Ansa-titanocene pyrrolyl complexes: The synthesis and structural characterization of [Me2Si(C5Me4)(2)]Ti(NC4H4)X (X = H, Me, Cl and NC4H4) and [Me2Si(C5Me4)(C5Me3CH2)]Ti(NC4H4)

Abstract

A series of titanium-pyrrolyl compounds, namely [Me2Si(C5Me4)(2)]Ti(NC4H4)X (X = H, Me, Cl, NC4H4) and [Me2Si-(C5Me4)(C5Me3CH2)]Ti(NC4H4) has been synthesized and structurally characterized by X-ray diffraction. Analysis of the Ti-NC4H4 bond lengths in these complexes indicates that pyrrolyl does not, by comparison to dialkylamido, act as an efficient it-donor ligand. The fulvene complex [Me2Si(CsMe4)(C5Me3CH2)]Ti(NC4H4) is obtained via thermal elimination of CH4 and H-2 from [Me2Si(C5Me4)(2)]Ti(NC4H4)Me and [Me2Si(C5Me4)(2)]Ti(NC4H4)H, respectively. The latter transformation is reversible, with [Me2Si(C5Me4)(C5Me3CH2)]Ti(NC4H4) reacting with H-2 to give [Me2Si(C5Me4)(2)]Ti(NC4H4)H at room temperature. In accord with this reversibility, treatment of [Me2Si(C5Me4)(2)]Ti(NC4H4)H with D-2 results in incorporation of deuterium into the hydride and one ring methyl group of each cyclopentadienyl ring of the [Me2Si(C5Me4)(2)] ligand. (c) 2005 Elsevier Ltd. All rights reserved.