Substituent Effects of Isophthalate Derivatives on the Construction of

Article pubs.acs.org/crystal

Substituent Effects of Isophthalate Derivatives on the Construction of Zinc(II) Coordination Polymers Incorporating Flexible Bis(imidazolyl) Ligands Xiaoju Li,*,† Zhenjiang Yu,†,‡ Tena Guan,† Xinxiong Li,‡ Guangchao Ma,† and Xiaofang Guo† †

College of Chemistry and Chemical Engineering, and Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China ‡ State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, China S Supporting Information *

ABSTRACT: Eight Zn(II) coordination polymers, [Zn(EtOip)(bimb)] n (DMF) n (1), [Zn(PrO-ip)(bimb) 0.5 ] n (2), [Zn 2 (NO 2 -ip) 2 (bimb) 2 ] n (H 2 O) n (3), [Zn 2 (NO 2 -ip) 2 (bimb)1.5]n(H2O)n (4), [Zn(MeO-ip)(bmib)0.5]n(H2O)0.5n (5), [Zn(EtO-ip)(bmib)0.5]n (6), [Zn(PrO-ip)(bmib)]n (7), and [Zn (NO2-ip)(bmib)]n (8) (EtO-ip = 5-ethoxyisophthalate, PrO-ip = 5-propoxyisophthalate, NO2-ip = 5-nitroisophthalate, MeO-ip = 5-methoxyisophthalate, bimb = 1,4bis(imidazol-1′-yl)butane, bmib = 1,4-bis(2-methylimidazol-1′-yl)butane), have been prepared and characterized by singlecrystal X-ray diffraction analyses. In 1, bis-monodentate EtO-ip and exo-bidentate bimb connect four-coordinated Zn(II) into a corrugated 2-D layer. In 2, μ2,η2-carboxylate and monodentate carboxylate in PrO-ip bridge dinuclear Zn(II) units to generate a [Zn2(PrO-ip)4]n layer, which is further extended by bimb into a 3-D network. Interestingly, bis-monodentate NO2-ip and bimb in 3 connect four-coordinated Zn(II) into two independent 2-D layers, which are stabilized by π···π stacking interactions from phenyl rings of NO2-ip in different layers. In 4, μ3-bridged NO2-ip alternately links single Zn(II) ions and dinuclear Zn(II) units into a 1-D chain containing square-shaped cavities, which is further extended by bimb into a 2-fold interpenetrating 3-D framework. However, μ3-bridged MeO-ip and EtO-ip together with bmib in 5 and 6 link dinuclear Zn(II) units into a 2-D layer. In 7, bis-monodentate PrO-ip and bmib connect four-coordinated Zn(II) ions into a 2-D corrugated layer, while fourcoordinated Zn(II) ions in 8 are linked by bis-monodentate NO2-ip and bmib into a 3-fold interpenetrating framework consisting of left- and right-handed helical chains. The thermal stability and luminescent properties of 1−8 in the solid state were investigated in detail.

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INTRODUCTION The rational design and synthesis of metal−organic frameworks (MOFs) have been an attractive research field in supramolecular chemistry and material science owing to their intriguing topologies and potential applications in gas adsorption/ separation, magnetism, luminescence, and catalysis.1−7 Considerable progress has been made for controllable synthesis of MOFs through deliberate selection of the functionalized organic ligands and/or coordination geometries of metal ions.8−12 In the context, aromatic carboxylates are well-known to be promising ligands, and they usually possess versatile coordination modes and strong coordination ability to transition metal ions, which allow for the synthesis of coordination complexes ranging from discrete oligonuclear species to one- (1-D), two- (2-D), and three-dimensional (3-D) frameworks.13,14 The introduction of additional N-donor bridging ligands into the carboxylate systems may generate more topological structures than the use of single carboxylate ligands;15−25 flexible bis(imidazolyl) ligands, such as © XXXX American Chemical Society

1,4-bis(imidazol-1′-yl)butane (bimb) and 1,4-bis(2-methylimidazol-1′-yl)butane (bmib),21−23 have been widely used as auxiliary ligands in the controllable synthesis of MOFs. The flexible nature of spacers between imidazolyl rings may allow them to freely rotate and twist to meet for preferential coordination geometries of metal ions in the assembly process, which results in MOFs with beautiful aesthetics and useful properties. The combinational use of 5-substituted isophthalates and flexible exo-bidentate N-donor ligands is one of the common approaches in the construction of MOFs.26−34 Two carboxylate groups in the rigid dicarboxylate ligands are predisposed around 120° of the central phenyl ring, and may link metal ions or clusters into charge-neutral macrocycles, cages, 1-D chains, and Received: September 4, 2014 Revised: November 13, 2014

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dx.doi.org/10.1021/cg501327u | Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design

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Table 1. Crystal Data and Structure Refinement Results for Complexes 1−8 empirical formula formula weight crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z F(000) ρcalcd (g cm−3) μ (mm−1) reflections collected unique reflections parameters Rint S on F2 R1 (I > 2s(I))a wR2 (I > 2s(I))b R1 (all data)a wR2 (all data)b Δρmax and min [e·Å−3] empirical formula formula weight crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z F(000) ρcalcd (g cm−3) μ (mm−1) reflections collected unique reflections parameters Rint S on F2 R1 (I > 2σ(I))a wR2 (I > 2σ(I))b R1 (all data)a wR2 (all data)b Δρmax and min [e·Å−3] a

1

2

3

4

C23H29N5O6Zn 536.92 monoclinic P2(1)/c 9.116(3) 15.980(4) 17.767(6) 90.00 104.794(5) 90.00 2502.2(12) 4 1120 1.425 1.029 18799 5600 319 0.0312 1.062 0.0416 0.1197 0.0504 0.1265 0.886 and −0.301 5 C15H16N2O5.5Zn 377.71 triclinic P1̅ 8.745(7) 9.586(7) 11.067(8) 109.630(7) 98.883(2) 110.217(6) 780.6(10) 2 388 1.607 1.604 6119 3541 219 0.0236 1.036 0.0393 0.0889 0.0486 0.0938 0.622 and −0.635

C16H17N2O5Zn 382.73 monoclinic P2(1)/c 9.822(3) 11.243(3) 14.853(4) 90.00 102.329(6) 90.00 1602.3(8) 4 788 1.586 1.562 12254 3647 218 0.0217 1.058 0.0234 0.0636 0.0256 0.0646 0.299 and −0.246 6 C16H17N2O5Zn 382.73 triclinic P1̅ 8.391(6) 9.592(7) 11.629(8) 105.315(3) 99.009(4) 112.488(9) 798.5(10) 2 394 1.592 1.567 6229 3633 219 0.0216 1.055 0.0350 0.0864 0.0414 0.0904 0.460 and −0.529

