Coordination assemblies of the MII-tm/bpt (M = Zn/Cd/Co/Ni) mixed-ligand system: positional isomeric effect, structural diversification and properties

Fu-Ping Huangab, Peng-Fei Yaoa, Wei Luoa, Hai-Ye Lia, Qing Yua, He-Dong Bian*a and Shi-Ping Yan*b
aKey Laboratory for The Chemistry and Molecular Engineering of Medicinal Resources (School of Chemistry and Pharmacy, Guangxi Normal University), Ministry of Education of China, Guilin, 541004, P. R. China. E-mail: gxunchem@163.com
bDepartment of Chemistry, Nankai University, Tianjin 300071, P.R. China. E-mail: yansp@nankai.edu.cn

Received 18th April 2014 , Accepted 5th September 2014

First published on 5th September 2014


Abstract

To further investigate the influence of the positional isomeric ligands on structural topologies, six new coordination polymers with three positional isomeric dipyridyl ligands (4,4′-Hbpt, 3,4′-Hbpt and 3,3′-Hbpt) and trimellitic acid (H3tm), namely, {[Zn3(tm)2(4,4′-Hbpt)2(H2O)2]·10H2O}n (1), [Zn3(tm)2(3,3′-Hbpt)2]n (2), {[Cd2(tm)(3,4′-bpt)(H2O)2]·H2O}n (3), {[Cd4(tm)2(3,3′-bpt)2(H2O)2]·3H2O}n (4), {[Co3(tm)2(3,4′-Hbpt)2(H2O)6]·2H2O}n (5), {[Ni3(tm)2(3,3′-Hbpt)4(H2O)2]·7H2O}n (6), have been synthesized under hydrothermal conditions and characterized. Structural analysis reveals that: 1 and 5 both have 3D 4-connected networks, with the (4.64.8)(42.63.8)2(44.62)2 Schläfli symbol for 1 and (42.52.72)(52.62.7.8)2(4.52.6.72)2 symbol for 5. 2 and 3 both have 3D (4,5)-connected networks, with the (34.42.52)2(42.84)(3.43.52.6.72.8)2 symbol for 2 and (34.42.52)2(42.84)(3.43.52.6.72.8)2 symbol for 3. 4 has a 3D trinodal (3,4,5)-connected net with the (3.44.53.6.7) (43.62.7)(44.62)(42.6)2(45.64.8)2 symbol. And 6 has a 2D (3,4)-connected layer with (3.62)2(3.4.62.72)2(5.63.82) symbol. These results indicate that the versatile coordination modes of tm and the isomeric nature of bpt play crucial roles in modulating structural topologies of these complexes. Moreover, the luminescent properties of 1–4 and the magnetic behavior of 5–6, have been investigated.


Introduction

The design and construction of coordination polymers have achieved considerable interest in the realm of crystal engineering, not only for their tremendous potential applications as functional materials,1–6 but also for their intriguing variety of topological structures.7–10 The structural natures are diverse depending on the metal ions, PH value, solvents, the ligands, synthetic methods, etc.11–13 One of the most useful and important ways to study the controllable construction is still the deliberate modification of the organic ligands.14,15 Among the reported studies, much effort has focused on the construction of coordination polymers using multidentate ligands such as polycarboxylate and N-heterocyclic ligands.16 Recently, our group reported a series of CoII/ZnII/CdII coordination polymers with different topological structures based on the mixed-ligand systems of three positional isomeric N-heterocyclic-like ligands: 1H-3,5-bis(4-pyridyl)-1,2,4-triazole (4,4′-Hbpt), 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4′-Hbpt), 1H-3,5-bis(3-pyridyl)-1,2,4-triazole (3,3′-Hbpt) and three positional isomeric aromatic dicarboxylic anions: o-BDC, m-BDC, p-BDC (BDC = benzenedicarboxylate anion).17

As an extension of this work, we choose trimellitic acid (H3tm) and the above-mentioned isomeric N-heterocyclic ligands to construct new coordination frameworks with versatile topological symbols. Tm with versatile coordination modes, can be considered as a bent building block like o, m-BDC, and a linear building block like p-BDC (Scheme 1). A series of coordination polymers, namely, {[Zn3(tm)2(4,4′-Hbpt)2(H2O)2]·10H2O}n (1), [Zn3(tm)2(3,3′-Hbpt)2]n (2), {[Cd2(tm)(3,4′-bpt)(H2O)2]·H2O}n (3), {[Cd4(tm)2(3,3′-bpt)2(H2O)2]·3H2O}n (4), {[Co3(tm)2(3,4′-Hbpt)2(H2O)6]·2H2O}n (5), {[Ni3(tm)2(3,3′-Hbpt)4(H2O)2]·7H2O}n (6) were constructed successfully. The positional isomeric effects of the bpt bridges on the coordination assemblies were elucidated. In addition, the magnetic and luminescent properties of these compounds have been investigated.


image file: c4ra03545c-s1.tif
Scheme 1 The versatile coordination modes of tm used in this work.

Experimental section

Materials and physical measurements

With the exception of the ligands of 4,4′-Hbpt, 3,4′-Hbpt, and 3,3′-Hbpt, which were prepared according to the literature procedure,18 all reagents and solvents for synthesis and analysis were commercially available and used as received. IR spectra were taken on a Perkin-Elmer spectrum One FT-IR spectrometer in the 4000–400 cm−1 region with KBr pellets. Elemental analyses for C, H and N were carried out on a Model 2400 II, Perkin-Elmer elemental analyzer. The magnetic susceptibility measurements of the polycrystalline samples were measured over the temperature range of 2–300 K with a Quantum Design MPMS-XL7 SQUID magnetometer using an applied magnetic field of 1000 Oe. Field dependences of magnetization were measured using a flux magnetometer in an applied field up to 50 kOe generated by a conventional pulsed technique. A diamagnetic correction to the observed susceptibilities was applied using Pascal's constants. X-ray powder diffraction (XRPD) intensities were measured on a Rigaku D/max-IIIA diffractometer (Cu-Kα, λ = 1.54056 Å). The single crystalline powder samples were prepared by crushing the crystals and scanned from 3 to 60° with a step of 0.1° s−1. Calculated patterns of 1–6 were generated with PowderCell.

Syntheses of complexes 1–6

{[Zn3(tm)2(4,4′-Hbpt)2(H2O)2]·10H2O}n (1). A mixture containing H3tm (105 mg, 0.5 mmol), Zn(NO3)2·6H2O (149 mg, 1 mmol), 4,4′-Hbpt (112 mg, 0.5 mmol), NaOH (40 mg, 1 mmol), water(10 mL) and ethanol (5 mL) was sealed in a Teflon-lined stainless steel vessel (23 mL), which was heated at 140 °C for 3 days and then cooled to room temperature at a rate of 5 °C h−1. Colorless block crystals of 1 were obtained and picked out, washed with distilled water and dried in air. Yield: 48% (based on Zn(II)). Elemental analysis for C42H50N10Zn3O24 (%) calcd: C, 39.56; H, 3.95; N, 10.98. Found: C, 39.97; H, 3.27; N, 10.52. IR (KBr, cm−1): 3421s, 1623s, 1556s, 1411s, 1314s, 1055m, 841w, 608m.
[Zn3(tm)2(3,3′-Hbpt)2]n (2). A mixture containing H3tm (105 mg, 0.5 mmol), Zn(NO3)2·6H2O (149 mg, 1 mmol), 3,3′-Hbpt (112 mg, 0.5 mmol), NaOH (40 mg, 1 mmol) and water (10 mL) was sealed in a Teflon-lined stainless steel vessel (23 mL), which was heated at 140 °C for 3 days and then cooled to room temperature at a rate of 5 °C h−1. Colorless block crystals of 2 were obtained and picked out, washed with distilled water and dried in air. Yield: 34% (based on Zn(II)). Anal. calcd for (C42H24N10Zn3O12): C, 47.73; H, 2.29; N, 13.25. Found: C, 47.79; H, 3.00; N, 13.52%. IR (KBr, cm−1): 3401s, 1611s, 1543s, 1403s, 1343s, 1067m, 845w, 611m.
{[Cd2(tm)(3,4′-bpt)(H2O)2]·H2O}n (3). The same synthetic procedure as that for 2 was used except that Zn(NO3)2·6H2O and 3,3′-Hbpt was replaced by Cd(Ac)2·2H2O and 3,4′-bpt, respectively, giving colorless block X-ray-quality crystals of 3 in a 40% yield (based on Cd(II)). Anal. calcd for (C21H17Cd2N5O9): C, 35.61; H, 2.42; N, 9.89. Found: C, 35.81; H, 2.50; N, 9.97%. IR (KBr, cm−1): 3396m, 1615m, 1585s, 1492w, 1384s, 1067m, 823w, 790w, 738w.
{[Cd4(tm)2(3,3′-bpt)2(H2O)2]·3H2O}n (4). The same synthetic procedure as that for 2 was used except that Zn(NO3)2·6H2O was replaced by Cd(Ac)2·2H2O giving colorless block X-ray-quality crystals of 4 in a 38% yield (based on Cd(II)). Anal. Calcd for (C42H28Cd4N10O15): C, 37.03; H, 2.07; N, 10.28. Found: C, 37.19; H, 2.10; N, 10.52%. IR (KBr, cm−1): 3401m, 1583w, 1561s, 1536w, 1372s, 1166m, 853m, 831m, 768m, 752w, 702m, 571m.
{[Co3(tm)2(3,4′-Hbpt)2(H2O)6]·2H2O}n (5). The same synthetic procedure as that for 1 was used except that Zn(NO3)2·6H2O and 4,4′-Hbpt was replaced by Co(NO3)2·6H2O and 3,4′-bpt, respectively, giving red columnar X-ray-quality crystals of 5 in a 34% yield (based on Co(II)). Anal. calcd for (C42H40Co3N10O20): C, 42.69; H, 3.41; N, 11.85. Found: C, 42.57; H, 3.72; N, 11.52%. IR (KBr, cm−1): 3402s, 1613s, 1576s, 1412s, 1348s, 1055m, 845w, 613m.
{[Ni3(tm)2(3,3′-Hbpt)4(H2O)2]·7H2O}n (6). The same synthetic procedure as that for 2 was used except that Zn(NO3)2·6H2O was replaced by Ni(NO3)2·6H2O giving green block X-ray-quality crystals of 6 in a 44% yield (based on Ni(II)). Anal. calcd for (C66H62N20Ni3O22): C, 47.65; H, 3.76; N, 16.84. Found: C, 47.57; H, 3.72; N, 16.52%. IR (KBr, cm−1): 3412s, 1632s, 1556s, 1421s, 1344s, 1051m, 842w, 608m.

