Linked benzylamido-cyclopentadienyl ligands: Synthesis and characterization of alkyl titanium complexes

Titanium complexes of the general type Ti(eta(5):eta(1)-C5H4Si-Me(2)NCH(2)C(6)H(3)X(2)-2,5)Cl-2 (X = H, F), containing a linked benzylamido-cyclopentadienyl ligand, were prepared by reaction of Ti(eta(5)-C(5)H(4)SiMe(2)Cl)Cl-3 with lithium amide Li(NHCH(2)C(6)H(3)X(2)-2,5). A single-crystal X-ray structural analysis of Ti(eta(5):eta(1)-C(5)H(4)SiMe(2)NCH(2)C(6)H(3)F(2)-2,5)Cl-2 revealed a conformation in the solid state in which the aryl ring is turned away from the metal center. Ti(eta(5):eta(1)-C5H4Si-Me(2)NCH(2)C(6)H(5))Cl-2 can be alkylated with a variety of reagents to form extremely sensitive complexes of the type Ti(eta(5):eta(1)-C(5)H(4)SiMe(2)NCH(2)C(6)H(5))R(2) (R = Me, CH2C6H5, CH(2)SiMe(3), CH(2)CMe(2)C(6)H(5)). Reaction of Li-2[C(5)Me(4)Si-Me(2)NCH(2)C(6)H(5)] with TiCl3(THF)(3) gave Ti(eta(5):eta(1)-C(5)Me(4)Si-Me(2)NCH(2)C(6)H(5))Cl-2, which can also be alkylated to form dialkyl complexes of the type Ti(eta(5):eta(1)-C(5)Me(4)Si-Me(2)NCH(2)C(6)H(5))R(2) (R = Me, CH2C6H5, CH(2)SiMe(3), C6H5). A single-crystal X-ray structural analysis of Ti(eta(5):eta(1)-C(5)Me(4)Si-Me(2)NCH(2)C(6)H(5))(CH2C6H5)(2) suggests the presence of alpha-agostic bonding of one of the titanium-bound CH2C6H5 groups to the titanium center.