C36H36N10O13Zn2 947.55 monoclinic P2(1)/c 10.247(2) 23.161(5) 19.960(4) 90.00 106.049(9) 90.00 4552.5(16) 4 1964 1.396 1.124 36037 10334 550 0.0382 1.202 0.0842 0.2237 0.0949 0.2318 0.960 and −0.837 7 C23H28N4O5Zn 505.90 monoclinic P2(1)/c 9.385(2) 16.725(4) 14.749(4) 90.00 97.937(3) 90.00 2292.8(9) 4 1056 1.465 1.114 26071 5236 301 0.0335 1.092 0.0256 0.0703 0.0285 0.0717 0.372 and −0.278

C31H28N8O12.5Zn2 843.42 triclinic P1̅ 11.562(8) 12.576(8) 13.534(8) 62.825(14) 86.35(2) 85.12(2) 1744(2) 2 860 1.606 1.452 10756 6075 487 0.0419 1.118 0.0727 0.1454 0.1108 0.1657 0.505 and −0.357 8 C20H21N5O6Zn 492.82 orthorhombic Pnna 8.6341(4) 17.5103(10) 14.8764(7) 90.00 90.00 90.00 2249.1(2) 8 1016 1.455 1.138 16244 2590 148 0.0214 1.095 0.0333 0.0875 0.0375 0.0905 0.567 and −0.335

R1 = ∑∥Fo| − |Fc∥/∑|Fo|. bwR2 = [∑w(Fo2− Fc2)2/∑w(Fo2)2]1/2.

isophthalates on structures and performances of the resultant MOFs. For examples, Du et al. have demonstrated that the coordination-inert substitutes may influence structural diversity of the final MOFs.32 Braga et al. found that the size of the substituents may induce different shapes and functions of the target complexes.35 Wang et al. reported that a bulky toluene substitutent may result in the formation of low-dimensional

2-D networks. Furthermore, the structures and properties of resultant MOFs are readily modified through changing electronic and steric characters in five-positioned substituents of isophthalates.32−34 It has been reported that a slight variation of the substituents may generate MOFs with different structures, and many efforts have been devoted to investigating the effects of steric and electronic characters of 5-positioned substituents in B



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Figure 1. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 1. (b) View of the 1-D chain constructed by Zn(II) and EtO-ip. (c) View of a corrugated 2-D layer along the a axis in 1. (d) View of the packing diagram along the c axis in 1. (e) View of the packing diagram with DMF guest molecules along the a axis in 1.

coordination polymers.36 In our previous study, we have also reported a series of layer-pillared MOFs through the assembly of 5-hydroxyisophthalate and flexible bis(imidazolyl) ligands.37−40 In these MOFs, the hydroxyl of 5-hydroxyisophthalate (HO-ip) is not involved in coordination toward transition metal ions, but it can serve as a hydrogen-bonded donor to induce the formation of interpenetration of two or more independent frameworks through strong hydrogen-bonded interaction between hydroxyl and carboxylate oxygen atoms. It can be speculated that the replacement of hydroxyl of HO-ip by an alkyloxo group can prevent the formation of the hydrogen bond and take on some spatial effects in the assembly process, resulting in MOFs with

different structures and functions.41−44 As a continuation of our effort in the construction of MOFs using 5-substituted isophthalates and flexible bis(imidazolyl) ligands,37−40 herein, we report the syntheses, structures, and luminescent properties of eight Zn(II) coordination polymers, [Zn(EtO-ip)(bimb)]n(DMF)n (1), [Zn(PrO-ip)(bimb)0.5]n (2), [Zn2(NO2-ip)2(bimb)2]n(H2O)n (3), [Zn2(NO2-ip)2(bimb)1.5]n(H2O)n (4), [Zn(MeO-ip)(bmib) 0.5 ] n (H 2 O) 0.5n (5), [Zn(EtO-ip)(bmib)0.5]n(6), [Zn(PrO-ip)(bmib)]n (7), and [Zn(NO2-ip)(bmib)]n (8) (MeO-ip = 5-methoxyisophthalate, EtO-ip = 5-ethoxyisophthalate, PrO-ip = 5-propoxyisophthalate, NO2-ip = 5-nitroisophthalate). C



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Figure 2. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 2. (b) View of the 2-D layer along the a axis in 2. (c) View of the 3-D network of 2. (d) View of six-connected binuclear Zn(II) unit in 2. (e) View of the 3-D topology in 2.

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H, and N elemental analyses were determined on an EA1110 CHNS-0 CE element analyzer. Synthesis of [Zn(EtO-ip)(bimb)]n(DMF)n (1). A mixture of EtOH2ip (42 mg, 0.20 mmol), bimb (38 mg, 0.20 mmol), Zn(NO3)2·6H2O (49 mg, 0.17 mmol), NaOCH3 (10 mg, 0.19 mmol), and DMF (8 mL) was placed in a Teflon-lined stainless steel vessel (20 mL) and then heated to 100 °C for 3 days, followed by slowly cooling to room temperature at a rate of 5 °C·h−1. After they cooled to room temperature, the colorless crystals of 1 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 34 mg [37% based on Zn(NO3)2·6H2O]. Anal. Calcd for C20H22N4O5Zn·DMF (536.92): C, 51.45; H, 5.44; N, 13.04; Found: C, 50.78; H, 5.35; N, 12.91. IR (KBr, cm−1): 3443 (s), 3128 (s), 2980 (w), 2936 (w), 2872 (vw), 1622 (vs), 1578 (vs), 1531 (s), 1452 (s), 1385 (vs), 1352 (vs), 1261 (s),

EXPERIMENTAL SECTION 43

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Materials and General Methods. MeO-H2ip, EtO-H2ip, PrOH2ip,44 bimb,45 and bmib46 were prepared according to the literature methods. All other chemicals were commercially available and used as purchased. IR spectra (KBr pellets) were recorded on a Magna 750 FT-IR spectrophotometer in the range of 400−4000 cm−1. Luminescent spectra were recorded on an Edinburgh Instruments FLS920 spectrofluorimeter equipped with both continuous-wave (450 W) and pulse xenon lamps. Powder X-ray diffraction data (PXRD) were recorded on a PANaytical X′pert pro X-ray diffractometer with graphite-monochromatized Cu−Kα radiation (λ = 1.542 Å). Thermogravimetric analyses (TGA) were carried out on a NETSCHZ STA 449C thermoanalyzer under N2 at a heating rate of 10 °C/min. C, D



