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Cationic ruthenium dihydrogen complexes of the form (({eta}-C{sub 5}H{sub 5})Ru(L)(L{prime})({eta}{sup 2}-H{sub 2}))BF{sub 4} (L = CO, L{prime} = PCy{sub 3} (1a), PPh{sub 3} (2a), PMe{sub 2}Ph (3a), PMe{sub 3} (4a) have been prepared by protonation of the corresponding neutral hydrides. Carbonyl free derivatives such as (({eta}-C{sub 5}H{sub 5})Ru(P P{prime})({eta}{sup 2}-H{sub 2}))BF{sub 4} (P P{prime} = 1,2-bis(dimethylphosphino)ethane (dmpe) (5a), (1,1-dimethyl-2,2-diphenylphosphino)ethane (dmdppe) (6a), (R)-(+)-1,2-bis(diphenylphosphino)propane ((R)-prophos) 8a), bis(PPh{sub 3}) (9a)) were similarly prepared. Identification of these species as dihydrogen complexes is based upon observation of substantial H-D coupling (22-32 Hz) in the {sup 1}H NMR spectra of the Hd analogues, prepared by protonation of the corresponding deuterides.

Since the initial discovery by Kubas, dihydrogen complexes of the transition metals have been the subject of considerable interest since they may serve as models for the very important process of oxidative addition of dihydrogen. In this context, Kubas has recently reported a tungsten complex in which a dihydride is in reversible equilibrium with a dihydrogen complex. The authors now report further examples of such equilibria in cationic complexes of ruthenium.

Etude de la protonation et de l'heterolyse du coordinat dihydrogene des complexes [η 5 -C 5 M 5 (Ru)(CO) 2 (η 2 -H 2 )] BF 4 et [η 5 -C 5 M 5 (Re)(CO)(NO)(η 2 -H 2 )] BF 4 , au moyen de la spectrometrie RMN

Premiere presentation de la coordination d'une olefine avec un carboxylate de Rh(II), et des constantes d'equilibre pour les composes resultant de l'addition de Rh 2 (OOCCF 3 ) 4 et d'alkenes. Etude a partir des spectres visibles