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Two novel 3D MOFs based on the biphenyl-2,4,6,3′,5′-pentacarboxylic acid ligand: Synthesis, crystal structure and luminescence properties
Inorganic Chemistry Communications 106 (2019) 111–115
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Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche
Short communication
Two novel 3D MOFs based on the biphenyl-2,4,6,3′,5′-pentacarboxylic acid ligand: Synthesis, crystal structure and luminescence properties
T
Ping Jua, En-sheng Zhanga,c, , Long Jiangb, ⁎
⁎
a
College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, PR China MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China c Laboratory of New Energy&New Function Materials, College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, Shaanxi 716000, PR China b
GRAPHICAL ABSTRACT
Two novel 3D fluorescence metal-organic frameworks [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been constructed by using the self-assembly of biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) and Zn2+/Cd2+ ions.
ARTICLE INFO
ABSTRACT
Keywords: Metal-organic frameworks Biphenyl-2 4 6 3′ 5′-pentacarboxylic acid Crystal structure Luminescent properties
Two novel 3D metal-organic frameworks [Cd3 (bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been synthesized by using biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) as the ligand under solvothermal/hydrothermal conditions. The complexes were characterized by elemental analysis, single-crystal X-ray diffraction (XRD), powder X-ray diffraction (PXRD), IR spectra and thermogravimetric analysis (TGA). Structural analysis revealed that complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3-OH)2] SBUs with unusual topology, while complex 2 exhibits a (3, 3, 6)connected 3D framework. The structural difference between 1 and 2 indicated that the coordination fashion of bpbc5− and the kind of metal ions could play critical role in the construction of MOFs. In addition, new fluorescence emissions were observed for 1 and 2, and the solid state luminescent properties were investigated.
1. Introduction In recent years, metal-organic frameworks (MOFs) have received considerable interests due to their diverse structures, intriguing topologies and great potential applications [1]. Although, thousands of
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MOFs with different topologies have been reported thus far, the design and synthesis of MOFs with novel architecture or new function is still attractive [2]. Generally, MOFs could be constructed by metal ions and multidentate polycarboxylate ligands through coordination bonds. However,
Corresponding authors. E-mail addresses: [email protected] (E.-s. Zhang), [email protected] (L. Jiang).
https://doi.org/10.1016/j.inoche.2019.06.003 Received 26 April 2019; Received in revised form 1 June 2019; Accepted 2 June 2019 Available online 03 June 2019 1387-7003/ © 2019 Elsevier B.V. All rights reserved.
Inorganic Chemistry Communications 106 (2019) 111–115
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the final topological structure of MOFs are hardly controlled because the synthesis processes are influenced by different factors, such as the structural characteristics of the organic ligands [3], the coordination nature of metal ions [4], the solvent preference [5], the pH value of the solution [6], the reaction temperature [7] and the metal/ligand ratios [8], etc. Among these factors, the choice of organic ligands and metal ions play an important role in the construction of MOFs. The effect of metal ions can be explained in terms of their differences in ionic radii, coordination ability and coordination modes to organic ligands. The organic ligands are the most important factor which greatly influence the self-assembly process and the overall framework of the MOFs [9]. Biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) could be an excellent organic ligand which will induce various coordination modes and higher dimensionality structures. According to the previous literature, only few MOFs based on H5bpbc have been reported thus far [10]. In this context, we herein disclosed the synthesis, crystal structure and luminescence properties of two novel 3D metal-organic frameworks [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc) (DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) based on the multidentate polycarboxylate ligand H5bpbc. Structural analysis revealed that H5bpbc ligand adopt two different coordination modes with metal ions, which lead to the formation of two different 3D frameworks [11]. Complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3OH)2] SBUs with unusual topology, while complex 2 exhibits a (3, 3, 6)connected 3D framework. In addition, the thermal stability and luminescent properties of 1 and 2 were also discussed.
Interestingly, to some structural features complex 2 is quite different from complex 1. In complex 2, the reaction of Zn (II) salt with H5bpbc in the presence of NaNO3 leads to the incorporation of Na+ ions in the product [14]. Single-crystal X-ray diffraction analysis revealed that complex 2 crystallized in the triclinic system with P1 space group. The asymmetric unit contains two crystallographically independent Zn2+ ions, one Na+ ion, one bpbc5−, one and a half coordinated DMF, half coordinated EtOH, five coordinated water molecules, and half lattice water molecule. As shown in Fig. 2a, Zn1 is five-coordinated by four carboxylic oxygen atoms (O1, O5#3, O9# 1, O10# 1) from three different bpbc5− ligands and one oxygen atom from the coordinated DMF molecule (O11). Meanwhile, Zn2 is four-coordinated by three carboxylic oxygen atoms (O2, O4#5 and O8#4) from three bpbc5− anions and one water molecule (O1w). The ZneO distances are in the range of 1.931 (3)Å to 2.018 (3)Å, which are comparable to those documented values in previous literatures [15]. Na1 is coordinated by five O atoms from H2O molecules, one O3 atom from bpbc5− ligand, one O atom from EtOH molecule and one O atom from DMF molecule to form a [Na (H2O)4 (DMF)0.5 (EtOH)0.5]+ counterion. The distance of NaeO bonds