Titanium indenyldimethylamido complexes: synthesis, characterisation and theoretical calculations. Crystal structure of [Ti(eta(5)-Ind)(NMe2)Cl-2]

摘要

Reactions of Ti(Ind)Cl-3, 1, with LiNMe2 afforded the corresponding titanium indenyldimethylamido complexes Ti(Ind)(NMe2)Cl-2, 2, Ti(Ind)(NMe2)(2)Cl, 3, and Ti(Ind)(NMe2)(3), 4, depending on the reaction conditions. Treatment of 2 and 3 with LiMe yielded Ti(Ind)(NMe2)Me-2, 5, and Ti(Ind)(NMe2)(2)Me, 6, respectively. Chloride metathesis reactions of Ti(Ind)(NMe2)(2)Cl with Me3SiCH2MgCl, LiC=CPh and LiC=CSiMe3 gave Ti(Ind)(NMe2)(2)(CH2SiMe3), 7, Ti(Ind)(NMe2)(2)(C=CPh), 8 and Ti(Ind)(NMe2)(2)(C=CSiMe3), 9. The solid-state molecular structure of 2 was determined. H-1 and C-13 NMR data and DFT calculations (full geometry optimisations) showed that the indenyl ring remains approximately planar and exhibits an eta (5) co-ordination mode in all the complexes. The amido groups have a preference for binding in the way that favours pi bonding to the titanium. Even in the trisamido complex the indenyl remains eta (5), pi bonding to the ring being preferred to that from the amides. [References: 75]