Synthesis and Reactivity of Low-Coordinate Titanium Synthons Supported by a Reduced Redox-Active Ligand.
To further explore the reactivity and redox capability of the bis-arylimino acenaphthylene ligand (BIAN) in early transition metal complexes, the coordinatively unsaturated titanium synthons, [(dpp-BAAN)Ti(R)2] ([dpp-BAAN](2-) = N,N'-bis(2,6-diisopropylphenylamido)acenaphthylene and R = O(t)Bu (2) or CH2C(CH3)3 (3)), in which the BAAN ligand is reduced by two electrons, were isolated in good yields via sterically induced radical elimination reactions. Addition of p-tolyl azide to complex 3 initiated reductive elimination of the neopentyl ligands to generate a putative imido species. The imido species was trapped by a second oxidative addition of chloride ligands to yield the titanium imido complex, [(dpp-BIAN)Ti[═N(4-C6H4Me)]Cl2 (4). These reactions demonstrate that the BAAN ligand can provide redox equivalents for enhanced reactivity that includes oxidative addition and reductive elimination at d(0) metal centers.
Department of Chemistry, University of California , Irvine, California 92697.
Kensha Marie
KM
Clark