Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807043942/at2383sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807043942/at2383Isup2.hkl |
CCDC reference: 663593
A mixture of 4-cyanobenzoic acid (147 mg, 1 mmol), CuO (40 mg, 0.5 mmol), pyrimidine (1 ml) and H2O (9 ml) was loaded into a 25-ml sealed Teflon-lined autoclave, and heated at 160 °C for 5 d, after which it was cooled to room temperature. Blue pismatic crystals of 1 were obtained by filtration of the result solution, and washed by ethanol and diethyl ether successively. IR peaks (cm-1): 3363 (m), 3273 (m), 1605 (versus), 1502 (m), 1448 (s), 1390 (versus), 1356 (versus), 1219 (m), 1147 (m), 1070 (m), 1024 (w), 889 (w), 849 (m), 754 (s), 698 (s), 652 (m), 571 (m), 509 (w).
H atoms of coordination water molecules (O1W) were located in a difference Fourier map and refined as riding in their as-found relative positions, with Uiso(H) = 1.5Ueq(O). The DFIX commands were used to restrain the O—H bond distances of water molecules (Table 1). The H atoms of uncoordinated water molecules (O2W) were not included. Other H atoms were allowed to ride on their respective parent atoms with C—H distances of 0.93 Å, and were included in the refinement with isotropic displacement parameters Uiso(H) = 1.2Ueq(C). ISOR was applied to O2W atom to avoid large adp.
Many interesting in situ reactions such as hydrolysis (Lin et al., 1998; Evans et al., 1999; Lin et al., 2000; Sun et al., 2001), redox (Xiong et al., 1998; Ma et al., 1999; Evans et al., 2000; Tao et al., 2002), and dehydration (Gutschke et al., 2000) can occur under solvothermal environment. It has been found that cyano substituted aromatic compound can be hydrolyzed and the cyano group would be changed to carboxylic acid. For example, Lin's group reported that 3-cyanopyridine or 4-cyanopyridine undergoes a hydrolysis reaction to form 3-pyridinecarboxylic acid (Lin et al., 2000) and 4-pyridinecarboxylic acid (Evans et al., 1999), respectively; Hong's group revealed that the hydrolysis of 1,4-dicyanobenzene gives rise to 1,4-benzenedicarboxylate acid (Sun et al., 2001). The present example shows that 4-cyanobenzoic acid also undergoes a similar hydrolysis procedure.
The hydrothermal reaction of 4-cyanobenzoic acid, CuO, pyridine (py) and water under weak basified conditions gave rise to the title compound (1) as blue prismatic crystals, which were very easy to be efflorescent and become opaque when out of the mother liquid. The IR spectrum of (1) exhibits strong bands at 1605 and 1390 cm-1, which are attributed to the Vas and Vas peaks of COO- group, respectively. The absence of peaks in the range of 2240—2220 cm-1 shows that there exists no cyano group in (1).
A single-crystal X-ray diffraction analysis revealed that compund (1) has a similar 1-D chain structure as that of CuL1(py)2(H2O).py.H2O (L1 = 1,4-benzenedicarboxylate ligand; Ohmura et al., 2003). The crystallographically independent unit of (1) consists of one L1 ligand, two py ligands, one copper(II) atom, one coordination water molecule and hemisemi lattice water molecule. As show in Fig. 1, each copper(II) atom is almost in a square-based pyramidal environment, of which the axial position is occupied by coordination water molecule O1w (Cu1—O1w = 2.243 (3) Å) and the square plane is defined by two nitrogen atoms from two py ligands (Cu—N = 1.996 (3) and 2.010 (3) Å), two oxygen atoms from two L1 ligands (Cu—O = 1.931 (2) and 1.934 (2) Å) with an O24—Cu1—O22 bond angle of 178.3 (1) °. The bond angles of O1w—Cu1—X (X = the atoms in the square plane) vary from 89.4 (1) to 96.2 (1) °, which indicates that O1w is approximately perpendicular to the square plane. In this way, each L1 ligand links two symmetry-related copper(II) atoms (Cu···Cu, ca 10.901 Å) into a 1-D chain along the c direction. Compound 1 crystallizes in space group P212121, and the 1-D chain perfectly lies in the 21 axis. Hence, the 1-D chain is in a helical mode as the case found in the structure of [Cu(L2)(NO3)2]8 (L2 = 2,5-bis(2-pyridyl)-1,3,4-oxodiazole) (Bu et al., 2002). To the best of our knowledge, 1-D helical chiral compound with bridging L1 ligands has only a reported example in the literature (Cutland et al., 2001).
