title: Protonated paramagnetic redox forms of di-o-quinone bridged withp-phenylene-extended TTF: A EPR spectroscopy study.
abstract: The chemical oxidation and reduction processes of deprotonated, direducedo-quinone-exTTF-o-quinone in protic solvents were studied by EPR spectroscopy. The formation of relatively stable paramagnetic protonated redox forms of the parent triad was very surprising. The character of spin-density distribution in the semiquinone-quinone and semiquinone-catechol redox forms indicates that thep-phenylene-extended tetrathiafulvalene connector provides a quite effective electronic communication channel between dioxolene coordination sites. It was found that the deprotonated, direducedo-quinone-exTTF-o-quinone is capable to reduction of the metal copper in solution. The radical anion species formed in this reaction exists in solution as a solvent-separated ion pair with a copper cation. A character of spin-density distribution in a radical anion species leads to the conclusion that the ligand corresponds to type III of the Robin-Day classification.
authors.affiliation: Laboratory of Organoelement Compounds, G.A. Razuvaev Institute of Organometallic Chemistry of RAS, 603950, GSP-445, Tropinina str., 49, Nizhny Novgorod, Russia; N. I. Lobachevsky Nizhny Novgorod State University, Gagarina av., 23, Nizhny Novgorod, Russia.
authors.forename: Nikolay O
authors.initials: NO
authors.lastname: Chalkov
authors.affiliation: Laboratory of Organoelement Compounds, G.A. Razuvaev Institute of Organometallic Chemistry of RAS, 603950, GSP-445, Tropinina str., 49, Nizhny Novgorod, Russia; N. I. Lobachevsky Nizhny Novgorod State University, Gagarina av., 23, Nizhny Novgorod, Russia.
authors.forename: Vladimir K
authors.initials: VK
authors.lastname: Cherkasov
authors.affiliation: Laboratory of Organoelement Compounds, G.A. Razuvaev Institute of Organometallic Chemistry of RAS, 603950, GSP-445, Tropinina str., 49, Nizhny Novgorod, Russia.
authors.forename: Gleb A
authors.initials: GA
authors.lastname: Abakumov
authors.affiliation: Southern Scientific Center of Russian Academy of Science, 344006, Chekhov str., 41, Rostov-on-Don, Russia.
authors.forename: Andrey G
authors.initials: AG
authors.lastname: Starikov
authors.affiliation: Laboratory of Organoelement Compounds, G.A. Razuvaev Institute of Organometallic Chemistry of RAS, 603950, GSP-445, Tropinina str., 49, Nizhny Novgorod, Russia.
authors.forename: Viacheslav A
authors.initials: VA
authors.lastname: Kuropatov
keywords: EPR spectroscopy; acceptor–donor–acceptor triad; bridging ligand; extended tetrathiafulvalene; protonated semiquinone