The first example of half-sandwich cobalt(III) complex with hydrotris(pyrazolyl)borate ligand

This paper presents the synthesis, crystal structure and spectroscopic properties of a novel half-sandwich mononuclear cobalt(III) complex with hydrotris(3,5-dimethylpyrazolyl)borate ligand and thiocyanate [Tp*Co(Hpz*)(NCS)2]·H2O·CH3OH (Tp*: hydrotris(3,5-dimethyl- pyrazolyl)borate, Hpz*: 3,5-dimethylpyrazole). The structure was determined by X-ray diffraction. The complex crystallizes in the monoclinic system, space group Cc, a=18.591(6) Å, b=10.536(3) Å, c=17.568(5) Å, β=11.284(5)°, Z=4, R1=0.0501, wR2=0.1179. The cobalt(III) ion in the complex is six-coordinated with nitrogen atoms, three from Tp*, two from pyrazole and two from two thiocyanates, to form octahedral environment. The hydrogen atoms of O(2) of water molecule are connected by hydrogen bonds with S atoms of two adjacent complex molecules to form 1-D chains. The hydrogen atom of N(8) of complex molecule is connected by hydrogen bond with methanol. The spectroscopic results are consistent with the crystallographic study.