Coordination compounds of 5-methyl[1,2,4]triazolo[1,5- a]pyrimidin-7-ol and transition metal(II) halides. Synthesis, spectral and magnetic properties

Abstract

The synthesis and spectroscopic and magnetic properties of a series of polynuclear metal coordination compounds are described. The compounds have the general formula MX 2(mtpH) 2 (with M=Mn, Fe, Co, Ni, Cu and Cd; X=Cl, Br; mtpH=5-methyl[1,2,4]triazolo[1,5- a]pyrimidin-7-ol). The IR spectra and X-ray powder-diffraction patterns indicate the presence of two structure types within the series. On the basis of their ligand-field spectra and magnetic properties a pseudo-octahedral halide-bridged linear-chain structure is derived for most of the compounds. In this structure the metal ions are surrounded by four bridging anions and two N-coordinated, mtpH ligands. Structural exceptions are MnBr 2(mtpH) 2 and CoBr 2(mtpH) 2. These compounds have a different, possibly five-coordinated, structure in which both N and O atoms of mtpH have interactions with the metal ions and/or hydrogen bonding systems.