X-ray crystallographic determination

All reflection data were collected on a Bruker SMART CCD instrument by using graphite-monochromatic Mo-Kα radiation (λ = 0.71073 Å) at room temperature. A semiempirical absorption correction by using the SADABS program was applied, and the raw data frame integration was performed with SAINT.19 The crystal structures were solved by the direct method using the program SHELXS-9720 and refined by the full-matrix least-squares method on F2 for all non-hydrogen atoms using SHELXL-9721 with anisotropic thermal parameters. All hydrogen atoms were located in calculated positions and refined isotropically, except the hydrogen atoms of water molecules were fixed in a difference Fourier map and refined isotropically. The details of the crystal data were summarized in Table 1, and selected bond lengths and angles for compounds 1–6 are listed in Table 2 (ESI).
Table 1 Crystal data and structure refinement for 1–6
Complex 1 2 3 4 5 6
Empirical formula C42H48N10Zn3O24 C42H24N10Zn3O12 C21H17Cd2N5O9 C42H28Cd4N10O15 C42H40Co3N10O20 C66H60N20Ni3O21
Formula weight 1273.09 1056.88 708.22 1362.39 1181.63 1645.39
Crystal system Monoclinic Monoclinic Triclinic Triclinic Triclinic Triclinic
Space group C2/c C2/c P[1 with combining macron] P[1 with combining macron] P[1 with combining macron] P[1 with combining macron]
a (Å) 10.586 (2) 15.633 (3) 10.118 (2) 10.246 (2) 9.998 (2) 11.324 (2)
b (Å) 28.043 (8) 12.490 (3) 10.261 (2) 14.057 (3) 10.036 (2) 12.462 (3)
c (Å) 17.448 (3) 20.931 (4) 12.483 (3) 15.526 (3) 12.674 (3) 13.474 (3)
α (°) 90 90 113.43 (3) 109.87 (3) 96.16 (3) 78.55 (3)
β (°) 92.08 (3) 95.38 (3) 97.44 (3) 97.37 (3) 112.99 (3) 71.71 (3)
γ (°) 90 90 94.64 (3) 93.56 (3) 94.10 (3) 71.54
Volume (Å3) 5176 (2) 4068.9 (2) 1166.6 (4) 2072.3 (7) 1155.0 (4) 1702.1 (6)
Z 4 4 2 2 1 1
Calculated density (Mg m−3) 1.623 1.725 2.016 2.184 1.699 1.623
Goodness-of-fit on F2 1.03 1.04 1.150 1.022 0.98 1.03
Independent reflections 4693 3670 4699 7428 4149 5872
R1[I > 2σ(I)] 0.057 0.061 0.055 0.070 0.052 0.109
wR2 (all data) 0.145 0.116 0.143 0.1500 0.145 0.247


Table 2 Selected bond lengths (Å) and angles (°) for 1–6
1 (symmetry codes: A: −x, y, −z + 1/2; B: x − 1, −y + 1, z + 1/2; C: −x + 1/2, −y + 1/2, −z + 1.)
Zn1–O1 1.979 (3) Zn1–N1 2.061 (4) Zn2–N5B 2.097 (4)
Zn2–O5C 2.113 (4) Zn2–O7 2.162 (4) Zn2–O3A 1.997 (3)
Zn2–O2 2.144 (3) Zn2–O6C 2.258 (3)    
O1A–Zn1–O1 134.0 (2) O1–Zn1–N1A 103.2 (2) O1–Zn1–N1 103.3 (2)
O1A–Zn1–N1A 103.3 (2) O1A–Zn1–N1 103.2 (2) N1A–Zn1–N1 108.2 (2)
O3A–Zn2–N5B 98.17 (2) O7–Zn2–O6C 89.65 (2) O5C–Zn2–O2 92.45 (2)
O3A–Zn2–O5C 106.53 (2) O5C–Zn2–O7 88.25 (2) O3A–Zn2–O7 91.87 (2)
N5B–Zn2–O5C 155.30 (2) O2–Zn2–O7 177.4 (2) N5B–Zn2–O7 91.13 (2)
O3A–Zn2–O2 85.50 (2) O3A–Zn2–O6C 166.5 (2) O5C–Zn2–O6C 60.14 (2)
N5B–Zn2–O2 89.30 (2) N5B–Zn2–O6C 95.18 (2) O2–Zn2–O6C 92.90 (2)

2 (symmetry codes: A: x + 1/2, y − 1/2, z; B: −x + 3/2, −y + 3/2, −z + 1; C: x − 1/2, y + 1/2, z; D: −x + 3/2, y + 1/2, −z + 3/2; E: −x + 1, y, −z + 3/2.)
Zn1–O5A 1.999 (3) Zn1–O1 2.025 (4) Zn1–N1 2.140 (5)
Zn1–O6B 2.021 (4) Zn1–N5B 2.137 (5) Zn2–O3 1.947 (4)
Zn2–O2C 1.942 (4) Zn2–O2D 1.942 (4) Zn2–O3E 1.947 (4)
O5A–Zn1–O6B 133.45 (2) O5A–Zn1–N5B 88.93 (2) O5A–Zn1–N1 90.98 (2)
O5A–Zn1–O1 135.29 (2) O6B–Zn1–N5B 88.13 (2) O6B–Zn1–N1 92.42 (2)
O6B–Zn1–O1 91.11 (2) O1–Zn1–N5B 89.25 (2) O1–Zn1–N1 90.34 (2)
N5B–Zn1–N1 179.3 (2) O2D–Zn2–O3E 112.1 (2) O2D–Zn2–O3 112.4 (2)
O2C–Zn2–O2D 102.6 (3) O2C–Zn2–O3 112.1 (2) O3E–Zn2–O3 105.4 (2)
O2C–Zn2–O3E 112.4 (2)        

3 (symmetry codes: (A) −x + 1, −y + 1, −z; (B) x, y + 1, z; (C) −x + 1, −y + 1, −z + 1; (D) −x, −y + 2, −z.)
Cd1–N1A 2.366 (6) Cd1–O4B 2.219 (5) Cd2–O3B 2.283 (5)
Cd1–N3 2.398 (6) Cd1–O5C 2.293 (5) Cd2–O5C 2.310 (5)
Cd1–O1 2.270 (5) Cd2–N4 2.320 (6) Cd2–O7 2.322 (5)
Cd1–O2 2.511 (6) Cd2–N5D 2.319 (6) Cd2–O8 2.300 (6)
Ni1–Cd1–N3 78.3 (2) O4B–Cd1–O2 88.1 (2) O3B–Cd2–O5C 88.7 (2)
Ni1–Cd1–O2 86.2 (2) O4B–Cd1–O5C 87.0 (2) O3B–Cd2–O7 174.8 (2)
N3–Cd1–O2 139.5 (2) O5C–Cd1–N1A 146.2 (2) O3B–Cd2–O8 97.0 (2)
O1–Cd1–N1A 105.9 (2) O5C–Cd1–N3 80.5 (2) O5C–Cd2–N4 86.1 (2)
O1–Cd1–N3 94.4 (2) O5C–Cd1–O2 126.3 (2) O5C–Cd2–N5D 170.2 (2)
O1–Cd1–O2 54.2 (2) N4–Cd2–O7 87.3 (2) O5C–Cd2–O7 96.6 (2)
O1–Cd1–O5C 101.7 (2) N5D–Cd2–N4 103.1 (2) O8–Cd2–N4 168.0 (2)
O4B–Cd1–N1A 85.0 (2) N5D–Cd2–O7 87.3 (2) O8–Cd2–N5D 84.4 (2)
O4B–Cd1–N3 126.8 (2) O3B–Cd2–N4 92.7 (2) O8–Cd2–O5C 87.1 (2)
O4B–Cd1–O1 138.8 (2) O3B–Cd2–N5D 87.6 (2) O8–Cd2–O7 83.7 (2)