Considering the short contacts shows that the neighboring parallel chains are interconnected by O—H···O hydrogen bonds [O1W···O21i = 2.735 (4) Å, O1w—Hw1···O21i = 133.7 (6) °; O1W···O23ii = 2.719 (3) Å, O1w—Hw2···O23ii = 165 (1)°; (i) x - 1, y, z; (ii) -0.5 - x, 1 - y, -1/2 + z. (Table 1)] to form a layer (Fig. 1). Each of these hydrogen bonds is established from an axially coordinated water molecule to one of the carboxylate group of a neighboring L1 ligand. The distance of two adjacent chains agrees with the Cu1···Cu1a separation of ca 5.990 Å, which is shorter than the L1-bridged Cu···Cu separation. However, considering the short contacts between two adjacent layers, only van der Waals interactions can be found (Fig. 2). The layers are crosswise arranged along the b direction to form a self-complementary structure (Seo et al., 2000) that apparently stabilizes the whole crystal structure. Uncoordinated water molecules locate in the channels along the a direction.
For related literature, see: Bu et al. (2002); Cutland et al. (2001); Evans & Lin (2000); Evans et al. (1999); Gutschke et al. (2000); Lin et al. (1998, 2000); Ma et al. (1999); Ohmura et al. (2003); Seo et al. (2000); Sun et al. (2001); Tao et al. (2002); Xiong et al. (1998).
Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1994); data reduction: XPREP (Siemens, 1995); program(s) used to solve structure: SHELXTL (Siemens, 1995); program(s) used to refine structure: SHELXTL (Siemens, 1995); molecular graphics: SHELXTL (Siemens, 1995); software used to prepare material for publication: SHELXTL (Siemens, 1995).
[Cu(C8H4O4)(C5H5N)2(H2O)]·0.25H2O | F(000) = 838 |
Mr = 408.37 | Dx = 1.375 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 1986 reflections |
a = 5.9896 (7) Å | θ = 2.3–25.1° |
b = 15.2593 (18) Å | µ = 1.14 mm−1 |
c = 21.581 (2) Å | T = 293 K |
V = 1972.4 (4) Å3 | Prismatic, blue |
Z = 4 | 0.48 × 0.24 × 0.14 mm |
Siemens SMART CCD diffractometer | 2927 independent reflections |
Radiation source: fine-focus sealed tube | 1689 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.073 |
ω scans | θmax = 25.1°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −6→7 |
Tmin = 0.874, Tmax = 1.000 | k = −11→18 |
5908 measured reflections | l = −23→25 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.065 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.141 | w = 1/[σ2(Fo2) + (0.032P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.002 |
2927 reflections | Δρmax = 0.71 e Å−3 |
191 parameters | Δρmin = −0.33 e Å−3 |
9 restraints | Absolute structure: Flack (1983), 876 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.31 (2) |
[Cu(C8H4O4)(C5H5N)2(H2O)]·0.25H2O | V = 1972.4 (4) Å3 |
Mr = 408.37 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.9896 (7) Å | µ = 1.14 mm−1 |
b = 15.2593 (18) Å | T = 293 K |
c = 21.581 (2) Å | 0.48 × 0.24 × 0.14 mm |
Siemens SMART CCD diffractometer | 2927 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1689 reflections with I > 2σ(I) |
Tmin = 0.874, Tmax = 1.000 | Rint = 0.073 |
5908 measured reflections |
R[F2 > 2σ(F2)] = 0.065 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.141 | Δρmax = 0.71 e Å−3 |
S = 1.01 | Δρmin = −0.33 e Å−3 |
2927 reflections | Absolute structure: Flack (1983), 876 Friedel pairs |
191 parameters | Absolute structure parameter: 0.31 (2) |
9 restraints |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Cu1 | 0.16689 (10) | 0.53883 (4) | 0.34904 (2) | 0.03936 (14) | |
O21 | 0.5303 (6) | 0.5146 (3) | 0.45248 (14) | 0.0864 (16) | |
O22 | 0.1645 (6) | 0.49792 (18) | 0.43385 (11) | 0.0459 (10) | |
O23 | −0.0356 (5) | 0.4486 (3) | 0.74787 (12) | 0.0625 (12) | |
O24 | 0.3310 (6) | 0.42383 (19) | 0.76355 (11) | 0.0486 (10) | |
C21 | 0.1555 (9) | 0.4372 (3) | 0.72974 (17) | 0.0406 (15) | |
C22 | 0.2054 (7) | 0.4467 (3) | 0.66137 (15) | 0.0368 (14) | |
C23 | 0.4192 (7) | 0.4528 (5) | 0.63920 (18) | 0.068 (2) | |
H23A | 0.5386 | 0.4453 | 0.6662 | 0.082* | |
C24 | 0.4604 (9) | 0.4698 (5) | 0.5775 (2) | 0.090 (2) | |
H24A | 0.6068 | 0.4770 | 0.5640 | 0.107* | |
C25 | 0.2899 (8) | 0.4763 (3) | 0.53580 (16) | 0.0410 (15) | |
C26 | 0.0789 (7) | 0.4670 (4) | 0.55662 (18) | 0.0547 (17) | |
H26A | −0.0401 | 0.4706 | 0.5291 | 0.066* | |
C27 | 0.0384 (8) | 0.4517 (4) | 0.62017 (18) | 0.0632 (19) | |
H27A | −0.1079 | 0.4449 | 0.6338 | 0.076* | |
C28 | 0.3415 (11) | 0.4975 (3) | 0.46790 (19) | 0.0523 (17) | |
N11 | 0.1812 (5) | 0.41556 (16) | 0.31642 (10) | 0.0500 (9) | |
C11 | 0.3632 (5) | 0.3621 (2) | 0.32926 (15) | 0.0810 (16) | |
H11A | 0.4814 | 0.3834 | 0.3528 | 0.097* | |
C12 | 0.3685 (8) | 0.2766 (2) | 0.3070 (2) | 0.103 (2) | |
H12A | 0.4903 | 0.2408 | 0.3156 | 0.124* | |
C13 | 0.1918 (9) | 0.24467 (19) | 0.27188 (19) | 0.111 (2) | |
H13A | 0.1953 | 0.1875 | 0.2570 | 0.133* | |
C14 | 0.0097 (8) | 0.2982 (2) | 0.25904 (18) | 0.128 (2) | |
