The isomers of complexes of α-amino-acids with copper(II)

Abstract

The absence of stereoselective effects in 1 : 2 complexes of copper(II) with bidentate α-amino-acids has been demonstrated in solution by measurement of electronic spectra and stability constants, and, in the solid state, by characterisation of compounds. The thermodynamic stabilities of the three isomers of bisamino-acid copper(II), i.e., [Cu(L)₂], [Cu(D)(L)], and [Cu(D)₂] are shown to be equal, for α-alanine, phenylalanine, valine, and proline. New dark blue crystalline forms of bis-[L(+)-α-alaninatocopper(II)] and of its enantiomer are described, in addition to the usual light blue forms.