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Figure 3. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 3. (b) View of the π···π interaction between two independent fragments. (c) Two independent 2-D (4,4) grids in 3. (d) Mutual interpenetration of two independent (4,4) grids in 3. water (10 mL), and CH3OH (8 mL) was placed in a Teflon-lined stainless steel vessel (25 mL) and then heated to 170 °C for 3 days, without a processing decrease. After they cooled to room temperature, the light yellow crystals of 4 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 28 mg [27% based on NO2-H2ip]. Anal. Calcd for C31H27N8O12Zn2·0.5H2O (843.42): C, 44.15; H, 3.35; N, 13.29; Found: C, 44.28; H, 3.29; N, 13.36. IR (KBr, cm−1): 3565 (w), 3479 (s), 3133 (s), 3047 (vw), 2952 (s), 2868 (w), 2817 (vw), 2693 (vw), 1933 (vw), 1859 (vw), 1660 (vs), 1636 (vs), 1574 (s), 1534 (vs), 1459 (vs), 1403 (s), 1384 (vs), 1366 (vs), 1350 (vs), 1282 (s), 1253 (s), 1240 (s), 1202 (w), 1165 (vw), 1112 (vs), 1095 (vs), 1077 (s), 1037 (s), 1029 (w), 998 (vw), 951 (vs), 930 (s), 922 (s), 848 (s), 787 (vs), 760 (s), 732 (vs), 722 (vs), 658 (s), 624 (s), 535 (s), 510 (vw), 487 (vw), 460 (w). Synthesis of [Zn(MeO-ip)(bmib)0.5]n(H2O)0.5n (5). A mixture of MeO-H2ip (49 mg, 0.25 mmol), bmib (55 mg, 0.25 mmol), Zn(OAc)2· 2H2O (55 mg, 0.25 mmol), deionized water (2 mL), and five drops of aqueous NaOH (1 mol·L−1) was placed in a Teflon-lined stainless steel vessel (20 mL) and then heated to 180 °C for 3 days, followed by slowly cooling to room temperature at a rate of 5 °C·h−1. After they cooled to room temperature, the light yellow block crystals of 5 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 37 mg [39% based on Zn(OAc)2·2H2O]. Anal. Calcd for C15H15N2O5Zn·0.5H2O (377.71): C, 47.70; H, 4.27; N, 7.42; Found: C, 47.93; H, 4.19; N, 7.33. IR (KBr, cm−1): 3854 (vw), 3745 (vw), 3448 (s), 3152 (w), 3124 (s), 3089 (w), 3014 (w), 2963 (w), 2940 (w), 2834 (vw), 2366 (vw), 2345 (vw), 1635 (vs), 1560 (vs), 1507 (s), 1450 (vs), 1404 (vs), 1384 (vs), 1350 (vs), 1283 (s), 1264 (vs), 1221 (w), 1166 (s), 1131 (s), 1099 (vw), 1056 (vs), 1019 (s), 944 (vw), 923 (w), 905 (w), 880 (w), 810 (w), 781 (vs), 757 (s), 722 (s), 678 (w), 636 (w), 587 (w), 530 (vw), 494 (vw), 482 (vw), 437 (w), 420 (vw). Synthesis of [Zn(EtO-ip)(bmib)0.5]n (6). A mixture of EtO-H2ip (52 mg, 0.25 mmol), bmib (55 mg, 0.25 mmol), Zn(OAc)2·2H2O (165 mg, 0.75 mmol), deionized water (12 mL), and five drops of aqueous NaOH (1 mol·L−1) was placed in a Teflon-lined stainless steel vessel (20 mL) and then heated to 120 °C for 3 days, followed by slowly cooling to room temperature at a rate of 3 °C·h−1. After they cooled to

1238 (s), 1165 (vw), 1113 (vs), 1053 (s), 1003 (vw), 984 (vw), 953 (s), 918 (vw), 876 (w), 841 (w), 783 (vs), 752 (s), 729 (s), 658 (s), 629 (w), 546 (w), 465 (w). Synthesis of [Zn(PrO-ip)(bimb)0.5]n (2). A mixture of PrO-H2ip (63 mg, 0.30 mmol), bimb (29 mg, 0.15 mmol), Zn(NO3)2·6H2O (87 mg, 0.30 mmol), NaOCH3 (27 mg, 0.50 mmol), and deionized water (15 mL) was placed in a Teflon-lined stainless steel vessel (20 mL) and then heated to 160 °C for 3 days, followed by slowly cooling to room temperature at a rate of 3 °C·h−1. After they cooled to room temperature, the colorless crystals of 2 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 36 mg [31% based on bimb]. Anal. Calcd for C16H17N2O5Zn (382.73): C, 50.21; H, 4.48; N, 7.32; Found: C, 50.60; H, 4.52; N, 7.47. IR (KBr, cm−1): 3446 (w), 3137 (w), 3095 (s), 3056 (vw), 3022 (vw), 2962 (s), 2941 (w), 2878 (w), 2361 (vw), 2344 (vw), 1684 (w), 1624 (vs), 1578 (vs), 1534 (s), 1448 (s), 1437 (s), 1418 (vs), 1390 (vs), 1362 (vs), 1319 (s), 1306 (w),1287 (vw), 1265 (s), 1254 (w), 1109 (s), 1047 (s), 994 (vw), 958 (s), 930 (w), 904 (s), 898 (s), 889 (s), 855 (vw), 800 (s), 778 (vs), 756 (s), 722 (s), 662 (s), 603 (vw), 554 (w), 455 (w). Synthesis of [Zn2(NO2-ip)2(bimb)2]n(H2O)n (3). A mixture of NO2-H2ip (106 mg, 0.5 mmol), bimb (95 mg, 0.5 mmol), Zn(NO3)2· 6H2O (19 mg, 0.064 mmol), and DMF (10 mL) was placed in a Teflonlined stainless steel vessel (25 mL) and then heated to 120 °C for 3 days, without a processing decrease. After they cooled to room temperature, the light yellow crystals of 3 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 10 mg [33% based on Zn(NO3)2·6H2O]. Anal. Calcd for C36H34N10O12Zn2·H2O (947.55): C, 45.63; H, 3.83; N, 14.78; Found: C, 45.22; H, 4.23; N, 15.01. IR (KBr, cm−1): 3449 (s), 3130 (s), 3049 (vw), 2946 (s), 2864 (w), 2813 (vw), 2361 (vw), 2337 (vw), 1669 (vs), 1636 (vs), 1573 (vs), 1559 (s), 1529 (vs), 1490 (vw), 1449 (vs), 1384 (vs), 1352 (vs), 1281 (w), 1239 (s), 1222 (w), 1196 (w), 1158 (w), 1107 (vs), 1035 (w), 994 (vw), 954 (s), 923 (s), 858 (s), 788 (vs), 730 (vs), 659 (vs), 630 (s), 543 (w), 453 (w). Synthesis of [Zn2(NO2-ip)2(bimb)1.5]n(H2O)n (4). A mixture of NO2-H2ip (43 mg, 0.25 mmol), bimb (44 mg, 0.25 mmol), Zn(NO3)2· 6H2O (87 mg, 0.30 mmol), NaOCH3 (27 mg, 0.50 mmol), deionized E



