The Conformations of Copper(II) Complexes with edda-Type Optically Active Polyamino Carboxylic Acids in Aqueous Solutions

Abstract

Abstract A copper(II) complex with (S,S)-1,1′-ethylenedipyrrolidine-2,2′-dicarboxylic acid (H2epro) was prepared, and its absorption and CD spectra were measured in an aqueous solution. A weak absorption band at 9500 cm−1 was indicative of the apical coordination of the carboxylate group. Furthermore, from the fact that the effect of unidentate bases, such as pyridine and ammonia, on the absorption and CD spectra of the epro complex was quite different from that of bidentate bases, the epro complex was expected to take a Λ-uns-cis conformation. In addition, the base-addition effect was measured for the complexes of (S,S)-α,α′-dimethyl-N,N′-ethylenediaminediacetic acid(H2eddp), (S,S)-α,α′-diisopropyl-N,N′-ethylenediaininediacetic acid(H2eddv), and (S,S)-α,α′-dibenzy-N,N′-ethylenediaminediacetic acid(H2eddc). The conformations of these complexes are also discussed on the basis of the information obtained for the epro complex.