title: Nickelacyclic-cobaltocene vs. nickelacyclic-nickelocene. Synthesis, X-ray structures, electron transfer activity, EPR spectroscopy, and theoretical calculations.
abstract: Reactions of 9-nickelafluorenyllithium with cobalt and nickel pentamethylcyclopentadienyl-acetylacetonates resulted in the formation of the novel nickelacyclic-cobaltocene 2 and nickelacyclic-nickelocene 3, respectively, in which the central metal atom is bonded to the nickelafluorenyl ring. On the basis of their redox propensity, compounds 2 and 3 were oxidized to the corresponding monocations [2](+) and [3](+). The crystal and molecular structures of both the redox couples were determined by single-crystal X-ray analysis. In spite of their structural similarity, they display a rather different electron transfer ability. To throw light on such an aspect, the pertinent redox couples have been examined by EPR spectroscopy and the nature of the frontier orbitals involved in the redox activity of the neutral precursors has been supported by extended Huckel theoretical calculations.
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland. pjb@ch.pw.edu
authors.forename: Piotr
authors.initials: P
authors.lastname: Buchalski
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Kamińska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piwowar
authors.forename: Kinga
authors.initials: K
authors.lastname: Suwińska
authors.forename: Lucjan
authors.initials: L
authors.lastname: Jerzykiewicz
authors.forename: Fulvio
authors.initials: F
authors.lastname: Rossi
authors.forename: Franco
authors.initials: F
authors.lastname: Laschi
authors.forename: Fabrizia Fabrizi
authors.initials: FF
authors.lastname: de Biani
authors.forename: Piero
authors.initials: P
authors.lastname: Zanello