- Email: [email protected]
Two novel 3D MOFs based on the flexible (E)-1,4-di(1H-imidazol-1-yl)but-2-ene and multi-carboxylate ligands: Synthesis, structural diversity and luminescence property
Journal Pre-proofs Two novel 3D MOFs based on the flexible (E)-1,4-di(1H-imidazol-1yl)but-2-ene and multi-carboxylateligands: Synthesis, structural diversity and luminescence property Ping Ju, En-sheng Zhang, Xicheng Liu, Long Jiang PII: DOI: Reference:
S1387-7003(19)30980-3 https://doi.org/10.1016/j.inoche.2019.107641 INOCHE 107641
To appear in:
Inorganic Chemistry Communications
Received Date: Revised Date: Accepted Date:
27 September 2019 26 October 2019 27 October 2019
Please cite this article as: P. Ju, E-s. Zhang, X. Liu, L. Jiang, Two novel 3D MOFs based on the flexible (E)-1,4di(1H-imidazol-1-yl)but-2-ene and multi-carboxylateligands: Synthesis, structural diversity and luminescence property, Inorganic Chemistry Communications (2019), doi: https://doi.org/10.1016/j.inoche.2019.107641
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
Two novel 3D MOFs based on the flexible (E)-1,4-di(1H-imidazol-1-yl)but-2-ene and multi-carboxylate ligands: Synthesis, structural diversity and luminescence property Ping Ju a, En-sheng Zhang a, c,*, Xicheng Liu a, Long Jiang b,* a
College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R.
China. b
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and
Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China. c
Laboratory of New Energy＆New Function Materials, College of Chemistry and Chemical
Engineering, Yan’an University, Yan’an, Shaanxi ,716000, P. R. China.
Email：[email protected]; [email protected]
Abstract: Two
novel
metal-organic
benzene-1,2,4,5-tetracarboxylic
frameworks
acid,
dib
=
[Zn(btec)0.5(dib)]·H2O
(1)
(H4btec
(E)-1,4-di(1H-imidazol-1-yl)but-2-ene)
= and
[Cd(btc)(dib)]·(C2H6N) (2) (H3btc = benzene-1,3,5-tricarboxylic acid) have been synthesized under solvothermal conditions. Complexes 1 and 2 were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and thermogravimetric analysis (TGA). Crystal structure analysis reveals that complex 1 is a complicated three-dimensional (3D) non-interpenetrated porous framework, while complex 2 displays a 2-fold interpenetration 3D framework. The solid state photoluminescent properties of complexes 1-2 were recorded and discussed. Keywords: Metal-organic frameworks, (E)-1,4-di(1H-imidazol-1-yl)but-2-ene, Structural diversity,
Luminescent property 1. Introduction Three-dimensional (3D) metal-organic frameworks (MOFs) as a new kind of porous material have attracted considerable interests due to their intriguing properties such as high porosity, large surface area, regular porous channel and diverse topological structure [1]. In virtue of their unique characteristics, functional MOFs have been implemented in many fields such as gas storage [2], molecular recognition [3], heterogeneous catalysis [4], nonlinear optics [5] and luminescent sensing [6], et al. It is noteworthy that luminescent metal-organic frameworks (LMOFs) have been proved to be efficient sensing materials in the detection of toxic metal ions [7] and harmful organic pollutants [8] with high selectivity/sensitivity and excellent reusability. Thus, the design and synthesis of LMOFs has drawn increasing research interests. crystal enginee
[10]
[Zn(btec)0.5(dib)]·H2O (1) and [Cd(btc)(dib)]·(C2H6N) (2) Structural analysis revealed that complex 1 is a complicated three-dimensional (3D) non-interpenetrated porous framework,
while complex 2 displays a 2-fold interpenetration 3D framework. In addition, the thermal stability and luminescent properties of 1 and 2 were also discussed.
2. Result and discussion [Zn(btec)0.5(dib)]·H2O (1) was synthesized under solvothermal conditions [11]. Single-crystal X-ray diffraction analysis reveals that complex 1 is a 3D network and crystallizes in the space group P21/c [12]. The asymmetric unit of 1 contains one Zn(II) ion, half of a btec4- ligand, one dib ligand and one water molecule. In complex 1, Zn(II) ion is four-coordinated in a distorted tetrahedral coordination geometry (Fig. 1a). Every Zn(II) ion is coordinated by two nitrogen atoms from two dib ligands (Zn1-N1 = 1.999(5)Å and Zn1-N3 = 2.012(4)Å), and two monodentate oxygen atom from two different btec4- ligands (Zn1-O1 = 1.978(4)Å and Zn1-O3 = 1.983(3)Å) (Table 2S). The deprotonated btec4- ligand serves as a µ4 bridging ligand, linking four Zn(II) ions to form a 2D layer network with (4, 4) topology (Fig. 1b). Meanwhile, the 2D layers are connected by dib forming a 3D framework (Fig. 1c). The dib ligands coordinated with metal ions adopt “V” shaped conformation. Each dib ligand coordinates with two Zn(II) ions using its two aromatic N atoms and acts as a bridging bidentate ligand. A better insight into the nature of this intricate framework can be acquired by using topological analysis. In complex 1, Zn ions can be considered as tetrahedral nodes, and btec4- ligands can be regarded as four-connected planar nodes; both the bridges of btec4- and dib can be simplified to be connectors (Fig. 1d). Thus, the framework of 1 can be represented as a (4, 4)-connected 3D network (Fig. 1e).
