English

• 0.   Introduction

  The design of coordination polymers (CPs) with diverse crystal structures is still a great challenge and has been an increasing interest in chemistry for decades due to not only the intriguing topologies but also their tremendous potential applications as functional materials in various fields, such as gas storage, sensors, catalysis, luminescent materials^[1-10]. One approach to the construction of CPs is based on polycarboxylic acids and complicated N-donor co-ligands. The metal centers are coordinated by both carboxylate oxygen atoms and nitrogen atoms, giving rise to extended structures with intriguing topologies^[1-10]. On the other hand, the assembly of the final structures is controlled by numerous factors, such as the ratio of materials, template, temperature, solvent, and pH^[1-10].

  Our group focuses on the design of novel CPs with diverse topologies and interesting properties, using polycarboxylate ligands and pyridine or imidazole derivatives^[8-10]. In this paper, three different 5-substituted isophthalic acids as ligands, including H₂ipa, 5-OH-ipaH₂, and 5-Me-ipaH₂, are chosen to prepare CPs. Three zinc complexes, {[Zn₂(bipmo)₂(ipa)₂]·3H₂O}_n (1), {[Zn(bipmo)(5-OH-ipa)]·DMA·H₂O}_n (2), and {[Zn (bipmo)(5-Me-ipa)]·H₂O}_n (3), where bipmo=bis(4-(1H-imidazol‐1‐yl)phenyl)methanone (Scheme 1), were obtained under similar solvothermal conditions. Complexes 1-3 exhibit different kinds of 2D structures based on H₂ipa, 5-OH-ipaH₂, and 5-Me-ipaH₂, respectively. The structures were characterized by single‐ crystal X-ray diffraction analyses, elemental analyses, IR spectra, etc. The luminescence properties of 1-3 have also been investigated in detail.

  Scheme 1

  

  Scheme 1.  Structure of bipmo, H₂ipa, 5-OH-ipaH₂, and 5-Me-ipaH₂

  下载: 全尺寸图片 幻灯片

  1.   Experimental

  1.1   Materials and methods

  Reagents and solvents were purchased from Aladdin Industrial Corporation of Shanghai, China, and used as received. The bipmo ligand was prepared according to the literature method^[8]. Elemental analyses were performed on an Elementar Vario EL Ⅲ elemental analyzer. The IR spectra were recorded on a Bruker Vector 22 spectrophotometer with KBr pellets in the 4 000-400 cm^-1 region. The Luminescence spectra were measured on a Hitachi F-4600 fluorescence spectrometer. Thermogravimetric analyses (TGA) were carried out on a NETZSCH STA 449F3 unit at a heating rate of 10 ℃·min^-1 under a nitrogen atmosphere. Powder X-ray diffraction (PXRD) data were collected on a Rigaku SmartLab(3) diffractometer with Cu Kα radiation (λ=0.154 184 nm, 40 kV, 30 mA) and scans were run for each sample over a 2θ range of 3°-60°.

  1.2   Synthesis of complex 1

  A mixture of Zn(OAc)₂·2H₂O (0.1 mmol), bimpo (0.1 mmol), H₂ipa (0.1 mmol), and DMF/H₂O (2 mL/6 mL) was added in a 15 mL Teflon-lined stainless steel reactor at 95 ℃ for two weeks, and then slowly cooled to room temperature. Colorless block single crystals suitable for X-ray data collection were obtained by filtration. Yield: 62% (based on bipmo). Anal. Calcd. for C₅₄H₄₂N₈O₁₃Zn₂(%): C, 56.81; H, 3.71; N, 9.81. Found(%), C, 56.42; H, 3.53; N, 9.54. IR (cm^-1): 3 132, 3 091, 2 972, 1 670, 1 608, 1 558, 1 523, 1 496, 1 477, 1 432, 1 382, 1 307, 1 257, 1 184, 1 155, 1 126, 1 064, 962, 927, 877, 852, 746, 655, 621, 518, 474, 435.

