Syntheses, crystal structures and properties of novel zinc(II) complexes obtained by reactions of zinc(II) malonate with flexible multidentate ligands

摘要

Complex [Zn-2(bimb)(2)(mal)(2)(H2O)(2)] . 4H(2)O (1) (mal = -OCOCH2COO-) Was obtained by reaction of bidentate ligand 4,4'-bis(imidazole-1-ylmethyl)biphenyl (bimb) with zinc(II) salt of malonate, while the reaction of the same metal salt with 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) gives another novel complex [Zn-2(titmb)(2)(mal)][mal] . 12H(2)O (2). The structures of these complexes were determined by X-ray crystallography. The results revealed that 1 is a cyclic dinuclear complex in which the malonate groups act as terminators and prevent further aggregation, while 2 is a 2D honeycomb network in which each independent 2D sheet contains two sub-layers bridged by the malonate groups and complex 2 also contains free malonate as a counteranion connected to the 2D layer by C-H...O hydrogen bonds. The entirely different structure and topology of complexes 1 and 2, on the one hand, indicates that the nature of organic ligands affected the structures of assemblies greatly, and on the other, reveals the versatility of the malonate which can act as a bridging and/or blocking ligand. (C) 2004 Elsevier Inc. All rights reserved.