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Figure 4. (a) View of coordination environments of Zn(II) with thermal ellipsoid at 30% level in 4. (b) View of the 1-D chain constructed by NO2-ip and Zn(II). (c) View of 2-D layer generated through bimb bridging 1-D chains in 4. (d) View of the 3-D framework in 4. (e) 2-fold interpenetrating (4, 6)connected fsh topology in 4. room temperature, the light yellow block crystals of 6 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 35 mg [37% based on EtO-H2ip]. Anal. Calcd for C16H17N2O5Zn (382.73): C, 50.21; H, 4.48; N, 7.32; Found: C, 50.47; H, 4.57; N, 7.36. IR (KBr, cm−1): 3443 (s), 3139 (w), 3108 (s), 3079 (w), 2980 (s), 2933 (s), 2889 (w), 2648 (vw), 2529 (vw), 2372 (vw), 2346 (w), 2289 (w), 1627 (vs), 1594 (vs), 1558 (vs), 1507 (s), 1457 (s), 1419 (s), 1386 (vs), 1355 (vs), 1323 (s), 1282 (s), 1264 (s), 1165 (s), 1132 (s), 1115 (s), 1057 (s), 1004 (s), 987 (w), 907 (w), 880 (w), 808 (s), 792 (s), 779 (s), 723 (s), 680 (w), 628 (w), 613 (w), 574 (vw), 537 (w), 487 (w), 450 (vw), 432 (w). Synthesis of [Zn(PrO-ip)(bmib)]n (7). A mixture of PrO-H2ip (34 mg, 0.15 mmol), bmib (66 mg, 0.30 mmol), Zn(NO3)2·6H2O (87 mg, 0.30 mmol), NaOCH3 (27 mg, 0.50 mmol), and deionized water (8 mL) was placed in a Teflon-lined stainless steel vessel (20 mL) and then heated to 160 °C for 3 days, followed by slowly cooling to room temperature at a rate of 3 °C·h−1. After they cooled to room temperature, the colorless crystals of 7 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 21 mg [28% based on PrO-H2ip]. Anal. Calcd for C23H28N4O5Zn (505.90): C, 54.60; H, 5.58; N, 11.07; Found: C, 54.68; H, 5.54; N, 11.05. IR (KBr, cm−1): 3460 (s), 3117 (w), 3103 (s), 3073 (w), 2970 (s), 2938 (w), 2923 (w), 2913 (w), 2875 (w), 2637 (vw), 1623 (vs), 1589 (vs), 1544 (s), 1503 (s), 1451 (s), 1431 (s), 1378 (vs), 1326 (vs), 1281 (vs), 1262 (s), 1250 (s), 1197 (vw), 1165 (w), 1156 (w), 1141 (w), 1119 (s), 1098 (s), 1051 (s), 1038 (w), 1014 (s), 991 (w), 945 (vw), 925 (vw),

908 (w), 874 (vw), 810 (vw), 795 (s), 773 (vs), 719 (vs), 681 (s), 674 (s), 625 (w), 593 (vw), 550 (vw), 512 (w), 481 (w). Synthesis of [Zn (NO2-ip) (bmib)]n (8). A mixture of NO2-H2ip (40 mg, 0.20 mmol), bmib (33 mg, 0.15 mmol), Zn(NO3)2·6H2O (60 mg, 0.20 mmol), deionized water (2 mL), CH3OH (4 mL), and five drops of aqueous NaOH (1 mol·L−1) was placed in a Teflon-lined stainless steel vessel (10 mL) and then heated to 160 °C for 3 days, followed by slowly cooling to room temperature at a rate of 3 °C·h−1. After they cooled to room temperature, the light yellow block crystals of 8 were obtained. The crystals were collected by filtration, washed with H2O, and dried in air. Yield: 28 mg [38% based on bmib]. Anal. Calcd for C20H21N5O6Zn (492.82): C, 48.74; H, 4.30; N, 14.21; Found: C, 48.14; H, 4.10; N, 14.05. IR (KBr, cm−1): 3436 (w), 3744 (vw), 3688 (vw), 3150 (vw), 3129 (s), 3096 (w), 2972 (w), 2940 (w), 2865 (vw), 1859 (vw), 1638 (vs), 1578 (s), 1534 (vs), 1506 (s), 1486 (vw), 1450 (s), 1384 (s), 1374 (s), 1355 (vs), 1340 (vs), 1319 (s), 1305 (s), 1281 (s), 1158 (s), 1124 (s), 1089 (s), 1078 (s), 1002 (s), 931 (s), 921 (w), 787 (s), 776 (w), 761 (s), 754 (s), 736 (vs), 730 (vs), 723 (vs), 693 (s), 667 (vs), 624 (w), 577 (vw), 555 (w), 507 (vw), 459 (s). X-ray Crystallography. Single crystals of complexes 1−8 were mounted on a glass fiber for X-ray diffraction analysis. Data sets were collected on a Rigaku AFC7R equipped with a graphite-monochromated Mo−Kα radiation (λ = 0.71073 Å) from a rotating anode generator at 293 K. Intensities were corrected for LP factors and empirical absorption using the ψ scan technique. The structures were solved by direct methods and refined on F2 with full-matrix least-squares F



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Figure 5. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 6. (b) View of the 1-D double chain constructed by Zn(II) and EtO-ip in 6. (c) View of the 2-D layer in complex 6. (d) View of the packing diagram of the 2-D layers in complex 6. (e) View of the packing diagram of the 2-D layers in complex 5. techniques using the SHELX-97 program package.47,48 All nonhydrogen atoms were refined anisotropically. The positions of hydrogen atoms were generated geometrically (C−H bond fixed at 0.96 Å), assigned isotropic thermal parameters, and allowed to ride on their parent carbon atoms before the final cycle of refinement. Crystal data as well as details of data collection and refinement for complexes 1−8 are summarized in Table 1. The selected bond distances and bond angles are given in Table S1 (Supporting Information). Crystallographic data of 1−8 have been deposited in the Cambridge Crystallographic Data Centre as supplementary publication with CCDC numbers: 1022165− 1022172.

Scheme 1. Coordinaton Modes of 5-Substituted Isophthalates Used in This Work

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RESULTS AND DISCUSSION Structural Descriptions. Crystal Structure of [Zn(EtO-ip)(bimb)]n(DMF)n (1). Single-crystal X-ray diffraction analysis shows that complex 1 crystallizes in the monoclinic space group P2(1)/c, and is a corrugated 2-D layer. The asymmetric unit contains one Zn(II), one EtO-ip, one bimb, and one DMF molecule. As shown in Figure 1a, Zn(II) shows a distorted tetrahedral geometry and is coordinated by two carboxylate oxygen atoms from different MeO-ip and two imidazolyl nitrogen atoms from different bimb ligands. The average Zn−O and Zn−N bond distances are 1.969 and 2.022 Å, respectively. In 1, EtO-ip acts as a bis-monodentate bridge (Scheme 1a), the twisting angles of two carboxylate groups with the central phenyl ring are 12.453° and 13.795°, respectively. EtO-ip connects Zn(II) into a 1-D chain (Figure 1b), where the adjointing Zn···Zn separation is 9.158 Å. Such a 1-D chain is further linked by exo-bidentate bimb to form a corrugated 2-D

layer (Figure 1c), in which the Zn···Zn distance separated by bimb is 12.787 Å. Bimb adopts an anti-anti-gauche conformation with the dihedral angle between two imidazolyl rings being 25.462°. Interestingly, each layer is partially interpenetrated with the adjacent layers in an offset mode through the EtO group of EtO-ip (Figure 1d). DMF serves as guest molecules and further fill with the void space in complex 1. Crystal Structure of [Zn(PrO-ip)(bimb)0.5]n (2). Complex 2 also crystallizes in the monoclinic space group P2(1)/c. As shown in Figure 2a, two equivalent Zn(II) are bridged by two μ2,η2carboxylate groups from different PrO-ip to form a dinuclear Zn(II)-dicarboxylate unit. The Zn···Zn distance in the dinuclear G



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Figure 6. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 7. (b) View of the 1-D chain constructed by Zn(II) and bmib. (c) View of the 2-D layer along the a axis in 7. (d) View of the packing diagram along the c axis in 7.