  1.3   Synthesis of complex 2

  A mixture of Zn(NO₃)₂·6H₂O (0.2 mmol), bipmo (0.1 mmol), 5-OH-ipaH₂ (0.1 mmol), and DMA/H₂O (4 mL/1 mL) was added to a 15 mL Teflon-lined stainless steel reactor and heated at 95 ℃ for 5 d, and then slowly cooled to room temperature. Colorless plate single crystals suitable for X‐ray data collection were obtained by filtration. Yield: 41% (based on bipmo). Anal. Calcd. for C₃₁H₂₉N₅O₈Zn(%): C, 55.99; H, 4.40; N, 10.53. Found(%), C, 55.61; H, 4.14; N, 10.61. IR (cm^-1): 3 136, 1 664, 1 627, 1 606, 1 579, 1 523, 1 498, 1 427, 1 398, 1 301, 1 282, 1 184, 1 124, 1 058, 999, 968, 927, 896, 856, 842, 779, 765, 742, 725, 669, 646, 594, 545, 518, 484, 428.

  1.4   Synthesis of complex 3

  A mixture of Zn(NO₃)₂·6H₂O (0.2 mmol), bipmo (0.1 mmol), 5-Me-ipaH₂ (0.1 mmol), and DMF/H₂O (3 mL/3 mL) was added to a 15 mL Teflon-lined stainless steel reactor and heated at 95 ℃ for a week, and then slowly cooled to room temperature. Colorless block single crystals suitable for X-ray data collection were obtained by filtration. Yield: 45% (based on bipmo). Anal. Calcd. for C₂₈H₂₂N₄O₆Zn(%): C, 58.40; H, 3.85; N, 9.73. Found(%), C, 58.02, H, 3.58; N, 9.46. IR (cm^-1): 3 136, 1 650, 1 608, 1 579, 1 525, 1 500, 1 427, 1 398, 1 340, 1 309, 1 292, 1 263, 1 189, 1 126, 1 064, 964, 933, 850, 794, 771, 729, 673, 648, 617, 565, 520, 449, 420.

  1.5   X-ray crystallography

  The measurement of complex 1 was made on an Agilent Technology SuperNova Eos Dual system with a (Mo Kα, λ=0.071073 nm) microfocus source and processed using CrysAlis^{Pro [11]}, while those of complexes 2-3 were made on a Bruker Smart-1000 CCD diffractometer (Mo Kα). Absorption corrections of 1‐3 were applied using the program SADABS^[12]. The structures were solved by Direct Methods^[12] with the SHELXTL program (version 6.10)^[12-13] and refined by full-matrix least-squares techniques on F ² with SHELXTL^[12-13]. All non-hydrogen atoms were refined anisotropically. For the disordered atoms C26, C27, O3, O4, O5, and O6 in 1, SIMU and SADI commands in SHELXTL (version 6.10)^[12] were used to restrict their displacement parameters. The hydrogen atoms bonded to carbon atoms were localized in their calculated positions and refined using a riding model. The water hydrogen atoms were located in differential Fourier maps and refined with an O—H length of 0.085(2) nm and an H…H length of 0.135(2) nm as restraints. Crystallographic data and structure refinements for complexes 1-3 are listed in Table 1. Selected bond distances and angles for 1-3 are summarized in Table 2.

  Table 1

  

  Table 1.  Crystallographic data and refinement parameters for complexes 1-3

  下载: 导出CSV

  Parameter	1	2	3
  Formula	C54H42N8O13Zn2	C31H29N5O8Zn	C28H22N4O6Zn
  Formula weight	1 141.74	664.98	575.86
  Temperature/K	293(2)	293(2)	150(2)
  Crystal system	Monoclinic	Monoclinic	Monoclinic
  Crystal size/mm	0.29×0.27×0.26	0.34×0.27×0.17	0.25×0.22×0.19
  Space group	P21/c	P21/c	P21/n
  a/nm	1.065 78(2)	1.280 69(10)	0.943 35(5)
  b/nm	1.303 36(3)	1.101 58(9)	1.640 58(8)
  c/nm	2.001 64(5)	2.335 33(17)	1.595 22(9)
  β/(°)	114.847(2)	109.399(4)	95.098(2)
  V/nm3	2.523 09(10)	3.107 6(4)	2.459 1(2)
  Dc/(g·cm-3)	1.503	1.421	1.555
  Z	2	4	4
  μ/mm-1	1.026	0.849	1.052
  F(000)	1 172	1 376	1 184
  Unique reflection	4 481	7 160	4 499
  Observed reflection [I > 2σ(I)]	3 662	5 245	3 585
  Number of parameters	431	409	356
  GOF	1.065	1.026	1.073
  Final R indices [I > 2σ(I)]	0.052 4, 0.137 1	0.040 4, 0.094 5	0.083 3, 0.204 7
  R indices (all data)	0.064 6, 0.146 7	0.067 5, 0.105 5	0.102 9, 0.219 9