H14A | −0.1085 | 0.2768 | 0.2355 | 0.154* | |
C15 | 0.0044 (6) | 0.3836 (2) | 0.28131 (15) | 0.0891 (17) | |
H15A | −0.1173 | 0.4194 | 0.2727 | 0.107* | |
N31 | 0.2070 (5) | 0.66163 (17) | 0.37881 (11) | 0.0500 (9) | |
C31 | 0.3862 (5) | 0.7127 (2) | 0.35951 (16) | 0.0810 (16) | |
H31A | 0.4865 | 0.6908 | 0.3305 | 0.097* | |
C32 | 0.4155 (7) | 0.7964 (2) | 0.3836 (2) | 0.103 (2) | |
H32A | 0.5354 | 0.8305 | 0.3707 | 0.124* | |
C33 | 0.2655 (9) | 0.8290 (2) | 0.4270 (2) | 0.111 (2) | |
H33A | 0.2851 | 0.8850 | 0.4431 | 0.133* | |
C34 | 0.0863 (8) | 0.7780 (2) | 0.44630 (18) | 0.128 (2) | |
H34A | −0.0140 | 0.7999 | 0.4753 | 0.154* | |
C35 | 0.0571 (6) | 0.6943 (2) | 0.42221 (15) | 0.0891 (17) | |
H35A | −0.0628 | 0.6602 | 0.4351 | 0.107* | |
O1W | −0.2068 (4) | 0.54786 (18) | 0.35159 (9) | 0.0553 (10) | |
H1WA | −0.2573 (15) | 0.5095 (3) | 0.37645 (16) | 0.083* | |
H1WB | −0.2802 (11) | 0.5393 (6) | 0.31842 (15) | 0.083* | |
O2W | 0.026 (4) | 0.2549 (17) | 0.4836 (10) | 0.178 (5) | 0.25 |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.0449 (3) | 0.0560 (3) | 0.01714 (19) | 0.0003 (4) | −0.0009 (3) | 0.0010 (3) |
O21 | 0.040 (2) | 0.178 (4) | 0.0409 (18) | −0.022 (3) | 0.0112 (19) | 0.033 (2) |
O22 | 0.050 (2) | 0.068 (2) | 0.0196 (13) | 0.0003 (19) | 0.0030 (19) | 0.0028 (13) |
O23 | 0.034 (2) | 0.126 (3) | 0.0277 (15) | −0.010 (3) | 0.0127 (16) | 0.005 (2) |
O24 | 0.047 (2) | 0.079 (2) | 0.0201 (14) | 0.000 (2) | −0.0019 (19) | 0.0022 (14) |
C21 | 0.042 (3) | 0.053 (3) | 0.027 (2) | −0.025 (3) | −0.007 (3) | −0.0031 (19) |
C22 | 0.037 (3) | 0.058 (3) | 0.0153 (19) | 0.004 (3) | −0.004 (2) | −0.004 (2) |
C23 | 0.021 (3) | 0.162 (5) | 0.022 (2) | −0.006 (4) | −0.008 (2) | 0.013 (3) |
C24 | 0.034 (3) | 0.206 (7) | 0.029 (2) | 0.004 (5) | 0.004 (3) | 0.028 (4) |
C25 | 0.038 (3) | 0.068 (3) | 0.0175 (19) | 0.006 (3) | −0.003 (2) | 0.006 (2) |
C26 | 0.028 (3) | 0.117 (4) | 0.019 (2) | −0.002 (3) | 0.000 (2) | 0.003 (3) |
C27 | 0.026 (3) | 0.133 (5) | 0.030 (2) | −0.001 (4) | 0.007 (2) | −0.005 (3) |
C28 | 0.054 (3) | 0.076 (4) | 0.028 (2) | −0.006 (3) | 0.001 (3) | 0.005 (2) |
N11 | 0.0537 (19) | 0.0574 (18) | 0.0388 (13) | 0.0086 (17) | −0.0068 (17) | 0.0085 (12) |
C11 | 0.084 (3) | 0.068 (3) | 0.091 (3) | −0.009 (3) | −0.012 (3) | −0.002 (2) |
C12 | 0.115 (5) | 0.052 (3) | 0.143 (4) | −0.015 (3) | 0.010 (3) | −0.016 (3) |
C13 | 0.144 (5) | 0.071 (3) | 0.118 (3) | −0.002 (3) | 0.004 (4) | −0.040 (3) |
