КООРДИНАЦИОННАЯ ХИМИЯ, 2015, том 41, № 8, с. 488-495
УДК 541.49
TWO SUPRAMOLECULES CONSTRUCTED FROM 2-o-CHLOROPHENYLIMIDAZOLE DICARBOXYLATE: SYNTHESES, CRYSTAL STRUCTURES, AND THERMAL PROPERTIES
© 2015 M. J. Gao, X. Ren, Z. F. Yue, and G. Li*
College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001 P.R. China
*E-mail: gangli@zzu.edu.cn Received December 15, 2014
Two mononuclear complexes, [M(o-ClPhH2IDC)2(H2O)2] • 4H2O (o-ClPhH2IDC = 2-(o-chlorophenyl)-1#-imidazole-4,5-dicarboxylicacid; M = Co(I) and Mn(II)), have been solvothermally synthesized and structurally characterized by single crystal X-ray diffraction (CIF files CCDC nos. 1036900 (I) and 1036899 (II)), elemental analyses, IR spectroscopy, and powder X-ray diffractionIn both supramolecules, the [Co(o-ClPhH2IDC)2(H2O)2] or [Mn(o-ClPhH2IDC)2(H2O)2] units are joined through the n-n interactions and intermolecular hydrogen bonds to form the 3D solid-state architectures. Their thermal properties under are have been investigated as well.
DOI: 10.7868/S0132344X15070014
INTRODUCTION
Recently, along with the progresses in the field of coordination chemistry, more and more supramolecules with fascinating architectures and potential application in photoluminescence, magnetism, gas storage, ion exchange and catalysis [1—4]. Consequently, a great number of supramolecules showing one-dimensional (1D) chains [5] and ladders [6], two-dimensional (2D) grids [7], three-dimensional (3D) interpenetrated [8] and helical networks [9] have been investigated.
For the construction of supramolecular complexes, the key is to select a powerful organic ligand [10—12], which is helpful to form weak intra- and intermolecular H bonds, and n—n stacking effects. As well known, 1#-imidazole-4,5-dicarboxylic acid (H3IDC) [13, 14] has been proved as an outstanding ligand not only for the possession of six coordination sites: two imidazole nitrogen atoms and four carboxylate oxygen atoms, but also for its potential ability as hydrogen-bonding donors and acceptors [15—20]. To enhance the n—n stacking effects of H3IDC, our laboratory has paid much concern on the functionalized imidazole dicar-boxylate ligands bearing 2-position aromatic groups and designed a series of efficient related ligands successfully.
Hence, 2-(2-chlorophenyl)-1#-imidazole-4,5-dicarboxylic acid (o-ClPhH3IDC) is designed and
prepared. In this study, we will investigate the reactions of the o-ClPhH3IDC ligand with transition metals, namely Co(II) and Mn(II) under solvother-mal conditions. Fortunately, two supramolecular complexes, [Co(o-ClPhH2IDC)2(H2O)2] • 4H2O (I) and [Mn(o-ClPhH2IDC)2(H2O)2] • 4H2O (II), have been synthesized (Scheme) and structurally characterized. Herein, we will present IR spectra, single-crystal X-ray diffraction, elemental analyses, and thermal analyses of the complexes I and II, anddescribe the coordination mode of o-C!PhH2IDC- ligand (Fig. 1).
^ O(1)
N(1) C C C V Cl(1) C C O(2)
H
N(2) C
C C C O(3)
M
O(4)
Fig. 1. Coordination mode of o-ClPhH2IDC anion.
HOOC COOH
CoCl,
HN .N
+
CI
H,O, Et3N, 150°C, 4d
[C0(0-ClPhH2IDC)2(H2O)2] • 4H2O (I)
MnCl, ■ 4H,O
CH3CN/H2O, Et3N 160°C, 4d
[Mn(o-ClPhH2IDC)2(H2O)2] • 4H2O (II)
Scheme.
