SIGMA-BONDED ORGANIC DERIVATIVES OF A COBALT(3) MACROCYCLIC COMPLEX

A new series of vitamin B12 coenzyme model compounds has been prepared. They contain 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene (CR) (structure I) as the planar ligand and σ--bonded alkyl groups (R) as one of the axial ligands, [RCoIII(CR)X]Y. The compounds have been characterized by elemental analysis, electrical conductivity, infrared spectra, and nmr spectra. Their electronic spectra exhibit significant features. The electronic spectral bands are tentatively assigned and correlated with the photolability, which is characteristic of this type of compound. © 1969, American Chemical Society. All rights reserved.