Redox non-innocence permits catalytic nitrene carbonylation by (dadi)TiNAd (Ad = adamantyl)

Abstract

Application of the diamide, diimine {–CHN(1,2-C₆H₄)N(2,6-ⁱPr₂-C₆H₃)}₂^m ((dadi)^m) ligand to titanium provided adducts (dadi)TiL_x (1-L_x; L_x = THF, PMe₂Ph, (CNMe)₂), which possess the redox formulation [(dadi)⁴⁻]Ti(IV)L_x, and 22 πe⁻ (4n + 2). Related complexes containing titanium-ligand multiple bonds, (dadi)TiX (2X; X = O, NAd), exhibit a different dadi redox state, [(dadi)²⁻]Ti(IV)X, consistent with 20 πe⁻ (4n). The Redox Non-Innocence (RNI) displayed by dadi^m impedes binding by CO, and permits catalytic conversion of AdN₃ + CO to AdNCO + N₂. Kinetics measurements support carbonylation of 2NAd as the rate determining step. Structural and computational evidence for the observed RNI is provided.