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

Reaction of tetraphenyl-21-thiaporphyrin (HSTPP) with cobalt salt yields a pentacoordinated high-spin 3/2 [Co II Cl(STTP)] ( 1 ). Through ion exchange, a roughly square-planar-geometry low-spin 1/2 Co II STTP(BArF 24 ) ( 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 [Co I (STTP)] ( 3 ), [Co III (STTP)Cl(CH 3 CN)](BF 4 ) ( 4 ), and [Co III (STTP)Cl 2 ] ( 5 ). The products of the chemical redox reactions were isolated and fully characterized. In addition, the reactivity of [Co II Cl(STTP)] ( 1 ) was examined by azide (N 3 ), cyanate (OCN), and thiocyanate (SCN) and featured a preferential N -coordination to the cobalt metal.