is in the range from 1.967 (18)Å to 2.40 (2)Å. In complex 2, bpbc5− ligand exhibits obvious torsion with a dihedral angle of 51.64° between the two benzene rings. Each μ6-bpbc5− ligand connect with six Zn2+ ions and one Na+ ion to afford μ1-ŋ1: ŋ1 chelating mode, μ1-ŋ1: ŋ0 and μ2-ŋ1: ŋ1 coordination mode, respectively (Fig. 2a). Zn1 and Zn2 ions are bridged by bppc5− ligands to form a 3D porous structure with tetragonal channels (Fig. 2b), but the channels were filled with [Na (H2O)4 (DMF)0.5(EtOH)0.5]+ counterion. Analysis of the network topology of 2 reveals that each Zn2+ ion acted as a 3connected node to connect with three bpbc5−. Bpbc5− served as 6connected node to connect with six Zn2+ ions. Thus, the whole framework can be simplified as an unprecedented (3, 3, 6)-connected framework (Fig. 2c). It is worth mentioning that two coordination modes of the bpbc5− ligands were observed from the above structural analysis. In complex 1, the bpbc5− ligands adopt a complicated 5-bridging fashion to link the [Cd6 (COO)10 (μ3-OH)2] SBUs, which make it possible for forming a 3D structure. In complex 2, each bpbc5− ligand adopts a 6-bridging mode to combine with Zn2+ ions to obtain 3D framework. By comparison of 1 and 2, it can be concluded that different structures can be rationalized by changing the coordination mode of the multi-carboxylate ligands. In addition, metal ions also played an important role in the preparation of MOFs with the same ligands. For example, in complex 1 the [Cd6 (COO)10 (μ3-OH)2] SBUs act as 10-connected nodes to form a (5, 10)connected framework, while in complex 2 Zn2+ ions serve as 3-connected nodes, resulting an unusual (3, 3, 6)-connected framework. The phase purity of the as-synthesized complexes 1 and 2 were confirmed by X-ray powder diffraction (XRD) measurements. As shown in Fig. S1, the PXRD pattern of the as-synthesized complex 1 and 2 matches well with the simulated one based on the single-crystal diffraction data, which revealing the good purity of complexes 1 and 2. Thermogravimetric measurements for complexes 1 and 2 were carried out from room temperature to 800 °C under N2 atmosphere. As shown in Fig. S2, the TG curve of complex 1 shows a weight loss of 9.2% from room temperature to 260 °C, which is corresponding to the removal of the lattice and coordinated water molecules (calcd 9 1.%). The desolvated framework is stable up to 450 °C, further increasing temperature the framework will start to collapse. Complex 2 lost its coordinated and lattice water molecules in the temperature range from 25 °C to 230 °C and the weight loss founded is 12.1, which is consistent with the calculated (13.1%) data. Another two steps of weight losses could be observed for the desolvated framework after 230 °C. It is well known that MOFs constructed by d10 metal centers and conjugated organic ligands have attracted increasing attentions due to their great potential applications in the field of chemical sensors and photochemistry. In order to reveal the luminescent property, the solidstate fluorescence spectra of complex 1, 2 and H5bpbc were recorded on
2. Result and discussion Complex 1 is synthesized by Cd (NO3)3·4H2O and H5bpbc under hydrothermal conditions at 160 °C [12]. Single-crystal X-ray diffraction indicated that complex 1 crystallizes in monoclinic space group C 2/c. The asymmetric unit of 1 is composed by three Cd2+, one bpbc5− ligand, one μ3-OH– group, three coordinated water molecules and one lattice water molecule. As shown in Fig. 1a, Cd1, Cd3 and Cd4 ions exhibit distorted octahedral arrangement, and Cd2 ion presents a distorted pentagonal bipyramid geometry. Cd1 ion coordinated with four oxygen atoms (O4#2, O4#3, O6 and O6#1) from four different ligands and two hydroxyl oxygen atoms (O11 and O11#1); Cd2 ion coordinated with six oxygen atoms (O1#4, O2#4, O3#3, O4#3, O5 and O8#5) from four different ligands and one hydroxyl oxygen (O11) atom. Cd3 ion coordinated with four oxygen atoms (O6#1, O7#5, O9#3 and O10#3) from three different ligands, one coordinated water molecule and one hydroxyl oxygen atom (O11). Cd4 ion coordinated with two oxygen atoms (O1 and O1#4) from two different ligands, four coordinated water molecules (O2w, O2w#4, O3w and O3w#4). In complex 1, two μ3-OH−, ten bridging carboxylate groups (from ten distinct bpbc5− ligands) and six Cd2+ ions were connected by coordination bond to form a [Cd6 (COO)10 (μ3-OH)2] secondary building unit (SBU) (Fig. 1b). In the SBUs, the distance between two Cd2+ ions are 3.3779 (8)Å for Cd1···Cd2, 3.5858(10)Å for Cd1···Cd3 and 4.2510(9) Å for Cd2···Cd4, respectively. The SBUs are alternately connected by the Cd4 ions and bpbc5− ligands to form the one-dimensional chain (Fig. 1b). In this structure, the bpbc5− ligand shows obvious torsion with a dihedral angle of 70.35° between the two benzene rings. Each bpbc5− ligand connect with ten Cd2+ ions to form the μ1-ŋ1: ŋ1 chelating mode, μ2-ŋ1: ŋ1 bridging mode, μ3-ŋ2: ŋ1 and μ2-ŋ2: ŋ1 coordination modes, respectively (Fig. 1c). Complex 1 possess 1D chains based on [Cd6 (COO)10 (μ3-OH)2] SBUs, which are further extended to 3D network via rigid bpbc5−. From the topological point of view, each bpbc5− ligand can be viewed as a 5connected node, each [Cd6 (COO)10 (μ3-OH)2] SBU as a 10-connected node (Fig. 1d), so the whole framework can be simplified as a (5,10)connected framework (Fig. 1e and f). Without guest molecules, the effective free volume of 1 is about 26%, which was calculated by using PLATON [13]. 112
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Fig. 1. (a) Coordination environments of Cd (II) in 1 (symmetry codes: # 1: −x , y, −z + 1/2; #2: x − 1/2, y + 1/2, z; #3: - x + 1/2, y + 1/2, −z + 1/2; #4: −x + 1, y, −z + 1/2; #5: x, −y + 1, z − 1/2; #6: x, −y + 1, z + 1/2; #7: −x, −y + 1, −z + 1; #8: x + 1/2, y − 1/2, z; #9: −x + 1/2, y − 1/2, −z + 1/2); (b) View of the [Cd6 (COO)10 (μ3-OH)2] SBUs; (c) Coordination mode of bpbc5− ligand; (d) Each [Cd6 (COO)10(μ3-OH)2] SBU coordinated with ten bpbc5− ligands; (e) View of the 3D framework based on [Cd6(COO)10(μ3-OH)2] SBUs; (f) Schematic representation of the (5, 10)-connected network of 1 (Color codes: turquoise for 10connected [Cd6 (COO)10(μ3-OH)2] SBU, blue for 5-connected bpbc5− ligands). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 2. (a) Coordination environments of Zn (II) in 2 (symmetry codes: # 1: 1 - x, 2 - y, 1 - z; #2: 1 + x, + y, + z; #3: 1 - x, 2 - y, − z; #4: 1 - x, 1 - y, 1 - z; #5: - 1 + x, + y, + z; #6: 1 - x, 1 - y, − z); (b) View of the 3D structure constructed by the Zn centers and bpbc5− ligands; (c) Schematic representation of the (3, 3, 6)-connected network of complex 2 (Color codes: turquoise for 3-connected Zn2+ ions, blue for 6-connected bpbc5− ligands). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
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Acknowledgements This work was financially supported by the Startup Foundation for Doctors of Qufu Normal University and Natural Science Foundation of Shaanxi Province (2018JQ2079, 2018JQ2040). Appendix A. Supplementary material Crystallographic data for the structural analysis have been deposited to the Cambridge Crystallographic Data Centre, CCDC No. 1910551–1910552 for complexes 1–2. The data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www. ccdc.cam.ac.uk/data request/cif. Supplementary data to this article can be found online at doi:https://doi.org/10.1016/j.inoche.2019.06.003. References [1] (a) K. Manna, P. F. Ji, Z. K. Lin, F. X. Greene, A. Urban, N. C. Thacker, W. B. Lin, Chemo-selective single-site earth-abundant metal catalysts at metal-organic framework nodes, Nat. Commun. 7 (2016) 12610−12620; (b) M. Li, D. Li, M. O'Keeffe, O. M. Yaghi, Topological analysis of metal–organic frameworks with polytopic linkers and/or multiple building units and the minimal transitivity principle, Chem. Rev. 114 (2013) 1343−1370; (c) S. S. Sun, J. H. Zhang, Z. Wang, Y. Q. Yu, C. Y. Zhu, M. Pan, C. Y. Su, Anomalous thermally-activated NIR emission of ESIPT modulated Nd-complexes for optical fiber sensing devices, Chem. Commun. 54 (2018) 6304–6307. [2] (a) P. Ju, L. Jiang, T. B. Lu, An unprecedented dynamic porous metal-organic framework assembled from fivefold interlocked closed nanotubes with selective gas adsorption behaviors, Chem. Commun. 49 (2013) 1820–1822. (b) B. F. Abrahams, S. R. Batten, M. J. Grannas, H. Hamit, B. F. Hoskins, R. Robson, Ni(tpt)(NO3)2 a three-dimensional network with the exceptional (12, 3) topology: a self-entangled single net, Angew. Chem. Int. Ed. 38 (1999) 1475–1477 (c) K. C. Wang, N. Yang, D. G. Xu, D. B. Luo, Z. E. Lin, New open-framework beryllium phosphates with hcb, sql, and bnn topologies, Inorg. Chem. Commun. 58 (2015) 95-98 [3] (a) Y. W. Li, H. Ma, Y. Q. Chen, K. H. He, Z. X. Li, X. H. Bu, Structure modulation in Zn(II)-1,4-bis(imidazol-1-yl)benzene frameworks by varying dicarboxylate anions, Cryst. Growth Des. 12 (2012) 189–196; (b) L. Fan, X. Zhang, W. Zhang, Y. Ding, W. Fan, L. Sun, X. Zhao, Syntheses, structures, and properties of a series of 2D and 3D coordination polymers based on trifunctional pyridinedicarboxylate and different (bis)imidazole bridging ligands, CrystEngComm. 16 (2014) 2144−2157. [4] S. Seth, G. Savitha, J.N. Moorthy, Metal-mediated self-assembly of a twisted biphenyl-tetraacid linker with semi-rigid core and peripheral flexibility: concomitant formation of compositionally-distinct MOFs, Cryst. Growth Des. 18 (2018) 2129–2137. [5] K.Q. Hu, X. Jiang, C.Z. Wang, L. Mei, Z.N. Xie, W.Q. Tao, X.L. Zhang, Z.F. Chai, W.Q. Shi, Solvent-dependent synthesis of porous anionic uranyl-organic frameworks featuring a highly symmetrical (3,4)-connected ctn or bor topology for selective dye adsorption, Chem. Eur. J. 23 (2017) 529–532. [6] X. He, X.P. Lu, Z.F. Ju, C.J. Zhang, Q.K. Zhang, M.X. Li, Syntheses, structures, and photoluminescent properties of ten metal-organic frameworks constructed by a flexible tetracarboxylate ligand, CrystEngComm 15 (2013) 2731–2744. [7] Y.B. Go, X. Wang, E.V. Anokhina, A.J. Jacobson, Influence of the reaction temperature and pH on the coordination modes of the 1, 4-benzenedicarboxylate (BDC) ligand: a case study of the NiII (BDC)/2, 2′-bipyridine system, Inorg. Chem. 44 (2005) 8265–8271. [8] F.H. Zhao, S. Jing, Y.X. Che, J.M. Zheng, Metal-ligand ratio-controlled assembly of two pairs of Co(II) complexes: syntheses, structures and magnetic properties, CrystEngComm 14 (2012) 4478–4485. [9] D.H. Chen, L. Lin, T.L. Sheng, Y.H. Wen, X.Q. Zhu, L.T. Zhang, S.M. Hua, R.B. Fu, X.T. Wu, Syntheses, structures, luminescence and magnetic properties of seven isomorphous metal-organic frameworks based on 2,7-bis(4-benzoic acid)-N-(4benzoic acid) carbazole, New J. Chem. 42 (2018) 2830–2837. [10] (a) Z. H. Zhou, M. L. Han, Y. P. Wu, W. W. Dong, D. S. Li, J. Y. Lu, N-donor coligands driven two new Co(II)-coordination polymers with bi- and trinuclear units: Crystal structures, and magnetic properties, J. Solid. State. Chem. 242 (2016) 207–211; (b) M. L. Han, L. Bai, P. Tang, X. Q. Wu, Y. P. Wu, J. Zhao, D. S. Li, Y. Y. Wang, Biphenyl-2,4,6,3’,5’-pentacarboxylic acid as a tecton for six new Co(II) coordination polymers: pH and N-donor ligand-dependent assemblies, structure diversities and magnetic properties, Dalton Trans. 44 (2015) 14673−14685. [11] The single-crystal data of 1 and 2 were collected on a Xcalibur Eos Gemini fourcircle diffractometer with Mo Kα radiation (λ = 0.71073 Å) at 200K and 293K, respectively. Using Olex2, the structures were solved with the ShelXS program by direct methods, and refined with the ShelXL refinement package with full-matrix least-squares minimization. All the metal atoms were first located. Then carbon, nitrogen and hydrogen atoms of the organic framework were subsequently found. All of the non-hydrogen atoms were located from the initial solution and refined anisotropically. The crystallographic data for 1 and 2 are summarized in Table S1, and the selected bond lengths and angles are listed in Table S2. [12] Synthesis of [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1): Cd(NO3)3·4H2O (15.4 mg, 0.05 mmol), H5bpbc (7.3 mg, 0.02 mmol) were dissolved in 10 mL H2O, then NaOH (100
Fig. 3. Solid-state photoluminescent spectra of compound 1, 2 and H5bpbc at room temperature (λex = 300 nm).
an Agilent Cary Eclipse fluorescence spectrophotometer upon excitation at 300 nm at room temperature (slits: 5 nm/10 nm). As shown in Fig. 3, no fluorescence emission was observed for the free H5bpbc ligand, which might be due to the thermal intra-ligand rotations between the two benzene rings resulting in the non-radiative decay of the ligands [16]. The thermal intra-ligand rotations have been forbidden due to the rigid conformation formed in the coordination processes. The dihedral angles between the two benzene rings in complex 1 and 2 are 70.35° and 51.64°, respectively. Consequently, shoulder emissions at 362 nm were observed in complex 1 and 2, which may be ascribed to the intra-ligand π* → π or π* → n transitions. As known, the photoluminescence behavior of MOFs is closely associated with the metal ions and the ligands [17]. The fluorescence emission spectra of MOFs could be tuned by changing the kind of metal center or organic ligands as well as the conformations of the ligand [18]. As shown in Fig. 3, complex 1 displayed a broad emission band centered at 404 nm, while complex 2 shown a broad emission band range from 375 nm to 430 nm. The remarkable fluorescence emissions of complex 1 and 2 might attributed to the ligand-to-metal charge transfer (LMCT) [19]. The different fluorescence emissions of complex 1 and 2 is probably caused by the differences coordination environment around Cd2+/Zn2+ ions. In addition, the stronger fluorescence emission of complex 1 presumably due to the presence of high-nucleus metal clusters [Cd6 (COO)10 (μ3-OH)2], which would tighten the whole skeleton and resulting in much weaker vibrations as well as less non-radiative decay [16]. 3. Conclusions In conclusion, two novel 3D MOFs [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been synthesized by using H5bpbc as the organic ligand under solvothermal/ hydrothermal conditions. Complexes 1 and 2 have been fully characterized with elemental analysis, single-crystal X-ray diffraction, powder X-ray diffraction, IR spectra and thermogravimetric analysis. Structural analysis revealed that complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3-OH)2] SBUs with unusual topology, while complex 2 displays a (3, 3, 6)-connected 3D framework. The structural difference between 1 and 2 revealed that the coordination fashion of bpbc5− and the kind of metal ions have great influence on the structure and topologies of products. Furthermore, the solid-state photoluminescence properties of complexes 1 and 2 were investigated and discussed.
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[13] [14]
[15] [16]
μL, 0.1 M) was added. The mixture was sealed in a Teflon-lined stainless steel vessel (25 mL) and heated at 160°C for 5 days. Then, the reaction mixture was cooled to room temperature over 24 h and colorless prism crystals 1 were obtained. Yield: 58% (based on Cd(II)). Anal. Calcd. for C17H14O15Cd3 (%): C, 25.67; H, 1.77; O, 30. 17. Found (%): C, 25.21; H, 2.19; O, 30.54. IR (KBr, cm−1): 3501(s), 3238(s), 1610 (s), 1574 (s), 1543 (vs), 1442 (s), 1414 (s), 1377 (vs), 1353 (s), 1118 (w), 937 (m), 905 (w), 854 (w), 803 (w), 791(m), 768 (m), 738 (w), 720 (w), 545 (w), 436 (w). A.L. Spek, Single-crystal structure validation with the program PLATON, J. Appl. Crystallogr. 36 (2003) 7–13. Synthesis of [Zn2Na(bpbc)(DMF)1.5(EtOH)0.5(H2O)5]·0.5H2O (2): Zn(NO3)3·6H2O (14.9 g, 0.05 mmol), H5bpbc (7.3 mg, 0.02 mmol), NaNO3(0.0025 g, 0.03 mmol) and HNO3 (6 M, 1d) were added to a 20 mL glass scintillation vial. A 3:1:3 (v/v/v) mixture of DMF (3 mL), EtOH (1 mL) and H2O (3 mL) was added to the mixture. The content was heated at 90°C for 48 h. Colorless lamellar crystal was obtained and washed with DMF, then dried in air (45% yield based on Zn). Anal. Calcd. for C22. 5H29.5N1.5O17.5NaZn2 (%): C, 35.80; H, 3.94; N, 2.78. Found (%): C, 35.52; H, 4.21; N, 2.42. IR (KBr, cm−1): 3436 (s), 1659 (vs), 1608(vs), 1573 (s), 1433 (s), 1374 (vs), 1120 (w), 1062 (w), 1017 (w), 960 (w), 927 (w), 870 (w),778 (m), 726 (m), 690 (w), 567 (w) , 479 (w). J. Sahu, M. Ahmad, P.K. Bharadwaj, Structural diversity and luminescence properties of coordination polymers built with a rigid linear dicarboxylate and Zn(II)/Pb (II) ion, Cryst. Growth Des. 13 (2013) 2618–2627. (a) S. F. Gan, W. W. Luo, B. R. He, L. Chen, H. Nie, R. R. Hu, A. J. Qin, Z. J. Zhao, B.
Z. Tang, Integration of aggregation-induced emission and delayed fluorescence into electronic donor–acceptor conjugates, J. Mater. Chem. C, 4(2016) 3705–3708 (b) W. Tang, Y. Xiang, A. J. Tong, Salicylaldehyde azines as fluorophores of aggregation-induced emission enhancement characteristics, J. Org. Chem., 74(2009) 2163–2166. [17] S.Q. Zang, Y. Su, Y.Z. Li, J.G. Lin, X.Y. Duan, Q.J. Meng, S. Gao, Four 2D metal–organic networks incorporating Cd-cluster SUBs: hydrothermal synthesis, structures and photoluminescent properties, CrystEngComm 11 (2009) 122–129. [18] R.H. Wang, D.Q. Yuan, F.L. Jiang, L. Han, Y.Q. Gong, M.C. Hong, Anion effect on the structural conformation of Tetranuclear cadmium(II) complexes, Cryst. Growth Des. 6 (2006) 1351–1360. [19] (a) M. D. Allendorf, C. A. Bauer, R. K. Bhakta, R. J. T. Houk, Luminescent metalorganic frameworks, Chem. Soc. Rev. 38 (2009) 1330−1352 (b) Q. Y. Liu, Y. L. Wang, L. Xu, Synthesis, crystal structures and photoluminescent properties of three novel cadmium(II) compounds constructed from 5-sulfoisophthalic acid (H3SIP), Eur. J. Inorg. Chem. 23 (2006) 4843–4851; (c) X. W. Wang, J. Z. Chen, J. H. Liu, Photoluminescent Zn(II) metal-organic frameworks built from tetrazole ligand: 2D four-connected regular honeycomb (43 63)-net, Cryst. Growth Des. 7 (2007) 12271229; (d) G. Yuan, C. Zhang, K. Z. Shao, W. L. Zhou, X. Wei, F. C. Wang, Z. M. Su, Syntheses, crystal structures and fluorescence properties of three coordination polymers assembled from flexible bis-(imidazole-4,5-dicarboxylate) ligand and d10/ s2 metal ions, Inorg. Chem. Commun. 100 (2019) 16-20.
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Short communication
Two novel 3D MOFs based on the biphenyl-2,4,6,3′,5′-pentacarboxylic acid ligand: Synthesis, crystal structure and luminescence properties
T
Ping Jua, En-sheng Zhanga,c, , Long Jiangb, ⁎
⁎
a
College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, PR China MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China c Laboratory of New Energy&New Function Materials, College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, Shaanxi 716000, PR China b
GRAPHICAL ABSTRACT
Two novel 3D fluorescence metal-organic frameworks [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been constructed by using the self-assembly of biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) and Zn2+/Cd2+ ions.
ARTICLE INFO
ABSTRACT
Keywords: Metal-organic frameworks Biphenyl-2 4 6 3′ 5′-pentacarboxylic acid Crystal structure Luminescent properties
Two novel 3D metal-organic frameworks [Cd3 (bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been synthesized by using biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) as the ligand under solvothermal/hydrothermal conditions. The complexes were characterized by elemental analysis, single-crystal X-ray diffraction (XRD), powder X-ray diffraction (PXRD), IR spectra and thermogravimetric analysis (TGA). Structural analysis revealed that complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3-OH)2] SBUs with unusual topology, while complex 2 exhibits a (3, 3, 6)connected 3D framework. The structural difference between 1 and 2 indicated that the coordination fashion of bpbc5− and the kind of metal ions could play critical role in the construction of MOFs. In addition, new fluorescence emissions were observed for 1 and 2, and the solid state luminescent properties were investigated.
1. Introduction In recent years, metal-organic frameworks (MOFs) have received considerable interests due to their diverse structures, intriguing topologies and great potential applications [1]. Although, thousands of
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MOFs with different topologies have been reported thus far, the design and synthesis of MOFs with novel architecture or new function is still attractive [2]. Generally, MOFs could be constructed by metal ions and multidentate polycarboxylate ligands through coordination bonds. However,
Corresponding authors. E-mail addresses: [email protected] (E.-s. Zhang), [email protected] (L. Jiang).
https://doi.org/10.1016/j.inoche.2019.06.003 Received 26 April 2019; Received in revised form 1 June 2019; Accepted 2 June 2019 Available online 03 June 2019 1387-7003/ © 2019 Elsevier B.V. All rights reserved.
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the final topological structure of MOFs are hardly controlled because the synthesis processes are influenced by different factors, such as the structural characteristics of the organic ligands [3], the coordination nature of metal ions [4], the solvent preference [5], the pH value of the solution [6], the reaction temperature [7] and the metal/ligand ratios [8], etc. Among these factors, the choice of organic ligands and metal ions play an important role in the construction of MOFs. The effect of metal ions can be explained in terms of their differences in ionic radii, coordination ability and coordination modes to organic ligands. The organic ligands are the most important factor which greatly influence the self-assembly process and the overall framework of the MOFs [9]. Biphenyl-2, 4, 6, 3′, 5′-pentacarboxylic acid (H5bpbc) could be an excellent organic ligand which will induce various coordination modes and higher dimensionality structures. According to the previous literature, only few MOFs based on H5bpbc have been reported thus far [10]. In this context, we herein disclosed the synthesis, crystal structure and luminescence properties of two novel 3D metal-organic frameworks [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and [Zn2Na (bpbc) (DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) based on the multidentate polycarboxylate ligand H5bpbc. Structural analysis revealed that H5bpbc ligand adopt two different coordination modes with metal ions, which lead to the formation of two different 3D frameworks [11]. Complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3OH)2] SBUs with unusual topology, while complex 2 exhibits a (3, 3, 6)connected 3D framework. In addition, the thermal stability and luminescent properties of 1 and 2 were also discussed.
