The solvent effect on the isotropic hyperfine interaction in some aliphatic polyamine copper(II) complexes

✍ Scribed by V. G. K. M. Pisipati; N. V. S. Rao; V. Muralikrishna; V. S. Murthy; T. Kesavan

• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 609 KB
• Volume: 22
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270221007

✦ Synopsis

ESR and optical absorption studies are described for a number of copper(1I) chelates with aliphatic polyamines, exhibiting both square pyramidal and square bipyramidal coordination around the copper ion. The complexes studied were bis(N,N'-dimethylethylenediamine)copper(II) sulphate tetrahydrate, bis(N,N'-diethylethylenediamine)copper(II) nitrate, diaquosulphato(N,N,W,N'-tetramethylethylenediamine)copper(II) hydrate, dinitrato(N,N,N',N'-tetramethylethylenediamine)copper(II), dichloro(NJV,N',N'-tetramethy1ethylenediamine)copper (n) and dithiocyanato(N,NJV',iV-tetramethylethylenediamine)copper(II). The ESR measurements were carried out in methanol, dimethyl sulphoxide, dimethylformamide and pyridine, at room and liquid nitrogen temperatures. The molecular orbital coefficients were estimated assuming an axial symmetry. The parameter x, proportional to the hyperfine constants shows a variation with the solvent for all these complexes. The x values in solution are lower than the corresponding average x values reported in the solid state for each complex. The solvent effect and the influence of 4s character in the ground state are discussed. The x values, either calculated or reported, for a number of copper complexes for [40], [30, N], [ZO, 2N], [0,3N] and [4N] environments around copper(Il) are presented.