title: Synthesis, structure and reactivity of dinuclear rare earth metal bis(o-aminobenzyl) complexes bearing a 1,4-phenylenediamidinate co-ligand.
abstract: A series of phenylenediamidinate rare earth metal complexes 1,4-C6H4[C(NR)2Ln(o-CH2C6H4NMe2)2]2 (R = 2,6-(i)Pr2-C6H3, Ln = Y (2a), Lu (2b), Sc (2c)) were synthesized by deprotonation of 1,4-C6H4[C(NR)(NHR)]2 (1) with two equivalents of n-BuLi followed by reacting with two equivalents of anhydrous LnCl3 and subsequently four equivalents of Li(o-CH2C6H4NMe2), or by protolysis of [Ln(o-CH2C6H4NMe2)3] with 0.5 equivalent of 1 in THF or toluene. Treatment of complexes 2a and 2b with four equivalents of phenyl isocyanate and phenyl isothiocyanate gave the corresponding insertion products 1,4-C6H4[C(NR)2Ln{OC(CH2C6H4NMe2-o)NPh}2(THF)]2 (Ln = Y (3a), Lu (3b)) and 1,4-C6H4[C(NR)2Ln{SC(CH2C6H4NMe2-o)NPh}2]2 (Ln = Y (4a), Lu (4b)), respectively. The structures of 1, 3b, and 4a were established by X-ray diffraction studies. Complexes 2 show high activity for rac-lactide and ε-caprolactone polymerization; for the former a synergistic effect between two metal centers is observed.
authors.affiliation: Shanghai Key Laboratory of Molecular Catalysis and Innovative Material, Department of Chemistry, Fudan University, Shanghai, 200433, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Jianquan
authors.initials: J
authors.lastname: Hong
authors.forename: Zhenxia
authors.initials: Z
authors.lastname: Chen
authors.forename: Xigeng
authors.initials: X
authors.lastname: Zhou
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang