Coordination chemistry of substituted [1,2,4]triazolo[1,5-a]pyrimidines with first-row transition-metal ions: Synthesis, spectroscopy and single-crystal structure analysis

A number of new coordination compounds with transition-metal salts and triazole-based heterocyclic ligands is described. The ligands used are disubstituted [1,2,4]triazolo[1,5-a]pyrimidines, with as substituents: ethyl, methyl and phenyl, and in addition a 2-methylthio-dimethyl ligand was used (sdmtp). To determine the structures of the coordination compounds in a number of cases 3D crystal structure determinations have been carried out, i.e. for [Fe(NCS)2(detp)3(H2O)], [Co(NCS)2(sdmtp)2(H2O)], [ZnBr2(fmtp)2], [Ni(NCS)2(detp)3(CH3OH)] and [Fe(NCS)2(fmtp)2(H2O)2](fmtp). The latter compound is quite unusual as it contains an uncoordinated fmtp ligand in the crystal lattice with special packing features. The ligands and the coordination compounds have been further characterized by NMR, IR and LF spectra, as well as by C, H, N element analyses. The coordination around the metal varies from 4 (Zn), via 5 (Co) to 6 (for Ni and Fe).