Novel Low-Coordinate Lanthanoid(I1) and -(III) Aryloxide Complexes -the X-ray Structures of Bis(2,6-diphenylphenolato)tris(tetrahydrofuran)-ytterbium(II), Bis( 1,2-dime t hox yet hane) bis( 2,6-dip henylphenola t 0) ytterbium( 11), and 1,2-Dimet hox ye t hane tris( 2,6-diphenylphenolato)yt ter bium(II1) and -neodymium ( 111 IntroductionIn the family of lanthanoid(II1) complexes with bulky aryloxide ligands12-6', which include 2,6-di-tevt-butyl-4-Xphenolates (e.g. X = H, tBu, 2,6-diisopropylphenoIates181 and 2,6-dimethylphen0lates[~], lanthanoid tris(2,6-diphenylphenolates) Ln(Odpp)3 occupy a distinctive position. (2) We now report the synthesis of ytterbium(I1) 2,6-diphenylphenolate by reduction of Yb(Odpp),, and the X-ray crystal structures of [Yb(Odpp)2(THF),1 and [Yb(od~p)~(DME)~l, (DME = 1,2-dimethoxyethane). In addition, the structurcs of the novel five-coordinate lanthanoid(II1) complexes [L1i(0dpp)~(DME)] (Ln = Nd or Yb) have also been determined. Results and Discussion SynthesisReduction of tris(2.6-diphenylphenolato)ytterbium(III) to the ytterbium(I1) complex was achieved by prolonged

~P P ~~) ( ~-P P ~~) ( C O ) ~~ 1 resulted in a sequence of Ru-Ru bond cleavage and formation reactions; the structures of two of the products, R U ~( ~~-C ~) ( ~-S M ~) ~( ~-P P ~~) ~( C O ) , ~ 3 and R u & L ~-C , ) ( ~-S M ~) ~( ~-P P ~~) ~( C O ) , 4, which contain dicarbon (C,) attached to open and closed Rug pentagons, respectively, are described.

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