Syntheses of titanium mu-arylimido and mu-pyridylimido complexes bearing (un)substituted cyclopentadienyl ligand

The reactions of (eta(5)-C5H4CH2CH2Br)TiBr3, (eta(5)-C5H4CH2CH2OCH3)TiCl3, (eta(5)-C5H4-CH2-cyclo-C4H7O)TiCl3 and (eta(5)-C5H5)TiCl3 with an equivalen t of 2-MeOC6H4NHLi in the presence of Et3N afford mu-arylimido complexes, [ (eta(5)-C5H4CH2CH2Br)Ti(Br)(mu-NC6H4OCH3-2)](2) (1), [(eta(5)-C5H4CH2OCH3)T i(Cl)(mu-NC6H4OCH3-2)](2) (2), [(eta(5)-C5H4-CH2-cyclo-C4H7O)Ti(Cl)(mu-NC6H 4-OCH3-2)](2) (3), [(eta(5)-C5H5)Ti(Cl)(mu-NC6H4OCH3-2)](2) (4), which incl ude intramolecular titanium and oxygen coordination. Complex 4 can also be obtained by reaction of the (eta(5)-C5H5)(2)TiCl2 with 2-MeOC6H4NHLi. Meanw hile refluxing of (eta 5-C5H5)(3)TiCl2 with an equivalent of 2-Me2NC6H4NMg. THF in toluene gives another mu-arylimido complex, [(eta(5)-C5H5)Ti(Cl)(mu- NC6H4NMe2-2)](2), which contains intramolecular titanium and nitrogen coord ination. In addition, the analogous reactions of the above substituted half -sandwich Cp titanium complexes with PhNHLi in the presence of Et3N lead to [(eta(5)-C5H4CH2CH2Br)Ti(Br)(mu-NPh)](2), [(eta(5)-C5H4CH2OCH3)Ti(Cl)(mu-N Ph)](2). The addition of 2-MeC6H4NHLi to (eta(5)-C5H4CH2CH2OCH3)TiCl3 and ( eta(5)-C5H5)TiCl3 affords imido derivatives [(eta(5)-C5H5)Ti(Cl)(mu-NC6H4CH 3-2)](2) and [(eta(5)-C5H4CH2OCH3)Ti(Cl)(mu-NC6H4CH3-2)](2). [(eta(5)-C5H5) Ti(Cl)(mu-NC6H3Me2-2,6)](2) is prepared by refluxing of (eta(5)-C5H5)TiCl3 and 2,6-Me2C6H3NMg.THF in toluene. The titanium mu-pyridylimido complexes, [(eta(5)-C5H5)Ti(Cl)(mu-NPy-2)](2), [(eta 5-C5H4CH2CH2OCH3)Ti(Cl)(mu-NPy-2) ](2) and [(eta(5)-C5H4CH2CH2Br)Ti(Br)(mu-NPy-2)](2), are synthesized by rea ctions of the above corresponding half sandwich Cp titanium complexes with an equivalent of 2-PyNHLi in the presence of Et3N, respectively. Compound 1 crystallizes in the triclinic space group P (1) over bar (no. 2) with a = 9.942(2), b = 10.057(3), c = 8.457(2) Angstrom, alpha = 111.28(2), beta = 1 06.71(2), gamma = 98.12(2)degrees, V = 725.5(4) Angstrom(3), Z = 2. The cat alytic activity and selectivity of compound 4 for the styrene polymerizatio n is also investigated. (C) 2000 Elsevier Science S.A. All rights reserved.