Crystal Structure of [Zn2(NO2-ip)2(bimb)2]n(H2O)n (3). Complex 3 also crystallizes in the monoclinic space group P2(1)/c, but it consists of two sets of mutual interweaving 2-D layers. As shown in Figure 3a, the asymmetric unit contains two independent molecular fragments; each Zn(II) is fourcoordinated by two carboxylate oxygen atoms from different NO2-ip and two imidazolyl nitrogen atoms from different bimb in a distorted tetrahedral geometry. Interestingly, two distinct fragments form a π···π stacking interaction through phenyl rings of NO2-ip with a centroid-to-centroid distance of ca. 3.629 Å (Figure 3b), which is responsible for the stabilization of the whole structural framework. Similar to EtO-ip in 1, NO2-ip adopts a bis-monodentate bridging mode (Scheme 1c). The other interestering feature in 3 is that there are three kinds of bimb ligands, namely, bimb1 (N1-N4), bimb2 (N7-N8), and bimb3 (N9-N10). bimb1 and bimb2 adopt a gauche-anti-gauche configuration, while bimb3 shows an anti-gauche-anti conformation. NO2-ip and bimb1 link Zn1 into a (4,4) grid (Figure 3c, left). The Zn···Zn distances separated by NO2-ip and bimb1 are 10.247 and 11.812 Å, respectively. Zn2 is bridged by NO2-ip, bimb2, and bimb3 to form the other (4,4) grid (Figure 3c, right). The Zn···Zn distances across NO2-ip, bimb2, and bimb3 are 10.014, 12.544, and 13.990 Å, respectively. Mutual interpenetration

metal unit is 3.938 Å. Each Zn(II) is in a distorted tetrahedral geometry and is coordinated by three oxygen atoms from different PrO-ip and one nitrogen atom from bimb. Different from the coordination mode of EtO-ip in 1, PrO-ip serves as a μ3-bridge through its μ2,η2-carboxylate and monodentate carboxylate groups (Scheme 1b). The twisting angle of the former with the central phenyl ring is 3.231°, which is slightly larger than that of the latter (1.876°). Notably, PrO-ip links two adjacent dinuclear metal units into a 2-D layer (Figure 2b), in which the PrO group of PrO-ip alternately points toward opposite directions. The neighboring layers are extended by exo-bidentate bimb, generating a 3-D network (Figure 2c), in which bimb adopts a gauche-anti-gauche conformation, and two imidazolyl rings are parallel to each other owing to center symmetry. In order to better understand the final architecture of complex 2, the topological analysis was carried out. Taking the dinuclear Zn(II) unit as one node, each dinuclear unit becomes a six-connected node (Figure 2d). PrO-ip and bimb can be regarded as independent two-connected vertices that link two adjacent dinuclear metal units. The interlinkage of six dinuclear metal units with four PrO-ip ligands and two bimb ligands generates a six-connected mab topology (Figure 2e). The Schläfli symbol is (44.610.8). H



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of the two types of (4,4) grids results in the formation of a 3-D framework (Figure 3d). Crystal Structure of [Zn2(NO2-ip)2(bimb)1.5]n(H2O)n (4). Complex 4 crystallizes in the triclinic space group P1̅ and is a 2-fold interpenetrating 3-D network. As shown in Figure 4a, there are two crystallographically independent Zn(II) ions (Zn1 and Zn2). Zn1 is in a distorted square-pyramidal geometry. The basal plane is determined by four carboxylate oxygen atoms from different NO2-ip with the average bond length of Zn1−O being 2.031 Å. The apical position is occupied by one imidazolyl nitrogen atom with the bond length of Zn1−N being 2.012 Å. Each pair of Zn1(II) is equivalently bridged by four μ2,η2carboxylate groups from different NO2-ip to generate a classical [Zn2(O2C)4] paddle-wheel dinuclear metal unit. The Zn···Zn distance in the dinuclear metal unit is 3.029 Å, which is much shorter than that in 2. Zn2 is in a distorted tetrahedral geometry and is coordinated by two carboxylate oxygen atoms from different NO2-ip and two imidazolyl nitrogen atoms from different bimb. Similar to PrO-ip in 2, two carboxylate groups in NO2-ip function in μ2,η2-bridging and monodentate modes, respectively (Scheme 1d), and their twisting angles with the central phenyl rings are 6.437° and 10.915°, respectively, which are slightly larger than the corresponding values in 2. NO2-ip alternately links single metal centers and dinuclear metal units into a 1-D chain containing square-shaped cavities (Figure 4b). There are two kinds of bimb. One adopts an anti-gauche-gauche conformation and connects the adjacent 1-D chains into a 2-D layer through bridging between single Zn(II) ions and dinuclear Zn(II) units (Figure 4c), where the Zn···Zn separation across bimb and the dihedral angle between two imidazolyl rings in bimb are 10.409 Å and 51.048°, respectively. The other adopts a gauche-anti-gauche conformation to further stretch the 2-D layer into a 3-D framework by bridging single Zn(II) ions (Figure 4d). The Zn···Zn distance between layers bridged by bimb is 12.402 Å, and two imidazolyl rings are parallel to each other owing to center symmetry. However, due to the absence of large guest molecules to fill the void space in the 3-D framework, instead of forming an open microporous structure, a 2-fold interpenetrating 3-D architecture is generated. From the topological view, each dinuclear [Zn2(O2C)4] unit can be considered as a six-connected node, and Zn2 is taken as a four-connected node. NO2-ip and bimb can be regarded as independent two-connected linkers. Thus, the 3-D structure of 4 can be simplified to a bimodal (4, 6)connected fsh network with the Schläfli symbol of (43.63)2(46.66.83) (Figure 4e). Crystal Structures of [Zn(MeO-ip)(bmib)0.5]n(H2O)0.5n (5) and [Zn(EtO-ip)(bmib)0.5]n (6). The structures of complexes 5 and 6 are very similar to each other and feature a 2-D network; herein, we only describe the structure of 6 in detail and mention the difference between 5 and 6. As shown in Figure 5a, the asymmetric unit of 6 is made up of one Zn(II), one EtO-ip, and half of bmib. The distorted tetrahedral Zn(II) is coordinated by one imidazolyl nitrogen atom from bmib and three carboxylate oxygen atoms from different EtO-ip. The Zn−N and Zn−O bond lengths are in the range of 1.904−2.008 Å and are comparable with those in complexes 1−4. EtO-ip bridges three Zn(II) through its μ2,η2-carboxylate and monodentate carboxylate groups (Scheme 1e), and the twisting angle between the μ2,η2-carboxylate group and the central phenyl ring is 17.580°, which is larger than that between the monodentate carboxylate and the phenyl ring (12.912°). Two symmetry-related Zn(II) are bridged by a pair of syn-anti carboxylate groups from different EtO-ip to form a dinuclear metal unit, and the Zn···Zn distance in

