Three Oxidation States of Cobalt(I/II/III) Complexes by Thiaporphyrin.

Abstract

Reaction of tetraphenyl-21-thiaporphyrin (HSTPP) with cobalt salt yields a pentacoordinated high-spin 3/2 [CoIICl(STTP)] (1). Through ion exchange, a roughly square-planar-geometry low-spin 1/2 CoIISTTP(BArF24) (2) complex was isolated. These two paramagnetic precursors were examined by single X-ray diffraction, nuclear magnetic resonance, electron paramagnetic resonance, superconducting quantum interference device, and density functional theory calculations. These two allowed the development of one electron reduction and oxidation to give [CoI(STTP)] (3), [CoIII(STTP)Cl(CH3CN)](BF4) (4), and [CoIII(STTP)Cl2] (5). The products of the chemical redox reactions were isolated and fully characterized. In addition, the reactivity of [CoIICl(STTP)] (1) was examined by azide (N3), cyanate (OCN), and thiocyanate (SCN) and featured a preferential N-coordination to the cobalt metal.