title: Ytterbium(II) complex bearing a diaminobis(phenolate) ligand: synthesis, structure, and one-electron-transfer and epsilon-caprolactone polymerization reactions.
abstract: The first divalent ytterbium complex supported by a diaminobis(phenolate) ligand, YbL(THF)2.0.5C7H8 (1; THF = tetrahydrofuran), was synthesized in good yield by the amine elimination reaction of Yb[N(SiMe3)2]2(THF)2 with H2L (L = [Me2NCH2CH2N(CH2-2-OC6H2-3,5-But2)2]) in a 1:1 molar ratio. X-ray structural determination shows complex 1 to be a THF-solvated monomer, which adopts a distorted octahedral coordination geometry around the Yb atom. Complex 1 can react with PhNCO and PhCCH, as a single electron-transfer reagent, to give the corresponding reduction coupling product [(YbLOCNPh)(THF)]2.4THF (2) and the alkynide complex YbLCCPh(DME) (3; DME = 1,2-dimethoxyethane). Complexes 2 and 3 have been characterized by X-ray crystal structural analysis. In complex 2, the dianionic oxamide ligand resulting from the reductive coupling of two phenyl isocyanate molecules coordinates to two Yb atoms in a mu,eta4 fashion. Complex 3 has a monomeric structure with a Yb-C(terminal phenylacetynide) bond length of 2.374(3) A. Complex 1 is also a highly efficient catalyst for ring-opening polymerization of epsilon-caprolactone.
authors.affiliation: Key Laboratory of Organic Synthesis of Jiangsu Province, Department of Chemistry and Chemical Engineering, Dushu Lake Campus, Suzhou University, Suzhou 215123, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.forename: Huadong
authors.initials: H
authors.lastname: Guo
authors.forename: Yingming
authors.initials: Y
authors.lastname: Yao
authors.forename: Liying
authors.initials: L
authors.lastname: Zhou
authors.forename: Hongmei
authors.initials: H
authors.lastname: Sun
authors.forename: Hongting
authors.initials: H
authors.lastname: Sheng
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Shen