Interestingly, to some structural features complex 2 is quite different from complex 1. In complex 2, the reaction of Zn (II) salt with H5bpbc in the presence of NaNO3 leads to the incorporation of Na+ ions in the product [14]. Single-crystal X-ray diffraction analysis revealed that complex 2 crystallized in the triclinic system with P1 space group. The asymmetric unit contains two crystallographically independent Zn2+ ions, one Na+ ion, one bpbc5−, one and a half coordinated DMF, half coordinated EtOH, five coordinated water molecules, and half lattice water molecule. As shown in Fig. 2a, Zn1 is five-coordinated by four carboxylic oxygen atoms (O1, O5#3, O9# 1, O10# 1) from three different bpbc5− ligands and one oxygen atom from the coordinated DMF molecule (O11). Meanwhile, Zn2 is four-coordinated by three carboxylic oxygen atoms (O2, O4#5 and O8#4) from three bpbc5− anions and one water molecule (O1w). The ZneO distances are in the range of 1.931 (3)Å to 2.018 (3)Å, which are comparable to those documented values in previous literatures [15]. Na1 is coordinated by five O atoms from H2O molecules, one O3 atom from bpbc5− ligand, one O atom from EtOH molecule and one O atom from DMF molecule to form a [Na (H2O)4 (DMF)0.5 (EtOH)0.5]+ counterion. The distance of NaeO bonds is in the range from 1.967 (18)Å to 2.40 (2)Å. In complex 2, bpbc5− ligand exhibits obvious torsion with a dihedral angle of 51.64° between the two benzene rings. Each μ6-bpbc5− ligand connect with six Zn2+ ions and one Na+ ion to afford μ1-ŋ1: ŋ1 chelating mode, μ1-ŋ1: ŋ0 and μ2-ŋ1: ŋ1 coordination mode, respectively (Fig. 2a). Zn1 and Zn2 ions are bridged by bppc5− ligands to form a 3D porous structure with tetragonal channels (Fig. 2b), but the channels were filled with [Na (H2O)4 (DMF)0.5(EtOH)0.5]+ counterion. Analysis of the network topology of 2 reveals that each Zn2+ ion acted as a 3connected node to connect with three bpbc5−. Bpbc5− served as 6connected node to connect with six Zn2+ ions. Thus, the whole framework can be simplified as an unprecedented (3, 3, 6)-connected framework (Fig. 2c). It is worth mentioning that two coordination modes of the bpbc5− ligands were observed from the above structural analysis. In complex 1, the bpbc5− ligands adopt a complicated 5-bridging fashion to link the [Cd6 (COO)10 (μ3-OH)2] SBUs, which make it possible for forming a 3D structure. In complex 2, each bpbc5− ligand adopts a 6-bridging mode to combine with Zn2+ ions to obtain 3D framework. By comparison of 1 and 2, it can be concluded that different structures can be rationalized by changing the coordination mode of the multi-carboxylate ligands. In addition, metal ions also played an important role in the preparation of MOFs with the same ligands. For example, in complex 1 the [Cd6 (COO)10 (μ3-OH)2] SBUs act as 10-connected nodes to form a (5, 10)connected framework, while in complex 2 Zn2+ ions serve as 3-connected nodes, resulting an unusual (3, 3, 6)-connected framework. The phase purity of the as-synthesized complexes 1 and 2 were confirmed by X-ray powder diffraction (XRD) measurements. As shown in Fig. S1, the PXRD pattern of the as-synthesized complex 1 and 2 matches well with the simulated one based on the single-crystal diffraction data, which revealing the good purity of complexes 1 and 2. Thermogravimetric measurements for complexes 1 and 2 were carried out from room temperature to 800 °C under N2 atmosphere. As shown in Fig. S2, the TG curve of complex 1 shows a weight loss of 9.2% from room temperature to 260 °C, which is corresponding to the removal of the lattice and coordinated water molecules (calcd 9 1.%). The desolvated framework is stable up to 450 °C, further increasing temperature the framework will start to collapse. Complex 2 lost its coordinated and lattice water molecules in the temperature range from 25 °C to 230 °C and the weight loss founded is 12.1, which is consistent with the calculated (13.1%) data. Another two steps of weight losses could be observed for the desolvated framework after 230 °C. It is well known that MOFs constructed by d10 metal centers and conjugated organic ligands have attracted increasing attentions due to their great potential applications in the field of chemical sensors and photochemistry. In order to reveal the luminescent property, the solidstate fluorescence spectra of complex 1, 2 and H5bpbc were recorded on
2. Result and discussion Complex 1 is synthesized by Cd (NO3)3·4H2O and H5bpbc under hydrothermal conditions at 160 °C [12]. Single-crystal X-ray diffraction indicated that complex 1 crystallizes in monoclinic space group C 2/c. The asymmetric unit of 1 is composed by three Cd2+, one bpbc5− ligand, one μ3-OH– group, three coordinated water molecules and one lattice water molecule. As shown in Fig. 1a, Cd1, Cd3 and Cd4 ions exhibit distorted octahedral arrangement, and Cd2 ion presents a distorted pentagonal bipyramid geometry. Cd1 ion coordinated with four oxygen atoms (O4#2, O4#3, O6 and O6#1) from four different ligands and two hydroxyl oxygen atoms (O11 and O11#1); Cd2 ion coordinated with six oxygen atoms (O1#4, O2#4, O3#3, O4#3, O5 and O8#5) from four different ligands and one hydroxyl oxygen (O11) atom. Cd3 ion coordinated with four oxygen atoms (O6#1, O7#5, O9#3 and O10#3) from three different ligands, one coordinated water molecule and one hydroxyl oxygen atom (O11). Cd4 ion coordinated with two oxygen atoms (O1 and O1#4) from two different ligands, four coordinated water molecules (O2w, O2w#4, O3w and O3w#4). In complex 1, two μ3-OH−, ten bridging carboxylate groups (from ten distinct bpbc5− ligands) and six Cd2+ ions were connected by coordination bond to form a [Cd6 (COO)10 (μ3-OH)2] secondary building unit (SBU) (Fig. 1b). In the SBUs, the distance between two Cd2+ ions are 3.3779 (8)Å for Cd1···Cd2, 3.5858(10)Å for Cd1···Cd3 and 4.2510(9) Å for Cd2···Cd4, respectively. The SBUs are alternately connected by the Cd4 ions and bpbc5− ligands to form the one-dimensional chain (Fig. 1b). In this structure, the bpbc5− ligand shows obvious torsion with a dihedral angle of 70.35° between the two benzene rings. Each bpbc5− ligand connect with ten Cd2+ ions to form the μ1-ŋ1: ŋ1 chelating mode, μ2-ŋ1: ŋ1 bridging mode, μ3-ŋ2: ŋ1 and μ2-ŋ2: ŋ1 coordination modes, respectively (Fig. 1c). Complex 1 possess 1D chains based on [Cd6 (COO)10 (μ3-OH)2] SBUs, which are further extended to 3D network via rigid bpbc5−. From the topological point of view, each bpbc5− ligand can be viewed as a 5connected node, each [Cd6 (COO)10 (μ3-OH)2] SBU as a 10-connected node (Fig. 1d), so the whole framework can be simplified as a (5,10)connected framework (Fig. 1e and f). Without guest molecules, the effective free volume of 1 is about 26%, which was calculated by using PLATON [13]. 112
