Copper(II) complexes with optically active diamines. II. The effect of solvent, temperature and alkyl substituents at nitrogen atoms on circular dichroism spectra of copper(II) equally-paired and mixed-ligand complexes with (R)-1,2-diaminopropane

✍ Scribed by A.A. Kurganov; V.A. Davankov; L.Ya. Zhuchkova; T.M. Ponomaryova

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 447 KB
• Volume: 39
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(00)93662-4

✦ Synopsis

Circular dichroism (CD) spectra have been evaluated for copper(U) equally-paired and mkedligand complexes with different 1,2-diamines (R-pn, en and their N-benzyl and N-methyl derivatives) in solvents differing in the ability to coordinate in the axial positions. CD spectra of all the studied complexes contain two main bands at 500-550 and ca. 650 nm. The insertion of two or more substituents into the amino groups of the complex makes the sign of the 500-550 nm component negative. A similar, though weaker, effect is caused by an increase in the solvent polarity, higher band resolution being observed at lower temperature. These regularities are explained in terms of assumption of the dominant role of conformaional contribution to the overall CD spectrum of complexes containing two or more subsituents at amino groups.

For the copper(R) complex with (R)-N',N2dibenzyl-1,2diaminopropane, the structure formed is shown to be different from that of all the other complexes studied.