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Reaction of (η 5 -C 5 H 5 )Re(NO)(PPh 3 )(Cl) and C 6 H 5 Cu gives chiral, racemic phenyl complex (η 5 -C 5 H 5 )-Re(NO)(PPh 3 )(C 6 H 5 ), which undergoes a spontaneous resolution when crystallized from CH 2 Cl 2 /hexanes. Crystal structure monoclinic, P2 1

Donnees obtenues sur l'oxydation electrochimique de 12 complexes du type [Re(η-C 5 H 5 )(PPh 3 )(NO)R] avec R=CH 3 , CH 2 -CH 3 , CH 2 CH 2 Ph, etc, dans CH 2 Cl 2 , par voltammetrie cyclique

The regioselectivity and stereochemistry of these reactions are examined. Structures are evaluated with NMR. 4 figures, 4 tables.

[(η 5 -C 5 H 5 )Re(NO)(PPh 3 )(CHO)] cristallise dans le systeme monoclinique, groupe d'espace P2 1 /c et sa structure est affinee jusqu'a R=0,044, [(η 5 -C 5 H 5 )Re(NO)(PPh 3 )(COCH(CH 3 )CH 2 C 6 H 5 )•(THF) 0,5 (2•(THF) 0,5 )] cristallise dans le systeme triclinique, groupe d'espace P1 avec R=0,040

The mechanism of hydride abstraction from rhenium-alkyl complexes R-(Re) ((Re) = (eta/sup 5/-C/sub 5/H/sub 5/)Re(NO)(PPh/sub 3/)) by Ph/sub 3/C/sup +/PF/sub 6//sup -/ is probed by study of the equilibrium R-(Re) + Ph/sub 3/C/sup +/ in equilibrium R-(Re)/sup .+/ (eq v) and the effect of oxygen on the rate and deuterium kinetic isotope effect. Equilibrium constants K/sub 5/ are determined in CH/sub 2/Cl/sub 2/ at 208 K from reversible potential measurement for R = PhCH/sub 2/ (1, 2.5 x 10/sup -5/), (CH/sub 3/)/sub 2/CHCH/sub 2/ (2, 7.9 x 10/sup -3/), and Ph(CH/sub 3/)CH (3, 5.0 x 10/sup -2/). When generated electrochemically in separate experiments, R-(Re)/sup .+/ and Ph/sub 3/C/sup ./ are stable under the reaction conditions. Upon mixing CH/sub 2/Cl/sub 2/ solutions of the reactants in (v), rapid reactions ensue giving Ph/sub 3/CH and hydride abstraction products derived from R-(Re). Nearly diffusion controlled rate constants are found for the reaction between Ph/sub 3/C/sup ./ and O/sub 2/. Rate enhancements of ca. an order of magnitude are observed when reactions are carried out in the presence of oxygen, while the rhenium products are essentially unchanged. A deuterium kinetic isotope effect, k/sub H//k/sub D/ = 5.4, is found for reactions of PhCH/sub 2/-(Re)more » and PhCD/sub 2/-(Re) under nitrogen but not in the presence of oxygen. In the presence of O/sub 2/, as much as 70% of the organic product is benzophenone, arising from decomposition of Ph/sub 3/COOH.« less

La reaction du complexe du titre avec divers alcenes R-CH=CH 2 (R=PhCH 2 , Me, CH 3 -CH 2 -CH 2 ) donnent les complexes [(η 5 -C 5 H 5 ) Re(NO)(PPh 3 )(R−CH=CH 2 )] + BF 4 −

With Fe complex (III) as electron acceptor the methyl Re complex (I) combined with (II) at -78 °C reacts on warming to give (IV) and (V) and methane (VI); (IV) disproportionates to ethylene complex (VII) from which ethylene (X) may be liberated by nitrile (VIII).