Figure 7. (a) View of coordination environment of Zn(II) with thermal ellipsoid at 50% level in 8. (b) View of the 3D framework along the b axis (left) and two types of helical chains constructed from Zn(II) and NO2-ip (right). (c) View of 3-fold interpenetrating 4-connected dmp topology in 8.

the dinuclear metal unit is 3.953 Å, which is much longer than that in 4. The adjacent dinuclear Zn(II) units are connected by EtO-ip to form a 1-D chain (Figure 5b). The Zn···Zn distance across EtO-ip is 9.592 Å. The chains are further linked by bmib to generate a 2-D layer (Figure 5c), and the chain−chain distance separated by bmib is 12.702 Å. There are no worthywhile interactions among adjacent 2-D layers (Figure 5d). Interestingly, bmib in 6 adopts a gauche-anti-gauche conformation, while bmib in 5 shows an anti-anti-anti conformation with the Zn···Zn distance across bmib being 14.025 Å, which is larger than that in 6. The longer bridging length across bmib and the smaller 5-positioned MeO substitutent in 5 result in the presence of guest water molecules to fill void space of the structural framework (Figure 5e). I



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Scheme 2. Summary of Crystal Strutrues in Complexes 1−8

Crystal Structure of [Zn(PrO-ip)(bmib)]n (7). Similar to complex 1, complex 7 is also a 2-D corrugated layer, although different carboxylate and bis(imidazolyl) ligands are used. As shown in Figure 6a, Zn(II) is in a distorted tetrahedral geometry and is coordinated by two carboxylate oxygen atoms from different PrO-ip and two imidazolyl nitrogen atoms from different bmib. Different from 1, exo-bidentate bmib exhibits a gauche-gauche-gauche conformation, and the twisting angle between two imidazolyl rings is 64.635°, which is much larger than that of bimb in 1. Bmib bridges two adjacent Zn(II), forming a 1-D chain (Figure 6b), and the Zn···Zn separation across bmib is 11.810 Å. PrO-ip adopts a bis-monodentate bridging mode (Scheme 1f) and further links 1-D chains into a corrugated 2-D layer (Figure 6c). The adjoining Zn···Zn distance across PrO-ip is 7.875 Å. Different from 1, the PrO group in PrO-ip is completely threaded into the lateral void of the adjacent layers (Figure 6d). As a result, there is no free water molecule because the void space in the resultant network is occupied by the methyl group of bmib and the PrO group of PrO-ip. Crystal Structure of [Zn (NO2-ip)(bmib)]n (8). Complex 8 crystallizes in the orthorhombic space group Pnna and is a 3-fold interpenetrating 3-D framework. As shown in Figure 7a, Zn(II) is coordinated by two oxygen atoms from different NO2-ip and two nitrogen atoms from different bmib to form a ZnO 2N 2 tetrahedral geometry. The bond distances of Zn−O and Zn−N are 1.943 and 2.017 Å, respectively. Similar to NO2-ip in 3, two carboxylate groups in NO2-ip adopt a bis-monodentate coordination mode (Scheme 1c), but NO2-ip connects two adjacent Zn(II) into left-handed and right-handed helical chains (Figure 7b, right). The pitch of the helical chains is 17.510 Å, which is the same as the length of the b axis. It is noteworthy that left- and right-handed helical chains are present in equal numbers; thus, the whole crystal structure is racemic. In 8, bmib has a center symmetry and exhibits an anti-anti-anti conformation, and the plane of the N(CH2)4N spacer is steeply inclined to the plane of the imidazolyl ring by 76.609°. 1-D helical chains are extended by bmib to form a 3D reticular network (Figure 7b, left). There are no guest molecules inside the cavities. In order to minimize the presence of large cavities and stabilize the framework, the other two identical networks are filled in the cavities, giving a 3-fold interpenetrating architecture. From the topological view, Zn(II) can be considered as 4-connected nodes, and NO2-ip and bmib serve as twoconnected linkers. The structure of 8 shows a 4-connected (65.8)-dmp topology (Figure 7c).

Figure 8. TGA curves of complexes 1−8.

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DISCUSSION It is well-known that organic ligands play a crucial role in the construction of MOFs. Coordination-inert groups in organic ligands are not involved in coordination with metal ions, but their electronic and steric characters have important effects on the structures and properties of resultant MOFs. The assembly of HO-ip, bimb, and Zn(II) generated a 2D → 3D polythreaded framework,30 in which hydrogen bonds between hydroxyl and carboxylate of HO-ip play an inducing role for the formation of the unusual framework. The reaction of MeO-ip, bimb, and Zn(II) ion resulted in the formation of a corrugated 2-D layer.41 We have also constructed a series of MOFs using HO-ip and flexible bis(imidazolyl) ligands.39,40 These interesting results prompted us to systematically explore the effects of 5-positioned coordination-inert substitutents on the structures and performances of MOFs. As shown in Scheme 2, the hydrothermal reaction of EtO-ip, bimb, and Zn(II) produced complex 1, and its structural framework is similar to that from MeO-ip.41 Slight variation of 5-positioned substitutents from EtO to PrO resulted in the formation of a 3-D MOF consisting of dinuclear Zn(II) units (complex 2). As a comparison, the effect of electronwithdrawing substitutents on the assembly process was also explored. The reaction of NO2-ip, bimb, and Zn(II) gave rise to an unprecedented 3-D framework consisting of two independent 2-D layers (complex 3) and a 2-fold interpenetrating 3-D network (complex 4), respectively. In comparison with bimb, bmib possesses bulkier steric hindrance; their assembly with metal ions J



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Figure 9. Photoluminescence spectra and excitation spectra (inset) of 1−8 at room temperature.

group in PrO-ip is completely threaded into the lateral void of the adjacent layers, resulting in the absence of guest molecules in complex 7. Notably, NO2-ip adopts a bis-monodentate bridging mode and Zn(II) is in a distorted tetrahedral geometry in complexes 3 and 8, but their final structures are much different from each other. NO2-ip in complex 8 connects two adjacent Zn(II) into left-handed and right-handed helical chains, and further extension by bmib resulted in the formation of a 3-fold interpenetrating 3-D network. PXRD and Thermal Analysis. In order to check the phase purity of these complexes, PXRD of complexes 1−8 was

can produce distinct MOFs. The reaction of MeO-ip, bmib, and Zn(II) gave a 2-D layer consisting of dinuclear Zn(II) units (complex 5); similar structural framework was obtained when MeO-ip was replaced by EtO-ip (complex 6). These results show that MeO and EtO substitutents have no obvious effect on structures of the resultant MOFs. The framework of complexes 5 and 6 is much different from that in complex 1, which is probably ascribed to the difference of steric hindrance between bis(imidazolyl) ligands. Interestingly, the use of PrO-ip gave a complex 7, whose structure is similar to that of complex 1, but the bulky PrO K



