XX. The synthesis of YbCp2Cl(THF)0.5 (Cp=cyclopentadienyl; THF=tetrahydrofuran), YbCp2X(THF) (X=Br or I), and (YbCp2X)2 (X=Cl, Br or I) by oxidation of YbCp2 with metal and organic halides, and the determination of the X-ray structure of YbCp2I(THF)

Article abstract of DOI:10.1016/S0022-328X(96)06473-X

Reaction of YbCp2(DME) (Cp=cyclopentadienyl; DME=1,2-dimethoxyethane) with MCl2 (M=Hg, Cd, Zn, Pb, Sn, Cu, Pd, or Co) or MCl (M=Ag, Cu or Tl) in tetrahydrofuran (THF) gives the metal M and YbCp2Cl(YHF)0.5, generally in excellent yield, with small amounts of TlCp and CoCp2 also detected from TlCl and CoCl2 respectively.Similarly, YbCp2X(THF) (X=Br or I) and YbCp2Cl(DME)0.5 have been prepared in good yields analogous oxidation with suitable mercury(II) halides.However YbCp2(DME) and FeCl3 yield ferrocene.In simpler syntheses, YbCp2X(THF)_n (X=Cl, n=0.5; X=Br or I, n=1) have been obtained by reactions of YbCp2(DME) with C2Cl6 or (CH2X)2 (X=Br or I) in THF, and (YbCp2X)2 by analogous reactions of unsolvated YbCp2 in petroleum ether.The X-ray crystal structure of YbCp2I(THF) (monocyclic, P2₁/c, a=8.147(1), b=13.788(2), c=14.149(3) Angstroem, β=105.56(1) deg, Z=4, R=0.042, for 2324 observed data) shows the complex to be monomeric with formal eight coordination for ytterbium, and with a pseudo-tetrahedral array of the centroids of the Cp rings, oxygen, and iodine ( 2.565 Angstroem, Yb-O 2.311(5) Angsrtoem, Yb-I 2.9316(7) Angstroem). - Keywords: ytterbium; cyclopentadienyl; oxidation; rare earth; crystal structure; lanthanide