C14 | 0.140 (5) | 0.105 (4) | 0.140 (4) | 0.009 (4) | 0.018 (4) | −0.062 (3) |
C15 | 0.093 (4) | 0.096 (4) | 0.078 (3) | 0.015 (3) | −0.004 (3) | −0.030 (2) |
N31 | 0.0537 (19) | 0.0574 (18) | 0.0388 (13) | 0.0086 (17) | −0.0068 (17) | 0.0085 (12) |
C31 | 0.084 (3) | 0.068 (3) | 0.091 (3) | −0.009 (3) | −0.012 (3) | −0.002 (2) |
C32 | 0.115 (5) | 0.052 (3) | 0.143 (4) | −0.015 (3) | 0.010 (3) | −0.016 (3) |
C33 | 0.144 (5) | 0.071 (3) | 0.118 (3) | −0.002 (3) | 0.004 (4) | −0.040 (3) |
C34 | 0.140 (5) | 0.105 (4) | 0.140 (4) | 0.009 (4) | 0.018 (4) | −0.062 (3) |
C35 | 0.093 (4) | 0.096 (4) | 0.078 (3) | 0.015 (3) | −0.004 (3) | −0.030 (2) |
O1W | 0.051 (2) | 0.086 (2) | 0.0287 (13) | −0.003 (2) | −0.0029 (19) | 0.008 (2) |
O2W | 0.193 (7) | 0.164 (7) | 0.178 (7) | −0.005 (6) | −0.013 (6) | −0.022 (6) |
Cu1—O24i | 1.931 (2) | N11—C15 | 1.3900 |
Cu1—O22 | 1.934 (2) | C11—C12 | 1.3900 |
Cu1—N31 | 1.996 (3) | C11—H11A | 0.9300 |
Cu1—N11 | 2.010 (3) | C12—C13 | 1.3900 |
Cu1—O1W | 2.243 (3) | C12—H12A | 0.9300 |
O21—C28 | 1.208 (7) | C13—C14 | 1.3900 |
O22—C28 | 1.290 (6) | C13—H13A | 0.9300 |
O23—C21 | 1.222 (6) | C14—C15 | 1.3900 |
O24—C21 | 1.296 (6) | C14—H14A | 0.9300 |
O24—Cu1ii | 1.931 (2) | C15—H15A | 0.9300 |
C21—C22 | 1.513 (5) | N31—C31 | 1.3900 |
C22—C27 | 1.341 (6) | N31—C35 | 1.3900 |
C22—C23 | 1.370 (6) | C31—C32 | 1.3900 |
C23—C24 | 1.380 (6) | C31—H31A | 0.9300 |
C23—H23A | 0.9300 | C32—C33 | 1.3900 |
C24—C25 | 1.364 (6) | C32—H32A | 0.9300 |
C24—H24A | 0.9300 | C33—C34 | 1.3900 |
C25—C26 | 1.349 (6) | C33—H33A | 0.9300 |
C25—C28 | 1.532 (6) | C34—C35 | 1.3900 |
C26—C27 | 1.412 (6) | C34—H34A | 0.9300 |
C26—H26A | 0.9300 | C35—H35A | 0.9300 |
C27—H27A | 0.9300 | O1W—H1WA | 0.850 (4) |
N11—C11 | 1.3900 | O1W—H1WB | 0.850 (4) |
O24i—Cu1—O22 | 178.33 (13) | C15—N11—Cu1 | 119.12 (15) |
O24i—Cu1—N31 | 91.70 (12) | C12—C11—N11 | 120.0 |
O22—Cu1—N31 | 89.96 (11) | C12—C11—H11A | 120.0 |
O24i—Cu1—N11 | 86.63 (11) | N11—C11—H11A | 120.0 |
O22—Cu1—N11 | 91.70 (11) | C11—C12—C13 | 120.0 |
N31—Cu1—N11 | 170.51 (13) | C11—C12—H12A | 120.0 |
O24i—Cu1—O1W | 90.68 (12) | C13—C12—H12A | 120.0 |
O22—Cu1—O1W | 89.38 (12) | C14—C13—C12 | 120.0 |
N31—Cu1—O1W | 93.13 (11) | C14—C13—H13A | 120.0 |
N11—Cu1—O1W | 96.23 (12) | C12—C13—H13A | 120.0 |
C28—O22—Cu1 | 122.3 (3) | C15—C14—C13 | 120.0 |
C21—O24—Cu1ii | 119.8 (3) | C15—C14—H14A | 120.0 |
O23—C21—O24 | 127.0 (4) | C13—C14—H14A | 120.0 |
