Copper Complexes of New Redox-Active 4,5-Bisguanidino-Substituted Benzodioxole Ligands: Control of the Electronic Structure by Counter-Ligands, Solvent, and Temperature.
Herein, we analyze the possibility of controlling the electronic structure of mononuclear copper complexes featuring new redox-active 4,5-bisguanidino-substituted benzodioxole ligands. The nature of the guanidino groups, the anionic counter-ligands, the applied solvent (polarity), and the temperature are the parameters that decide if a CuIIcomplex with neutral ligand unit or a CuIcomplex with radical monocationic ligand unit is the adequate description. Under special conditions, a temperature-dependent equilibrium of the two valence tautomeric forms (CuII/neutral ligand and CuI/radical monocationic ligand) is achieved. Removal of a ligand-centered electron from a paramagnetic CuIIcomplex with a neutral ligand unit leads to a diamagnetic CuIcomplex with a dicationic ligand unit through a redox-induced electron-transfer (RIET) process.
Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 275, 69120, Heidelberg, Germany.
David Fridolin
DF
Schrempp
Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 275, 69120, Heidelberg, Germany.
Elisabeth
E
Kaifer
Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 275, 69120, Heidelberg, Germany.
Hubert
H
Wadepohl
Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 275, 69120, Heidelberg, Germany. hans-jorg.himmel@aci.uni-heidelberg.de.
Hans-Jörg
HJ
Himmel
copper complexes; electron transfer; electronic structures; redox-active ligands; valence tautomerism