Five imidazole/benzimidazole-based metal complexes, Cd(bim) 2 (L1) 2 (1) [L1 = 2-methyl-2-phenoxypropionate, bim = benzimidazole], Zn(im) 2 (L2) 2 (2) [L2 = 3-(4-methoxyphenyl)acrylate, im = imidazole], Zn(im) 2 (L3) 2 (3) [L3 = 3,4-(methylenedioxy)benzoate], [Cd(im) 2 (L3) 2 ] 2 ·4H 2 O (4) , and Cd(Bim) 2 (L4)·CH 3 CH 2 OH·H 2 O (5) (L4 = 1,4-cyclohexanedicarboxylate), were obtained by the introduction of the carboxylates as coligands and are structurally characterized by different techniques including elemental analysis, IR spectra, TG, and single-crystal X-ray diffraction analysis. The X-ray crystal structure analyses reveal that these complexes display mononuclear to dinuclear structures with tetrahedral coordination spheres around each central zinc atom, and octahedral coordination sphere around each central * Dr. S. Jin Fax: +86-571-6374-6755 E-Mail: Jinsw@zafu.edu.cn [a] Tianmu College 1717 cadmium atom. The imidazole ligands in all compounds are coordinated only in a monodentate fashion with their neutral nitrogen groups.The carboxylates coordinate to the metal in monodentate, chelating bidentate, and bridging bidentate fashions. The N-H···O hydrogen bonds from the NH donor of the neutral imidazole were found in all compounds. On the basis of X-ray crystallographic study the rich intraand intermolecular noncovalent interactions (including classical hydrogen bonds, C-H···O, CH 2 ···O, CH 3 ···O, CH 2 -N, C-H···π, CH 3 -π, O-H···π, and π-π interactions) are analyzed. The various nonbonding interactions in these compounds are responsible for different structures such as 3D network, 3D prismatic layer network, and 3D layer network structure. metric and asymmetric chelating, and bidentate and monodentate bridging. [10] Imidazole is also one of the most important ligands. [11][12][13][14][15] It can behave like a monodentate ligand as well as a bridging ligand. [16,17] But the complexes in the presence of carboxylic acids and imidazole derivatives have not been well studied to date. [18][19][20] As an extension of our study of mixed-ligand coordination compounds based on imidazole and carboxylate, [21] herein we report the preparation and structure of five coordination compounds by reacting the acetate salts of Zn/Cd, carboxylic acid, and imidazole/benzimidazole (Scheme 1). Their structures are fully characterized by elemental analysis, infrared (IR) spectroscopy, TG, and X-ray diffraction analyses.
Experimental Section
Materials and Physical MeasurementsThe chemicals and solvents used in this work were of analytical grade and available commercially and were used without further purification. The FT-IR spectra were recorded from KBr pellets in range 4000-400 cm -1 with a Mattson Alpha-Centauri spectrometer. Microanalytical (C, H, and N) data were obtained with a Perkin-Elmer Model 2400II elemental analyzer. Thermogravimetric analyses (TGA) were studied with a Delta Series TA-SDT Q600 in a nitrogen atmosphere between room temperature and 800°C at a heating rate of 10°C·min -1 .
