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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
Author(s) -
Evangelio Emi,
Bonnet MarieLaure,
Cabañas Miquel,
Nakano Motohiro,
Sutter JeanPascal,
Dei Andrea,
Robert Vincent,
RuizMolina Daniel
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902568
Subject(s) - chemistry , ligand (biochemistry) , intramolecular force , crystallography , electron transfer , metal , excited state , intermolecular force , imine , molecule , computational chemistry , photochemistry , stereochemistry , atomic physics , physics , organic chemistry , catalysis , biochemistry , receptor
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.