An efficient reduction of carboxylic acids, esters, and amides with trialkylsilanes is accomplished using a triruthenium carbonyl cluster bearing a bridging acenaphthylene ligand, (mu(3),eta(2):eta(3):eta(5)-acenaphthylene)Ru(3)(CO)(7), as the catalyst. Preactivation of the catalyst by hydrosilanes accelerates the reactions. Sterically small trialkylsilanes are effective in these reactions. Reduction of carboxylic acids and amides efficiently produces the corresponding silyl ethers and amines, respectively. Reduction of esters gives a mixture of silyl and alkyl ethers, but can be controlled by changing the silanes and solvents.

Oxidative addition of PhMe 2 SiH to di-and triruthenium carbonyl clusters bearing 4,6,8trimethylazulene as the bridging ligand was studied in relation to mechanisms of hydrosilylation of ketones catalyzed by these complexes. Reaction of PhMe 2 SiH with (µ 3 ,η 5 :η 5 -4,6,8trimethylazulene)Ru 3 (CO) 7 (3) resulted in liberation of a CO ligand, oxidative addition of the Si-H bond, and hydrogenation of one carbon-carbon double bond in the azulene ligand to form a novel 46-electron cluster, (µ 2 ,η 3 :η 5 -4,5-dihydro-4,6,8-trimethylazulene)Ru 3 (H)(SiMe 2 -Ph)(CO) 6 (6). In contrast, (µ 2 ,η 3 :η 5 -4,6,8-trimethylazulene)Ru 2 (CO) 5 (4) reacted with HMe 2 -SiPh to give (µ 2 ,η 3 :η 5 -4,5-dihydro-4,6,8-trimethylazulene)Ru 2 (CO) 5 (SiMe 2 Ph) 2 ( 7), which has a unique RufRu dative bond, by way of oxidative addition of two molecules of PhMe 2 SiH to the starting diruthenium complex followed by hydrogenation of a carbon-carbon double bond in the azulene ligand. In contrast to the fact that the diruthenium complexes 4 and 7 are not catalytically active, the triruthenium clusters 3 and 6 are catalysts for the hydrosilylation of acetophenone with moderate catalytic activity. NMR observation of intermediates in the catalytic hydrosilylation of acetophenone using 6 as catalyst suggests the existence of a reaction pathway without a cluster fragmentation, in which the triruthenium cluster is involved in the catalytic cycle.

The interfacial tension γ of the hexane solution of oleyl alcohol against water was measured as a function of temperature T and molality m1 under atmospheric pressure. The entropy change associated with the adsorption ∆s was dependent on both temperature and molality below about 35 mmol kg -1 while independent of both those above about 35 mmol kg -1 . The former is responsible for the contact of the double bond of oleyl alcohol with water at the hexane/water interface, but the latter is responsible for the similarity of the aggregates, which are formed by the alcohol molecules in their hexane solution, to the adsorbed films in the situation that hydrogen bonds are formed between the alcohol molecules. Considering the aggregate formation and the thermodynamic equation used, it was found that the decrease of the interfacial density Γ 1 H at a high concentration region is an artifact introduced by the assumption of the ideal solution at that region. Furthermore, by drawing the interfacial pressure π versus the mean area per adsorbed molecule A curves, the onset of the phase transition comes out at high temperatures and also oleyl alcohol does not form the condensed film because of the steric hindrance of the hydrocarbon chain of the alcohol molecules. The experiments by using other oils suggested that the alkene systems obviously exhibit the phase transition. Taking notice of the affinty between water and π-electrons and the occupied area just below and above the phase transition, it was concluded that the phase transition in this case is accompanied by the detachment of the double bond of the alcohol molecules from the interface, and therefore the driving force is the water-π-electrons interaction.

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