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consisting of dinuclear Zn(II) units, while 1 and 7 are corrugated 2-D layers consisting of Zn(II) ions. Complex 8 is a 3-fold interpenetrated network consisting of left- and right-handed helical chains. Zn(II) in complexes 1−8 is in a distorted tetrahedral geometry except that of the dinuclear paddle-wheel unit in complex 4. In summary, this study has demonstrated that 5-positioned coordination-inert substitutents of isophathlate and steric hindrance of flexible bis(imidazolyl) ligands play an important role in the construction of MOFs; this provides an interesting insight into the assembly of Zn(II) coordination polymers through varying inert substituents of organic ligands.

measured at room temperature. As shown in Figure S1 in the Supporting Information, the PXRD patterns for the assynthesized bulk materials match well with the simulated ones from the single-crystal X-ray diffraction analysis, demonstrating good phase purity of the complexes. The differences in intensity may be ascribed to the preferable orientation of the crystalline powder samples. To determine the thermal stability of these compounds, their TGA was investigated under a nitrogen atmosphere (Figure 8). For complex 1, the weight loss of 13.60% from 120 to 200 °C is assigned to the removal of free DMF molecules (calcd 13.61%). The complex starts to decompose after 310 °C. For 2, no obvious weight loss is observed before 300 °C. A weight loss of 1.97% is observed for 3 in the temperature range of 30−120 °C, which is attributed to the loss of lattice water molecules (calcd 1.90%), and the complex begins to decompose at 180 °C. For 4, the weight loss of free water molecules is observed below 140 °C (obsd 1.70%, calcd 1.07%), and the complex starts to decompose after 300 °C. The TGA curve of complex 5 reveals a weight loss from 34 to 227 °C, corresponding to the loss of lattice water molecules (observed, 1.70%, calculated, 2.38%). 6, 7, and 8 were stable up to 355, 330, and 350 °C, respectively. Photoluminescent Properties. The fluorescent properties of complexes 1−8 and the free ligands were studied in the solid state at room temperature. The free ligands bimb and bmib display photoluminescence with emission maxima at 410 nm (λex = 345 nm) and 422 nm (λex = 358 nm) (Figure S2, Supporting Information), respectively, which are assigned to a π* → π or π* → n transition.49 It was reported that the emission of aromatic dicarboxylate ligands belongs to π* → n transitions, which is very weak compared to that of the π* → π transition of bimb, so the dicarboxylates almost have no contribution to the fluorescent emission of as-synthesized complexes.50 The photoluminescent spectra of complexes 1−8 show the emission maxima at 454 nm for 1 (λex = 358 nm), 393 nm for 2 (λex = 324 nm), 408 nm for 3 (λex = 279 nm), 431 nm for 4 (λex = 273 nm), 452 nm for 5 (λex = 356 nm), 464 nm for 6 (λex = 364 nm), 435 nm for 7 (λex = 385 nm), and 409 nm for 8 (λex = 279 nm), respectively (Figure 9). Zn(II) is known to be difficult to oxidize or reduce because of its d10 configuration. As a result, the emissions of complexes 1−8 are neither metal-to-ligand charge transfer (MLCT) nor ligand-to-metal charge transfer (LMCT), which are ascribed to a mixture character of intraligand and ligand-to-ligand charge transition (LLCT).51 The shift of the bands in comparison to those of the free ligands may originate from coordination interactions between Zn(II) and ligands.

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ASSOCIATED CONTENT

S Supporting Information *

PXRD patterns, selected bond lengths and angles for complexes 1−8, photoluminescent spectra of bimb and bmib, X-ray crystallographic files for all the structures in CIF format, and other information. This material is available free of charge via the Internet at http://pubs.acs.org.

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected] (X.L.). Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (21001025), the Provincial Education Department of Fujian (JA12070) and the Program for Innovative Research Team in Science and Technology in Fujian Province University (IRTSTFJ).

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REFERENCES

(1) Cui, Y.; Chen, B.; Qian, G. Coord. Chem. Rev. 2014, 273, 76−86. (2) Foo, M. L.; Matsuda, R.; Kitagawa, S. Chem. Mater. 2014, 26, 310− 322. (3) Coronado, E.; Minguez Espallargas, G. Chem. Soc. Rev. 2013, 42, 1525−1539. (4) Mukherjee, S.; Mukherjee, P. S. Acc. Chem. Res. 2013, 46, 2556− 2566. (5) Li, X. X.; Xu, H. Y.; Kong, F. Z.; Wang, R. H. Angew. Chem., Int. Ed. 2013, 52, 13769−13773. (6) Dang, D.; Wu, P.; He, C.; Xie, Z.; Duan, C. J. Am. Chem. Soc. 2010, 132, 14321−14323. (7) Chen, J.; Li, K.; Chen, L.; Liu, R.; Huang, X.; Ye, D. Green Chem. 2014, 16, 2490−2499. (8) Li, B.; Zhang, Y.; Ma, D.; Ma, T.; Shi, Z.; Ma, S. J. Am. Chem. Soc. 2014, 136, 1202−1205. (9) Zhao, H. X.; Li, X. X.; Wang, J. Y.; Li, L. Y.; Wang, R. H. ChemPlusChem 2013, 78, 1491−1502. (10) Hui, A. K.; Losovyj, Y.; Lord, R. L.; Caulton, K. G. Inorg. Chem. 2014, 53, 3039−3047. (11) Jeong, S.; Kim, D.; Shin, S.; Moon, D.; Cho, S. J.; Lah, M. S. Chem. Mater. 2014, 26, 1711−1719. (12) Huang, J.; Liu, P. Y.; Zhu, H.; Bao, S. S.; Zheng, L. M.; Ma, J. ChemPlusChem 2012, 77, 1087−1095. (13) Zhao, D.; Timmons, D. J.; Yuan, D.; Zhou, H. C. Acc. Chem. Res. 2011, 44, 123−133. (14) LaDuca, R. L. Coord. Chem. Rev. 2009, 253, 1759−1792. (15) Liu, J. Q.; Huang, Y. S.; Zhao, Y. Y.; Jia, Z. B. Cryst. Growth Des. 2011, 11, 569−574. (16) Song, X. Z.; Song, S. Y.; Zhu, M.; Hao, Z. M.; Meng, X.; Zhao, S. N.; Zhang, H. J. Dalton Trans. 2013, 42, 13231−13240.

