Novel derivatives of ansa-titanocenes procured from 6-phenylfulvene:: a combined experimental and theoretical study

The previously prepared trans- [(1, 2-diphenyl-1,2-dicyclopentadienyl)ethanediyl] titanium(IV) dichloride, [1,2-(Ph)(2)C2H2{eta(5)-C5H4}(2)]Ti(Cl)(2), was synthesised using an alternative procedure, from which its crystal structure was determined. Using this compound, a variety of other ansa-titanocene derivatives were synthesised by replacement of the chloride ligands with selected substituents. Thus RTi(X)(Y) systems where R = 1, 2-(Ph)(2)C(2)eta(5)-(CH42)-H-5; X=Y=CH3; X=CH3, Y=Cl; X=Y=NCS; X = Y = NCO: X = Y = OPh and (X/Y) = O have been synthesised and characterised. DFT calculations were performed on the complexes trans+[(1, 2-diphenyl-1,2-dicyclopentadienyl)-ethanediyl] titanium(IV) dichloride, bis-(6,6-diphenylfulvene)titanium and bis-(6,6-diphenylfulvene)iron. This demonstrated the role that the metal centre plays in their formation, generating either an ansa-metallocene, a 'tucked in' fulvene complex or a metallocene coordinating fulvene anions. (C) 2003 Elsevier B.V. All rights reserved.