Fig. 1 (a) Coordination environment of Zn(II) ion in 1 (Hydrogen atoms are omitted for clarity. Symmetry codes 1: #1 + x, 1/2 - y, -1/2 + z; #2 - x, - y, 1 - z; #3 + x, 1/2 - y, 1/2 + z; #4 1 - x, -1/2 + y, 3/2 - z; #5 1 - x, 1/2 + y, 3/2 -z); (b) View of the 2D layer structure constructed from btec4− and Zn2+; (c) The 3D structure of 1; (d) The turquoise spheres represent Zn nodes, blue lines represent btec4− nodes and red lines stand for dib; (e) Topological view showing the 3D framework of 1 along bc plane. [Cd(btc)(dib)]·(C2H6N) (2) was obtained under solvothermal conditions [13]. Single-crystal X-ray diffraction analysis [12] reveals that complex 2 displays a 3D network and crystallizes in P21/c space group. The asymmetric unit of complex 2 consists of one Cd2+ ion, one btc3-, one dib
ligand and a dimethylammonium ion. The anionic framework is balanced by dimethylammonium counterions which are formed in situ in the reaction. The Cd(II) ion adopts an octahedral coordination geometry. Each Cd(II) ion coordinated by four oxygen atoms from three different btc3- ligands (Cd1-O = 2.242(7)-2.380(6)Å) and two nitrogen atoms from two dib ligands (Cd1-N1 = 2.261(15)Å and Cd1-N4 = 2.303(15)Å) (Fig. 2a and Table 2S). In complex 2, dib ligands display “S” shaped conformation. Two carboxylate groups in btc3- exhibit monodentate connectivity with Cd2+ and another carboxylate group shows a bidentate-chelating mode. Cd(II) ions coordinated with btc3- ligands to form a 2D layer network extending along the ab plane (Fig. 2b). Each dib ligand connects the adjacent 2D layers to afford a 3D framework. A 2-fold interpenetration 3D structure was formed in complex 2 due to the large pore of this framework (Fig. 2c). In complex 2, Cd(II) and btc3- anions can be regarded as 5-connected and 3-connected nodes, while dib acting as linkers (Fig. 2d). Thus, complex 2 holds a 2-fold interpenetration 3D structure as shown in Fig. 2e.
Fig. 2 (a) The asymmetry unit of 2 (all hydrogen atoms are omitted for clarity, symmetry code for 2: #1 - x, -1/2 + y, 3/2 - z; #2 -1 + x, + y, + z; #3 1 + x, + y, + z; #4 - x, 1/2 + y, 3/2 - z; #5 + x, + y, 1 + z; #6 + x, + y, -1 + z); (b) View of the 3D structure constructed by btc3−, dib and Zn2+; (c) Stacking of the two-fold interpenetrated framework of 2 along the ac plane; (d) The turquoise spheres represent Cd nodes, the combination of bright green spheres and red lines represent btc3− nodes, the red lines stand for dib; (e) Topology representation of the 2-fold interpenetrated 3D framework. From the structural descriptions above, it can be seen that the conformation of dib ligands and the kind of auxiliary ligands have great influence on the final crystal structures. Dib ligands can bend freely to form different conformations due to its flexibility and “V” shaped conformation in complex 1 was observed, while “S” shaped structure was formed in complex 2. In complex 1, benzene-1,2,4,5-tetracarboxylic acid (H4btec) was used as the auxiliary ligand and an unprecedented (4, 4)-connected 3D structure was finally obtained. However, when tricarboxylate ligand benzene-1,3,5-tricarboxylic acid (H3btc) was used as the auxiliary ligand, a novel 2-fold interpenetrated 3D structure was formed (complex 2). Furthermore, the kind of metal ion is another influence factor for the final crystal structures. Cd(II) ions in 2 have a higher coordination number than Zn(II) ions in 1 owing to its larger radius. In complex 1, each Zn(II) ion is tetra-coordinated by two distinct dib ligands and two different btec4- ligands, forming a (4,4)-connected 3D structure. However, in complex 2, each Cd(II) ion
shows octahedral coordination geometry and coordinated by three different btc3- ligands and two distinct dib ligands, leading to a 3D 2-fold interpenetrated structure. The purity of the bulky crystalline sample of complexes 1 and 2 were confirmed by PXRD at room temperature. As shown in Fig. 3, the PXRD pattern of the complexes 1 and 2 matched well with the simulated one based on the single-crystal diffraction data, which confirmed the good purity of complexes 1 and 2.
Fig. 3 The PXRD patterns of complexes 1 and 2. The stability of 1 and 2 were evaluated by the thermogravimetric analysis. As depicted in Fig. 4, the TGA curve of complex 1 shows a weight loss of 4.1% in the temperature range of 30-220°C, which corresponding to the loss of the lattice water molecules in channels (calcd. 4.5 %). The discrepancy between the found and theoretical values could be attributed to the loss of the lattice water at room temperature. The desolvated framework is stable up to 305°C and obvious weight loss could be observed after that temperature. Complex 2 can be stable up to 300°C, after that the framework structure begin to collapse.
100 Complex 1 Complex 2
90
Weight (%)
80 70 60 50 40 30 20 10 100
200
300
400
500 O
600
700
800
Temperature ( C ) Fig. 4 TG curves of complex 1 and 2. The solid-state fluorescence spectra of complexes 1-2 and the free ligands were recorded on an Agilent Cary Eclipse fluorescence spectrophotometer at room temperature (slits: 5 nm/10 nm). As shown in Fig. 5, the emission peaks of H4btec, H3btc and dib are at 330 nm (ex = 300 nm), 332 nm (ex = 290 nm) and 385 nm (ex = 300 nm), respectively. Complexes 1 and 2 exhibit strong emission bands centered at 435 nm (ex = 320 nm) and 422 nm (ex = 320 nm), respectively. The emission peak of 1 and 2 could attribute to the intra-ligand fluorescent emission of dib [16]. However, the fluorescent intensities of complexes 1-2 are stronger than that of the free dib ligand. As shown in Fig. 1 and Fig. 2, rigid conformations of dib ligands were formed which could forbid the thermal intra-ligand rotations and reduce the non-radiative decay of dib [17]. Complexes 1-2 have 50 nm and 37 nm red shifts compare with the free dib ligand, respectively. Due to the d10 configuration, Zn(II)/Cd(II) ions are difficult to oxidation and reduction [18]. The emissions are neither metal-to-ligand charge transfer (MLCT) nor ligand-to-metal charge transfer (LMCT). Thus, the fluorescent emissions of 1 and 2 can be attributed to the intra-ligand charge transitions (n→π* or π→π*) [19].
FL. Intensity (a.u.)
450 H4btec
400
H3btc
350
Complex 1 Complex 2 dib
300 250 200 150 100 50 0 320
360
400
440
480
520
560
Wavelength (nm) Fig. 5 Solid-state photoluminescent spectra of complexes 1-2, H4btec, H3btc and dib at room temperature.
3. Conclusion In
summary,
two
novel
coordination
polymers
[Zn(btec)0.5(dib)]·H2O
(1)
and
[Cd(btc)(dib)]·(C2H6N) (2) have been successfully synthesized by using the
Zn(II)/Cd(II) ions under solvothermal conditions. Crystal structure analysis reveals that complex 1 is an unprecedented (4, 4)-connected 3D network, while complex 2 exhibits a 2-fold interpenetration 3D structure. The structural differences revealed that the conformation of dib and the kind of the carboxylate ligands/metal ions have great influence on the final structure of the MOFs. In addition, the luminescent properties of complexes 1 and 2 have been recorded and discussed.