4 (symmetry codes: A: x − 1, y, z; B: −x + 2, −y + 1, −z + 1; C: x + 1, y, z; D: −x, −y, −z; E: −x + 2, −y + 2, −z + 1.)
Cd1–O4A 2.234 (7) Cd2–O8 2.287 (7) Cd3–O7 2.506 (7)
Cd1–N1 2.261 (8) Cd2–O13 2.303 (9) Cd4–N8 2.186 (9)
Cd1–O1 2.292 (8) Cd2–O4A 2.334 (7) Cd4–O5A 2.202 (7)
Cd1–O3B 2.329 (7) Cd2–O7 2.454 (7) Cd4–N10E 2.233 (9)
Cd1–O2 2.410 (8) Cd3–N4 2.192 (8) Cd4–O15 2.402 (13)
Cd1–O9C 2.412 (7) Cd3–O11C 2.202 (7) Cd4–O6A 2.535 (8)
Cd2–O9C 2.213 (7) Cd3–N5D 2.288 (9) Cd4–O2 2.777 (8)
Cd2–N6 2.260 (9) Cd3–O14 2.338 (9)    
O4A–Cd1–N1 95.2 (3) N6–Cd2–O13 91.6 (4) O11C–Cd3–O7 88.3 (3)
O4A–Cd1–O1 161.2 (3) O8–Cd2–O13 92.1 (3) N5D–Cd3–O7 83.0 (3)
N1–Cd1–O1 94.8 (3) O9C–Cd2–O4A 75.3 (3) O14–Cd3–O7 160.8 (3)
O4A–Cd1–O3B 103.7 (3) N6–Cd2–O4A 105.9 (3) N8–Cd4–O5A 131.4 (3)
N1–Cd1–O3B 93.2 (3) O8–Cd2–O4A 94.6 (3) N8–Cd4–N10E 108.3 (3)
O1–Cd1–O3B 91.6 (3) O13–Cd2–O4A 160.8 (3) O5A–Cd4–N10E 114.7 (3)
O4A–Cd1–O2 110.4 (3) O9C–Cd2–O7 107.9 (3) N8–Cd4–O15 97.0 (4)
N1–Cd1–O2 149.5 (3) N6–Cd2–O7 148.2 (3) O5A–Cd4–O15 112.9 (4)
O1–Cd1–O2 56.2 (3) O8–Cd2–O7 55.7 (3) N10E–Cd4–O15 77.9 (4)
O3B–Cd1–O2 96.4 (3) O13–Cd2–O7 82.3 (3) N8–Cd4–O6A 93.8 (3)
O4A–Cd1–O9C 73.4 (2) O4A–Cd2–O7 86.7 (3) O5A–Cd4–O6A 54.9 (3)
N1–Cd1–O9C 87.5 (3) N4–Cd3–O11B 127.2 (3) N10E–Cd4–O6A 152.7 (3)
O1–Cd1–O9C 91.2 (3) N4–Cd3–N5D 115.5 (3) O15–Cd4–O6A 83.7 (4)
O3B–Cd1–O9C 177.0 (3) O11C–Cd3–N5D 116.0 (3) N8–Cd4–O2 92.0 (3)
O2–Cd1–O9C 84.4 (3) N4–Cd3–O14 97.5 (3) O5A–Cd4–O2 77.2 (3)
O9C–Cd2–N6 103.5 (3) O11C–Cd3–O14 103.3 (3) N10E–Cd4–O2 76.7 (3)
O9C–Cd2–O8 161.8 (3) N5D–Cd3–O14 78.2 (3) O15–Cd4–O2 154.6 (3)
N6–Cd2–O8 93.6 (3) N4–Cd3–O7 87.0 (3) O6A–Cd4–O2 119.4 (2)
O9C–Cd2–O13 93.2 (3)        

5 (symmetry codes: A: −x + 2, −y, −z + 1; B: x − 1, y, z; C: −x + 3, −y, −z + 1; D: −x + 2, −y − 1, −z + 1; E: −x + 1, −y, −z; F: x + 1, y − 1, z + 1; G: −x + 2, −y, −z.)
Co1–O1 2.048 (3) Co1–O6B 2.078 (3) Co1–O7 2.145 (3)
Co2–O2 2.071 (3) Co2–O8 2.137 (3) Co2–N5E 2.125 (4)
Co3–O3 2.069 (3) Co3–N1 2.123 (4) Co3–O9 2.147 (3)
O1–Co1–O7 94.47 (1) O1–Co1–O6C 89.71 (1) O1A–Co1–O7 85.53 (1)
O6B–Co1–O7 90.77 (1) O6B–Co1–O7A 89.23 (1) O7–Co1–O7A 180.00
O2–Co2–O8 83.24 (1) N5E–Co2–O8 89.40 (1) O2D–Co2–N5E 88.27 (1)
O2–Co2–N5E 91.73 (1) O2D–Co2–O8 96.76 (1) N5E–Co2–N5F 180.00
O3–Co3–N1 88.39 (4) O3–Co3–O9 95.65 (3) N1–Co3–O9 89.31 (4)
O3–Co3–N1G 91.61 (4) O3–Co3–O9G 84.35 (3) N1G–Co3–N1 180.00

6 (symmetry codes: (A) −x + 1, −y + 2, −z; (B) −x, −y + 2, −z + 1; (C) x + 1, y + 1, z − 1; (D) −x + 1, −y + 3, −z.)
Ni1–N1 2.130 (8) Ni1–O4A 2.027 (6) Ni2–O3 2.074 (6)
Ni1–N5A 2.131 (7) Ni1–O7 2.111 (6) Ni2–O3D 2.074 (6)
Ni1–N6 2.105 (7) Ni2–N10B 2.089 (7) Ni2–O5 2.088 (7)
Ni1–O1 2.096 (6) Ni2–N10C 2.089 (7) Ni2–O5D 2.088 (7)
N1–Ni1–N5A 173.3 (3) O4A–Ni1–N6 96.4 (3) O3–Ni2–O3D 180
N6–Ni1–N1 97.9 (3) O4A––Ni1–O1 86.5 (2) O3–Ni2–O5D 88.5 (3)
N6–Ni1–N5A 88.2 (3) O4A–Ni1–O7 173.2 (2) O3D–Ni2––O5 88.5 (3)
N6–Ni1–O7 89.6 (3) O7–Ni1–N1 91.3 (3) O3–Ni2–O5 91.5 (3)
O1–Ni1–N1 86.8 (3) O7–Ni1–N5A 91.5 (3) O3D–Ni2–O5D 91.5 (3)
O1–Ni1–N5A 87.2 (3) N10B–Ni2–N10C 180 O5–Ni2–N10C 86.8 (3)
O1–Ni1–N6 174.4 (3) O3–Ni2–N10C 87.8 (3) O5D–Ni2–N10C 93.2 (3)
O1–Ni1–O7 87.3 (2) O3D–Ni2–N10B 87.8 (3) O5D–Ni2–N10B 86.8 (3)
O4A–Ni1–N1 91.1 (3) O3D–Ni2–N10C 92.2 (3) O5–Ni2–N10B 93.2 (3)
O4A–Ni1–N5A 85.4 (3) O3–Ni2–N10B 92.2 (3) O5–Ni2–O5D 180


XRPD results

To confirm whether the crystal structures are truly representative of the bulk materials, X-ray powder diffraction (XRPD) experiments have also been carried out for 1–6. The XRPD experimental and computer-simulated patterns of the corresponding complexes are shown in ESI, Fig. S2–S7. Although the experimental patterns have a few unindexed diffraction lines and some are slightly broadened in comparison with those simulated from the single crystal models, it can still be considered favorably that the bulk synthesized materials and the as-grown crystals are homogeneous for 1–6.

