Spectroscopic and electron-transfer reactivity studies of bulky bis( N-cycloalkyl-3,5- t Bu 2-salicylaldiminato)copper(II) complexes: Generation of uncoordinated and coordinated phenoxyl radicals

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2010-07, Vol.76 (2), p.99-106
• Main Authors: Kasumov, Veli T., Köksal, Fevzi, Kutluay, Ayşegül
• Format: Article
• Language: English
• Subjects: Bis[ N-cycloalkyl-3,5- tBu 2-salicylaldiminato]Cu(II) complexes; Phenoxyl radicals; Redox reactivity; Spectroscopy
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2010.02.016

This work summarizes the results of our studies on the spectral, magnetic, electrochemical and chemical redox properties of N-cycloalkyl-3,5- t Bu 2-salicylaldimine ligands [cycloalkyl = cyclo-C 5H 9( HL 1 ), cyclo-C 6H 11 ( HL 2 ), cyclo-C 7H 13 ( HL 3 ), cyclo-C 8H 15 ( HL 4 ), 1-adamantyl ( HL 5 ), 2-adamantyl ( HL 6 )] and their copper(II) complexes ( 1– 6). The compounds have been characterized by IR, 1H NMR, UV–vis, EPR spectroscopy, electrochemical and magnetic susceptibility measurements. The geometry of 1– 6, according to their EPR ( g II and g II/ A II) and visible spectral data, exhibit a significant amount distortion from slightly distorted square-planar to pseudo-tetrahedral. The cyclic voltammetric studies of 1– 6 reveal that as the extent of the tetrahedral distortion of Cu II center increases on going from 1 to 5, the values of Cu II/Cu I potentials became more negative. The compounds have been oxidized electrochemically and chemically and the generated relatively stable uncoordinated phenoxyl [ HL x ] + and coordinated Cu(II)-phenoxyl radical [1–6] + species have been characterized by UV/vis and EPR spectroscopy.