EXPERIMENTAL
Materials and methods. All chemicals were of reagent grade quality obtained from commercial sources and used without further purification. The organic ligand o-ClPhH3IDC was prepared according to literature method [21]. The C, H, and N microanalyses were carried out on a FLASH EA 1112 analyzer. IR spectra were recorded on a BRUKER TENSOR 27 spectrophotometer as KBr pellets in the 400—4000 cm-1 region. TG measurements were performed by heating the crystalline sample from 30 to 850°C at a rate of 10°C min-1 in the air on a Netzsch STA 409PC differential thermal analyzer. X-ray powder diffraction (PXRD) measurements were recorded on a Panalyti-cal X'pert PRO X-ray diffractometer.
Synthesis of I. A mixture of CoCl2 • 6H2O (23.8 mg, 0.1 mmol), o-ClPhH3IDC (26.6 mg, 0.1 mmol), H2O (7 mL), Et3N (0.014 mL, 0.1 mmol) were sealed in a 25 mL Teflon-lined stainless steel autoclave, heated at 150°C for four days, and then cooled to room temperature. Amaranth orthorhombic crystals of I were isolated, washed with distilled water, and dried in air (69% yield based on Co).
IR (KBr; v, cm-1): 3418 s, 1722 m, 1548 s, 1471 s, 1385 m, 1290 m, 1128 w, 1060 m, 982 w, 740 m, 551 w.
For C22H24N4O14aCo
anal. calcd., %: C, 37.82; H, 3.44; N, 8.02. Found, %: C, 37.99; H, 3.18; N, 7.84.
Synthesis of II. A mixture ofMnCl2 • 4H2O (20.2 mg, 0.1 mmol), o-ClPhH3IDC (26.6 mg, 0.1 mmol), CH3CN-H2O (3 : 4, 7 mL), Et3N (0.014 mL, 0.1 mmol) were sealed in a 25 mL Teflon-lined stainless steel autoclave, heated at 150°C for four days, and then cooled to room temperature. Colorless orthor-hombic crystals of II were isolated, washed with distilled water, and dried in air (58% yield based on Mn).
IR (KBr; v, cm-1): 3422 s, 1722 m, 1571 s, 1547 s, 1466 s, 1385 m, 1287 w, 1059 m, 980 w, 740 m.
For C22H24N4O14aMn
anal. calcd., %: Found, %:
C, 38.09; C, 37.78;
H, 3.32; H, 3.46;
N, 8.08. N, 7.79.
X-ray crystallography. Measurements of compounds I and II were made on a Bruker smart APEXII CCD diffractometer with a graphite-monochromated MoZa radiation (X = 0.71073 A). Single crystals of I and II were selected and mounted on a glass fiber. All data were collected at room temperature (296(2) K) using the ®-29 scan technique and corrected for Lorenz-polarization effects. A correction for secondary extinction was applied. The two structures were solved by direct methods and expanded using the Fourier technique. The non-hydrogen atoms were refined with anisotropic thermal parameters. Hydrogen atoms were included but not refined. The final cycle of full-matrix least squares refinement was based on 6133 observed reflections and 440 variable parameters for I, 6181 observed reflections and 451 variable parameters for II. All calculations were performed using the SHELX-97 crystallographic software package [22]. Crystal data and experimental details for compounds I and II are contained in Table 1. The selected bond lengths and angles and hydrogen bonding parameters are listed in Table 2 and Table 3, respectively. Supplementary material has been deposited with the Cambridge Crystallographic Data Centre (nos. 1036900 and 1036899 for I and II, respectively; depos-it@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
RESULTS AND DISCUSSION
A single-crystal X-ray diffraction study shows that compound I is a mononuclear structure. An appropriate drawing of the molecular structure with atom labeling scheme is shown in Fig. 2a.