Acknowledgements This work was financially supported by the Startup Foundation for Doctors of Qufu Normal University, Natural Science Foundation and Innovative Talents Promotion Plan of Shaanxi Province (2019KJXX-075, 2018JQ2079, 2018JQ2040). Appendix A. Supplementary material Crystallographic data for the structural analysis have been deposited to the Cambridge Crystallographic Data Centre, CCDC No. 1952508-1952509 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.
References [1]
(a) 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; (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.
[2]
(a) O. K. Farha, A. Ö. Yazaydın, I. Eryazici, C. D. Malliakas, B. G. Hauser, M. G. Kanatzidis, S. T. Nguyen, R. Q. Snurr, J. T. Hupp, De novo synthesis of a metal-organic framework material featuring ultrahigh surface area and gas storage capacities, Nat. Chem., 2(2010) 944-948; (b) 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; (c) Y. Xiong, Y. Z. Fan, R. Yang, S. Chen, M. Pan, J. J. Jiang, C. Y. Su, Amide and N-oxide functionalization of T-shaped ligands for isoreticular MOFs with giant enhancements in CO2 separation, Chem. Commun., 50(2014) 14631-14634.
[3]
(a) B. L. Chen, S. C. Xiang, G. D. Qian, Metal-organic frameworks with functional pores for recognition of small molecules, Acc. Chem. Res. 43(2010) 1115-1124; (b) H. W. Li, X. Feng, Y. X. Guo, D. D. Chen, R. Li, X. Q. Ren, X. Jiang, Y. P. Dong, B. Wang, A malonitrile-functionalized metal-organic framework for hydrogen sulfide detection and selective amino acid molecular recognition, Scientific Reports, 4(2014), 4366; (c) L. Chen, J. W. Ye, H. P. Wang, M. Pan, S. Y. Yin, Z. W. Wei, L. Y. Zhang, K. Wu, Y. N. Fan, C. Y. Su, Ultrafast water sensing and thermal imaging by a metal-organic framework with switchable luminescence, Nat. Commun. 8(2017), 15985.
[4]
(a) J. W. Liu, L. F. Chen, H. Cui, J. Y. Zhang, L. Zhang, C. Y. Su, Applications of metal-organic frameworks in heterogeneous supramolecular catalysis, Chem. Soc. Rev. 43(2014) 6011-6061; (b) J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen, J. T. Hupp, Metal-organic framework materials as catalysts, Chem. Soc. Rev. 38(2009) 1450-1459; (c) B. Gole, U. Sanyal, R. Banerjee, P. S. Mukherjee, High loading of Pd nanoparticles by interior functionalization of MOFs for heterogeneous catalysis, Inorg. Chem. 55(2016) 2345-2354.
[5] (a) W. Cheng, T. Zhang, W. B. Lin, Rational synthesis of noncentrosymmetric metal-organic frameworks for second-order nonlinear optics, Chem. Rev. 112 (2011) 1084-1104; (b) H. Reinsch, M. A. van der Veen, B. Gil,
B. Marszalek, T. Verbiest, D. De Vos, N. Stock, Structures, sorption characteristics, and nonlinear optical properties of a new series of highly stable aluminum MOFs, Chem. Mater. 25(2013) 17-26. [6] (a) Y. J. Cui, B. L. Chen, G. D. Qian, Lanthanide metal-organic frameworks for luminescent sensing and light-emitting applications, Coordin. Chem. Rev. 273 (2014) 76-86; (b) Z. C. Hu, B. J. Deibert, J. Li, Luminescent metal-organic frameworks for chemical sensing and explosive detection, Chem. Soc. Rev. 43(2014) 5815-5840. [7] (a) I. M. El-Sewify, M. A.Shenashen, A. Shahat, H. Yamaguchi, M. M. Selim, M. M. Khalil, S. A. El-Safty, Dual colorimetric and fluorometric monitoring of Bi3+ ions in water using supermicroporous Zr-MOFs chemosensors, J Lumin. 198 (2018) 438-448; (b) Z. Z. Xiao, L. J. Han, Z. J. Wang, H. G. Zheng, Three Zn (II)-based MOFs for luminescence sensing of Fe3+ and Cr2O72− ions, Dalton Trans. 47(2018) 3298-3302; (c) E. S. Zhang, P. Ju, Z. Zhang, H. Yang, L. Tang, X. Y. Hou, J. M. You, J. J. Wang, A novel multi-purpose Zn-MOF fluorescent sensor for 2,4-dinitrophenylhydrazine, picric acid, La3+ and Ca2+: Synthesis, structure, selectivity, sensitivity and recyclability, Spectrochim. Acta A. 222(2019) 117207. [8]
(a) Y. H. Pi, X. Y. Li, Q. B. Xia, J. L. Wu, Y. W. Li, J. Xiao, Z. Li, Adsorptive and photocatalytic removal of persistent organic pollutants (POPs) in water by metal-organic frameworks (MOFs), Chem. Eng. J., 337(2018) 351-371; (b) D. Jiang, P. Xu, H. Wang, G. Zeng, D. Huang, M. Chen, C. Lai, C. Zhang, J. Wan, W. J. Xue, Strategies to improve metal organic frameworks photocatalyst’s performance for degradation of organic pollutants. Coordin. Chem. Rev. 376(2018) 449-466; (c) W. Ren, J. Gao, C. Lei, Y. Xie, Y. Cai, Q. Ni, J. Yao, Recyclable metal-organic framework/cellulose aerogels for activating peroxymonosulfate to degrade organic pollutants, Chem. Eng. J. 349(2018) 766-774; (d) E. M. Dias, C. Petit, Towards the use of metal-organic frameworks for water reuse: a review of the recent advances in the field of organic pollutants removal and degradation and the next steps in the field, J. Mater. Chem. A. 3(2015) 22484-22506.
[9]
(a) Z. F. Tian, J. G. Lin, Y. Su, L. L. Wen, Y. M. Liu, H. Z. Zhu, Q. J. Meng, Flexible ligand, structural, and opological diversity: isomerism in Zn(NO3)2 coordination polymers, Cryst. Growth Des. 7(2007) 1863-1867; (b) Z. J. Lin, J. Lü, M. Hong, R. Cao, Metal-organic frameworks based on flexible ligands (FL-MOFs): structures and applications, Chem. Soc. Rev. 43(2014) 5867-5895.
