| Summary: | The reactions of the titanium imido complexes [Ti(NR)Cl2(py)3] (R = But 1, C6H3Me2-2,6 2 or C6H3Pri 2-2,6 3) with α-diimines (1,4-diaza-1,3-butadienes) of the type ArNC(R′)C(R′)NAr (Ar = phenyl or substituted phenyl, R′ = H or methyl) are reported. The reaction products and metal complex stability are critically dependent on the nature of both the imido N- and diimine N- and backbone C-substituents. Reaction of 3 with PhNC(Me)C(Me)NPh gave the crystallographically characterised adduct [Ti(NC6H3Pri 2-2,6)Cl 2{η2-PhNC(Me)C(Me)NPh}(py)] 4 which posseses mutually trans Cl ligands and has one diimine nitrogen atom cis and one trans to the arylimido group. The compound 4 is the first crystallographically characterised titanium complex to have a formally neutral (i.e. non-reduced) α-diimine ligand and decomposes fairly quickly in solution at room temperature. 1H NMR evidence only is presented for the formation of the tert-butyl- and 2,6-dimethylphenyl-imido homologues of 4, namely [Ti(NR)Cl2{η2-ArNC(Me)C(Me)NAr}(py)] (R = But or C6H3Me2-2,6; Ar = Ph or tolyl, Tol): these compounds are considerably less stable in solution, rapidly decomposing to a number of products including the corresponding amines RNH2 and [Ti(NR)Cl2(py)n] (H = 2 or 3). Reaction of 1 with α-diimines of the type ArNC(H)C(H)NAr (Ar = Tol or 2,6-C6H3Me2), i.e. without methyl substituents in the backbone, do not give detectable adducts analogous to 4. In these cases titanium imide/organic imine metathesis occurs to form [Ti(NAr)Cl2(py)n] (n = 2 or 3) and ButNC(H)C(H)NAr and/or ButNC(H)C(H)NBut.
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