The catalytic properties of several ruthenium, osmium and rhodium hydride complexes for hydrogen/deuterium (H/D) exchange between olefins and deuterium oxide (D 2 O) were investigated. The most effective catalytic precursor was found to be the carbonylchlorohydridotris(triphenylphosphine)-

The catalytic properties of a series of ruthenium complexes for H/D exchange between D 2 O and alcohols were studied. The catalytic activity of the ruthenium complexes and the regioselectivity of the H/D exchange reactions were found to be dependent on the auxiliary ligands. While ruthenium η 6 -cymene complexes such as [(η 6 -c ym e ne) Ru C l (NH 2 CH 2 CH 2 NTs)]Cl, (η 6 -cymene)RuCl 2 / NH 2 CH 2 CH 2 OH, and (η 6 -cymene)Ru{(S,S)-NHCHPhCHPhNTs} catalyzed regioselective deuteration of alcohols with D 2 O at the β-carbon positions only, octahedral ruthenium complexes such as RuCl 2 (2-NH 2 CH 2 Py)(PPh 3 ) 2 (2-NH 2 CH 2 Py = 2-aminomethylpyridine) and RuCl 2 (NH 2 CH 2 CH 2 NH 2 )(PPh 3 ) 2 catalyzed regioselective H/D exchange reactions of D 2 O with alcohols at both the α-and β-carbon positions of alcohols. The H/D exchange reactions proceed through reversible dehydrogenation of alcohols and hydrogenation of carbonyl compounds involving hydride species and H/D exchange among D 2 O and carbonyl and hydride species. The different regioselectivities of the H/D exchange reactions can be related to the relative ease of H/D exchange of ruthenium hydride intermediates with D 2 O.

Treatment of CpRuH(PP) (PP=dppm, dppe) with TlPF produced [CpRu(H)(Tl)(PP)]PF . X-ray diffraction and computational studies suggest that the complexes contain a Ru-H-Tl 3c-2e bond and can be viewed as the first σ-complexes of period 6 main-group hydrides [CpRu{η -(H-Tl)}(PP)]PF or [Tl{η -H-RuCp(PP)}]PF . The complexes can be stored as a solid at room temperature for days without appreciable decomposition, but are unstable in solution and evolved to the trimetallic complexes [{CpRu(PP)} (μ-Tl)]PF .

A convenient method for regioselective H/D exchange between D(2)O and alcohols at the β-carbon position using the catalytic system [(p-cymene)RuCl(2)]/ethanolamine/KOH is described. This method is applicable for deuteration of both primary and secondary alcohols. The H/D exchange reactions proceed through an oxidation/modification/reduction reaction sequence. Alcohols are first temporarily oxidized to carbonyl compounds by the hydrogen transfer catalyst. The carbonyl compounds then undergo deuteration at the carbon adjacent to the carbonyl group by keto-enol tautomerization in the presence of D(2)O and a catalytic amount of base. The deuterated carbonyl compounds are then reduced to produce deuterated alcohols. In support of the reaction mechanism, a well-defined bimetallic ruthenium complex was isolated from the reaction of [{(p-cymene)RuCl(2)}(2)] with ethanolamine. The activity of this complex is similar to that of [{(p-cymene)RuCl(2)}(2)]/ethanolamine.