Synthesis and structure of triphenylmethyl derivatives of ytterbium 2+2- and 2+2-

Article abstract of DOI:10.1016/0022-328X(95)91121-Y

Ionic triphenylmethyl complexes of ytterbium ²⁺2^- (1) and <(THF)4Yb(μ-Cl)2Yb(THF)4>^2+- (2) have been synthesized by the reaction of Ph3CCl with ytterbium in THF.Complex 1 has also been prepared by the reaction of ytterbium with a dimer of triphenylmethyl radicals in THF.It was found that this reaction was catalyzed by ytterbium dihalides.According to X-ray diffraction result the crystal structures of 1 and 2 are composed of isolated ions.The²⁺ cation has an ideal octahedral coordination of the central Yb atom with the Yb-O distance of 2.390(7) Angstroem.The <(THF)4Yb(μ-Cl)2Yb(THF)4>²⁺ cation is a centrosymmetrical dimer in which each Yb atom is bonded to four oxygen atoms of THF molecules and two (THF)4Yb units are linked via two symmetrical μ-Cl bridges, both Yb-Cl distances being 2.715(4) Angstroem.The ^- anion in 1 and 2 has a propeller-type geometry with the planar environment of the central carbon atom (within 0.02 Angstroem in 1 and 0.006 Angstroem in 2).The Ph rings are rotated out of the average CC3 plane of the central fragment of ^- anion by 28.2 deg in 1 and by 26.6, 31.9, 33.7 deg in 2. Keywords: Ytterbium; Lanthanide complexes; Carbanions; Triphenylmethyl derivatives; X-ray diffraction