[10] B. J. Zhang, C. J. Wang, G. M. Qiu, S. Huang, X. L. Zhou, J. Weng, Y. Y. Wang, Polycarboxylate anions effect on the structures of a series of transition metal-based coordination polymers: Syntheses, crystal structures and bioactivities, Inorg. Chim. Acta, 397 (2013) 48-59. [11] Synthesis of [Zn(btec)0.5(dib)]·H2O (1): Zn(NO3)2·6H2O (0.015 g, 0.05 mmol), H4btec (0.0076 g, 0.3 mmol), dib (0.0038 g, 0.02 mmol) and HNO3 (6M, 2d) were added to a 20 mL glass scintillation vial. A 1:1 (v/v)
mixture of DMF (3 mL) and H2O (3 mL) were added to the mixture. The content was heated at 90°C for 48 h. The colorless prism crystals were obtained and washed with DMF, then dried in air (65% yield based on Zn). Anal. Calcd. for C15H15N4O5Zn (%): C, 45.42; H, 3.81; N, 14.12. Found (%): C, 45.07; H, 4.18; N, 13.86; IR (KBr, cm−1): 3439 (w), 3137 (w), 1611 (vs), 1532 (w), 1491 (w), 1413 (m), 1365 (vs), 1321 (s), 1282 (w), 1228 (w), 1112 (m), 1086 (w), 990 (w), 952 (m), 930 (w), 864 (m), 814 (m),767(w), 745 (w), 677 (w), 655 (m), 620 (w), 556 (m), 476 (w). [12] The single-crystal data of 1 and 2 were collected on Bruker D8 Venture system, with Mo Kα radiation (λ = 0.71073 Å) at 273K using Olex2 [14] the structure was solved with the ShelXS structure solution program by direct methods and refined with the ShelXL refinement package with Least-squares minimization [15]. All the Zn(II)/Cd(II) 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. Crystallographic data and structure refinements for complexes 1 and 2 were displayed in Table 1S. The selected bond lengths and bond angles were summarized in Table 2S. [13] Synthesis of [Cd(btc)(dib)]·(C2H6N) (2): Cd(NO3)2·6H2O (0.017 g, 0.05 mmol), H3btc (0.0063g, 0.3 mmol), dib (0.0038 g, 0.02 mmol) and HBF4 (45%, 2d) were added to a 20 mL glass scintillation vial. A 3:1:1 (v/v) mixture of DMF (3 mL), EtOH (1 mL) and H2O (1 mL) were added to the mixture. The content was heated at 90°C for 48 h. The colorless prism crystals were obtained and washed with DMF, then dried in air (81% yield based on Cd). Anal. Calcd. for C21H21N5O6 Cd (%): C, 45.71; H, 3.84; N, 12.69. Found (%): C, 45.96; H, 4.04; N, 12.89. IR (KBr, cm−1): 3433 (s), 3122 (w), 1673 (vs), 1618 (s), 1557 (s), 1521(w), 1435 (s), 1386 (vs), 1257 (w), 1230 (w), 1197 (w), 1095 (m), 979 (w), 940 (w), 828 (w), 760 (m), 726 (m), 685 (w), 670 (w), 657 (m), 625 (w). [14] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard, H. Puschmann, OLEX2: a complete structure solution, refinement and analysis program, J. Appl. Crystallogr. 42(2009) 339-341. [15] G. M. Sheldrick, A short history of SHELX, Acta Cryst. 2008, A64 112-122. [16] D. Liu, Y. Ge, N. Y. Li, W. Ma, X. Y. Tang, Coordination assemblies of Zn(NO3)2 with 4-pyrpoly-2-ene and polycarboxylates: structural diversification and photoluminescence properties, RSC Adv. 5(2015) 45467-45478 . [17] 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.
[18] S. Q. Guo, D. Tian, X. Zheng, H. Zhang, A (3, 4, 10)-connected 3D sandwich-type metal-organic framework with trinuclear zinc(II) cluster and two kinds of discrete zinc(II) ions, Inorg. Chem. Commun. 14 (2011) 1876-1879. [19] (a) S. Zhao, X. X. Lv, L. L. Shi, B. L. Li, Bi. Wu, An unusual (4, 4)-connected 3D porous cadmium metal-organic framework as a luminescent sensor for detection of nitrobenzene, RSC Adv. 6(2016) 56035-56041; (b) K. Li, V. A. Blatov, T. Fan, T. R. Zheng, Y. Q. Zhang, B. L. Li, B. Wu, A series of Cd(II) coordination polymers based on flexible bis(triazole) and multicarboxylate ligands: topological diversity, entanglement and properties, CrystEngComm 19 (2017) 5797-5808.
Revised Fig. 1 to Fig. 3
Fig. 1 (a) Coordination environment of Zn(II) ion in 1 (Hydrogen atoms are omitted for clarity. Symmetry codes 1: #1 + x, 1/2 - y, -1/2 + z; #2 - x, - y, 1 - z; #3 + x, 1/2 - y, 1/2 + z; #4 1 - x, -1/2 + y, 3/2 - z; #5 1 - x, 1/2 + y, 3/2 -z); (b) View of the 2D layer structure constructed from btec4− and Zn2+; (c) The 3D structure of 1; (d) The turquoise spheres represent Zn nodes, blue lines represent btec4− nodes and red lines stand for dib; (e) Topological view showing the 3D framework of 1 along bc plane.
Fig. 2 (a) The asymmetry unit of 2 (all hydrogen atoms are omitted for clarity, symmetry code for 2: #1 - x, -1/2 + y, 3/2 - z; #2 -1 + x, + y, + z; #3 1 + x, + y, + z; #4 - x, 1/2 + y, 3/2 - z; #5 + x, + y, 1 + z; #6 + x, + y, -1 + z); (b) View of the 3D structure constructed by btc3−, dib and Zn2+; (c) Stacking of the two-fold interpenetrated framework of 2 along the ac plane; (d) The turquoise spheres represent Cd nodes, the combination of bright green spheres and red lines represent btc3− nodes, the red lines stand for dib; (e) Topology representation of the 2-fold interpenetrated 3D framework.
Fig. 3 The PXRD pattern of complexes 1 and 2.
Graphical Abstract Two novel 3D fluorescent metal-organic frameworks [Zn(btec)0.5(dib)]·H2O (1) and [Cd(btc)(dib)]·(C2H6N) (2) with interesting topological and structural diversities have been successfully constructed under solvothermal conditions.
Highlights (1) Two novel 3D coordination polymers were prepared by using flexible dib as the organic ligand. (2) Interesting topological and structural diversities were observed for complexes 1 and 2. (3) The fluorescence properties of complexes 1 and 2 were recorded and discussed.
There are no conflict of interest to declare.
S1387-7003(19)30980-3 https://doi.org/10.1016/j.inoche.2019.107641 INOCHE 107641
To appear in:
Inorganic Chemistry Communications
Received Date: Revised Date: Accepted Date:
27 September 2019 26 October 2019 27 October 2019
Please cite this article as: P. Ju, E-s. Zhang, X. Liu, L. Jiang, Two novel 3D MOFs based on the flexible (E)-1,4di(1H-imidazol-1-yl)but-2-ene and multi-carboxylateligands: Synthesis, structural diversity and luminescence property, Inorganic Chemistry Communications (2019), doi: https://doi.org/10.1016/j.inoche.2019.107641
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
Two novel 3D MOFs based on the flexible (E)-1,4-di(1H-imidazol-1-yl)but-2-ene and multi-carboxylate ligands: Synthesis, structural diversity and luminescence property Ping Ju a, En-sheng Zhang a, c,*, Xicheng Liu a, Long Jiang b,* a
College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R.
China. b
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and
Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China. c
Laboratory of New Energy＆New Function Materials, College of Chemistry and Chemical
Engineering, Yan’an University, Yan’an, Shaanxi ,716000, P. R. China.
Email：[email protected]; [email protected]
Abstract: Two
novel
metal-organic
benzene-1,2,4,5-tetracarboxylic
frameworks
acid,
dib
=
[Zn(btec)0.5(dib)]·H2O
(1)
(H4btec
(E)-1,4-di(1H-imidazol-1-yl)but-2-ene)
= and
[Cd(btc)(dib)]·(C2H6N) (2) (H3btc = benzene-1,3,5-tricarboxylic acid) have been synthesized under solvothermal conditions. Complexes 1 and 2 were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and thermogravimetric analysis (TGA). Crystal structure analysis reveals that complex 1 is a complicated three-dimensional (3D) non-interpenetrated porous framework, while complex 2 displays a 2-fold interpenetration 3D framework. The solid state photoluminescent properties of complexes 1-2 were recorded and discussed. Keywords: Metal-organic frameworks, (E)-1,4-di(1H-imidazol-1-yl)but-2-ene, Structural diversity,
Luminescent property 1. Introduction Three-dimensional (3D) metal-organic frameworks (MOFs) as a new kind of porous material have attracted considerable interests due to their intriguing properties such as high porosity, large surface area, regular porous channel and diverse topological structure [1]. In virtue of their unique characteristics, functional MOFs have been implemented in many fields such as gas storage [2], molecular recognition [3], heterogeneous catalysis [4], nonlinear optics [5] and luminescent sensing [6], et al. It is noteworthy that luminescent metal-organic frameworks (LMOFs) have been proved to be efficient sensing materials in the detection of toxic metal ions [7] and harmful organic pollutants [8] with high selectivity/sensitivity and excellent reusability. Thus, the design and synthesis of LMOFs has drawn increasing research interests. crystal enginee
[10]
[Zn(btec)0.5(dib)]·H2O (1) and [Cd(btc)(dib)]·(C2H6N) (2) Structural analysis revealed that complex 1 is a complicated three-dimensional (3D) non-interpenetrated porous framework,
while complex 2 displays a 2-fold interpenetration 3D framework. In addition, the thermal stability and luminescent properties of 1 and 2 were also discussed.
2. Result and discussion [Zn(btec)0.5(dib)]·H2O (1) was synthesized under solvothermal conditions [11]. Single-crystal X-ray diffraction analysis reveals that complex 1 is a 3D network and crystallizes in the space group P21/c [12]. The asymmetric unit of 1 contains one Zn(II) ion, half of a btec4- ligand, one dib ligand and one water molecule. In complex 1, Zn(II) ion is four-coordinated in a distorted tetrahedral coordination geometry (Fig. 1a). Every Zn(II) ion is coordinated by two nitrogen atoms from two dib ligands (Zn1-N1 = 1.999(5)Å and Zn1-N3 = 2.012(4)Å), and two monodentate oxygen atom from two different btec4- ligands (Zn1-O1 = 1.978(4)Å and Zn1-O3 = 1.983(3)Å) (Table 2S). The deprotonated btec4- ligand serves as a µ4 bridging ligand, linking four Zn(II) ions to form a 2D layer network with (4, 4) topology (Fig. 1b). Meanwhile, the 2D layers are connected by dib forming a 3D framework (Fig. 1c). The dib ligands coordinated with metal ions adopt “V” shaped conformation. Each dib ligand coordinates with two Zn(II) ions using its two aromatic N atoms and acts as a bridging bidentate ligand. A better insight into the nature of this intricate framework can be acquired by using topological analysis. In complex 1, Zn ions can be considered as tetrahedral nodes, and btec4- ligands can be regarded as four-connected planar nodes; both the bridges of btec4- and dib can be simplified to be connectors (Fig. 1d). Thus, the framework of 1 can be represented as a (4, 4)-connected 3D network (Fig. 1e).
Fig. 1 (a) Coordination environment of Zn(II) ion in 1 (Hydrogen atoms are omitted for clarity. Symmetry codes 1: #1 + x, 1/2 - y, -1/2 + z; #2 - x, - y, 1 - z; #3 + x, 1/2 - y, 1/2 + z; #4 1 - x, -1/2 + y, 3/2 - z; #5 1 - x, 1/2 + y, 3/2 -z); (b) View of the 2D layer structure constructed from btec4− and Zn2+; (c) The 3D structure of 1; (d) The turquoise spheres represent Zn nodes, blue lines represent btec4− nodes and red lines stand for dib; (e) Topological view showing the 3D framework of 1 along bc plane. [Cd(btc)(dib)]·(C2H6N) (2) was obtained under solvothermal conditions [13]. Single-crystal X-ray diffraction analysis [12] reveals that complex 2 displays a 3D network and crystallizes in P21/c space group. The asymmetric unit of complex 2 consists of one Cd2+ ion, one btc3-, one dib
ligand and a dimethylammonium ion. The anionic framework is balanced by dimethylammonium counterions which are formed in situ in the reaction. The Cd(II) ion adopts an octahedral coordination geometry. Each Cd(II) ion coordinated by four oxygen atoms from three different btc3- ligands (Cd1-O = 2.242(7)-2.380(6)Å) and two nitrogen atoms from two dib ligands (Cd1-N1 = 2.261(15)Å and Cd1-N4 = 2.303(15)Å) (Fig. 2a and Table 2S). In complex 2, dib ligands display “S” shaped conformation. Two carboxylate groups in btc3- exhibit monodentate connectivity with Cd2+ and another carboxylate group shows a bidentate-chelating mode. Cd(II) ions coordinated with btc3- ligands to form a 2D layer network extending along the ab plane (Fig. 2b). Each dib ligand connects the adjacent 2D layers to afford a 3D framework. A 2-fold interpenetration 3D structure was formed in complex 2 due to the large pore of this framework (Fig. 2c). In complex 2, Cd(II) and btc3- anions can be regarded as 5-connected and 3-connected nodes, while dib acting as linkers (Fig. 2d). Thus, complex 2 holds a 2-fold interpenetration 3D structure as shown in Fig. 2e.
