Reactivity of a Scandium Terminal Imido Complex Towards Unsaturated Substrates

摘要

Over the last two decades, terminal imido complexes of early transition metals, which contain the M=N double bond, have attracted intensive interest and have been extensively studied. The research on such complexes has revealed rich reactivities and applications in the group transfer and catalytic reactions. In contrast, the chemistry of rare-earth-metal terminal imido complexes remains unexplored. Owing to a relative mismatch in LUMO/HOMO orbital energies between the d~0 rare-earth-metal ions and the imido groups, the Ln=N (Ln = rare-earth metal) bonds are highly polar and reactive.The rare-earth-metal terminal imido species once formed can easily assemble into more stable μ. or μ_n (n = 3,4) bridged bimetallic or multimetallic species, or undergo reactions with solvents by C-H bond activation. Meanwhile, the chemistry of the rare-earth-metal terminal imido complexes is of great interest, as the highly polar and reactive Ln= N bonds should lead to rich reactivity. Recently, we have synthesized and characterized the first rare-earth-metal terminal imido complex, a scandium terminal imido complex. Herein, we uncover reactions of the scandium terminal imido complex with a series of unsaturated substrates that show interesting reactivity and lead to novel products.