Results and discussion

Crystal structures

{[Zn3(tm)2(4,4′-Hbpt)2(H2O)2]·10H2O}n (1). As shown in Fig. 1a, 1 reveals a novel 3D coordination polymer with a V-shaped trinuclear Zn(II) unit bridged by tm anions. In the trinuclear unit, the middle Zn1 ions lying on a twofold axis exhibit a four-coordinated tetrahedrally environment with two carboxylic O atoms (O1, O1A, symmetry code: A: −x, y, −z + 1/2) from two tm anions and two N atoms (N1, N1A) from two 4,4′-Hbpt ligands. The terminal Zn2 ions exhibit a distorted octahedral geometry, which is provided by one pyridyl N (N5B, B: x – 1, −y + 1, z + 1/2) donor, four carboxylate O (O2, O3A, O5C, O6C, C: −x + 1/2, −y + 1/2, −z + 1) atoms and one water molecule (O7). The middle Zn1 ion is linked to terminal Zn2 ions with one synanti carboxylate from tm [Zn⋯Zn = 4.411(1) Å] to form the V-shaped unit. The adjacent trinuclear units are linked by tm to generate straight-like chains running along the crystallographic c axis (Fig. 1b), in which tm exhibit a coordinating mode of mode 1 (Scheme 1) and three carboxylate groups of tm exhibit three different coordination patterns (unidentate, chelating, and synanti bridge modes, respectively). On the other hand, the adjacent trinuclear units are bridged by 4,4′-bpt ligands to result in zigzag-like chains along the a axis (Fig. 1c).
image file: c4ra03545c-f1.tif
Fig. 1 Structural characterization of 1: (a) the local coordination environments of the Zn(II) atoms (symmetry codes: A: −x, y, −z + 1/2; B: x − 1, −y + 1, z + 1/2; C: −x + 1/2, −y + 1/2, −z + 1.); (b) the 1D [Zn(tm)] chain; (c) the 1D [Zn(4,4′-Hbpt)] chain; (d) the 3D pillared network; (e) the schematic description for the 3D architecture with (4.64.8)(42.63.8)2(44.62)2 symbol; (f) the simplified topologie with 52.64 considering the trinuclear Zn(II) unit as a node.

As a consequence, the adjacent trinuclear units are further connected by tm and 4,4′-Hbpt components, resulting into the generation of a 3D coordination polymeric network (Fig. 1d). A topological analysis reveals that each tm serves as a 4-connected node to join four Zn(II) ions, both Zn1 and Zn2 play the 4-connected role to link each other via the 4,4′-Hbpt spacers and tm nodes. According to Wells' topology definition,22 an unprecedented 4-connected topology with the short Schläfli symbol of (4.64.8)(42.63.8)2(44.62)2 is formed (Fig. 1e). Considering the trinuclear Zn(II) unit as a node to simply the structure of 1, simplified topologie could also be determined with the short Schläfli symbol of 52.64 (Fig. 1f). Interestingly, the void space in the single framework is so large that there identical 3D frameworks interpenetrate each other, leaving a small space for the inclusion of solvent water molecules.

[Zn3(tm)2(3,3′-Hbpt)2]n (2). The asymmetric unit of 2 consists of two Zn(II) ions, the Zn1 ion adopts a slightly distorted trigonal-dipyramidal geometry surround by two N atoms (N1, N5B, B: −x + 3/2, −y + 3/2, −z + 1) from two 3,3′-Hbpt ligands in the axial position, three O atoms (O1, O5A, O6B, A: x + 1/2, y − 1/2, z) from three tm anions in the equatorial plane. The Zn2 center lying on a twofold axis has a tetrahedron geometry from four carboxylate O atoms (O2C, O2D, O3, O3E, C: x − 1/2, y + 1/2, z; D: −x + 3/2, y + 1/2, −z + 3/2; E: −x + 1, y, −z + 3/2) (Fig. 2a). Tm in 2 exhibit a coordinating mode of mode 2 (Scheme 1), and three carboxylate groups of tm exhibit three different coordination patterns: one is in monodentate fashion, another group bridge two Zn(II) centers in synsyn mode to form a binuclear Zn(II) unit (Zn⋯Zn = 3.767 (2) Å), leading to a 1-D chain along the crystallographic c axis (Fig. 2b), and the third carboxylate group adopts a synanti mode bridging adjacent Zn(II) atoms with the Zn⋯Zn separation of 4.172 (2) Å. The adjacent Zn(II) centers in 2 are connected by tm components, resulting into the generation of a 3D [Zn(tm)] coordination polymeric network (Fig. 2c). In addition, the 3D [Zn(tm)] network are further fixed by 3,3′-Hbpt ligands with synsyn mode bridging the adjacent Zn(II) atoms. (Fig. 2d).
image file: c4ra03545c-f2.tif
Fig. 2 Structural characterization of 2: (a) the local coordination environments of the Zn(II) atoms (symmetry codes: A: x + 1/2, y − 1/2, z; B: −x + 3/2, −y + 3/2, −z + 1; C: x − 1/2, y + 1/2, z; D: −x + 3/2, y + 1/2, −z + 3/2; E: −x + 1, y, −z + 3/2.); (b) the 1D chain along the c axis bridged by tm and 3,3′-Hbpt connector; (c) the 3D [Zn(tm)] network; (d) the 3D pillared architecture of 2; (e) the schematic description for the 3D architecture; (f) the simplified topologie with (44.62)(48.66.8) considering the dinuclear Zn(II) unit as a node.

On the basis of the connectivity of Zn1 and Zn2 atoms, both of them are viewed to be 4-connected nodes. Moreover, tm also can be viewed as a 4-connected node and the 3,3′-Hbpt as a linker. In this way, this framework can be simplified to be a 4-connected topology with the short Schläfli symbol of (34.42.52)2(42.84)(3.43.52.6.72.8)2 (Fig. 2e). Considering the dinuclear Zn(II) unit bridged by tm anions as a node to simply the structure of 2, simplified topologies could also be determined with the short Schläfli symbol of (44.62) (48.66.8) (Fig. 2f).

{[Cd2(tm)(3,4′-bpt)(H2O)2]·H2O}n (3). 3 features a 3D coordination polymeric architecture, containing two independent Cd(II) cations (Fig. 3a). The Cd1 ion is coordinated by one pyridyl N donor (N1C, C: −x + 1, −y + 1, −z + 2), one triazole N donor (N3), and four carboxylate O atoms (O1B, O2B, O4A, O5, A: x + 1, −y, −z + 1; B: −x + 1, −y + 1, −z + 1), to form a distorted octahedral geometry. The Cd2 ion also adopts a distorted octahedral geometry, which is provided by one triazole N atom of 3,4′-bpt (N4) and one water O atom (O8), two carboxylate O atoms (O3A, O5) from two tm anions, one water O atom (O7) and one pyridyl N atom 3,4′-bpt (N5D, D: −x + 2, −y, −z + 2). The Cd2 ion is linked to Cd1 ion with mixed bridges through one μ2 carboxyl O atom, one synsyn carboxylate [Cd⋯Cd = 3.5739(9) Å, Cd1–O5–Cd2 = 101.84(2)°] and two triazole N atoms to form a dinuclear unit. The adjacent dinuclear units are linked by tm to generate a 1-D chain running along the crystallographic b axis (Fig. 3b). Tm in 3 exhibit a coordinating mode of mode 3 (Scheme 1). And three carboxylate groups on the tm anion of the 1-D chain display different coordination patterns (μ2-carboxyl O, chelating, and synsyn bridge modes, respectively). The 3,4′-bpt ligand exhibit a coordinating mode of μ41111. The adjacent dinuclear units are also connected by 3,4′-bpt ligand to generate a 1D chain (Fig. 3c). As a consequence, adjacent dinuclear units are connected by tm and 3,4′-bpt ligand, resulting into the generation of a 3D coordination polymeric network (Fig. 3d).
image file: c4ra03545c-f3.tif
Fig. 3 Structure of 3 showing (a) the local coordination environments of the Cd(II) atoms (symmetry codes: (A) −x + 1, −y + 1, −z; (B) x, y + 1, z; (C) −x + 1, −y + 1, −z + 1; (D) −x, −y + 2, −z.), (b) the 1D chain bridged by tm, (c) the 1D chain bridged by the 3,4′-bpt, (d) view of the 3D novel (4,5)-connected pillared architecture of 3, (e) its schematic description; (f) the simplified topologie with (42.6)(42.65.83) considering the dinuclear Cd(II) unit as a node.

A better insight into the nature of this 3D coordination polymeric network can be achieved by topological analysis, as shown in Fig. 3e. In 3, Cd1 and Cd2 atoms can be viewed as 5-connected and 4-connected nodes, respectively. And the 3D network can be further simplified by considering tm as 5-connected nodes and 3,4′-bpt as 4-connected nodes, respectively. Thus, the structure can be simplified as a (4,5)-connected topology with (3.44.5.63.8)(3.43.62)(33.44.5.62)(43.62.8) Schläfli symbol. Considering the dinuclear Cd(II) unit as a node to simply the structure of 3, simplified topologies could also be determined with the short Schläfli symbol of (42.6) (42.65.83) (Fig. 3f). Different from bpt ligands reported before,17 which act as linkers, the 3,4′-bpt ligands in 3 act as a 4-connected node, with two triazolyl nitrogen donors coordinating with two Cd atoms. As a result, compound 3 reveals a more complicated architecture than before.