Fig. 2 (a) The asymmetry unit of 2 (all hydrogen atoms are omitted for clarity, symmetry code for 2: #1 - x, -1/2 + y, 3/2 - z; #2 -1 + x, + y, + z; #3 1 + x, + y, + z; #4 - x, 1/2 + y, 3/2 - z; #5 + x, + y, 1 + z; #6 + x, + y, -1 + z); (b) View of the 3D structure constructed by btc3−, dib and Zn2+; (c) Stacking of the two-fold interpenetrated framework of 2 along the ac plane; (d) The turquoise spheres represent Cd nodes, the combination of bright green spheres and red lines represent btc3− nodes, the red lines stand for dib; (e) Topology representation of the 2-fold interpenetrated 3D framework. From the structural descriptions above, it can be seen that the conformation of dib ligands and the kind of auxiliary ligands have great influence on the final crystal structures. Dib ligands can bend freely to form different conformations due to its flexibility and “V” shaped conformation in complex 1 was observed, while “S” shaped structure was formed in complex 2. In complex 1, benzene-1,2,4,5-tetracarboxylic acid (H4btec) was used as the auxiliary ligand and an unprecedented (4, 4)-connected 3D structure was finally obtained. However, when tricarboxylate ligand benzene-1,3,5-tricarboxylic acid (H3btc) was used as the auxiliary ligand, a novel 2-fold interpenetrated 3D structure was formed (complex 2). Furthermore, the kind of metal ion is another influence factor for the final crystal structures. Cd(II) ions in 2 have a higher coordination number than Zn(II) ions in 1 owing to its larger radius. In complex 1, each Zn(II) ion is tetra-coordinated by two distinct dib ligands and two different btec4- ligands, forming a (4,4)-connected 3D structure. However, in complex 2, each Cd(II) ion
shows octahedral coordination geometry and coordinated by three different btc3- ligands and two distinct dib ligands, leading to a 3D 2-fold interpenetrated structure. The purity of the bulky crystalline sample of complexes 1 and 2 were confirmed by PXRD at room temperature. As shown in Fig. 3, the PXRD pattern of the complexes 1 and 2 matched well with the simulated one based on the single-crystal diffraction data, which confirmed the good purity of complexes 1 and 2.
Fig. 3 The PXRD patterns of complexes 1 and 2. The stability of 1 and 2 were evaluated by the thermogravimetric analysis. As depicted in Fig. 4, the TGA curve of complex 1 shows a weight loss of 4.1% in the temperature range of 30-220°C, which corresponding to the loss of the lattice water molecules in channels (calcd. 4.5 %). The discrepancy between the found and theoretical values could be attributed to the loss of the lattice water at room temperature. The desolvated framework is stable up to 305°C and obvious weight loss could be observed after that temperature. Complex 2 can be stable up to 300°C, after that the framework structure begin to collapse.
100 Complex 1 Complex 2
90
Weight (%)
80 70 60 50 40 30 20 10 100
200
300
400
500 O
600
700
800
Temperature ( C ) Fig. 4 TG curves of complex 1 and 2. The solid-state fluorescence spectra of complexes 1-2 and the free ligands were recorded on an Agilent Cary Eclipse fluorescence spectrophotometer at room temperature (slits: 5 nm/10 nm). As shown in Fig. 5, the emission peaks of H4btec, H3btc and dib are at 330 nm (ex = 300 nm), 332 nm (ex = 290 nm) and 385 nm (ex = 300 nm), respectively. Complexes 1 and 2 exhibit strong emission bands centered at 435 nm (ex = 320 nm) and 422 nm (ex = 320 nm), respectively. The emission peak of 1 and 2 could attribute to the intra-ligand fluorescent emission of dib [16]. However, the fluorescent intensities of complexes 1-2 are stronger than that of the free dib ligand. As shown in Fig. 1 and Fig. 2, rigid conformations of dib ligands were formed which could forbid the thermal intra-ligand rotations and reduce the non-radiative decay of dib [17]. Complexes 1-2 have 50 nm and 37 nm red shifts compare with the free dib ligand, respectively. Due to the d10 configuration, Zn(II)/Cd(II) ions are difficult to oxidation and reduction [18]. The emissions are neither metal-to-ligand charge transfer (MLCT) nor ligand-to-metal charge transfer (LMCT). Thus, the fluorescent emissions of 1 and 2 can be attributed to the intra-ligand charge transitions (n→π* or π→π*) [19].
FL. Intensity (a.u.)
450 H4btec
400
H3btc
350
Complex 1 Complex 2 dib
300 250 200 150 100 50 0 320
360
400
440
480
520
560
Wavelength (nm) Fig. 5 Solid-state photoluminescent spectra of complexes 1-2, H4btec, H3btc and dib at room temperature.
3. Conclusion In
summary,
two
novel
coordination
polymers
[Zn(btec)0.5(dib)]·H2O
(1)
and
[Cd(btc)(dib)]·(C2H6N) (2) have been successfully synthesized by using the
Zn(II)/Cd(II) ions under solvothermal conditions. Crystal structure analysis reveals that complex 1 is an unprecedented (4, 4)-connected 3D network, while complex 2 exhibits a 2-fold interpenetration 3D structure. The structural differences revealed that the conformation of dib and the kind of the carboxylate ligands/metal ions have great influence on the final structure of the MOFs. In addition, the luminescent properties of complexes 1 and 2 have been recorded and discussed.
