title: Coexistence of two thermally induced intramolecular electron transfer processes in a series of metal complexes [M(Cat-N-BQ)(Cat-N-SQ)]/[M(Cat-N-BQ)2] (M = Co, Fe, and Ni) bearing non-innocent catechol-based ligands: a combined experimental and theoretical study.
abstract: The different thermally induced intermolecular electron transfer (IET) processes that can take place in the series of complexes [M(Cat-N-BQ)(Cat-N-SQ)]/[M(Cat-N-BQ)(2)], for which M = Co (2), Fe (3) and Ni(4), and Cat-N-BQ and Cat-N-SQ denote the mononegative (Cat-N-BQ(-)) or dinegative (Cat-N-SQ(2-)) radical forms of the tridentate Schiff-base ligand 3,5-di-tert-butyl-1,2-quinone-1-(2-hydroxy-3,5-di-tert-butylphenyl)imine, have been studied by variable-temperature UV/Vis and NMR spectroscopies. Depending on the metal ion, rather different behaviors are observed. Complex 2 has been found to be one of the few examples so far reported to exhibit the coexistence of two thermally induced electron transfer processes, ligand-to-metal (IET(LM)) and ligand-to-ligand (IET(LL)). IET(LL) was only found to take place in complex 3, and no IET was observed for complex 4. Such experimental studies have been combined with ab initio wavefunction-based CASSCF/CASPT2 calculations. Such a strategy allows one to solicit selectively the speculated orbitals and to access the ground states and excited-spin states, as well as charge-transfer states giving additional information on the different IET processes.
authors.affiliation: Centro de Investigación en Nanociencia y Nanotecnología (CIN2, CSIC-ICN), Edifici CM7, Campus UAB 08193, Cerdanyola del Vallès, Catalonia, Spain.
authors.forename: Emi
authors.initials: E
authors.lastname: Evangelio
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Bonnet
authors.forename: Miquel
authors.initials: M
authors.lastname: Cabañas
authors.forename: Motohiro
authors.initials: M
authors.lastname: Nakano
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: Sutter
authors.forename: Andrea
authors.initials: A
authors.lastname: Dei
authors.forename: Vincent
authors.initials: V
authors.lastname: Robert
authors.forename: Daniel
authors.initials: D
authors.lastname: Ruiz-Molina