O23—C21—C22 | 118.9 (4) | C14—C15—N11 | 120.0 |
O24—C21—C22 | 113.8 (4) | C14—C15—H15A | 120.0 |
C27—C22—C23 | 117.5 (4) | N11—C15—H15A | 120.0 |
C27—C22—C21 | 120.3 (4) | C31—N31—C35 | 120.0 |
C23—C22—C21 | 122.1 (4) | C31—N31—Cu1 | 121.51 (15) |
C22—C23—C24 | 121.2 (4) | C35—N31—Cu1 | 118.41 (15) |
C22—C23—H23A | 119.4 | C32—C31—N31 | 120.0 |
C24—C23—H23A | 119.4 | C32—C31—H31A | 120.0 |
C25—C24—C23 | 121.1 (5) | N31—C31—H31A | 120.0 |
C25—C24—H24A | 119.5 | C31—C32—C33 | 120.0 |
C23—C24—H24A | 119.5 | C31—C32—H32A | 120.0 |
C26—C25—C24 | 118.3 (4) | C33—C32—H32A | 120.0 |
C26—C25—C28 | 122.0 (4) | C32—C33—C34 | 120.0 |
C24—C25—C28 | 119.7 (4) | C32—C33—H33A | 120.0 |
C25—C26—C27 | 120.1 (4) | C34—C33—H33A | 120.0 |
C25—C26—H26A | 119.9 | C33—C34—C35 | 120.0 |
C27—C26—H26A | 119.9 | C33—C34—H34A | 120.0 |
C22—C27—C26 | 121.7 (4) | C35—C34—H34A | 120.0 |
C22—C27—H27A | 119.2 | C34—C35—N31 | 120.0 |
C26—C27—H27A | 119.2 | C34—C35—H35A | 120.0 |
O21—C28—O22 | 127.7 (4) | N31—C35—H35A | 120.0 |
O21—C28—C25 | 119.9 (5) | Cu1—O1W—H1WA | 109.2 (7) |
O22—C28—C25 | 112.4 (5) | Cu1—O1W—H1WB | 119.1 (5) |
C11—N11—C15 | 120.0 | H1WA—O1W—H1WB | 103.9 (6) |
C11—N11—Cu1 | 120.88 (15) |
Symmetry codes: (i) −x+1/2, −y+1, z−1/2; (ii) −x+1/2, −y+1, z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O21iii | 0.85 (1) | 2.08 (1) | 2.735 (4) | 134 (1) |
O1W—H1WB···O23iv | 0.85 (1) | 1.89 (1) | 2.719 (3) | 165 (1) |
Symmetry codes: (iii) x−1, y, z; (iv) −x−1/2, −y+1, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cu(C8H4O4)(C5H5N)2(H2O)]·0.25H2O |
Mr | 408.37 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 293 |
a, b, c (Å) | 5.9896 (7), 15.2593 (18), 21.581 (2) |
V (Å3) | 1972.4 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.14 |
Crystal size (mm) | 0.48 × 0.24 × 0.14 |
Data collection | |
Diffractometer | Siemens SMART CCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.874, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5908, 2927, 1689 |
Rint | 0.073 |
(sin θ/λ)max (Å−1) | 0.597 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.065, 0.141, 1.01 |
No. of reflections | 2927 |
No. of parameters | 191 |
No. of restraints | 9 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.71, −0.33 |
Absolute structure | Flack (1983), 876 Friedel pairs |
Absolute structure parameter | 0.31 (2) |
Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1994), XPREP (Siemens, 1995), SHELXTL (Siemens, 1995).