Acknowledgements This work was financially supported by the Startup Foundation for Doctors of Qufu Normal University, Natural Science Foundation and Innovative Talents Promotion Plan of Shaanxi Province (2019KJXX-075, 2018JQ2079, 2018JQ2040). Appendix A. Supplementary material Crystallographic data for the structural analysis have been deposited to the Cambridge Crystallographic Data Centre, CCDC No. 1952508-1952509 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.
References [1]
(a) 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; (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.
[2]
(a) O. K. Farha, A. Ö. Yazaydın, I. Eryazici, C. D. Malliakas, B. G. Hauser, M. G. Kanatzidis, S. T. Nguyen, R. Q. Snurr, J. T. Hupp, De novo synthesis of a metal-organic framework material featuring ultrahigh surface area and gas storage capacities, Nat. Chem., 2(2010) 944-948; (b) 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; (c) Y. Xiong, Y. Z. Fan, R. Yang, S. Chen, M. Pan, J. J. Jiang, C. Y. Su, Amide and N-oxide functionalization of T-shaped ligands for isoreticular MOFs with giant enhancements in CO2 separation, Chem. Commun., 50(2014) 14631-14634.
[3]
(a) B. L. Chen, S. C. Xiang, G. D. Qian, Metal-organic frameworks with functional pores for recognition of small molecules, Acc. Chem. Res. 43(2010) 1115-1124; (b) H. W. Li, X. Feng, Y. X. Guo, D. D. Chen, R. Li, X. Q. Ren, X. Jiang, Y. P. Dong, B. Wang, A malonitrile-functionalized metal-organic framework for hydrogen sulfide detection and selective amino acid molecular recognition, Scientific Reports, 4(2014), 4366; (c) L. Chen, J. W. Ye, H. P. Wang, M. Pan, S. Y. Yin, Z. W. Wei, L. Y. Zhang, K. Wu, Y. N. Fan, C. Y. Su, Ultrafast water sensing and thermal imaging by a metal-organic framework with switchable luminescence, Nat. Commun. 8(2017), 15985.
[4]
(a) J. W. Liu, L. F. Chen, H. Cui, J. Y. Zhang, L. Zhang, C. Y. Su, Applications of metal-organic frameworks in heterogeneous supramolecular catalysis, Chem. Soc. Rev. 43(2014) 6011-6061; (b) J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen, J. T. Hupp, Metal-organic framework materials as catalysts, Chem. Soc. Rev. 38(2009) 1450-1459; (c) B. Gole, U. Sanyal, R. Banerjee, P. S. Mukherjee, High loading of Pd nanoparticles by interior functionalization of MOFs for heterogeneous catalysis, Inorg. Chem. 55(2016) 2345-2354.
[5] (a) W. Cheng, T. Zhang, W. B. Lin, Rational synthesis of noncentrosymmetric metal-organic frameworks for second-order nonlinear optics, Chem. Rev. 112 (2011) 1084-1104; (b) H. Reinsch, M. A. van der Veen, B. Gil,
B. Marszalek, T. Verbiest, D. De Vos, N. Stock, Structures, sorption characteristics, and nonlinear optical properties of a new series of highly stable aluminum MOFs, Chem. Mater. 25(2013) 17-26. [6] (a) Y. J. Cui, B. L. Chen, G. D. Qian, Lanthanide metal-organic frameworks for luminescent sensing and light-emitting applications, Coordin. Chem. Rev. 273 (2014) 76-86; (b) Z. C. Hu, B. J. Deibert, J. Li, Luminescent metal-organic frameworks for chemical sensing and explosive detection, Chem. Soc. Rev. 43(2014) 5815-5840. [7] (a) I. M. El-Sewify, M. A.Shenashen, A. Shahat, H. Yamaguchi, M. M. Selim, M. M. Khalil, S. A. El-Safty, Dual colorimetric and fluorometric monitoring of Bi3+ ions in water using supermicroporous Zr-MOFs chemosensors, J Lumin. 198 (2018) 438-448; (b) Z. Z. Xiao, L. J. Han, Z. J. Wang, H. G. Zheng, Three Zn (II)-based MOFs for luminescence sensing of Fe3+ and Cr2O72− ions, Dalton Trans. 47(2018) 3298-3302; (c) E. S. Zhang, P. Ju, Z. Zhang, H. Yang, L. Tang, X. Y. Hou, J. M. You, J. J. Wang, A novel multi-purpose Zn-MOF fluorescent sensor for 2,4-dinitrophenylhydrazine, picric acid, La3+ and Ca2+: Synthesis, structure, selectivity, sensitivity and recyclability, Spectrochim. Acta A. 222(2019) 117207. [8]
(a) Y. H. Pi, X. Y. Li, Q. B. Xia, J. L. Wu, Y. W. Li, J. Xiao, Z. Li, Adsorptive and photocatalytic removal of persistent organic pollutants (POPs) in water by metal-organic frameworks (MOFs), Chem. Eng. J., 337(2018) 351-371; (b) D. Jiang, P. Xu, H. Wang, G. Zeng, D. Huang, M. Chen, C. Lai, C. Zhang, J. Wan, W. J. Xue, Strategies to improve metal organic frameworks photocatalyst’s performance for degradation of organic pollutants. Coordin. Chem. Rev. 376(2018) 449-466; (c) W. Ren, J. Gao, C. Lei, Y. Xie, Y. Cai, Q. Ni, J. Yao, Recyclable metal-organic framework/cellulose aerogels for activating peroxymonosulfate to degrade organic pollutants, Chem. Eng. J. 349(2018) 766-774; (d) E. M. Dias, C. Petit, Towards the use of metal-organic frameworks for water reuse: a review of the recent advances in the field of organic pollutants removal and degradation and the next steps in the field, J. Mater. Chem. A. 3(2015) 22484-22506.
[9]
(a) Z. F. Tian, J. G. Lin, Y. Su, L. L. Wen, Y. M. Liu, H. Z. Zhu, Q. J. Meng, Flexible ligand, structural, and opological diversity: isomerism in Zn(NO3)2 coordination polymers, Cryst. Growth Des. 7(2007) 1863-1867; (b) Z. J. Lin, J. Lü, M. Hong, R. Cao, Metal-organic frameworks based on flexible ligands (FL-MOFs): structures and applications, Chem. Soc. Rev. 43(2014) 5867-5895.
