title: Cooperative reduction by Ln(2+) and Cp*(-) ions: synthesis and properties of Sm, Eu, and Yb complexes with 3,6-di-tert-butyl-o-benzoquinone.
abstract: The first examples of samarium, europium, and ytterbium complexes with 3,6-di-tert-butyl-o-benzoquinone(3,6-dbbq) in the form of catecholate have been obtained by reactions of the quinone with the corresponding lanthanocenes, [LnCp2*(thf)n] (n = 1 or 2) in solution. In the course of the reactions lanthanide ions lose one or two Cp* ligands, which take part in reduction of a quinone molecule into a catecholate anion (dbcat, 2(-)). As a result of the reactions, Sm and Yb clearly yield dimeric complexes[(LnCp*)2(dbcat)2], where each Ln ion loses one Cp* ligand. Eu forms a trimeric complex [(EuCp*)-(Eu·thf)2(dbcat)3], in which one Eu ion is coordinated by one Cp* ligand, while two Eu ions have lost all Cp* ligands and are coordinated by THF molecules instead. Magnetic properties corroborate the assignment of oxidation states made on the basis of single-crystal X-ray diffraction: all the quinone ligands are present in the catecholate state; both Sm/Yb ions in the dimers are in the +3 oxidation state, whereas the Eu trimer contains two Eu(II) and one Eu(III) ions. Cyclovoltammetry studies show the presence of two reversible oxidation waves for all complexes, presumably concerned with the redox transitions of the dbcat ligands.
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Akad. Lavrentieva str. 3, 630090 Novosibirsk, Russia. nikolay@niic.nsc.ru and Department of Natural Sciences, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia.
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Pushkarevsky
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Akad. Lavrentieva str. 3, 630090 Novosibirsk, Russia. nikolay@niic.nsc.ru.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Ogienko
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Akad. Lavrentieva str. 3, 630090 Novosibirsk, Russia. nikolay@niic.nsc.ru.
authors.forename: Anton I
authors.initials: AI
authors.lastname: Smolentsev
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Akad. Lavrentieva str. 3, 630090 Novosibirsk, Russia. nikolay@niic.nsc.ru.
authors.forename: Igor N
authors.initials: IN
authors.lastname: Novozhilov
authors.affiliation: Department of Chemistry and Pharmacy, Friedrich-Alexander-University of Erlangen-Nuremberg, Egerlandstr. 1, 91058 Erlangen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Witt
authors.affiliation: Department of Chemistry and Pharmacy, Friedrich-Alexander-University of Erlangen-Nuremberg, Egerlandstr. 1, 91058 Erlangen, Germany.
authors.forename: Marat M
authors.initials: MM
authors.lastname: Khusniyarov
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of RAS, Tropinina St. 49, 603950 Nizhny Novgorod, Russia and N. I. Lobachevsky Nizhny Novgorod State University, Gagarin Ave., 23, 603950, Nizhny Novgorod, Russia.
authors.forename: Vladimir K
authors.initials: VK
authors.lastname: Cherkasov
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Akad. Lavrentieva str. 3, 630090 Novosibirsk, Russia. nikolay@niic.nsc.ru and Department of Natural Sciences, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Konchenko