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Alkylation, Cation Formation, and Insertion Reactions in Titanium Tris(ketimide) Complexes

2006; American Chemical Society; Volume: 26; Issue: 1 Linguagem: Inglês

10.1021/om060554w

1520-6041

M.J. Ferreira, Inês Matos, José R. Ascenso, M. Teresa Duarte, M. Mercês Marques, Claire Wilson, Ana M. Martins,

Coordination Chemistry and Organometallics

Ti(NCtBu2)3Cl (1) reacts with TlPF6 in acetonitrile to afford [Ti(NCtBu2)3(N⋮CCH3)]PF6 (2), which proved to be unstable and decomposed at room temperature either in solution or in the solid state. Attempts to recrystallize 2 from a CH2Cl2/hexane mixture led to [Ti3(NCtBu2)6(μ2-F)3(μ3-F)2][PF6] (3). Treatment of 1 with LiMe and PhCH2MgCl gave the compounds Ti(NCtBu2)3CH2Ph (4) and Ti(NCtBu2)3Me (5), respectively. 4 was treated with B(C6F5)3 to afford [Ti(NCtBu2)3(CH2Ph)B(C6F5)3] (6), which exists in solution as a mixture of two species, the zwitterion [Ti(NCtBu2)3][(μ-CH2Ph)B(C6F5)3] (6A) and the solvate cation [Ti(NCtBu2)3(Solv)][(CH2Ph)B(C6F5)3] (6B). Above 60 °C, C6F5 is transferred to the metal center and Ti(NCtBu2)3(C6F5) (9) forms. This compound participates in a dynamic process in solution involving Ti···F interactions. The fluxional process observed for 6 can be stopped upon addition of 1 equiv of C⋮NMes, giving [Ti(NCtBu2)3(C⋮NMes)][(CH2Ph)B(C6F5)3] (7). C⋮NMes does not insert into Ti−N bonds, but it readily inserts into the Ti−C bond of Ti(NCtBu2)3(Me) (5) to afford [Ti(NCtBu2)3{η2-C(CH3)NMes}] (8).