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HYDROTHERMAL SYNTHESIS, CRYSTAL STRUCTURE OF THREE NOVEL COMPLEXES BASED ON THIABENDAZOLE AND 1,4-BENZENEDICARBOXYLATE LIGANDS
© 2013 S. Q. Wei1, 2, C. W. Lin1, X. H. Yin2, *, Y. J. Du2, and Z. Y. Xiong2
1College of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning, 530004 P.R. China 2College of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530006 P.R. China
*E-mail: yxhphd@163.com Received March 22, 2012
Three novel metal-organic complexes [Co(BDC)(TBZ)2] (I), [Cd2(BDC)2(TBZ)2(H2O)2] ■ 2(H2O) (II), [Mn2(BDC)(TBZ)4(SO4)] (III) (BDC = 1,4-benzenedicarboxylate, TBZ = thiabendazole) have been prepared and characterized by IR spectrum, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. X-ray structure analysis reveals that both three complexes are one-dimensional chain polymers. The 1D chain architecture of I is constructed from terephthalic acid and cobalt atoms. A simultaneous presence of chelating and monodentate coordination modes of BDC ligands is observed in complex II. In
complex III, the coordinated BDC ligands adopt monodentate mode and with SO4 anions alternately bridge the Mn2+ ions into 1D chains. The 3D structures of the three complexes are stabilized by n—n stacking interactions and hydrogen-bonds.
DOI: 10.7868/S0132344X13090090
INTRODUCTION
In the past decades, the design and synthesis of novel organic-inorganic hybrid materials have provoked significant interest owing to their enormous varieties of intriguing structural topologies and their fascinating properties [1—10]. In this process, judicious selection of ligands as basic building blocks is of great importance because slight structural changes about organic building blocks, such as length, flexibility and symmetry, can dramatically change the structural motifs of coordination polymers. As bridging ligands, car-boxylates, especially multi-carboxylates, are of immense interest in the construction of polymeric coordination architectures because not only the fact that these polymers have a wide range of structural diversities and potential applications as porous materials and magnetic materials, but also the multi-carboxylates are capable of functioning as hydrogen bond donors and/or acceptors [11]. The auxiliary ligands containing N-donor, such as TBZ, were introduced into the reaction systems so as to inhibit the expansion of polymeric frameworks to obtain the desired low dimensional coordination polymers [12]. TBZ aroused considerable interest in biology and medicine due to its antiproliferative activities [13, 14]. It is an antimicrobial drug belonging to the benzimidazole derivative and has exhibited wide applications in human and veterinary medicine [15]. The employment of mixed ligands has been demonstrated to be a very effective
approach for constructing diverse coordination frameworks [16, 17]. However, the hybrid coordination polymers constructed by TBZ and aryl-acid combined are rarely reported [18, 19], although these two ligands are familiar to us. Herein, we report synthesis, crystal structures, elemental analyses, IR spectrum and thermal properties of three novel cobalt(II) complexes with 1,4-benzenedicarboxylate (BDC) and thiabendazole (TBZ) ligands, [Co(BDC)(TBZ)2] (I), [Cd2(BDC)2(TBZ)2(H2O)2] ■ 2(H2O) (II), [Mn2(BDC)(TBZ)4(SO4)] (III), which are formed by n—n stacking interactions and hydrogen bonds.
EXPERIMENTAL
Materials and instrumentation. All chemicals were commercial materials of analytical grade and used without purification. Elemental analysis for C, H, N, and S was carried out on a PerkinElmer 2400 II elemental analyzer. The FT-IR spectrum was obtained on a PE Spectrum One FT-IR Spectrometer Fourier transform infrared spectroscopy in the 4000—400 cm-1 regions, using KBr pellets. PerkinElmer Diamond TG/DTA thermal analyzer was used to record simultaneous TG and DTG curves in the static air atmosphere at a heating rate of 10 K min-1 in the temperature range 25-1000°C using platinum crucibles.
Synthesis of I. A solution of TBZ (0.201 g, 1 mmol) in 3 mL DMF was added dropwise with stirring at
room temperature to a solution of Co(NO3)2 • 6H2O (0.291 g, 1 mmol), H2BDC (0.1660 g, 1 mmol) in the mixture of 10 mL water and 5 mL ethanol. Then an aqueous solution of sodium hydroxide was added dropwise with stirring to adjust the pH value of the solution being 6. The resulting mixture was sealed in a 23 mL Teflon-lined stainless reactor, kept under autogenous pressure at 130°C for 72 h, and then slowly cooled to room temperature at a rate of 5°C per hour. The red block crystals suitable for X-ray diffraction were isolated directly, washed with ethanol and dried in air (the yield was 65% based on Co).
For C28H18N6O4S2Co
anal. calcd., %: C, 53.76; H, 2.90; N, 13.43; S, 10.25. Found, %: C, 53.78; H, 2.93; N, 13.41; S, 10.24.
IR data (KBr; v, cm-1): 3490 br, 1653 s, 1593 v.s, 1553 s, 1495 m, 1218 m, 1116 m, 860 m, 720 s, 647 w.