{[Cd4(tm)2(3,3′-bpt)2(H2O)2]·3H2O}n (4). The asymmetric unit of 4 consists of four Cd(II) cations. As shown in Fig. 4a, Cd1 and Cd2 are displaying slightly distorted octahedral geometry, while Cd3 and Cd4 showing distorted tetragonal-pyramidal environment. The Cd1 ion is defined by five carboxylate O atoms (O1, O2, O3B, O4A, O9C, A: x − 1, y, z; B: −x + 2, −y + 1, −z + 1; C: x + 1, y, z) and one pyridyl N atoms (N1) of 3,3′-bpt; the coordination sites of Cd2 are occupied by four carboxylate O atom (O4A, O7, O8, O9C), one water O atoms (O13) and one pyridyl N atoms (N6) of 3,3′-bpt ligand; the Cd3 ion is coordinated by two carboxylate O atoms (O7, O11C) of two tm ligands, one water oxygen atoms (O14) and two N atoms (N4, N5D, D: −x, −y, −z) from two 3,3′-bpt ligands; the coordination sphere of Cd4 is made up of two carboxylate O atom (O5A, O6A) from one tm ligand, one water O atoms (O15) and two pyridyl N donor (N8, N10E, E: −x + 2, −y + 2, −z + 1) from two 3,3′-bpt ligands. In addition, the distance of Cd4 and O2 is 2.777(8) Å indicating a weak interaction. Tm in 4 exhibits two kinds of different coordinating modes: mode 4 and mode 5 (Scheme 1). The different modes of the tm is conducive to the formation of the centrosymmetric structural framework of 4. It is quite interesting that, tm adopt aforementioned coordinating modes, link the Cd(II) atoms to form a decorated ribbon chains along the a axis (Fig. 4b). In the middle of the chain, tm adopt mode 4. While on both sides of the chain tm adopt mode 5. The chain possesses a certain width because tm keeps two uncoordinated oxygen atoms outside the chain in mode 5, characteristics which are relatively rare in the reported articles.23 Then, the chain are cross-linked by pyridine N atoms and triazole N atoms of 3,3′-bpt ligands to generate a 3D network (Fig. 4c).
image file: c4ra03545c-f4.tif
Fig. 4 (a) Structure of 4 showing the local coordination environments of the Cd(II) atoms (symmetry codes: A: x − 1, y, z; B: −x + 2, −y + 1, −z + 1; C: x + 1, y, z; D: −x, −y, −z; E: −x + 2, −y + 2, −z + 1.); (b) the 1D chain formed by tm bridged Cd(II) coordination polymer; (c) view of the 3D (3,4,5)-connected architecture; (d) its schematic description of the “brick-wall”-like network; (e) the simplified topologie with (32.42.52) (32.45.56.62)2 considering the dinuclear Cd(II) unit as a node.

Considering of the connectivity of Cd atoms, Cd1 can be viewed as a 5-connected node, Cd2 and Cd3 are viewed as 4-connected nodes and Cd4 atom as 3-connected node, respectively (the ratio is 1[thin space (1/6-em)]:[thin space (1/6-em)]2[thin space (1/6-em)]:[thin space (1/6-em)]1). Thus, this 3D network can be further simplified by considering each tm as a 5-connected node and each 3,3′-bpt ligand as a 3-connected node. Therefore, the overall structure of 4, can be simplified as a trinodal (3,4,5)-connected net with the short Schläfli symbol of (3.44.53.6.7)(43.62.7)(44.62) (42.6)2(45.64.8)2 (Fig. 4d). Considering the dinuclear Cd(II) unit as a node to simply the structure of 3, simplified topologies could also be determined with the short Schläfli symbol of (32.42.52) (32.45.56.62)2 (Fig. 4e). Different from compound 3, the 3,3′-bpt ligands in 4 act as a 3-connected node, with a triazolyl nitrogen donor coordinating with a Cd atom. As a result, compound 4 also reveals a more complicated architecture than before.17

{[Co3(tm)2(3,4′-Hbpt)2(H2O)6]·2H2O}n (5). The asymmetric unit of 5 contains three independent Co(II) cations with octahedron coordination spheres (Fig. 5a). And all of the Co atoms lie on independent inversion centres. The Co1 center is coordinated by four equatorial carboxylate/water O atoms (O1, O1A, O7, O7A, A: −x + 2, −y, −z + 1) and two apical carboxylate O atoms (O6B, O6C, B: x − 1, y, z; C: −x + 3, −y, −z + 1). Co2 is coordinated by two water moleculars (O8, O8A) and two pyridyl N atoms (N5E, N5F, E: −x + 1, −y, −z; F: x + 1, y − 1, z + 1) in the equatorial plane, two carboxylate O atoms (O2, O2D, D: −x + 2, −y − 1, −z + 1) in the axial position. Co3 is coordinated by two carboxylate O atoms (O3, O3G, G: −x + 2, −y, −z) and two pyridyl N atoms (N1, N1G) in the equatorial plane, two water moleculars (O9, O9G) in the axial position.
image file: c4ra03545c-f5.tif
Fig. 5 View of (a) the local coordination environments of the Co(II) atoms (symmetry codes: A: −x + 2, −y, −z + 1; B: x − 1, y, z; C: −x + 3, −y, −z + 1; D: −x + 2, −y − 1, −z + 1; E: −x + 1, −y, −z; F: x + 1, y − 1, z + 1; G: −x + 2, −y, −z.); (b) the 2D [Co(tm)] layer and (c) the 3D four-connected pillared architecture of 5 and (d) its schematic description.

Tm in 5 exhibits a coordinating mode of mode 6 (Scheme 1). Three carboxylic groups of tm exhibit two kinds of coordination modes: one carboxylate group adopts a synanti bridging mode to connect the adjacent Co(II) cations with a separation of 5.011 (2) Å to furnish a 1-D chain along the b axis whereas the other two carboxylate groups are monodentate. As a consequence, the adjacent Co(II) centers are connected by tm components, resulting in the generation of a 3D coordination polymeric network (Fig. 5b). In addition, the 3D Co-tm network are further fixed by 3,4′-Hbpt ligands through bridging the adjacent Co atoms (Fig. 5c). From a topology view, all of the Co1, Co2, Co3 and tm can be viewed as 4-connected nodes, and the 3,4′-Hbpt can be viewed as a linker. As a result, this framework can be simplified as a 4-connected topology with the short Schläfli symbol of (42.52.72)(52.62.7.8)2(4.52.6.72)2 (Fig. 5d).

{[Ni3(tm)2(3,3′-Hbpt)4(H2O)2]·7H2O}n (6). 6 reveals a novel 2D coordination polymer with a linear trinuclear Ni(II) unit. The asymmetric unit of 6 has one and a half crystallographically independent Ni atoms (Ni2 lies on a symmetry site). Both of them display slightly distorted octahedral coordination geometries (Fig. 6a). The Ni1 center is coordinated by three carboxylate O atoms from three tm anions (O1, O7, O4A, A: −x + 1, −y, −z + 2, Ni1–O = 2.026(6)–2.096(6) Å) and three N atoms from three 3,3′-Hbpt ligands (N1, N5A, N6, Ni1–N = 2.108(8)–2.133(8) Å). Ni2 lying on an inversion centre is coordinated by four carboxylate O atoms from two tm anions (O3, O3B, O5, O5B, B: −x + 1, −y − 1, −z + 2, Ni2–O = 2.072(6)–2.082(7) Å) and two pyridyl N donors from two 3,3′-Hbpt ligands (N10C, N10D, C: x − 1, y − 1, z + 1, D: −x + 2, −y, −z + 1, Ni2–N = 2.086(8) Å). The middle Ni2 ion is linked to two terminal Ni1 atoms with one synanti carboxylate from tm with a separation of 5.373(1) Å to furnish a linear trinuclear Ni(II) unit (Fig. 6d). These Ni3 subunits are further extended by tm into a 1D chain along the b axis (Fig. 6b) in which tm exhibit a coordinating mode of mode 7 (Scheme 1) and three carboxylate groups of tm exhibit two different coordination patterns (unidentate and synanti bridge modes). Adjacent chains are further connected by 3,3′-Hbpt pillars to generate a 2D layer (Fig. 6e). From a topological perspective, both Ni1 and Ni2 act as the 4-connected node, tm can be viewed as 3-connected node and the 3,3′-bpt ligand can be viewed as the linker. In this way, this framework can be simplified to be a (3,4)-connected 2D layer architecture with the short Schläfli symbol of (3.62)2(3.4.62.72)2(5.63.82) (Fig. 6f). Considering the trinuclear Ni(II) unit bridged by tm anions as a node to simply the structure of 6, simplified topologie could also be determined with the short Schläfli symbol of 44.62 (Fig. 6g). It is interesting that the lattice water molecules were embedded in the interlaced ABAB… arrangement model of 2D layer. The 3,3′-Hbpt ligands in 6 adopt two different bridging modes to link adjacent Ni atom (Fig. 6c). The intermolecular packing is further controlled by hydrogen bonds (Table S1) among the triazole N atoms, carboxylate O atoms and water molecules, to generate a 3D supramolecular architecture.
image file: c4ra03545c-f6.tif
Fig. 6 View of (a) the local coordination environments of the Ni(II) atoms (symmetry codes: (A) −x + 1, −y + 2, −z; (B) −x, −y + 2, −z + 1; (C) x + 1, y + 1, z − 1; (D) −x + 1, −y + 3, −z.); (b) the 1D [Ni(tm)] chain and (c) the 1D [Ni(3,3′-Hbpt)] chain; (d) the Ni3 subunit; (e) the 2D architecture of 6 and (f) its schematic description; (f) the simplified topologie with 44.62 considering the trinuclear Ni(II) unit as a node.

