Isolation and Characterization of a Trinuclear Cobalt Complex Containing Trigonal-Prismatic Cobalt in Secondary Alcohol Aerobic Oxidation

An unusual trinuclear cobalt complex
was successfully isolated
and characterized in the Co­(OAc)2·4H2O-catalyzed
aerobic oxidation of pyridine-based secondary alcohols. In this complex,
a cobalt ion (the one in the middle, labeled Co2) has a novel trigonal-prismatic
structure coordinated with six oxygen atoms from the substrate. The
molecular oxygen present in air plays a major role in enabling this
transformation to be catalytic. This aerobic catalytic reaction is
very selective to pyridine-based secondary alcohols over primary alcohols.