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摘要
Four zinc(II) complexes, namely, Zn(Hdmpz)(2)(L1)(2) (1) (Hdmpz = 3,5-dimethylpyrazole, HL1 = trichloroacetic acid), Zn(Hdmpz)(2)(L2)(2) (2) (HL2 = 2,4-dichlorophenoxyacetic acid), [Zn-2(mu-dmpz)(2)(Hdmpz)(2)(L3)(2)] (3) (HL3 = 1-naphthylacetic acid), and [Zn(Hdmpz)(2)(L4)(2)]center dot H2O (4) (HL4 = indole-3-acetic acid) were prepared and structurally characterized by different techniques including elemental analysis, IR spectroscopy, TG, and single-crystal X-ray diffraction analysis. The complexes display 2D to 3D structures with tetrahedral to pentagonal coordination around the central zinc atom. The X-ray studies suggested that 1, 2, and 4 are mononuclear complexes, whereas 3 is a centrosymmetric dinuclear complex. The pyrazole ligand is coordinated in both terminal as well as a bridging fashion in the dinuclear moiety but the pyrazole ligand in the mononuclear complexes is coordinated only in monodentate terminal fashion with its neutral N group. The carboxylate groups behave as monodentate ligands in 1-3, whereas the carboxylate in 4 functioned as both monodentate and chelating bidentate ligand. On the basis of X-ray crystallographic study the rich intra-and intermolecular weak interactions such as classical hydrogen bonds, C-H center dot center dot center dot O, CH3 center dot center dot center dot O, CH-Cl, Cl-Cl, C-H center dot center dot center dot pi, CH2-pi, CH3-pi, O-pi, and pi-pi are analyzed. All these noncovalent interactions help to assemble the discrete complexes into high-dimensional ordered superamolecular structures.
