Spectral and electrochemical investigations on some condensation products of copper(II)-amino acid complexes

Summary Condensation products of several copper(II) amino acid complexes with formaldehyde or acetaldehyde have been prepared together with ethene-bridged copper(II) amino acid complexes. Structures were deduced from analytical and spectral data. Electronic spectral, e.s.r. and electrochemical behaviour at neutral and various low pH conditions were examined. Spectra of the unbridged complexes indicate the formation of [CuL]⁺ type species at pHca. 5, whereas the bridged complexes are stable at pH 3. The electrochemical behaviour of each complex is identical except for the doubly bridged complex. These results are explained in terms of a three-step electrode mechanism. The data show that the planarity of the complexes increases from unbridged, to bridged, to doubly bridged structures.