Structural diversity of 1–6

It should be note that a variety of framework structures can be achieved on the basis of the choice of the aromatic tricarboxylate and triazole-containing dipyridyl isomers with differently oriented pyridyl groups as building blocks.24 As a result, 1–5 form 3D network architecture and 6 form 2D layer architecture, with diversiform connectivity. The phenomenon of structural diversification in 1–6 may arise from some different sources in line with our previous work.17 First of all, phenyl dicarboxylate ligands play an important role in constructing the polymer structures. These dicarboxylate isomers exhibit several coordination patterns (see Scheme 1), in which the carboxylate groups can adopt the bridging, unidentate and chelating modes, respectively. Secondly, the differently oriented pyridyl N atoms in these triazole-containing bpt isomers, which has a bent backbone, may play significant roles in the formation of different topological structures. Thirdly, metal-directing effect is also important for the structural diversity. In 2, the two Zn(II) centers adopt a slightly distorted trigonal-dipyramidal geometry and a tetrahedron geometry respectively. While in 4, two Cd(II) centers adopt slightly distorted octahedral geometry, the other two Cd(II) centers show distorted tetragonal-pyramidal geometry. The ionic radius of Cd(II) is longer than Zn(II), Co(II) and Cu(II) which means the Cd(II) center can adopt higher coordination numbers leading to a distinct polymeric framework. Different from reported, tm with three carboxylate groups exhibits more complicated coordination patterns. And the tm linker can be not only considered as bent building blocks like o-BDC, m-BDC, but also linear building blocks like p-BDC (Scheme 1). Furthermore, the triazolyl nitrogen atoms of the isomeric bpt ligands can provide potential coordination sites (in 3 and 4), which is different from other bpt ligands act as links, may influence the final coordination architectures more complicated.25

Fluorescent properties

In this paper, the luminescence spectra of compounds 1–4 in the solid state were studied at room temperature, and their emission spectra are depicted in Fig. 7a. The emission spectra have broad peaks with maxima at 426 nm (λex = 371 nm), 464 nm (λex = 411 nm), 367 nm (λex = 310 nm) and 427 nm (λex = 349 nm) for 1–4, respectively, whereas the emission peaks for the free ligands 4,4′-Hbpt, 3,4′-Hbpt, and 3,3′-Hbpt were observed at 447 nm, 451 nm, and 488 nm (λex = 368 nm, 378 nm, and 419 nm, respectively). The blue shifts of the luminescence emission maxima in 1–4 are presumably owing to the result of the coordination of the relevant ligands to a metal center, which effectively increases the rigidity and asymmetry of the ligands.26
image file: c4ra03545c-f7.tif
Fig. 7 (a) The solid-state emission spectra of 1–4 at room temperature; (b) the TG curves of compounds 1–6.

Thermal stabilities of the compounds

Thermogravimetric analyses (TG) were carried out for complexes 1–6 and the results are shown in Fig. 7b. The TGA curves of 1 suggest that the first weight loss of 16.47% in the region 65–302 °C corresponds to the release of the lattice water and coordinated water (calculated 16.94%), and then, a series of complicated weight losses were observed as the temperature increased until heating ends. For 2, the complex is stable up to 379 °C, followed by a series of consecutive steps of weight loss that do not stop until heating ends. For 3, the weight loss of the lattice water and the coordinated water (7.45%) occurs in the range of 80–213 °C (calculated 7.62%). The main framework remains intact until it is heated to 375 °C and then there are a series of complicated steps of weight loss that do not end until heating ends. For 4, the first observed weight loss of 7.04% in the region of 62–162 °C corresponds to the dehydration process (calculated 6.61%). The residual framework starts to decompose owing to the expulsion of the lattice water and the coordinated water molecules beyond 162 °C with a series of complicated weight losses and does not stop until heating ends at 986 °C. For 5, the first weight loss of 12.49% in the region of 65–210 °C corresponds to the release of the lattice water and the coordinated water molecules (calculated 12.19%). The residual framework starts to decompose beyond 210 °C with a series of complicated weight losses and does not stop until heating ends. For 6, the weight loss of the lattice water and the coordinated water (10.59%) occurs in the range of 60–293 °C (calculated 10.82%). And then there are a series of complicated steps of weight loss that do not end until heating ends.

Magnetic properties

Magnetic susceptibility measurements were carried out on polycrystalline samples of 5 and 6 in the temperature range 2.0–300.0 K at 1000 Oe. For 5 (Fig. 8a), the data above 30 K follow the Curie–Weiss law with C = 10.49 cm3 K mol−1 and θ = −17.64 K. The χMT value at 300 K is 9.91 emu K mol−1, which is much larger than the spin-only value 5.64 emu K mol−1 for three magnetically active Co(II) ions (S = 3/2, g = 2.0), as expected for Co(II) systems with a significant contribution from the effects of spin–orbital coupling. As the temperature is lowered, the χMT values decrease continuously and reaches a local minimum of 5.96 emu K mol−1 at about 2 K, indicative of a strong single-ion behavior admixture with a weak antiferromagnetic interaction.27
image file: c4ra03545c-f8.tif
Fig. 8 Plots of χMT vs. T (blue) and 1/χM vs. T (black) for 5 (a) and 6 (b), the lines across 1/χM curves represent the best fit.

For 6, (Fig. 8b), the data above 2 K follow the Curie–Weiss law with C = 3.49 cm3 K mol−1 and θ = 0.17 K. The χMT value at 300 K is 3.49 emu K mol−1, which is in good agreement with the spin-only value 3.00 emu K mol−1 for three magnetically active Ni(II) ions (S = 1, g = 2.0). After lowering the temperature, the χMT value slightly increases to 3.53 emu K mol−1 at 30 K, then increases rapidly to reach a maximum of. 3.68 emu K mol−1 at 7 K, indicating a weak ferromagnetic coupling between the adjacent Ni(II) ions bridged by the synanti carboxylate groups. The final decrease of χMT may be attributed to the saturation effect, zero-field splitting of Ni(II) ions and/or the presence of anti-ferromagnetic interactions via exchange bridges between the adjacent Ni3 units. No divergence between the zero-field-cooled (ZFC) and field-cooled (FC) magnetization, and thus no long-range magnetic ordering of 6 at low temperature (Fig. S8 in the ESI), was observed.

Conclusions

In this paper, we have presented the synthesis and crystal structures of six coordination polymers generated from mixed-ligand systems of H3tm and positional isomeric dipyridyl bridging ligands (4,4′-Hbpt, 3,4′-Hbpt and 3,3′-Hbpt), reacted with Zn(II), Cd(II), Co(II) and Ni(II) salts. The structural diversities indicate that the trimellitic acid (H3tm) and the differently oriented pyridyl N atoms in these triazole-containing bpt isomers, as well as the metal-directing effect play dominating roles in modulating the formation of structures of these crystalline materials. Different from our previous work,17 tm with three carboxylate groups exhibits more coordination patterns. And the tm linker can be act as bent building blocks like o-BDC, m-BDC and linear building blocks like p-BDC simultaneously. As a result, more diverse and interesting architectures than before were obtained: 1 and 5 both have a 3D 4-connected topology, with (4.64.8)(42.63.8)2(44.62)2 Schläfli symbol for 1 and (42.52.72)( 52.62.7.8)2(4.52.6.72)2 symbol for 5, respectively. 2 and 3 both have a 3D (4,5)-topology, with (34.42.52)2(42.84)(3.43.52.6.72.8)2 Schläfli symbol for 2 and (34.42.52)2(42.84)(3.43.52.6.72.8)2 symbol for 3, respectively. 4 has a 3D trinodal (3,4,5)-connected net with the short Schläfli symbol of (3.44.53.6.7)(43.62.7)(44.62) (42.6)2(45.64.8)2. 6 reveal a 2D (3,4)-connected layer with the short Schläfli symbol of (3.62)2(3.4.62.72)2(5.63.82). Accordingly, our present findings will further enrich the crystal engineering strategy and offer the possibility of controlling the formation of the desired network structures.

Acknowledgements

We gratefully acknowledge the National Nature Science Foundation of China (nos. 21171101, 21101035, 21061002 and 90922032), Guangxi Natural Science Foundation of China (2012GXNSFBA053017, 2012GXNSFAA053035) and the Foundation of Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources.

