화학공학소재연구정보센터
Journal of Electroanalytical Chemistry, Vol.837, 76-85, 2019
Redox behaviour of bis(beta-diketonato)copper(II) complexes
In this study for the first time, a comprehensive report was compiled on the electrochemical behavior of a series of eight square planar bis(beta-diketonato)copper(II) complexes, with a variety of substituents R-1 and R-2 on the beta-diketonato ligand ((RCOCHCOR2)-C-1)(-). The character of the observed redox features was determined by computational chemistry calculations of the frontier molecular orbitals involved. The experimentally obtained electrochemically irreversible Cu-II/Cu-I reduction potentials, E-pc(Cu-II/Cu-I), were related to various electronic descriptors (such as electronegativities, Hammett constants and Lever electronic parameters), which describe the electron withdrawing power of the beta-diketonato ligands attached to the copper metal. Linear relationships have also been obtained between E-pc(Cu-II/Cu-I) and computational chemistry calculated energies of the eight bis(beta-diketonato)copper(II) complexes. These linear relationships confirmed good communication between the copper metal and the eight different beta-diketonato ligands attached to it. Furthermore, the experimentally observed electrochemically irreversible Cu-II/Cu-I reduction potentials of those [Cu-II(beta-diketonato)(2)] complexes which are metal based, were also linearly related to the reduction potentials of the uncoordinated free beta-diketones which are ligand based. Furthermore, the DFT calculated LUMO energies reproduce the experimental absolute reduction potential.