title: Rubidium-mediated birch-type reduction of 1,2-diphenylbenzene in tetrahydrofuran.
abstract: The reaction of 1,2-diphenylbenzene with rubidium metal in THF yields extremely sensitive and pyrophoric [η(5)-{1,2-diphenyl-2,5-cyclohexadienyl}rubidium](∞) (1). Compound 1 characterizes a possible intermediate in a Birch-type reaction and represents a very rare example of a fully characterized organorubidium complex as well as an open main-group metal pentadienide as part of a six-membered ring. In the solid state the rubidium atoms interact with the cyclohexadienyl moiety, whereas the coordination sphere of the soft cation is additionally stabilized exclusively by several metal π-arene interactions despite the presence of strongly coordinating donors. The bonding situation was elucidated by MP2/def2-TZVPP calculations including population analysis.
authors.affiliation: Institut für Chemie/Bereich Anorganische Chemie, Karl-Franzens-Universität Graz, Schubertstrasse 1, A-8010 Graz, Austria.
authors.forename: Sven
authors.initials: S
authors.lastname: Krieck
authors.forename: Robert
authors.initials: R
authors.lastname: Kretschmer
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.forename: Matthias
authors.initials: M
authors.lastname: Westerhausen