References

  1. (a) Y. K. Park, S. B. Choi, H. Kim, K. Kim, B. H. Won, K. Choi, J. S. Choi, W. S. Ahn, S. Kim, D. H. Jung, S. H. Choi, G. H. Kim, S. S. Cha, Y. H. Jhon, J. K. Yang and J. Kim, Angew. Chem., Int. Ed., 2007, 46, 8230 CrossRef CAS PubMed; (b) X.-Z. Wang, D.-R. Zhu, Y. Xu, J. Yang, X. Shen, J. Zhou, N. Fei, X.-K. Ke and L.-M. Peng, Cryst. Growth Des., 2010, 10, 887 CrossRef CAS; (c) A. Aijaz, E. C. Sa udo and P. K. Bharadwaj, Cryst. Growth Des., 2011, 11, 1122 CrossRef CAS.
  2. (a) I. G. Georgiev and L. R. MacGillivray, Chem. Soc. Rev., 2007, 36, 1239 RSC; (b) J. Yuasa and S. Fukuzumi, J. Am. Chem. Soc., 2008, 130, 566 CrossRef CAS PubMed; (c) F. M. Zhang, P. F. Yan, X. Y. Zou, J. W. Zhang, G. F. Hou and G. M. Li, Cryst. Growth Des., 2014, 14, 2014 CrossRef CAS.
  3. (a) Y.-Z. Zheng, W. Xue, M.-L. Tong, X.-M. Chen, F. Grandjean and G. J. Long, Inorg. Chem., 2008, 47, 4077 CrossRef CAS PubMed; (b) H. Miyasaka, M. Julve, M. Yamashita and R. Clerac, Inorg. Chem., 2009, 48, 3420 CrossRef CAS PubMed; (c) B. V. Harbuzaru, A. Corma, F. Rey, J. L. Jord, D. Ananias, L. D. Carlos and J. Rocha, Angew. Chem., Int. Ed., 2009, 48, 6476 CrossRef CAS PubMed.
  4. (a) M. Kurmoo, Chem. Soc. Rev., 2009, 38, 1353 RSC; (b) L. Armelaoa, S. Quici, F. Barigelletti, G. Accorsi, G. Bottarod, M. Cavazzini and E. Tondello, Coord. Chem. Rev., 2010, 254, 487 CrossRef PubMed; (c) A. M. Kirillov, Coord. Chem. Rev., 2011, 255, 1603 CrossRef CAS PubMed; (d) B. Xu, J. Xie, H.-M. Hu, X.-L. Yang, F.-X. Dong, M.-L. Yang and G.-L. Xue, Cryst. Growth Des., 2014, 14, 1629 CrossRef CAS.
  5. (a) W.-J. Chuang, I.-J. Lin, H.-Y. Chen, Y.-L. Chang and C. N. H. Sodio, Inorg. Chem., 2010, 49, 5377 CrossRef CAS PubMed; (b) P. Antunes, R. Delgado, M. G. B. Drew, V. Félix and H. Maecke, Inorg. Chem., 2007, 46, 3144 CrossRef CAS PubMed; (c) P. J. Barnard, J. P. Holland, S. R. Bayly, T. J. Wadas, C. J. Anderson and J. R. Dilworth, Inorg. Chem., 2009, 48, 7117 CrossRef CAS PubMed; (d) D. Jarzab, M. Lu, H. T. Nicolai, P. W. M. Blom and M. A. Loi, Soft Matter, 2011, 7, 1702 RSC.
  6. (a) R.-Q. Zou, A. I. Abdel-Fattah, H.-W. Xu, A. K. Burrell, T. E. Larson, T. M. McCleskey, Q. Wei, M. T. Janicke, D. D. Hickmott, T. V. Timofeeva and Y.-S. Zhao, Cryst. Growth Des., 2010, 10, 1301 CrossRef CAS; (b) X. Du, Y.-L. Sun, B.-E. Tan, Q.-F. Teng, X.-J. Yao, C.-Y. Su and W. Wang, Chem. Commun., 2010, 46, 970 RSC; (c) Y.-F. Zeng, J.-P. Zhao, B.-W. Hu, X. Hu, F.-C. Liu, J. Ribas, A. J. Ribas and X.-H. Bu, Chem.–Eur. J., 2007, 13, 9924 CrossRef CAS PubMed; (d) D. K. Gale, C. Jeffryes, T. Gutu, J. Jiao, C.-H. Chang and G. L. Rorrer, J. Mater. Chem., 2011, 21, 10658 RSC.
  7. (a) W. Wei, M. Y. Wu, Y. G. Huang, Q. Gao, Q. F. Zhang, F. L. Jiang and M. C. Hong, CrystEngComm, 2009, 11, 576 RSC; (b) J. J. Vittal, Coord. Chem. Rev., 2007, 251, 1781 CrossRef CAS PubMed; (c) G. Férey, Chem. Soc. Rev., 2008, 37, 191 RSC; (d) J. P. Zhang, X. C. Huang and X. M. Chen, Chem. Soc. Rev., 2009, 38, 2385 RSC; (e) J.-M. Lin, W.-B. Chen, X.-M. Lin, A.-H. Lin, C.-Y. Ma, W. Dong and C.-E. Tian, Chem. Commun., 2011, 47, 2402 RSC.
  8. (a) A. Y. Robin and K. M. Fromm, Coord. Chem. Rev., 2006, 250, 2127 CrossRef CAS PubMed; (b) Frontiers in Crystal Engineeringed. E. Tiekink and J. J. Vittal, John-Wiley & Sons Ltd., New York, 2006 Search PubMed; (c) N. L. Rosi, J. Kim, M. Eddaoudi, B. Chen, M. ÓKeeffe and O. M. Yaghi, J. Am. Chem. Soc., 2005, 127, 1504 CrossRef CAS PubMed; (d) V. A. Blatov, M. ÓKeeffe and D. M. Proserpio, CrystEngComm, 2010, 12, 44 RSC.
  9. (a) S.-S. Zhang, S.-Z. Zhan, M. Li, R. Peng and D. Li, Inorg. Chem., 2007, 46, 4365 CrossRef CAS PubMed; (b) H.-X. Yang, J.-X. Lin, J.-T. Chen, X.-D. Zhu, S.-Y. Gao and R. Cao, Cryst. Growth Des., 2008, 8, 2623 CrossRef CAS; (c) Q.-R. Fang, G.-S. Zhu, Z. Jin, Y.-Y. Ji, J.-W. Ye, M. Xue, H. Yang, Y. Wang and S.-L. Qiu, Angew. Chem., Int. Ed., 2007, 46, 6638 CrossRef CAS PubMed; (d) X.-L. Li, K. Chen, Y. Liu, Z.-X. Wang, T.-W. Wang, J.-L. Zuo, Y.-Z. Li, Y. Wang, J.-S. Zhu, J.-M. Liu, Y. Song and X.-Z. You, Angew. Chem., Int. Ed., 2007, 46, 6820 CrossRef CAS PubMed; (e) T. R. Cook, Y.-R. Zheng and P. J. Stang, Chem. Rev., 2013, 113, 734 CrossRef CAS PubMed.
  10. (a) R.-Q. Zou, H. Sakurai, S. Han, R.-Q. Zhong and Q. Xu, J. Am. Chem. Soc., 2007, 129, 8402 CrossRef CAS PubMed; (b) X. Y. Wang, Z. M. Wang and S. Gao, Chem. Commun., 2008, 281 RSC; (c) A.-J. Lan, K.-H. Li, H.-H. Wu, L.-Z. Kong, N. Nijem, D. H. Olson, T. J. Emge, Y. J. Chabal, D. C. Langreth, M.-C. Hong and J. Li, Inorg. Chem., 2009, 48, 7165 CrossRef CAS PubMed; (d) J. Zhang, S.-M. Chen, R. A. Nieto, T. Wu, P.-Y. Feng and X.-H. Bu, Angew. Chem., Int. Ed., 2010, 49, 1267 CrossRef CAS PubMed; (e) H.-Q. Hao, W.-T. Liu, W. Tan, Z.-J. Lin and M.-L. Tong, Cryst. Growth Des., 2009, 9, 457 CrossRef CAS.
  11. (a) G. Zhang, G. Yang, Q. Chen and J.-S. Ma, Cryst. Growth Des., 2005, 5, 661 CrossRef CAS; (b) D.-F. Sun, R. Cao, Y.-Q. Sun, W.-H. Bi, D.-Q. Yuan, Q. Shi and X. Li, Chem. Commun., 2003, 1528 RSC.
  12. (a) R. Heck, J. Bacsa, J. E. Warren, M. J. Rosseinsky and D. Bradshaw, CrystEngComm, 2008, 10, 1687 RSC; (b) L.-L. Qu, Y.-L. Zhu, Y.-Z. Li, H.-B. Du and X.-Z. You, Cryst. Growth Des., 2011, 11, 2444 CrossRef CAS; (c) C.-H. Li, K.-L. Huang, Y.-N. Chi, X. Liu, Z.-G. Han, L. Shen and C.-W. Hu, Inorg. Chem., 2009, 48, 2010 CrossRef CAS PubMed; (d) Y. Tao, J.-R. Li, Q. Yu, W.-C. Song, X.-L. Tong and X.-H. Bu, CrystEngComm, 2008, 10, 699 RSC.
  13. (a) Y. Wang, X.-Q. Zhao, W. Shi, P. Cheng, D.-Z. Liao and S.-P. Yan, Cryst. Growth Des., 2009, 9, 2137 CrossRef CAS; (b) Y.-B. Lu, M.-S. Wang, W.-W. Zhou, G. Xu, G.-C. Guo and J.-S. Huang, Inorg. Chem., 2008, 47, 8935 CrossRef CAS PubMed; (c) B. Zheng, H. Dong, J. Bai, Y. Li, S. Li and M. Scheer, J. Am. Chem. Soc., 2008, 130, 7778 CrossRef CAS PubMed.