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Fig. 1. (a) Coordination environments of Cd (II) in 1 (symmetry codes: # 1: −x , y, −z + 1/2; #2: x − 1/2, y + 1/2, z; #3: - x + 1/2, y + 1/2, −z + 1/2; #4: −x + 1, y, −z + 1/2; #5: x, −y + 1, z − 1/2; #6: x, −y + 1, z + 1/2; #7: −x, −y + 1, −z + 1; #8: x + 1/2, y − 1/2, z; #9: −x + 1/2, y − 1/2, −z + 1/2); (b) View of the [Cd6 (COO)10 (μ3-OH)2] SBUs; (c) Coordination mode of bpbc5− ligand; (d) Each [Cd6 (COO)10(μ3-OH)2] SBU coordinated with ten bpbc5− ligands; (e) View of the 3D framework based on [Cd6(COO)10(μ3-OH)2] SBUs; (f) Schematic representation of the (5, 10)-connected network of 1 (Color codes: turquoise for 10connected [Cd6 (COO)10(μ3-OH)2] SBU, blue for 5-connected bpbc5− ligands). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 2. (a) Coordination environments of Zn (II) in 2 (symmetry codes: # 1: 1 - x, 2 - y, 1 - z; #2: 1 + x, + y, + z; #3: 1 - x, 2 - y, − z; #4: 1 - x, 1 - y, 1 - z; #5: - 1 + x, + y, + z; #6: 1 - x, 1 - y, − z); (b) View of the 3D structure constructed by the Zn centers and bpbc5− ligands; (c) Schematic representation of the (3, 3, 6)-connected network of complex 2 (Color codes: turquoise for 3-connected Zn2+ ions, blue for 6-connected bpbc5− ligands). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
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Acknowledgements This work was financially supported by the Startup Foundation for Doctors of Qufu Normal University and Natural Science Foundation of Shaanxi Province (2018JQ2079, 2018JQ2040). Appendix A. Supplementary material Crystallographic data for the structural analysis have been deposited to the Cambridge Crystallographic Data Centre, CCDC No. 1910551–1910552 for complexes 1–2. The data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www. ccdc.cam.ac.uk/data request/cif. Supplementary data to this article can be found online at doi:https://doi.org/10.1016/j.inoche.2019.06.003. References [1] (a) K. Manna, P. F. Ji, Z. K. Lin, F. X. Greene, A. Urban, N. C. Thacker, W. B. Lin, Chemo-selective single-site earth-abundant metal catalysts at metal-organic framework nodes, Nat. Commun. 7 (2016) 12610−12620; (b) M. Li, D. Li, M. O'Keeffe, O. M. 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Shi, Solvent-dependent synthesis of porous anionic uranyl-organic frameworks featuring a highly symmetrical (3,4)-connected ctn or bor topology for selective dye adsorption, Chem. Eur. J. 23 (2017) 529–532. [6] X. He, X.P. Lu, Z.F. Ju, C.J. Zhang, Q.K. Zhang, M.X. Li, Syntheses, structures, and photoluminescent properties of ten metal-organic frameworks constructed by a flexible tetracarboxylate ligand, CrystEngComm 15 (2013) 2731–2744. [7] Y.B. Go, X. Wang, E.V. Anokhina, A.J. Jacobson, Influence of the reaction temperature and pH on the coordination modes of the 1, 4-benzenedicarboxylate (BDC) ligand: a case study of the NiII (BDC)/2, 2′-bipyridine system, Inorg. Chem. 44 (2005) 8265–8271. [8] F.H. Zhao, S. Jing, Y.X. Che, J.M. Zheng, Metal-ligand ratio-controlled assembly of two pairs of Co(II) complexes: syntheses, structures and magnetic properties, CrystEngComm 14 (2012) 4478–4485. [9] D.H. Chen, L. Lin, T.L. Sheng, Y.H. Wen, X.Q. Zhu, L.T. Zhang, S.M. Hua, R.B. Fu, X.T. Wu, Syntheses, structures, luminescence and magnetic properties of seven isomorphous metal-organic frameworks based on 2,7-bis(4-benzoic acid)-N-(4benzoic acid) carbazole, New J. Chem. 42 (2018) 2830–2837. [10] (a) Z. H. Zhou, M. L. Han, Y. P. Wu, W. W. Dong, D. S. Li, J. Y. Lu, N-donor coligands driven two new Co(II)-coordination polymers with bi- and trinuclear units: Crystal structures, and magnetic properties, J. Solid. State. Chem. 242 (2016) 207–211; (b) M. L. Han, L. Bai, P. Tang, X. Q. Wu, Y. P. Wu, J. Zhao, D. S. Li, Y. Y. Wang, Biphenyl-2,4,6,3’,5’-pentacarboxylic acid as a tecton for six new Co(II) coordination polymers: pH and N-donor ligand-dependent assemblies, structure diversities and magnetic properties, Dalton Trans. 44 (2015) 14673−14685. [11] The single-crystal data of 1 and 2 were collected on a Xcalibur Eos Gemini fourcircle diffractometer with Mo Kα radiation (λ = 0.71073 Å) at 200K and 293K, respectively. Using Olex2, the structures were solved with the ShelXS program by direct methods, and refined with the ShelXL refinement package with full-matrix least-squares minimization. All the metal atoms were first located. Then carbon, nitrogen and hydrogen atoms of the organic framework were subsequently found. All of the non-hydrogen atoms were located from the initial solution and refined anisotropically. The crystallographic data for 1 and 2 are summarized in Table S1, and the selected bond lengths and angles are listed in Table S2. [12] Synthesis of [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1): Cd(NO3)3·4H2O (15.4 mg, 0.05 mmol), H5bpbc (7.3 mg, 0.02 mmol) were dissolved in 10 mL H2O, then NaOH (100
Fig. 3. Solid-state photoluminescent spectra of compound 1, 2 and H5bpbc at room temperature (λex = 300 nm).
