Spectral and magnetic studies on normal cobalt(II) planar and cobalt(III) octahedral, spin-crossover cobalt(III) octahedral and planar-tetrahedral cobalt(II) carbodithioates

Article abstract of DOI:10.1016/0277-5387(95)00178-U

Five cobalt(II) complexes, a normal complex Co(4-PPipzcdt=4-phenylpiperazine-1-carbodithioate), and four zwitterionic complexes, Co(4-PPipzcdtH)2X2 and Co(4-MPipzcdtH)2X2 (X=Cl, Br; 4-PPipzcdtH=4-phenylpiperazine-1-carbodithioic acid, 4-MPipzcdtH=4-methylpiperazine-1-carbodithioic acid),have been synthesized. Normal cobalt(III) complexes of the type Co(4-MP ipzcdt)3 and Co2{2-MPipz(cdt)2}3 (2-MPipz(cdt)2=2-methylpiperazine-1,4-dicarbodithioate) and two zwitterionic cobalt(III) complexes of the type Co(4-MPipzcdtH)3X3 (X=Cl, Br) have also been obtained. In addition to the room temperature IR and electronic spectra and magnetic susceptibilitystudies, all the complexes, except the normal Co(4-MPipzcdt)3 and Co(4- PPipzcdt)2 and zwitterionic Co(4-MPipzcdtH)3Cl3, have been investigated by variable-temperature magnetic susceptibility measurements. The results of the variable-temperature magnetic susceptibility studies suggest that two cobalt(II) carbodithioates exhibit a square planar-tetrahedral equilibrium, while two cobalt(III) octahedral carbodithioates show a spin-crossover phenomenon.