  14. (a) M. J. Zaworotko, Nature, 2008, 451, 410 CrossRef CAS PubMed; (b) M. Dinca and J. R. Long, Angew. Chem., Int. Ed., 2008, 47, 6766 CrossRef CAS PubMed; (c) S. Kitagawa and R. Matsuda, Coord. Chem. Rev., 2007, 251, 2490 CrossRef CAS PubMed; (d) S. Henke and R. A. Fischer, J. Am. Chem. Soc., 2011, 133, 2064 CrossRef CAS PubMed.
  15. (a) H. Arora, F. Lloret and R. Mukherjee, Inorg. Chem., 2009, 48, 1158 CrossRef CAS PubMed; (b) H. Chun, H. Jung and J. Seo, Inorg. Chem., 2009, 48, 2043 CrossRef CAS PubMed; (c) Z. Chang, A.-S. Zhang, T.-L. Hu and X.-H. Bu, Cryst. Growth Des., 2009, 9, 4840 CrossRef CAS; (d) H. Kumagai, M. A. Tanaka, K. Inoue, K. Takahashi, H. Kobayashi, S. Vilminot and M. Kurmoo, Inorg. Chem., 2007, 46, 5949 CrossRef CAS PubMed.
  16. (a) R. Robson, Comprehensive Supramolecular Chemistry, Pergamon, New York, 1996 Search PubMed; (b) P. J. Hagrman, D. Hagrman and J. Zubieta, Angew. Chem., Int. Ed., 1999, 38, 2639 CAS; (c) A. J. Blake, N. R. Champness, P. Hubberstey, W. S. Li, M. A. Withersby and M. Schr€oder, Coord. Chem. Rev., 1999, 183, 117 CrossRef CAS; (d) S. Noro, R. Kitaura, M. Kondo, S. Kitagawa, T. Ishii, H. Matsuzaka and M. Yamashita, J. Am. Chem. Soc., 2002, 124, 2568 CrossRef CAS PubMed.
  17. (a) F.-P. Huang, J.-L. Tian, W. Gu, X. Liu, S.-P. Yan, D.-Z. Liao and P. Cheng, Cryst. Growth Des., 2010, 10, 1145 CrossRef CAS; (b) F.-P. Huang, J.-L. Tian, G.-J. Chen, D.-D. Li, W. Gu, X. Liu, S.-P. Yan, D.-Z. Liao and P. Cheng, CrystEngComm, 2010, 12, 1269 RSC; (c) F.-P. Huang, Z.-M. Yang, P.-F. Yao, Q. Yu, J.-L. Tian, H.-D. Bian, S.-P. Yan, D.-Z. Liao and P. Cheng, CrystEngComm, 2013, 15, 2657 RSC.
  18. N. N. Vyatsheslav, V. Z. Nikolay and Z. V. Sergey, ARKIVOC, 2005, 118 Search PubMed.
  19. SAINT Software Reference Manual, Bruker AXS, Madison, WI, 1998 Search PubMed.
  20. G. M. Sheldrick, Phase Annealing in SHELX-90: Direct Methods for Larger Structures, Acta Crystallogr., Sect. A: Found. Crystallogr., 1990, A46, 467 CrossRef CAS.
  21. G. M. Sheldrick, SHELXS-97, Program for X-ray Crystal Structure Solution, University of Göttingen, Göttingen, Germany, 1997 Search PubMed.
  22. (a) M. O'Keeffe and O. M. Yaghi, Reticular Chemistry Structure Resource, Arizona State University, Tempe, AZ, 2005, htpp://www%20okeeffews1.1a.asu.edu/rcsr/home.htm Search PubMed; (b) V. A. Blatov, Multipurpose crystallochemical analysis with the program package TOPOS, IUCr CompComm Newsletter, 2006, vol. 7, p. 4 Search PubMed; (c) V. A. Blatov, A. P. Shevchenko and V. N. Serezhkin, J. Appl. Crystallogr., 2000, 33, 1193 CrossRef CAS; (d) A. F. Wells, Three-Dimensional Nets and Polyhedra, Wiley Interscience, New York, 1977 Search PubMed.
  23. (a) Y. Yan, C.-D. Wu, X. He, Y.-Q. Sun and C.-Z. Lu, Cryst. Growth Des., 2005, 5, 821 CrossRef CAS; (b) C. Qin, X.-L. Wang, L. Carlucci, M.-L. Tong, E.-B. Wang, C.-W. Hua and X. Lin, Chem. Commun., 2004, 1876 RSC.
  24. (a) M. Du, C.-P. Li, C.-S. Liu and S.-M. Fang, Coord. Chem. Rev., 2013, 257, 1282 CrossRef CAS PubMed; (b) M. Du, X.-J. Jiang and X.-J. Zhao, Inorg. Chem., 2007, 46, 3984 CrossRef CAS PubMed; (c) M. Du, X.-J. Jiang and X.-J. Zhao, Inorg. Chem., 2006, 45, 3998 CrossRef CAS PubMed; (d) M. Du, X.-J. Jiang and X.-J. Zhao, Chem. Commun., 2005, 5521 RSC; (e) M. Du, Z.-H. Zhang, Y.-P. You and X.-J. Zhao, CrystEngComm, 2008, 10, 306 RSC; (f) C.-P. Li, J. Chen, Q. Yu and M. Du, Cryst. Growth Des., 2010, 10, 1623 CrossRef CAS.
  25. (a) F.-P. Huang, J.-L. Tian, D.-D. Li, G.-J. Chen, W. Gu, S.-P. Yan, X. Liu, D.-Z. Liao and P. Cheng, Inorg. Chem., 2010, 49, 2525 CrossRef CAS PubMed; (b) F.-P. Huang, J.-L. Tian, D.-D. Li, G.-J. Chen, W. Gu, S.-P. Yan, X. Liu, D.-Z. Liao and P. Cheng, CrystEngComm, 2010, 12, 395 RSC; (c) F.-P. Huang, J.-L. Tian, W. Gu and S.-P. Yan, Inorg. Chem. Commun., 2010, 13, 90 CrossRef CAS PubMed; (d) F.-P. Huang, Q. Zhang, Q. Yu, H.-D. Bian, H. Liang, S.-P. Yan, D.-Z. Liao and P. Cheng, Cryst. Growth Des., 2012, 12, 1890 CrossRef CAS; (e) F.-P. Huang, H.-Y. Li, Q. Yu, H.-D. Bian, J.-L. Tian, S.-P. Yan, D.-Z. Liao and P. Cheng, CrystEngComm, 2012, 14, 4756 RSC.
  26. (a) Y.-C. Qiu, Y.-H. Li, G. Peng, J.-B. Cai, L.-M. Jin, L. Ma, H. Deng, M. Zeller and S. R. Batten, Cryst. Growth Des., 2010, 10, 1332 CrossRef CAS; (b) M.-X. Li, H. Wang, S.-W. Liang, M. Shao, X. He, Z.-X. Wang and S.-R. Zhu, Cryst. Growth Des., 2009, 9, 4626 CrossRef CAS; (c) X.-L. Tong, D.-Z. Wang, T.-L. Hu, W.-C. Song, Y. Tao and X.-H. Bu, Cryst. Growth Des., 2009, 9, 2280 CrossRef CAS; (d) Y. Li, G. Xu, W.-Q. Zou, M.-S. Wang, F.-K. Zheng, M.-F. Wu, H.-Y. Zeng, G.-C. Guo and J.-S. Huang, Inorg. Chem., 2008, 47, 7945 CrossRef CAS PubMed.
  27. (a) L.-H. Jia, R.-Y. Li, Z.-M. Duan, S.-D. Jiang, B.-W. Wang, Z.-M. Wang and S. Gao, Inorg. Chem., 2011, 50, 144 CrossRef CAS PubMed; (b) N. Marino, O. F. Ikotun, M. Julve, F. Lloret, J. Cano and R. P. Doyle, Inorg. Chem., 2011, 50, 378 CrossRef CAS PubMed; (c) T. D. Keene, I. Zimmermann, A. Neels, O. Sereda, J. Hauser, M. Bonin, M. B. Hursthouse, D. J. Price and S. Decurtins, Dalton Trans., 2010, 4937 RSC; (d) S.-Q. Zang, X.-M. Ren, Y. Su, Y. Song, W.-J. Tong, Z.-P. Ni, H.-H. Zhao, S. Gao and Q.-J. Meng, Inorg. Chem., 2009, 48, 9623 CrossRef CAS PubMed; (e) L.-Q. Wei, B.-W. Li, S. Hu and M.-H. Zeng, CrystEngComm, 2011, 13, 510 RSC.

Footnote

Electronic supplementary information (ESI) available. CCDC 916306–916311. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ra03545c

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