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CONCLUSIONS Eight Zn(II) coordination polymers have been synthesized by the assembly of Zn(II) salts with 5-substituted isophthalates and flexible bis(imidazolyl) ligands. The 5-positioned substituents of isophthalate derivatives are not involved in coordination with Zn(II), but their steric and electronic characters have demonstrated important effects on structures, thermal stability, and photoluminescent properties of the resultant coordination polymers. Among these polymers, complex 3 exhibits an unprecdented structure consisting of two independent 2-D layers. In 2 and 4, NO2-ip and PrO-ip serve as a μ3-bridge, but complex 2 is a 3-D network consisting of dinuclear Zn(II) units, while complex 4 is a 2-fold interpenetrating 3-D framework consisting of mononuclear and binuclear Zn(II) units. Interestingly, when bmib with bulkier hindrance was used instead of bimb, MOFs with different structures were obtained. 5 and 6 feature 2-D layers L



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(17) Zhang, Z.; Ma, J. F.; Liu, Y. Y.; Kan, W. Q.; Yang, J. Cryst. Growth Des. 2013, 13, 4338−4348. (18) Chu, Q.; Su, Z.; Fan, J.; Okamura, T. a.; Lv, G. C.; Liu, G. X.; Sun, W. Y.; Ueyama, N. Cryst. Growth Des. 2011, 11, 3885−3894. (19) Fan, J.; Gan, L.; Kawaguchi, H.; Sun, W. Y.; Yu, K. B.; Tang, W. X. Chem.Eur. J. 2003, 9, 3965−3973. (20) Zhang, L.; Yao, Y. L.; Che, Y. X.; Zheng, J. M. Cryst. Growth Des. 2010, 10, 528−533. (21) Qi, Y.; Luo, F.; Batten, S. R.; Che, Y. X.; Zheng, J. M. Cryst. Growth Des. 2008, 8, 2806−2813. (22) Qin, J. H.; Ma, L. F.; Hu, Y.; Wang, L. Y. CrystEngComm 2012, 14, 2891−2898. (23) Qi, Y.; Luo, F.; Che, Y. X.; Zheng, J. M. Cryst.Growth Des. 2008, 8, 606−611. (24) Deng, Z. P.; Zhang, Z. Y.; Huo, L. H.; Ng, S. W.; Zhao, H.; Gao, S. CrystEngComm 2012, 14, 6548−6558. (25) Manna, P.; Tripuramallu, B. K.; Das, S. K. Cryst. Growth Des. 2014, 14, 278−289. (26) Dorazco-González, A.; Martinez-Vargas, S.; Hernández-Ortega, S.; Valdés-Martínez, J. CrystEngComm 2013, 15, 5961−5968. (27) Mihalcea, I.; Henry, N.; Loiseau, T. Eur. J. Inorg. Chem. 2014, 2014, 1322−1332. (28) Sengupta, S.; Ganguly, S.; Goswami, A.; Sukul, P. K.; Mondal, R. CrystEngComm 2013, 15, 8353−8365. (29) Panda, T.; Pachfule, P.; Banerjee, R. Chem. Commun. 2011, 47, 7674−7676. (30) Zhang, K. L.; Zhang, J. B.; Jing, C. Y.; Zhang, L.; Walton, R. I.; Zhu, P. Z.; Ng, S. W. J. Solid State Chem. 2014, 21, 18−20. (31) Zhang, Q.; Geng, A.; Zhang, H.; Hu, F.; Lu, Z. H.; Sun, D.; Wei, X.; Ma, C. Chem.Eur. J. 2014, 20, 4885−4890. (32) Chen, J.; Li, C. P.; Du, M. CrystEngComm 2011, 13, 1885−1893. (33) Li, D. X.; Chen, M. M.; Li, F. L.; Ren, Z. G.; Wu, B.; Lang, J. P. Inorg. Chem. Commun. 2013, 35, 302−306. (34) Song, X. Z.; Song, S. Y.; Qin, C.; Su, S. Q.; Zhao, S. N.; Zhu, M.; Hao, Z. M.; Zhang, H. J. Cryst. Growth Des. 2012, 12, 253−263. (35) Braga, D.; D’Agostino, S.; Grepioni, F. CrystEngComm 2011, 13, 1366−1372. (36) Chang, X. H.; Ma, L. F.; Hui, G.; Wang, L. Y. Cryst. Growth Des. 2012, 12, 3638−3646. (37) Li, X. J.; Guan, T. N.; Guo, X. F.; Li, X. X.; Yu, Z. J. Eur. J. Inorg. Chem. 2014, 2307−2316. (38) Li, X. J.; Cao, R.; Bi, W. H.; Wang, Y. Q.; Wang, Y. L.; Li, X.; Guo, Z. G. Cryst. Growth Des. 2005, 5, 1651−1656. (39) Li, X. J.; Cai, Y. Z.; Fang, Z. L.; Wu, L. J.; Wei, B.; Lin, S. Cryst. Growth Des. 2011, 11, 4517−4524. (40) Li, X. J.; Wang, X. Y.; Gao, S.; Cao, R. Inorg. Chem. 2006, 45, 1508−1516. (41) Yang, X. G.; Fang, S. M. Synth. React. Inorg., Met.-Org., Nano-Met. Chem. 2013, 43, 76−79. (42) Zhang, M. M.; Guo, F. Synth. React. Inorg., Met.-Org., Nano-Met. Chem. 2013, 43, 1040−1044. (43) Li, X. J.; Ma, G. C.; Xu, X. H. J. Coord. Chem. 2013, 66, 3249− 3260. (44) Abourahma, H.; Bodwell, J. B.; Lu, J. J.; Moulton, B.; Pottie, I. R.; Walsh, R. B.; Zaworotko, M. J. Cryst.Growth Des. 2003, 3, 513−519. (45) Ma, J. F.; Yang, J.; Zheng, G. L.; Li, L.; Liu, J. F. Inorg. Chem. 2003, 42, 7531−7534. (46) Liu, J. Q.; Huang, Y. S.; Zhao, Y. Y.; Jia, Z. B. Cryst. Growth Des. 2011, 11, 569−574. (47) Sheldrick, G. M. SHELXS97: Program for Crystal Structure Solution; University of Göttingen: Göttingen, Germany, 1997. (48) Sheldrick, G. M. SHELXL97: Program for Crystal Structure Refinement; University of Göttingen: Göttingen, Germany, 1997. (49) Sun, D.; Xu, M. Z.; Liu, S. S.; Yuan, S.; Lu, H. F.; Feng, S. Y.; Sun, D. F. Dalton Trans. 2013, 42, 12324−12333. (50) Chen, W.; Wang, J. Y.; Chen, C.; Yue, Q.; Yuan, H. M.; Chen, J. S.; Wang, S. N. Inorg. Chem. 2003, 42, 944−946. (51) Su, Z.; Fan, J.; Okamura, T.; Chen, M. S.; Chen, S. S.; Sun, W. Y.; Ueyama, N. Cryst. Growth Des. 2010, 10, 1911−1922. M


Substituent Effects of Isophthalate Derivatives on the Construction of

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