title: Synthesis, characterization and reactivity of heteroleptic rare earth metal bis(phenolate) complexes.
abstract: The synthesis, characterization and reactivity of heteroleptic rare earth metal complexes supported by the carbon-bridged bis(phenolate) ligand 2,2'-methylene-bis(6-tert-butyl-4-methyl-phenoxo) (MBMP2-) are described. Reaction of (C5H5)3Ln(THF) with MBMPH2 in a 1:1.5 molar ratio in THF at 50 degrees C produced the heteroleptic rare earth metal bis(phenolate) complexes (C5H5)Ln(MBMP)(THF)n (Ln=La, n=3 (); Ln=Yb (), Y (), n=2) in nearly quantitative yields. The residual C5H5- groups in complexes to can be substituted by the bridged bis(phenolate) ligands at elevated temperature to give the neutral rare earth metal bis(phenolate) complexes, and the ionic radii have a profound effect on the structures of the final products. Complex reacted with MBMPH2 in a 1:0.5 molar ratio in toluene at 80 degrees C to produce a dinuclear complex (MBMP)La(THF)(micro-MBMP)2La(THF)2 () in good isolated yield; whereas complexes and reacted with MBMPH2 under the same conditions to give (MBMP)Ln(MBMPH)(THF)2 (Ln=Yb (), Y ()) as the final products, in which one hydroxyl group of the phenol is coordinated to the rare earth metal in a neutral fashion. The reactivity of complexes and with some metal alkyls was explored. Reaction of complex with 1 equiv. of AlEt3 in toluene at room temperature afforded unexpected ligand redistributed products, and a discrete ion pair ytterbium complex [(MBMP)Yb(THF)2(DME)][(MBMP)2Yb(THF)2] () was isolated in moderate yield. Furthermore, reaction of complex with 1 equiv. of ZnEt2 in toluene gave a ligand redistributed complex [(micro-MBMP)Zn(THF)]2 () in reasonable isolated yield. Similar reaction of complex with ZnEt2 also afforded complex ; whereas the reaction of complex with 1 equiv. of n-BuLi in THF afforded the heterodimetallic complex [(THF)Yb(MBMP)2Li(THF)2] (). All of these complexes were well characterized by elemental analyses, IR spectra, and single-crystal structure determination, in the cases of complexes , and -.
authors.affiliation: Department of Chemistry and Chemical Engineering, Dushu Lake Campus, Suzhou University, Suzhou, 215123, PR China.
authors.forename: Ruipeng
authors.initials: R
authors.lastname: Qi
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xu
authors.forename: Zijian
authors.initials: Z
authors.lastname: Yang
authors.forename: Yingming
authors.initials: Y
authors.lastname: Yao
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Shen
mesh_terms: D018360:Crystallography, X-Ray; D008024:Ligands; D008674:Metals, Rare Earth / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D008024:Ligands; D008674:Metals, Rare Earth; D009942:Organometallic Compounds; D010636:Phenols