Preparation and Some Properties of Cobalt(III) Complexes with D-Penicillaminate and Its Derivatives

Abstract Three kinds of [Co(terdentate-N,O,S)2] type complexes were newly prepared; here terdentate-N,O,S denotes d-penicillaminate (d-pen), S-methyl-d-penicillaminate (d-smp) and S-methyl-l-cysteinate (l-smc). Each of the d-smp and l-smc complexes was chromatographically separated into three possible isomers; the d-pen complex was separated into two isomers. These isomers were characterized from their electronic absorption, CD and 1H NMR spectra. Two isomers isolated for [Co(d-pen)2]− were assigned to trans(N) and trans(O), respectively, on the basis of the spectral behavior of the sulfur-to-metal charge transfer band and the reaction with dimethyl sulfate. Three isomers for [Co(d-smp)2]+ were derived from each of two isomers for [Co(d-pen)2]+ by the reaction with dimethyl sulfate. The electronic absorption and CD spectral behaviors are discussed in relation to the comparison of the thioether and thiolato type complexes.