Synthetic corrin complexes

Abstract

In 1963 a description of the work in progress at the laboratories of the E.T.H. towards the synthesis of corrins was presented (Eschenmoser 1963). At that time, we were able to report the synthesis of the analytically and spectroscopically well defined crystalline nickel complex I; however, the ultimate problem of these studies, namely the cyclization of such precorrinoid systems to corrin complexes, remained unsolved. Since then, this final goal has been attained; nickel (n) as well as cobalt (III) complexes of the pentamethylcorrin ligand II ( R = CN, H) have been prepared, thus bringing the corrin system within the reach of synthetic organic chemistry.