Mononuclear coordination compounds based on a novel chelating triazole ligand: 1-vinyl-3-acetylamino-1,2,4-triazole

摘要

The synthesis, X-ray structure, magnetic and spectroscopic properties of new Co(II), Ni(II) and Cu(II) complexes with 1-vinyl-3-acetylamino-1,2,4-triazole (vaat) are reported. The crystal structures of [Ni(vaat)(2)(H2O)(2)](NO3)(2) and [Cu(vaat)(2)(H2O)(2)]Cl-2 have been determined by X-ray diffraction. In these mononuclear complexes, the metal ion is surrounded by two water molecules in axial positions and two oxygen and two nitrogen (N4) atoms coming from two trans-oriented chelating vaat molecules. Anions are noncoordinated and are involved in a hydrogen bonding network. The complex cations of [Cu(vaat)(2)(H2O)(2)]Cl-2 are aligned within chains. In the structure of [Ni(vaat)(2)(H2O)(2)](NO3)(2) the nitrate anions establish a bridge in the plane by hydrogen bonding giving a 2D character for this compound. In addition, a colour change from pink to blue upon heating has been observed for [Co(vaat)(2)(H2O)(2)]Cl-2, which is due to the removal of the two coordinated water molecules and the subsequent molecular reorganisation of the molecular structure. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 39]