[10] B. J. Zhang, C. J. Wang, G. M. Qiu, S. Huang, X. L. Zhou, J. Weng, Y. Y. Wang, Polycarboxylate anions effect on the structures of a series of transition metal-based coordination polymers: Syntheses, crystal structures and bioactivities, Inorg. Chim. Acta, 397 (2013) 48-59. [11] Synthesis of [Zn(btec)0.5(dib)]·H2O (1): Zn(NO3)2·6H2O (0.015 g, 0.05 mmol), H4btec (0.0076 g, 0.3 mmol), dib (0.0038 g, 0.02 mmol) and HNO3 (6M, 2d) were added to a 20 mL glass scintillation vial. A 1:1 (v/v)
mixture of DMF (3 mL) and H2O (3 mL) were added to the mixture. The content was heated at 90°C for 48 h. The colorless prism crystals were obtained and washed with DMF, then dried in air (65% yield based on Zn). Anal. Calcd. for C15H15N4O5Zn (%): C, 45.42; H, 3.81; N, 14.12. Found (%): C, 45.07; H, 4.18; N, 13.86; IR (KBr, cm−1): 3439 (w), 3137 (w), 1611 (vs), 1532 (w), 1491 (w), 1413 (m), 1365 (vs), 1321 (s), 1282 (w), 1228 (w), 1112 (m), 1086 (w), 990 (w), 952 (m), 930 (w), 864 (m), 814 (m),767(w), 745 (w), 677 (w), 655 (m), 620 (w), 556 (m), 476 (w). [12] The single-crystal data of 1 and 2 were collected on Bruker D8 Venture system, with Mo Kα radiation (λ = 0.71073 Å) at 273K using Olex2 [14] the structure was solved with the ShelXS structure solution program by direct methods and refined with the ShelXL refinement package with Least-squares minimization [15]. All the Zn(II)/Cd(II) 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. Crystallographic data and structure refinements for complexes 1 and 2 were displayed in Table 1S. The selected bond lengths and bond angles were summarized in Table 2S. [13] Synthesis of [Cd(btc)(dib)]·(C2H6N) (2): Cd(NO3)2·6H2O (0.017 g, 0.05 mmol), H3btc (0.0063g, 0.3 mmol), dib (0.0038 g, 0.02 mmol) and HBF4 (45%, 2d) were added to a 20 mL glass scintillation vial. A 3:1:1 (v/v) mixture of DMF (3 mL), EtOH (1 mL) and H2O (1 mL) were added to the mixture. The content was heated at 90°C for 48 h. The colorless prism crystals were obtained and washed with DMF, then dried in air (81% yield based on Cd). Anal. Calcd. for C21H21N5O6 Cd (%): C, 45.71; H, 3.84; N, 12.69. Found (%): C, 45.96; H, 4.04; N, 12.89. IR (KBr, cm−1): 3433 (s), 3122 (w), 1673 (vs), 1618 (s), 1557 (s), 1521(w), 1435 (s), 1386 (vs), 1257 (w), 1230 (w), 1197 (w), 1095 (m), 979 (w), 940 (w), 828 (w), 760 (m), 726 (m), 685 (w), 670 (w), 657 (m), 625 (w). [14] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard, H. Puschmann, OLEX2: a complete structure solution, refinement and analysis program, J. Appl. Crystallogr. 42(2009) 339-341. [15] G. M. Sheldrick, A short history of SHELX, Acta Cryst. 2008, A64 112-122. [16] D. Liu, Y. Ge, N. Y. Li, W. Ma, X. Y. Tang, Coordination assemblies of Zn(NO3)2 with 4-pyrpoly-2-ene and polycarboxylates: structural diversification and photoluminescence properties, RSC Adv. 5(2015) 45467-45478 . [17] 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.
[18] S. Q. Guo, D. Tian, X. Zheng, H. Zhang, A (3, 4, 10)-connected 3D sandwich-type metal-organic framework with trinuclear zinc(II) cluster and two kinds of discrete zinc(II) ions, Inorg. Chem. Commun. 14 (2011) 1876-1879. [19] (a) S. Zhao, X. X. Lv, L. L. Shi, B. L. Li, Bi. Wu, An unusual (4, 4)-connected 3D porous cadmium metal-organic framework as a luminescent sensor for detection of nitrobenzene, RSC Adv. 6(2016) 56035-56041; (b) K. Li, V. A. Blatov, T. Fan, T. R. Zheng, Y. Q. Zhang, B. L. Li, B. Wu, A series of Cd(II) coordination polymers based on flexible bis(triazole) and multicarboxylate ligands: topological diversity, entanglement and properties, CrystEngComm 19 (2017) 5797-5808.
Revised Fig. 1 to Fig. 3
Fig. 1 (a) Coordination environment of Zn(II) ion in 1 (Hydrogen atoms are omitted for clarity. Symmetry codes 1: #1 + x, 1/2 - y, -1/2 + z; #2 - x, - y, 1 - z; #3 + x, 1/2 - y, 1/2 + z; #4 1 - x, -1/2 + y, 3/2 - z; #5 1 - x, 1/2 + y, 3/2 -z); (b) View of the 2D layer structure constructed from btec4− and Zn2+; (c) The 3D structure of 1; (d) The turquoise spheres represent Zn nodes, blue lines represent btec4− nodes and red lines stand for dib; (e) Topological view showing the 3D framework of 1 along bc plane.
Fig. 2 (a) The asymmetry unit of 2 (all hydrogen atoms are omitted for clarity, symmetry code for 2: #1 - x, -1/2 + y, 3/2 - z; #2 -1 + x, + y, + z; #3 1 + x, + y, + z; #4 - x, 1/2 + y, 3/2 - z; #5 + x, + y, 1 + z; #6 + x, + y, -1 + z); (b) View of the 3D structure constructed by btc3−, dib and Zn2+; (c) Stacking of the two-fold interpenetrated framework of 2 along the ac plane; (d) The turquoise spheres represent Cd nodes, the combination of bright green spheres and red lines represent btc3− nodes, the red lines stand for dib; (e) Topology representation of the 2-fold interpenetrated 3D framework.
Fig. 3 The PXRD pattern of complexes 1 and 2.
Graphical Abstract Two novel 3D fluorescent metal-organic frameworks [Zn(btec)0.5(dib)]·H2O (1) and [Cd(btc)(dib)]·(C2H6N) (2) with interesting topological and structural diversities have been successfully constructed under solvothermal conditions.
Highlights (1) Two novel 3D coordination polymers were prepared by using flexible dib as the organic ligand. (2) Interesting topological and structural diversities were observed for complexes 1 and 2. (3) The fluorescence properties of complexes 1 and 2 were recorded and discussed.
There are no conflict of interest to declare.