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)₂C₂H₂{η⁵-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)₂C₂H₂η⁵-C₅H₄₂; 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.