2D 3-coordinated net with {63} topology.

Citation: Zeitschrift für Naturforschung B 74, 3; 10.1515/znb-2018-0197

Better insight into the nature of this three-dimensional (3D) framework can be achieved from the topological approach. As depicted in Figs. 3 and 4a, each Cd1 ion is surrounded by two tbip2− ligands and two bipmo ligands that bridge to other Cd1 ions. Thus, the Cd1 center can be regarded as a 3-connected node. Thus, the 2D structure of 2 is also a uninodal net with the Schläfli symbol of {63} (Fig. 4b).

3 Conclusions

In this article, we have reported the syntheses, crystal structures, and characterization of two coordination polymers based on the semirigid bipmo ligand. The dicarboxylate groups in 1 and 2 present different coordination modes. The topological structures of 1 and 2 are uninodal nets based on 3-connected nodes with the Schläfli symbol of {63}.

4 Experimental section

4.1 Materials and measurements

Reagents and solvents were purchased from Aladdin Industrial Corporation of Shanghai, China and used as-received. Bipmo was prepared according to the literature method [16]. Elemental analyses were performed on an Elementar Vario ELIII elemental analyzer. The infrared (IR) spectra were recorded on a Bruker Vector 22 spectrophotometer with KBr pellets in the 4000–400 cm−1 region.

4.2 Synthesis of {[Co(bipmo)(tbip)] ·3H2O}n (1)

A mixture of Co(OAc)2·4H2O (0.1 mmol), bipmo (0.1 mmol), and H2tbip (0.1 mmol) and H2O/MDF (3 mL/3 mL) was added to a 15 mL Teflon-lined stainless steel reactor and heated at 95°C for 14 days, and then slowly cooled to room temperature. Blue block single crystals suitable for X-ray data collection were obtained by filtration, washed with H2O-EtOH (5:1), and air-dried. Yield: 87% (based on bipmo). – Anal. for C31H32CoN4O8: calcd. C 57.50, H 4.98, N 8.65; found C 57.32, H 4.79, N 8.86%. – IR (cm−1): 3134, 3142, 2964, 1660, 1606, 1552, 1523, 1496, 1431, 1367, 1307, 1255, 1184, 1116, 1064, 929, 848, 827, 763, 732, 671, 653, 617, 522.

4.3 Synthesis of {[Cd(bipmo)(tbip)] ·3H2O}n (2)

Colorless block crystals of 2 were obtained in moderate yield (42% based on bipmo) using a similar method as described for 1 except that Cd(OAc)2·2H2O were used instead of Co(OAc)2·4H2O. – Anal. for C31H32CdN4O8: calcd. C 53.11, H 4.60, N 7.99; found C 53.02, H 4.38, N 7.63 %. – IR (cm−1): 3126, 2962, 1662, 1604, 1546, 1523, 1498, 1440, 1375, 1334, 1309, 1269, 1184, 1114, 1064, 958, 929, 852, 831, 763, 738, 671, 651, 518, 480, 445, 416.

4.4 X-ray crystallography

All measurements were made on an Agilent Technology SuperNova Eos Dual system with a micro focus source (Mo, λ=0.71073 Å) and focusing multilayer mirror optics. The data was collected at a temperature of 293 K and processed using CrysAlisPro [22]. Absorption corrections were applied using the program Sadabs [23]. The structures were solved by direct methods [24] with the Shelxtl program (version 6.10) [24], [25] and refined by full matrix least-squares techniques on F2 with Shelxtl [24], [25]. All nonhydrogen atoms were refined anisotropically. The ligand hydrogen atoms were localized in their calculated positions and refined using a riding model. The water hydrogen atoms were located in difference Fourier maps and refined with d(O–H)=0.85(2) Å and d(H···H)=1.35(2) Å distances as restraints.

CCDC 1863884 and 1863885 for 1 and 2 contain the supplementary crystallographic data for this article. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.

Acknowledgments

We are grateful for financial support from Young Teacher Starting-up Research of Yuncheng University (No. YQ-2015007) and Applied Research Projects of Yuncheng University (no. CY-2018019).

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    G-F. Wang, X. Zhang, S-W. Sun, H. Sun, X. Yang, H. Li, C-Z. Yao, S-G. Sun, Y-P. Tang, L-X. Meng, Z. Naturforsch. 2016, 71b, 869.

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    V. A. Blatov, Multipurpose crystallochemical analysis with the program package Topos, IUCr Comput. Commission Newsl. 2006, 7, 4. Available at http://iucrcomputing.ccp14.ac.uk/iucr-top/comm/ccom/newsletters/2006nov/.

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If the inline PDF is not rendering correctly, you can download the PDF file here.

  • [1]

    L. Ma, C. Abney, W. Lin, Chem. Soc. Rev. 2009, 38, 1248.

  • [2]

    J-R. Li, R. J. Kuppler, H-C. Zhou, Chem. Soc. Rev. 2009, 38, 1477.