an Agilent Cary Eclipse fluorescence spectrophotometer upon excitation at 300 nm at room temperature (slits: 5 nm/10 nm). As shown in Fig. 3, no fluorescence emission was observed for the free H5bpbc ligand, which might be due to the thermal intra-ligand rotations between the two benzene rings resulting in the non-radiative decay of the ligands [16]. The thermal intra-ligand rotations have been forbidden due to the rigid conformation formed in the coordination processes. The dihedral angles between the two benzene rings in complex 1 and 2 are 70.35° and 51.64°, respectively. Consequently, shoulder emissions at 362 nm were observed in complex 1 and 2, which may be ascribed to the intra-ligand π* → π or π* → n transitions. As known, the photoluminescence behavior of MOFs is closely associated with the metal ions and the ligands [17]. The fluorescence emission spectra of MOFs could be tuned by changing the kind of metal center or organic ligands as well as the conformations of the ligand [18]. As shown in Fig. 3, complex 1 displayed a broad emission band centered at 404 nm, while complex 2 shown a broad emission band range from 375 nm to 430 nm. The remarkable fluorescence emissions of complex 1 and 2 might attributed to the ligand-to-metal charge transfer (LMCT) [19]. The different fluorescence emissions of complex 1 and 2 is probably caused by the differences coordination environment around Cd2+/Zn2+ ions. In addition, the stronger fluorescence emission of complex 1 presumably due to the presence of high-nucleus metal clusters [Cd6 (COO)10 (μ3-OH)2], which would tighten the whole skeleton and resulting in much weaker vibrations as well as less non-radiative decay [16]. 3. Conclusions In conclusion, two novel 3D MOFs [Cd3(bpbc)(μ3-OH)(H2O)3]·H2O (1) and Zn2Na (bpbc)(DMF)1.5 (EtOH)0.5 (H2O)5]·0.5H2O (2) have been synthesized by using H5bpbc as the organic ligand under solvothermal/ hydrothermal conditions. Complexes 1 and 2 have been fully characterized with elemental analysis, single-crystal X-ray diffraction, powder X-ray diffraction, IR spectra and thermogravimetric analysis. Structural analysis revealed that complex 1 shows a (5, 10)-connected 3D network based on the [Cd6 (COO)10(μ3-OH)2] SBUs with unusual topology, while complex 2 displays a (3, 3, 6)-connected 3D framework. The structural difference between 1 and 2 revealed that the coordination fashion of bpbc5− and the kind of metal ions have great influence on the structure and topologies of products. Furthermore, the solid-state photoluminescence properties of complexes 1 and 2 were investigated and discussed.
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[13] [14]
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μL, 0.1 M) was added. The mixture was sealed in a Teflon-lined stainless steel vessel (25 mL) and heated at 160°C for 5 days. Then, the reaction mixture was cooled to room temperature over 24 h and colorless prism crystals 1 were obtained. Yield: 58% (based on Cd(II)). Anal. Calcd. for C17H14O15Cd3 (%): C, 25.67; H, 1.77; O, 30. 17. Found (%): C, 25.21; H, 2.19; O, 30.54. IR (KBr, cm−1): 3501(s), 3238(s), 1610 (s), 1574 (s), 1543 (vs), 1442 (s), 1414 (s), 1377 (vs), 1353 (s), 1118 (w), 937 (m), 905 (w), 854 (w), 803 (w), 791(m), 768 (m), 738 (w), 720 (w), 545 (w), 436 (w). A.L. Spek, Single-crystal structure validation with the program PLATON, J. Appl. Crystallogr. 36 (2003) 7–13. Synthesis of [Zn2Na(bpbc)(DMF)1.5(EtOH)0.5(H2O)5]·0.5H2O (2): Zn(NO3)3·6H2O (14.9 g, 0.05 mmol), H5bpbc (7.3 mg, 0.02 mmol), NaNO3(0.0025 g, 0.03 mmol) and HNO3 (6 M, 1d) were added to a 20 mL glass scintillation vial. A 3:1:3 (v/v/v) mixture of DMF (3 mL), EtOH (1 mL) and H2O (3 mL) was added to the mixture. The content was heated at 90°C for 48 h. Colorless lamellar crystal was obtained and washed with DMF, then dried in air (45% yield based on Zn). Anal. Calcd. for C22. 5H29.5N1.5O17.5NaZn2 (%): C, 35.80; H, 3.94; N, 2.78. Found (%): C, 35.52; H, 4.21; N, 2.42. IR (KBr, cm−1): 3436 (s), 1659 (vs), 1608(vs), 1573 (s), 1433 (s), 1374 (vs), 1120 (w), 1062 (w), 1017 (w), 960 (w), 927 (w), 870 (w),778 (m), 726 (m), 690 (w), 567 (w) , 479 (w). J. Sahu, M. Ahmad, P.K. Bharadwaj, Structural diversity and luminescence properties of coordination polymers built with a rigid linear dicarboxylate and Zn(II)/Pb (II) ion, Cryst. Growth Des. 13 (2013) 2618–2627. (a) S. F. Gan, W. W. Luo, B. R. He, L. Chen, H. Nie, R. R. Hu, A. J. Qin, Z. J. Zhao, B.
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