Synthesis of II. TBZ (0.201 g, 1 mmol) and H2BDC (0.1660 g, 1 mmol) were dissolved in the mixture of 6 mL H2O and 5 mL DMF. Then an aqueous solution of sodium hydroxide was added dropwise with srirring to adjust the pH value of the solution being 6. At last, 10 mL aqueous solution of Cd(NO3)2 • 4H2O (0.3085 g, 1 mmol) was input. The resulting mixture was sealed in a 23 mL Teflon-lined stainless reactor, kept under autogenous pressure at 130°C for 72 h, and then slowly cooled to room temperature at a rate of 5°C per hour. The red block crystals suitable for X-ray diffraction were isolated directly, washed with ethanol and dried in air (the yield was 45% based on Cd).
For C36H3eN6O12S2Cd2
anal. calcd., %: C, 42.08; H, 2.94; N, 8.18; S, 6.24. Found, %: C, 42.09; H, 2.96; N, 8.17; S, 6.25.
IR data (KBr; v, cm-1): 3410 br, 1649 s, 1596 v.s, 1556 s, 1494 s, 1221m, 1096 m, 850 m, 709 m.
Synthesis of III. The same synthetic procedure as that for I was used except that Co(NO3)2 • 6H2O (0.291 g, 1 mmol) was replaced by MnSO4 • H2O (0.169 g, 1 mmol). The red block crystals of III were obtained in 55% yield based on Mn.
For C48H32Mn2N12O8S5
anal. calcd., %: C, 49.06; H, 2.74; N, 14.30; S, 13.64. Found, %: C, 49.05; H, 2.77; N, 14.28; S, 13.62.
IR data (KBr; v, cm-1): 3420 br, 1645s, 1595 v.s, 1555 s, 1498 s, 1235 m, 1104 m, 1092 m, 845 m, 713 s, 644 m.
X-ray structure determination. Single crystal of the complex was mounted on glass ber and measured on a Bruker SMART CCD area detector at 296 K using graphite monochromated Mo^Ta radiation (X = 0.71073 A). Empirical absorption corrections were applied using
the SADABS program [20]. The structure was solved by the direct method and refined by full-matrix least squares on F2 using the SHELXTL program [21]. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were set in calculated positions and refined by a riding mode, with a common thermal parameter. The crystal data and structure refinement details for three complexes are shown in Table 1. Selected bond lengths and angles of the complexes are listed in Table 2, and possible hydrogen bond geometries are given in Table 3.
Supplementary material has been deposited with the Cambridge Crystallographic Data Centre (nos. 869946 (I), 869945 (II), 869947 (III); deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
RESULTS AND DISCUSSION
The structure of the compound I is formed by infinite one-dimensional chains. The simplest coordination pattern is observed in compound I, where each cobalt atom has an octahedral environment formed by four nitrogen atoms (N(1), N(2), N(3), N(4)) from two chelated TBZ ligands and two O atoms (O(1), O(3)) from different BDC ligands (Fig. 1). The car-boxy groups of BDC ligands are coordinated in a mo-nodentate mode. In the overall structure of I, units of [Co(TBZ)]2+ are connected by the bridging BDC ligands to generate a zigzag chain (Fig. 2). The 1D chains are linked by weak N(3)—H(3^)--0(2)# (symmetry code: # x + 1/2, y — 1/2, z + 3/2) hydrogen bonds (Table 3) with the distance of2.669(2) A to yield a layered network. Figure 2 also reveals that n—n interactions exist between TBZ ligands with the centroid-centroid distances of 3.767 A. Such contacts link the 2D layers into a 3D structure.
As shown in Fig. 3 for compound II, the BDC ligands have two types: A is bidentate and B is mono-dentate. The two crystallographically independent Cd atoms (Cd(1) and Cd(2)) are bridged by one BDC ligand which acts as a long bridge through the benzene ring. We can find that there are two independent Cd(II) centers showing two different coordination environments. The Cd(1) ion is seven-coordinated with four O atoms (O(6), O(7), O(8), O(9)) from two chelated BDC ligands, a water molecule (O(12)), and two nitrogen atoms (N(4), N(6)) from chelated TBZ to form a distorted decahedron as shown in Fig. 4. The Cd(2) center is coordinated to two N donors (N(1), N(3)) of one TBZ, three oxygen atoms (O(2), o(4), O(5)) belonging to two different carboxyl groups of two different terephthalic acid molecules and one water molecule (O(1)), forming a distorted octahedral geometry. The structure of II is stabilized by hydrogen bonds formed by N—H - O hydrogen bonds from N—H of TBZ together with water molecule (N(2)— H(2)-0(10), N(5)—H(5)-O(11)) and by the water molecule with oxygen atoms of BDC ligands (Table 3).
Table 1. Crystallographic data and details of structure refinements for complexes I—III
Parameter Value
I II III
Formula weight 625.53 1027.58 1175.04
Crystal system Orthorhombic Triclinic Triclinic
Space group Pbcn P1 P1
a, A 12.778(4) 11.031(3) 11.175(2)
b, A 10.465(3) 11.425(4) 13.791(3)
c, A 20.000(5) 16.625(4) 16.842(3)
a, deg 90 94.330(3) 92.520(3)
P, deg 90 94.600(3) 95.221(3)
Y, deg 90 113.926(3) 111.443(3)
Volume, A3 2674.6(13) 1895.5(10) 2397.6(8)
Z 4 2 2
Pcalcd g cm-3 1.553 1.800 1.628
Absorption coeffi
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