  • [3]

    C. Wang, T. Zhang, W. Lin, Chem. Rev. 2012, 112, 1084.

  • [4]

    M. P. Suh, Y. E. Cheon, E. Y. Lee, Coord. Chem. Rev. 2008, 252, 1007.

    • Crossref
    • Export Citation
  • [5]

    Z. Hu, B. J. Deibert, J. Li, Chem. Soc. Rev. 2014, 43, 5815.

  • [6]

    L. E. Kreno, K. Leong, O. K. Farha, M. Allendorf, R. P. V. Duyne, J. T. Hupp, Chem. Rev. 2012, 112, 1105.

    • Crossref
    • PubMed
    • Export Citation
  • [7]

    S. Kitagawa, R. Kitaura, S. Noro, Angew. Chem., Int. Ed. 2004, 43, 2334.

    • Crossref
    • Export Citation
  • [8]

    M. D. Allendorf, C. A. Bauer, R. K. Bhakta, R. J. T. Houk, Chem. Soc. Rev. 2009, 38, 1330.

    • Crossref
    • PubMed
    • Export Citation
  • [9]

    Y. Zhang, J. Yang, Y. Yang, J. Guo, J-F. Ma, Cryst. Growth Des. 2012, 12, 4060.

    • Crossref
    • Export Citation
  • [10]

    Q-Y. Liu, Z-J. Xiahou, Y-L. Wang, L-Q. Li, L-L. Chen, Y. Fu, CrystEngComm 2013, 15, 4930.

    • Crossref
    • Export Citation
  • [11]

    S-S. Chen, Z-H. Chen, J. Fan, T. Okamura, Z-S. Bai, M-F. Lv, W-Y. Sun, Cryst. Growth Des. 2012, 12, 2315.

    • Crossref
    • Export Citation
  • [12]

    J. Cui, Q. Yang, Y. Li, Z. Guo, H. Zheng, Cryst. Growth Des. 2013, 13, 1694.

    • Crossref
    • Export Citation
  • [13]

    Z. Zhang, J-F. Ma, Y-Y. Liu, W-Q. Kan, J. Yang, CrystEngComm 2013, 15, 2009.

    • Crossref
    • Export Citation
  • [14]

    G-F. Wang, S-W. Sun, Q-P. Han, W-C. Zhang, H. Sun, S-F. Song, G-H. Cui, Crystallogr. Rep. 2014, 59, 994.

  • [15]

    G-F. Wang, X. Zhang, S-W. Sun, Q-P. Han, X. Yang, H. Li, H-X. Ma, C-Z. Yao, H. Sun, H-B. Dong, Crystallogr. Rep. 2015, 60, 1038.

    • Crossref
    • Export Citation
  • [16]

    G-F. Wang, X. Zhang, S-W. Sun, H. Sun, X. Yang, H. Li, C-Z. Yao, S-G. Sun, Y-P. Tang, L-X. Meng, Z. Naturforsch. 2016, 71b, 869.

  • [17]

    G-F. Wang, S-W. Sun, K. Qian, H-X. Ma, X. Yang, Z-R. Liu, Z. Kristallogr. NCS 2015, 230, 101.

  • [18]

    G-F. Wang, Z. Naturforsch. 2015, 70b, 165.

  • [19]

    G-F. Wang, S-W. Sun, Y-C. Wang, J. Struct. Chem. 2018, 59, 160.

    • Crossref
    • Export Citation
  • [20]

    G-F. Wang, S-W. Sun, J. Struct. Chem. 2018, 59, 725.

  • [21]

    V. A. Blatov, Multipurpose crystallochemical analysis with the program package Topos, IUCr Comput. Commission Newsl. 2006, 7, 4. Available at http://iucrcomputing.ccp14.ac.uk/iucr-top/comm/ccom/newsletters/2006nov/.

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    CrysAlis Pro (version 1.171.35.19.), Agilent Technologies Inc., Santa Clara, CA (USA) 2011.

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    G. M. Sheldrick, Sadabs, Program for Empirical Absorption Correction of Area Detector Data, University of Göttingen, Göttingen (Germany) 1996.

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    G. M. Sheldrick, Shelxtl (version 6.1), Software Reference Manual, Bruker AXS Inc., Madison, WI (USA) 2000.

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    G. M. Sheldrick, Acta Crystallogr. 2008, A64, 112.

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  • View in gallery

    Molecular formula of the ligand bis(4-(1H-imidazol-1-yl)phenyl)methanone (bipmo) and 5-tert-butylisophthalic acid (H2tbip).

  • View in gallery

    Coordination environments of complex 1. The hydrogen atoms and water molecules are omitted for clarity. Symmetry codes: #1x, 1/2 – y, –1/2 + z; #2 1 – x, 1 – y, 1 – z.

  • View in gallery

    View of the layer in complex 1. (a) Simplified 3-connected node in complex 1. (b) Schematic representation of the simplified 2D 3-coordinated net with {63} topology.

  • View in gallery

    Coordination environments of complex 2. The hydrogen atoms are omitted for clarity. Symmetry codes: #1 3 – x, 1 – y, 1 – z; #2x, 1/2 – y, 1/2 + z.

  • View in gallery

    View of the layer in complex 2. (a) Simplified 3-connected node in complex 1. (b) Schematic representations of the simplified 2D 3-coordinated net with {63} topology.