Organochromium π-complexes. VI: The preparation of Cp'(η3-allyl)2Cr compounds and their reactions with donor ligands

Abstract The title compounds have been prepared by reacting a Cp′CrCl 2 or a (η 3 -allyl) 2 CrCl species with either an allylmagnesium halide or a substituted cyclopentadienyllithium derivative. The compounds react further at room temperature to give the dinuclear species [Cp′(μ-η 3 -allyl)Cr] 2 , and with P-donor ligands with reductive coupling of the allyl groups to give Cp′(η 2 ,η 2 -1,5-hexadiene)CrPR 3 species. Diene exchange is observed upon reacting the hexadiene compounds with butadiene or cyclohexadiene. The crystal structures of [Cp(μ-η 3 -C 3 H 5 )Cr] 2 , [(η 5 -indenyl)(μ-η 3 -C 3 H 5 )Cr] 5 )Cr 2 , (η 5 -indenyl) (η 2 ,η 2 -1,5-hexadiene)CrP(OMe) 3 and three compounds containing a 1,3-diene, viz. Cp(η 4 -1,3-C 4 H 6 )CrPMe 3 , (η 5 -Me 5 C 5 )(η 4 -1,3-C 4 H 6 )CrCO and Cp(η 4 -1,3-cyclohexadiene)CrP(OMe) 3 have been established by X-ray diffraction.