Allyldicyclopentadienyltitanium(III) and (DI)methylallyl homologues

Abstract

Allyldicyclopentadienyltitanium(III) complexes (C 5H 5) 2 TiR with R=allyl, 1-methylallyl, 1-methylallyl, 1,3-dimethylallyl, 1,1-dimethylallyl, have been prepared by reaction of 1 mole of dicyclopentadienyltitanium dichloride with 2 moles of the (methyl)allyl Grignard reagent in ether or tetrahydrofuran solution. The stable, but extremely air-sensitive complexes are monomeric in benzene solution; they have one unpaired electron per molecule. The infrared spectra indicate that the (methyl)allyl ligands are π-bonded to the metal, as are the cyclopentadienyl ligands. The methyl substituents at carbon atoms 1 and 3 probably prefer the syn-position. The 1,1-dimethylallyl complex in which both a syn-and an anti-methyl group are present, is much less stable than the other complexes. Som chemical properties of the complexes, in particular the reactions with hydrogen chloride [which gives (C 5H 5) 2TiCl + RH] and with molecular hydrogen (ar room temperature and atmospheric pressure) have also been studied.