. Can. J. Chem. 53,817 (1975). Perfluoro(2,3-diphenylbutane-2,3-diol), CF3(C6F5)C(OH)C(OH)(C6F5)CF3, prepared by the reductive dimerization of C6F5COCF3, has been separated into meso-and DL-isomers and the latter resolved via its cinchonidine salt into optical enantiomers. The doubly ionized diol, PDBDZ-, acts as a dinegative, chelating, ligand, and neutral complexes of the form (PDBD)-MLz may be isolated, where L is a neutral nitrogen-or phosphorus-containing ligand and M = NiZ+ or C u z + . Use of the resolved diol enables optically active metal complexes to be prepared, and from their o.r.d.1c.d. spectra we assign an absolute configuration to the diol. The partially fluorinated diols CF3(C6H5)C(OH)C(OH)(C6H5)CF3 and CH3(C6F,)C(OH)-C(OH)(C6F5)CH3 have also been prepared from the appropriate ketones. The former, which appears to be exclusively the meso-isomer, has more limited chelating ability than the fully fluorinated analog, while the latter shows no ligand properties; these differences are ascribed to the reduced acidity resulting from the lower degree of fluorination.Nuclear magnetic resonance studies suggest hindered rotation of the C6F5 groups through steric interaction with CF3 groups in perfluoro(2,3-diphenylbutane-2,3-diol); an alternate explanation involving hydrogen bonding from the hydroxylic proton to aromatic fluorine atoms is considered less likely. C,F5)CH3. Le premier, qui semble Ctre exclusivernent I'isomere miso, a des propriktks chtlatantes plus limitees que son analogue completement fluore alors que le dernier ne prtsente aucune propriett comme ligand; on attribue ces differences a une acidit6 reduite resultant du degre plus bas de fluoration.Des etudes par resonance magnetique nuclkaire suggerent une rotation empCchCe des groupes C6F5 due a des interactions sttriques du groupe CF3 dans le perfluoro diphinyl-2,3 butanediol-2,3; on considere comme moins probable l'explication impliquant des liens hydrogene entre les protons hydroxyliques et les atomes de fluor du noyau aromatique.[Traduit par le journal]We have previously (1) reported the preparation of perfluoro(2,3-diphenylbutane-2,3-diol) C6F5C0CF3 (1) by the reductive dimerization of octafluoroacetophenone, and noted that the product appeared to contain more than one isomer. We now confirm this by the separation of the mesoisomer (la) and the DL-isomer (lb), followed by 'Presented in part at the 7th International Symposium on Fluorine Chemistry, Santa Cruz, California, July, 1973. Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.191.190.102 on 05/12/18For personal use only.