  Table 2

  

  Table 2.  Selected bond lengths (nm) and bond angles (°) for complexes 1-3

  下载: 导出CSV

  1
  Zn1—N3	0.202 5(3)	Zn1—N4#2	0.204 3(3)	Zn1—O3	0.230 0(8)
  Zn1—O4	0.214 1(8)	Zn1—O5#1	0.245 5(7)	Zn1—O6#1	0.192 4(8)
  O6#1—Zn1—N3	91.6(2)	O4—Zn1—O3	54.4(3)	N4#2—Zn1—O4	140.1(3)
  O6#1—Zn1—O5#1	57.7(3)	O6#1—Zn1—O3	131.0(3)	N3—Zn1—O5#1	149.2(2)
  N3—Zn1—O3	128.1(3)	O3—Zn1—O5#1	78.2(3)	N4#2—Zn1—O3	89.1(3)
  2
  Zn1—O3#1	0.191 55(17)	Zn1—O1	0.192 86(15)	Zn1—N1	0.199 38(19)
  Zn1—N4#2	0.201 65(19)
  O3#1—Zn1—O1	108.29(8)	O1—Zn1—N4#2	96.40(8)	O3#1—Zn1—N1	110.40(9)
  N1—Zn1—N4#2	109.76(8)	O1—Zn1—N1	117.33(8)	O3#1—Zn1—N4#2	114.17(8)
  3
  Zn1—O1	0.195 5(4)	Zn1—O3#1	0.198 3(4)	Zn1—N1	0.200 9(5)
  Zn1—N4#2	0.202 2(5)
  O1—Zn1—O3#1	110.53(17)	O1—Zn1—N4#2	94.2(2)	O1—Zn1—N1	122.99(19)
  O3#1—Zn1—N4#2	120.35(19)	O3#1—Zn1—N1	102.99(19)	N1—Zn1—N4#2	107.0(2)
  Symmetry codes: #1: -x, y+1/2, -z+3/2; #2: -x+2, y+1/2, -z+3/2 for 1; #1: -x, y+1/2, -z+3/2; #2: x-1, y-1, z for 2; #1: x-1/2, -y+1/2, z-1/2; #2: -x+1, -y+1, -z+1 for 3.

  2.   Results and discussion

  2.1   Preparation and characterization of the complexes

  Complexes 1‐3 can be prepared in moderate yields by solvothermal reaction of Zn(NO₃)₂·6H₂O (or Zn(OAc)₂·2H₂O) with bipmo and 5-substituted isophthalic acid. The products are crystalline solids that exhibit insolubility in common solvents such as EtOH, MeOH, H₂O, and CH₂Cl₂. In the region around 3 100 cm^-1 (3 132 cm^-1 for 1 and 3 136 cm^-1 for 2-3, respectively), there were prominent and sharp peaks corresponding to the C—H stretching mode of the aryl groups. Peaks ranging from 1 650 to 1 670 cm^-1 (1 670, 1 664, 1 650 cm^-1 for 1-3, respectively) indicate the presence of asymmetric stretching vibrations (ν_as) of COO^-, which are characteristic of the complexes. Strong peaks at 1 400 cm^-1 were observed in complexes 1-3, which can be attributed to the symmetric stretching vibrations (ν_s) of COO^-. The IR spectra and elemental analyses of the complexes are consistent with the structural models obtained from X-ray diffraction studies.

  2.2   Description of crystal structures

  2.2.1   Structure of complex 1

  Complex 1 crystallizes in the monoclinic space group P2₁/c with Z=2. Its asymmetric unit contains one crystallographically independent Zn²⁺ cation, one ipa^2- anion, one bipmo ligand, and one‐and‐a‐half lattice water molecules. As shown in Fig. 1, Zn1 is six‐ coordinated with a distorted octahedron coordination geometry by two nitrogen atoms originating from two distinct bipmo ligands, and four oxygen atoms deriving from two ipa^2- ligands. The Zn—N distances are 0.202 5(3) and 0.204 3(3) nm, and the Zn—O bond lengths range between 0.192 4(8) and 0.244 5(7) nm.

  Figure 1

  

  Figure 1.  Coordination environment of Zn(Ⅱ) in complex 1

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1:-x, y+1/2, -z+3/2; #2:-x+2, y+1/2, -z+3/2.

  下载: 全尺寸图片 幻灯片

  In complex 1, each ipa^2- anion adopts a μ₁-η¹∶η¹ coordination mode connecting two Zn(Ⅱ) centers in O, O-chelating mode. Thus, the Zn(Ⅱ) centers are extended via the ipa^2- ligands to form a zigzag chain, with a pitch of 0.949 7(6) nm and a Zn…Zn…Zn angle of 86.657(4)°, which are further linked by bipmo ligands, generating a 2D layered structure along the [001] direction (Fig. 2). To gain a deeper understanding of the 2D layer present in 1, we define Zn(Ⅱ) centers as 4‐ connected nodes, ipa^2- ligands and bipmo ligands as linkers. The resulting structure of 1 can be described as a 2-fold interpenetrating with Schläfli symbol {4⁴·6²} (Fig. 2)^[14].

  Figure 2

  

  Figure 2.  Schematic representation of the 2-fold interpenetrating nets with Schläfli symbol of {4⁴·6²} for complex 1

  下载: 全尺寸图片 幻灯片

  2.2.2   Structure of complex 2

  Complex 2 crystallizes in the monoclinic crystal system with space group P2₁/c. The asymmetric unit contains one crystallographically independent Zn²⁺ ion, one 5-OH-ipa^2- anion, one bipmo ligand, one DMA molecule, and one lattice water molecule. As depicted in Fig. 3, the Zn1 ion is four-coordinated by two carboxylate oxygen atoms from two different 5-OH-ipa^2- anions, and two N atoms from two bipmo ligands to form its distorted tetrahedral geometry. The Zn—N bond distances are 0.199 38(19) and 0.201 65(19) nm, while the Zn—O bond lengths are 0.191 55(17) and 0.192 86(15) nm, respectively. The bond angles around Zn²⁺ range from 96.40(8)° to 117.33(8)°.

  Figure 3

  

  Figure 3.  Coordination environment of Zn(Ⅱ) in complex 2

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1:-x, y+1/2, -z+3/2; #2: x-1, y-1, z.

  下载: 全尺寸图片 幻灯片

  In complex 2, each bipmo serves as a bridge, connecting two Zn(Ⅱ) ions through its imidazole groups and forming a zigzag chain. These chains are further connected by 5-OH-ipa^2- ligands to create a 2D network, in which the carboxylate groups possess μ₁-η¹∶η⁰ connectivity. A better insight into the crystal structure of 2 can be achieved by the application of a topological approach^[14]. To reduce multidimensional structures to simple node-and-linker nets, each metal center can be defined as a 4-connected node, the 5-OH-ipa^2- ligands and bipmo ligands act as bridges (Fig. 4). From a topological perspective, the resulting structure of 2 can be described as a 4-connected net with the Schläfli symbol {6⁵·8} (Fig. 4).

  Figure 4

  

  Figure 4.  Schematic representation of the 2D framework with the {6⁵·8} topology of complex 2

  下载: 全尺寸图片 幻灯片

  2.2.3   Structure of complex 3

  X-ray analysis reveals that complex 3 possesses a 2D structure, which crystallizes in the space group P2₁/n with Z=4. Its asymmetric unit consists of one Zn²⁺ ion, one 5-Me-ipa^2- anion, one bipmo ligand, and one lattice water molecule. As shown in Fig. 5, each Zn(Ⅱ) ion is in a distorted tetrahedral coordination geometry coordinated by two oxygen atoms from two individual 5-Me-ipa^2- ligands, and two nitrogen atoms from two individual bipmo ligands. The Zn—O distances are 0.195 5(4) and 0.198 3(4) nm, and the Zn—N bonds range from 0.200 9(5) to 0.202 2(5) nm. In addition, the bond angles around each Zn(Ⅱ) range from 94.2(2)° to 122.99(19)° (Table 2).

  Figure 5

  

  Figure 5.  Coordination environment of Zn(Ⅱ) in complex 3

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1: x-1/2, -y+1/2, z-1/2; #2: -x+1, -y+1, -z+1.

