Circular Dichroism Spectra of Cobalt(III)–Ammine Complexes Containing Optically Active 1,3-Diphenyl-1,3-propanediamine or 1,2-Diphenyl-1,2-ethanediamine

Abstract

Abstract A series of optically active cobalt(III) ammine complexes containing (S,S)-1,3-diphenyl-1,3-propanediamine (dppn) or (S,S)-1,2-diphenyl-1,2-ethanediamine (stien) were prepared. The sign of circular dichroism (CD) of [Co(NH3)4(S,S-dppn)]Br3 depends on solvents in the first absorption band region. The CD magnitude of trans-[Co(NH3)2(S,S-dppn)2]3+ varies significantly with solvent variations in the same energy region. The CD curve of the vicinal effect of (S,S)-dppn derived from the two diastereomers of cis-[Co(NH3)2(S,S-dppn)2]3+ is different from the CD spectra of both [Co(NH3)4(S,S-dppn)]3+ and trans-[Co(NH3)2(S,S-dppn)2]3+. The CD spectra of the (S,S) -stien complexes are insensitive to solvent variations and the vicinal contributions of the (S,S)-stien calculated from a variety of the (S,S)-stien complexes are similar to one another.