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O21i | 0.850 (4) | 2.078 (7) | 2.735 (4) | 133.7 (6) |
O1W—H1WB···O23ii | 0.850 (4) | 1.889 (5) | 2.719 (3) | 164.9 (10) |
Symmetry codes: (i) x−1, y, z; (ii) −x−1/2, −y+1, z−1/2. |
Many interesting in situ reactions such as hydrolysis (Lin et al., 1998; Evans et al., 1999; Lin et al., 2000; Sun et al., 2001), redox (Xiong et al., 1998; Ma et al., 1999; Evans et al., 2000; Tao et al., 2002), and dehydration (Gutschke et al., 2000) can occur under solvothermal environment. It has been found that cyano substituted aromatic compound can be hydrolyzed and the cyano group would be changed to carboxylic acid. For example, Lin's group reported that 3-cyanopyridine or 4-cyanopyridine undergoes a hydrolysis reaction to form 3-pyridinecarboxylic acid (Lin et al., 2000) and 4-pyridinecarboxylic acid (Evans et al., 1999), respectively; Hong's group revealed that the hydrolysis of 1,4-dicyanobenzene gives rise to 1,4-benzenedicarboxylate acid (Sun et al., 2001). The present example shows that 4-cyanobenzoic acid also undergoes a similar hydrolysis procedure.
The hydrothermal reaction of 4-cyanobenzoic acid, CuO, pyridine (py) and water under weak basified conditions gave rise to the title compound (1) as blue prismatic crystals, which were very easy to be efflorescent and become opaque when out of the mother liquid. The IR spectrum of (1) exhibits strong bands at 1605 and 1390 cm-1, which are attributed to the Vas and Vas peaks of COO- group, respectively. The absence of peaks in the range of 2240—2220 cm-1 shows that there exists no cyano group in (1).
A single-crystal X-ray diffraction analysis revealed that compund (1) has a similar 1-D chain structure as that of CuL1(py)2(H2O).py.H2O (L1 = 1,4-benzenedicarboxylate ligand; Ohmura et al., 2003). The crystallographically independent unit of (1) consists of one L1 ligand, two py ligands, one copper(II) atom, one coordination water molecule and hemisemi lattice water molecule. As show in Fig. 1, each copper(II) atom is almost in a square-based pyramidal environment, of which the axial position is occupied by coordination water molecule O1w (Cu1—O1w = 2.243 (3) Å) and the square plane is defined by two nitrogen atoms from two py ligands (Cu—N = 1.996 (3) and 2.010 (3) Å), two oxygen atoms from two L1 ligands (Cu—O = 1.931 (2) and 1.934 (2) Å) with an O24—Cu1—O22 bond angle of 178.3 (1) °. The bond angles of O1w—Cu1—X (X = the atoms in the square plane) vary from 89.4 (1) to 96.2 (1) °, which indicates that O1w is approximately perpendicular to the square plane. In this way, each L1 ligand links two symmetry-related copper(II) atoms (Cu···Cu, ca 10.901 Å) into a 1-D chain along the c direction. Compound 1 crystallizes in space group P212121, and the 1-D chain perfectly lies in the 21 axis. Hence, the 1-D chain is in a helical mode as the case found in the structure of [Cu(L2)(NO3)2]8 (L2 = 2,5-bis(2-pyridyl)-1,3,4-oxodiazole) (Bu et al., 2002). To the best of our knowledge, 1-D helical chiral compound with bridging L1 ligands has only a reported example in the literature (Cutland et al., 2001).
Considering the short contacts shows that the neighboring parallel chains are interconnected by O—H···O hydrogen bonds [O1W···O21i = 2.735 (4) Å, O1w—Hw1···O21i = 133.7 (6) °; O1W···O23ii = 2.719 (3) Å, O1w—Hw2···O23ii = 165 (1)°; (i) x - 1, y, z; (ii) -0.5 - x, 1 - y, -1/2 + z. (Table 1)] to form a layer (Fig. 1). Each of these hydrogen bonds is established from an axially coordinated water molecule to one of the carboxylate group of a neighboring L1 ligand. The distance of two adjacent chains agrees with the Cu1···Cu1a separation of ca 5.990 Å, which is shorter than the L1-bridged Cu···Cu separation. However, considering the short contacts between two adjacent layers, only van der Waals interactions can be found (Fig. 2). The layers are crosswise arranged along the b direction to form a self-complementary structure (Seo et al., 2000) that apparently stabilizes the whole crystal structure. Uncoordinated water molecules locate in the channels along the a direction.