  下载: 全尺寸图片 幻灯片

  Topologically, if the bipmo and the 5-Me-ipa^2- are considered as single linkers, the Zn²⁺ is regarded as a three-connected node, and the structure of complex 3 can be classified as a 2D 3-connected net with the {6³} topology (Fig. 6).

  Figure 6

  

  Figure 6.  View of the network of complex 3 with the {6³} topology

  下载: 全尺寸图片 幻灯片

  It has been shown that different substituents around ligands can have a profound influence on the properties and the final structure of complexes^[15-16]. In complex 1, the coordination number is six with the 5-position of isophthalate being hydrogen, while those of complexes 2 and 3 are four with the 5-position of isophthalate being —OH and —CH₃ groups, respectively. Taking into account the electron-donating effect of —OH and —CH₃ groups in the phenyl rings, the substituent effects including the electronic effect and steric effect are considered. Additionally, solvents together with weak interactions such as hydrogen bonds (Table S1, Supporting information) play important roles in the formation of the final structures.

  2.3   PXRD analysis

  The PXRD patterns for complexes 1‐3 were recorded at room temperature to examine the phase purity of these complexes. The experimental PXRD patterns were in good agreement with the simulated ones except for the relative intensity variation, indicating good purities (Fig.S1-S3).

  2.4   TGA of complexes 1-3

  The thermal stability of complexes 1-3 was tested in a range of 30-900 ℃ at a heating rate of 10 ℃·min^-1 in N₂ (Fig. 7). The TGA curve of 1 displayed a first weight loss of 3.75% between 70 and 310 ℃, corresponding to the loss of three water molecules per formula unit (Calcd. 4.73%). It continued to decompose upon further heating and underwent a slow weight loss of 29.71% covering the temperature from 283 to 437 ℃, which corresponds to the destruction of ipa^2- fragments (Calcd. 28.75%). Complex 2 first lost one lattice water molecule (Obsd. 2.77%, Calcd. 2.71%) in a range of 70-134 ℃. Further weight loss in a range of 135-290 ℃ is responsible for a DMA molecule (Obsd. 12.88%, Calcd. 13.10%). It kept losing weight from 290 to 510 ℃, corresponding to the decomposition of the remaining 5-OH-ipa^2- fragments (Obsd. 26.76%, Calcd. 27.09%). For complex 3, the weight loss corresponding to the release of one lattice water molecule was observed from 30 to 290 ℃ (Obsd. 3.00%, Calcd. 3.13%). Then an advanced weight loss of 31.07% in the region of 291-480 ℃ took place which corresponds to the collapse of the 5-Me-ipa^2- fragments (Calcd. 30.93%).

  Figure 7

  

  Figure 7.  TGA curves of complexes 1-3

  下载: 全尺寸图片 幻灯片

  2.5   Luminescence property

  The luminescent properties of complexes incorporating d¹⁰ metal ions, such as Zn²⁺ and Cd²⁺, have garnered significant attention for their diverse applications in electroluminescent displays, photochemistry, chemical sensors, and so on^{[1, 7, 9-10, 17-20]}. Therefore, the solid-state luminescence spectra of 1-3 have been carried out at room temperature in this work. The emission spectra of 1-3 showed the main peaks at 488 nm for 1 (λ_ex=407 nm), 475 nm for 2 (λ_ex=412 nm), and 488 nm for 3 (λ_ex=412 nm), respectively (Fig. 8). It is reported that the bipmo ligand exhibit emission peaks at 447 (λ_ex=407 nm)^[9]. In contrast, the emissions for 1-3 are red-shifted by 41, 28, and 41 nm, respectively. These luminescence behaviors of 1-3 may be assigned to metal-to-ligand charge transfer (MLCT), and similar redshifts have been observed before^{[1, 9, 17-19]}.

  Figure 8

  

  Figure 8.  Solid-state emission spectra of complexes 1-3 at room temperature

  下载: 全尺寸图片 幻灯片

  3.   Conclusions

  In summary, three coordination polymers, [{[Zn₂(bipmo)₂(ipa)₂]·3H₂O}_n (1), {[Zn(bipmo)(5-OH-ipa)]·DMA·H₂O}_n (2), and {[Zn(bipmo)(5-Me-ipa)]·H₂O}_n (3), have been synthesized under solvothermal conditions and characterized by elemental analyses, IR, single-crystal X-ray diffraction analyses, etc. The structures of complexes 1-3 can be described as 2D nets with {4⁴·6²}, {6⁵·8}, and {6³} topologies, respectively. It is found that 5-substituted isophthalic acids play a significant effect on the final networks. In addition, the luminescent properties of 1-3 have also been investigated.

