Magnetic and spectroscopic characterizations of high-spin cobalt(II) complex with soft-scorpionate ligand

For the purpose of investigating the effect of sulfur ligands on the metal complex electronic states, a soft scorpionate ligand, which bears three sulfur coordination sites on a molecule, was used to afford a novel high-spin cobalt(II) complex, [CoII(Tbz)2] (Tbz− = hydrotris(2-mercaptobenzothiazolyl)borate), having an octahedral [CoIIS6] core. Based on the electronic spectrum of the complex consisting of two d-d bands, the ligand-field splitting and the Racah parameter were estimated as Δ0/hc = 8000 cm− 1 and B/hc = 560 cm− 1, respectively. The latter proved remarkable nephelauxetic effect arising from delocalization of d-electrons over the ligands. These parameters were successfully utilized in the simulation of the magnetic susceptibility.