The asymmetric unit of I consists of central Co(II), two discrete o-ClPhH3IDC anions, two coordinate waters and four free waters. The geometry around the Co(II) center is best portrayed as a distorted
Table 1. Crystallographic data and structural refinement information for compounds I and II
Parameter Value
I II
Fw 698.28 698.28
Crystal system Triclinic Triclinic
Crystal size, mm 0.22 x 0.21 x 0.18 0.24 x 0.18 x 0.16
Space group p1 p1
a, A 10.4974(5) 10.904(2)
b, A 11.4488(6) 11.032(2)
c, A 11.7474(6) 11.683(2)
a, deg 98.1520(10) 96.072(3)
P, deg 90.1610(10) 91.158(3)
Y, deg 97.4660(10) 94.055(3)
V, A3 1385.39(12) 1388.1(4)
Pcalcd mg m-3 1.674 1.659
Z 2 2
p., mm-1 0.890 0.704
Reflections 8893/6133 8403/6181
Collected/unique (Rint) (0.0109) (0.0391)
Data/restraints/parameters 6133/8/440 6181/21/451
GOOF on F 2 1.000 0.992
R 0.0265 0.0718
wR 0.0643 0.1984
Apmax and Ap^n e AT3 0.585 and -0.582 1.266 and -2.168
[CoO4N2] octahedral environment including two imidazole nitrogen (N(1) and N(3)) and two carbox-ylate oxygen atoms (O(4) and O(7)) from two individual o-ClPhH2IDC- anions, and two oxygen atoms (O(5) and O(6)) from the coordinated water molecules (Fig. 2a). The Co—O distances span from 2.0478(12) to 2.1678(12) Á, while Co-N bond lengths are in the range of 2.1232(14)-2.1325(14) Á. In addition, within in the organic ligand, the dihedral angle between the imidazole ring and the phenyl plane is 51.5° indicating the serious twist. The two imidazole rings are parallel to each others, whose plane distance is 10.5823 Á. Two plane distances between the phenyl rings are 4.7511 and 6.9136 Á.
It should be point that both the o-ClPhH2IDC-units and water molecules all participate in the formation of hydrogen bonds, especially the waters, which are an integral part of the crystal structure. Here is a view of the 3D structure of I (Fig. 2c). There are several types of hydrogen bonds in complex I (Table 3). The intramolecular H bonds consist of O(10)-H(10)-O(8) and O(2)-H(2)-O(3) between two carboxylate units ofthe same organic ligand. And the intermolecular H bond includes O(12)-H(20)---O(3),
O(11)—H(23)-"O(10), O(12)-H(21)"O(8), O(15)-H(52)--O(3), O(15)-H(53)-O(4) and O(14)-H(81)---O(1) between free waters and carboxyls of the ligands; O(5)-H(51)-O(9) and O(6)-H(6)-O(7) between the coordinate waters and carboxyls of ligands; N(4)—H(27)--O(11) and N(2)-H(28)-O(14) between N of the imidazole rings and the free waters; O(11)—H(22)-"O(15) and O(14)-H(80)-O(15) between the free waters and O(6)—H(30)---O(14) and O(5)—H(5)--O(12) between the coordinate waters and the free waters. In order to express the connection method of various units more clearly, a 2D ladder-like plane of the supermolecular structure is showed in Fig. 2b. The neighbor [Co(o-ClPhH2IDC)2(H2O)2] units are joined by the O—H—O H bonds (O(5)-H(51)-O(9) and O(6)-H(6)-O(7)) to form 1D jagged chains, and the intra-chain distances of adjacent Co(II) ions are 10.497, 5.358 and 9.164 A. Furthermore, the 2D layer is constituted via the linkages of the hydrogen bonds N(4)-H(27)-O(1), O(11)-H(22)-O(15), O(14)—H(80)-"O(15), O(15)-H(53)-O(4) and O(14)—H(81)-"O(1) between the adjacent chains. Moreover, the layers ar
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