  
  Supporting information is available at http://www.wjhxxb.cn
  
• 1. [1]

     Dutta A, Singh A, Wang X X, Kumar A, Liu J Q. Luminescent sensing of nitroaromatics by crystalline porous materials[J]. CrystEngComm, 2020, 22:  7736-7781. doi: 10.1039/D0CE01087A

  2. [2]

     Yang L F, Qian S H, Wang X B, Cui X L, Chen B L, Xing H B. Energy-efficient separation alternatives: Metal-organic frameworks and membranes for hydrocarbon separation[J]. Chem. Soc. Rev., 2020, 49:  5359-5406. doi: 10.1039/C9CS00756C

  3. [3]

     亢秀琪, 王嘉浩, 顾金忠. 三个含4,4'-(吡啶-3,5-二基)二苯甲酸配体的锌(Ⅱ)、镍(Ⅱ)和钴(Ⅱ)配位聚合物的合成、晶体结构及催化性质[J]. 无机化学学报, 2023,39,(12): 2385-2392. doi: 10.11862/CJIC.2023.190KANG X Q, WANG J H, GU J Z. Syntheses, crystal structures, and catalytic properties of three zinc(Ⅱ), nickel(Ⅱ) and cobalt(Ⅱ) coordination polymers constructed from 4,4'-(pyridin-3,5-diyl)dibenzoic acid[J]. Chinese J. Inorg. Chem., 2023, 39(12):  2385-2392. doi: 10.11862/CJIC.2023.190

  4. [4]

     Rao K P, Higuchi M, Duan J, Kitagawa S. pH-Dependent interpenetrated, polymorphic, Cd²⁺- and BTB-based porous coordination polymers with open metal sites[J]. Cryst. Growth Des., 2013, 13:  981-985. doi: 10.1021/cg301476p

  5. [5]

     夏雨沛, 王晨雪, 郑金玉, 李娜, 常泽, 卜显和. 基于咔唑羧酸配体构筑铁基金属有机框架及其对CO₂/CH₄混合气体的分离性质[J]. 高等学校化学学报, 2020,41,(11): 2415-2420. XIA Y P, WANG C X, ZHENG J Y, LI N, CHANG Z, BU X H. Construction of a Fe-MOF based on carbazole-carboxylate ligand for CO₂/CH₄ separation[J]. Chem. J. Chinese Universities, 2020, 41(11):  2415-2420.

  6. [6]

     Zhao Z H, Huang J R, Liao P Q, Chen X M. Highly efficient electroreduction of CO₂ to ethanol via asymmetric C—C coupling by a metal-organic framework with heterodimetal dual sites[J]. J. Am. Chem. Soc., 2023, 145:  26783-26790. doi: 10.1021/jacs.3c08974

  7. [7]

     Mu Y J, Ran Y G, Zhang B B, Du J L, Jiang C Y, Du J. Dicarboxylate ligands modulated structural diversity in the construction of Cd(Ⅱ) coordination polymers built from N-heterocyclic ligand: Synthesis, structures, and luminescent sensing[J]. Cryst. Growth Des., 2020, 20:  6030-6043. doi: 10.1021/acs.cgd.0c00739

  8. [8]

     Wang G F, Zhang X, Sun S W, Sun H, Yang X, Li H, Yao C Z, Sun S G, Tang Y P, Meng L X. Syntheses, crystal structures, and characterization of two Mn(Ⅱ) coordination polymers with bis(4-(1H-imidazol-1-yl)phenyl)methanone ligands[J]. Z. Naturforsch. B, 2016, 71:  869-874.

  9. [9]

     Wang G F. Structural diversity of two coordination polymers based on bis(4-(1H-imidazol-1-yl)phenyl)methanone and polycarboxylate coligands: Syntheses, structures, and fluorescent properties[J]. Russ. J. Coord. Chem., 2018, 44:  540-546. doi: 10.1134/S1070328418090075

  10. [10]

      王高峰, 孙述文, 宋少飞, 吕玫. 一种镉基配位聚合物的合成及其对2,4,6-三硝基苯酚的荧光识别[J]. 无机化学学报, 2023,39,(12): 2407-2414. WANG G F, SUN S W, SONG S F, LÜ M. Synthesis of a Cd(Ⅱ)-based coordination polymer for luminescence detecting 2,4,6-trinitrophenol[J]. Chinese J. Inorg. Chem., 2023, 39(12):  2407-2414.

