Rare-earth metal allyl and hydrido complexes supported by an (NNNN)-type macrocyclic ligand: Synthesis, structure, and reactivity toward biomass-derived furanics

Article abstract of DOI:10.1002/chem.201102145

The preparation and characterization of a series of neutral rare-earth metal complexes [Ln(Me₃TACD)(η³-C₃H ₅)₂] (Ln=Y, La, Ce, Pr, Nd, Sm) supported by the 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane anion (Me₃TACD ^-) are reported. Upon treatment of the neutral allyl complexes [Ln(Me₃TACD)(η³-C₃H₅) ₂] with Bronsted acids, monocationic allyl complexes [Ln(Me₃TACD)(η³-C₃H₅)(thf) ₂][B(C₆X₅)₄] (Ln=La, Ce, Nd, X=H, F) were isolated and characterized. Hydrogenolysis gave the hydride complexes [Ln(Me₃TACD)H₂]_n (Ln=Y, n=3; La, n=4; Sm). X-ray crystallography showed the lanthanum hydride to be tetranuclear. Reactivity studies of [Ln(Me₃TACD)R₂]_n (R=η³-C₃H₅, n=0; R=H, n=3,4) towards furan derivatives includes hydrosilylation and deoxygenation under ring-opening conditions.