  11. [11]

      CrysAlis^Pro, Version 1.171.35.19. Agilent Technologies Inc., Santa Clara, CA, USA, 2011.

  12. [12]

      Sheldrick G M. SHELXL 2014/7, Program for crystal structure refinement. University of Gö ttingen, Germany, 2014.

  13. [13]

      Sheldrick G M. A short history of SHELX[J]. Acta Crystallogr. Sect. A, 2008, (A64):  112-122.

  14. [14]

      Blatov V A. Multipurpose crystallochemical analysis with the program package TOPOS. [2023-11-03]. https://www.iucr.org/resources/commissions/crystallographic-computing/newsletters/7/topos

  15. [15]

      Wang C F, Yao Z S, Yang G Y, Tao J. Ligand substituent effects on the spin-crossover behaviors of dinuclear iron(Ⅱ) compounds[J]. Inorg. Chem., 2019, 58:  1309-1316. doi: 10.1021/acs.inorgchem.8b02789

  16. [16]

      Minnick J L, Raincrow J, Meinders G, Latifi R, Tahsini L. Synthesis, characterization, and spectroscopic studies of 2,6-dimethylpyridyl-linked Cu(Ⅰ)-CNC complexes: the electronic influence of aryl wingtips on copper centers[J]. Inorg. Chem., 2023, 62:  15912-15926. doi: 10.1021/acs.inorgchem.3c01973

  17. [17]

      He X, Lu C Z, Yuan D Q. Two 3D porous cadmium tetrazolate frameworks with hexagonal tunnels[J]. Inorg. Chem., 2006, 45:  5760-5766. doi: 10.1021/ic0520162

  18. [18]

      Ouellette W, Hudson B S, Zubieta J. Hydrothermal and structural chemistry of the zinc(Ⅱ)- and cadmium(Ⅱ)-1,2,4-triazolate systems[J]. Inorg. Chem., 2007, 46:  4887-4904. doi: 10.1021/ic062269a

  19. [19]

      Song X Z, Zhao L, Zhang N, Liu L, Ren X, Ma H M, Luo C N, Li Y Y, Wei Q. Zinc-based metal-organic framework with MLCT properties as an efficient electrochemiluminescence probe for trace detection of trenbolone[J]. Anal. Chem., 2022, 94:  14054-14060. doi: 10.1021/acs.analchem.2c03615

  20. [20]

      Zhang Y, Liu Y H, Huo F, Zhang B W, Su W Z, Yang X P. Photoluminescence quenching in recyclable water-soluble Zn-based metal-organic framework nanoflakes for dichromate sensing[J]. ACS Appl. Nano Mater., 2022, 5:  9223-9229. doi: 10.1021/acsanm.2c01556

• 

  Scheme 1  Structure of bipmo, H₂ipa, 5-OH-ipaH₂, and 5-Me-ipaH₂

  下载: 全尺寸图片 幻灯片
  

  Figure 1  Coordination environment of Zn(Ⅱ) in complex 1

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1:-x, y+1/2, -z+3/2; #2:-x+2, y+1/2, -z+3/2.

  下载: 全尺寸图片 幻灯片
  

  Figure 2  Schematic representation of the 2-fold interpenetrating nets with Schläfli symbol of {4⁴·6²} for complex 1

  下载: 全尺寸图片 幻灯片
  

  Figure 3  Coordination environment of Zn(Ⅱ) in complex 2

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1:-x, y+1/2, -z+3/2; #2: x-1, y-1, z.

  下载: 全尺寸图片 幻灯片
  

  Figure 4  Schematic representation of the 2D framework with the {6⁵·8} topology of complex 2

  下载: 全尺寸图片 幻灯片
  

  Figure 5  Coordination environment of Zn(Ⅱ) in complex 3

  The hydrogen atoms bonded to carbon atoms are omitted for clarity; 30% ellipsoid probability; Symmetry codes: #1: x-1/2, -y+1/2, z-1/2; #2: -x+1, -y+1, -z+1.

  下载: 全尺寸图片 幻灯片
  

  Figure 6  View of the network of complex 3 with the {6³} topology

  下载: 全尺寸图片 幻灯片
  

  Figure 7  TGA curves of complexes 1-3

  下载: 全尺寸图片 幻灯片
  

  Figure 8  Solid-state emission spectra of complexes 1-3 at room temperature

  下载: 全尺寸图片 幻灯片

  Table 1.  Crystallographic data and refinement parameters for complexes 1-3

  Parameter	1	2	3
  Formula	C54H42N8O13Zn2	C31H29N5O8Zn	C28H22N4O6Zn
  Formula weight	1 141.74	664.98	575.86
  Temperature/K	293(2)	293(2)	150(2)
  Crystal system	Monoclinic	Monoclinic	Monoclinic
  Crystal size/mm	0.29×0.27×0.26	0.34×0.27×0.17	0.25×0.22×0.19
  Space group	P21/c	P21/c	P21/n
  a/nm	1.065 78(2)	1.280 69(10)	0.943 35(5)
  b/nm	1.303 36(3)	1.101 58(9)	1.640 58(8)
  c/nm	2.001 64(5)	2.335 33(17)	1.595 22(9)
  β/(°)	114.847(2)	109.399(4)	95.098(2)
  V/nm3	2.523 09(10)	3.107 6(4)	2.459 1(2)
  Dc/(g·cm-3)	1.503	1.421	1.555
  Z	2	4	4
  μ/mm-1	1.026	0.849	1.052
  F(000)	1 172	1 376	1 184
  Unique reflection	4 481	7 160	4 499
  Observed reflection [I > 2σ(I)]	3 662	5 245	3 585
  Number of parameters	431	409	356
  GOF	1.065	1.026	1.073
  Final R indices [I > 2σ(I)]	0.052 4, 0.137 1	0.040 4, 0.094 5	0.083 3, 0.204 7
  R indices (all data)	0.064 6, 0.146 7	0.067 5, 0.105 5	0.102 9, 0.219 9

  下载: 导出CSV

  Table 2.  Selected bond lengths (nm) and bond angles (°) for complexes 1-3

  1
  Zn1—N3	0.202 5(3)	Zn1—N4#2	0.204 3(3)	Zn1—O3	0.230 0(8)
  Zn1—O4	0.214 1(8)	Zn1—O5#1	0.245 5(7)	Zn1—O6#1	0.192 4(8)
  O6#1—Zn1—N3	91.6(2)	O4—Zn1—O3	54.4(3)	N4#2—Zn1—O4	140.1(3)
  O6#1—Zn1—O5#1	57.7(3)	O6#1—Zn1—O3	131.0(3)	N3—Zn1—O5#1	149.2(2)
  N3—Zn1—O3	128.1(3)	O3—Zn1—O5#1	78.2(3)	N4#2—Zn1—O3	89.1(3)
  2
  Zn1—O3#1	0.191 55(17)	Zn1—O1	0.192 86(15)	Zn1—N1	0.199 38(19)
  Zn1—N4#2	0.201 65(19)
  O3#1—Zn1—O1	108.29(8)	O1—Zn1—N4#2	96.40(8)	O3#1—Zn1—N1	110.40(9)
  N1—Zn1—N4#2	109.76(8)	O1—Zn1—N1	117.33(8)	O3#1—Zn1—N4#2	114.17(8)
  3
  Zn1—O1	0.195 5(4)	Zn1—O3#1	0.198 3(4)	Zn1—N1	0.200 9(5)
  Zn1—N4#2	0.202 2(5)
  O1—Zn1—O3#1	110.53(17)	O1—Zn1—N4#2	94.2(2)	O1—Zn1—N1	122.99(19)
  O3#1—Zn1—N4#2	120.35(19)	O3#1—Zn1—N1	102.99(19)	N1—Zn1—N4#2	107.0(2)
  Symmetry codes: #1: -x, y+1/2, -z+3/2; #2: -x+2, y+1/2, -z+3/2 for 1; #1: -x, y+1/2, -z+3/2; #2: x-1, y-1, z for 2; #1: x-1/2, -y+1/2, z-1/2; #2: -x+1, -y+1, -z+1 for 3.

  下载: 导出CSV
•