The selective synthesis of linear silanes from internal alkenes or alkene mixtures is reported. Unsaturated 16 electrons hydrido–silyl–RhIII complexes are efficient catalysts for a tandem catalytic alkene isomerization–hydrosilylation reaction at room temperature under solvent‐free conditions. Such a process would be of value to the chemical industry, as mixtures of internal aliphatic olefins are substantially cheaper and more readily available than the pure terminal isomers.

The preparation and characterization of a dimeric RhIII complex containing two SSi ligands on each rhodium fragment is reported. {Rh[SiMe2(o‐C6H4SMe)]2Cl}2 (1) was obtained by reaction of thioether–silane SiMe2H(o‐C6H4SMe) (L1) with [Rh(cod)Cl]2. Mixed‐valent RhI/RhIII complex {(cod)Rh(μ‐Cl)2Rh[SiMe2(o‐C6H4SMe)]2} (2), which is an intermediate in the formation of 1, was isolated. Furthermore, 1H NMR spectroscopic monitoring revealed the formation of cyclooctenyl intermediates. The tridentate pincer proligand, SiMeH(o‐C6H4SMe)2 (L2), reacts with [Rh(cod)Cl]2 to yield a robust cyclooctenyl RhIII complex, {Rh(η3‐cyclooctenyl)[SiMe(o‐C6H4SMe)2]Cl} (3). Complexes 1–3 were characterized by X‐ray crystallography.

The selective synthesis of linear silanes from remote alkenes is reported. Four new silane‐thioether bidentate proligands [SiMe2H(o‐C6H4SR)] (R=iBu, pentyl, benzyl, neopentyl) have been synthesized and used to form unsaturated and cationic 16‐electron hydrido‐silyl‐RhIII complexes. These compounds are efficient catalysts for the tandem catalytic alkene isomerization‐hydrosilylation reaction at room temperature under solvent‐free conditions. The different size of the substituent on the sulfur atom results on a difference in the activity of this tandem reaction. Experimental observations demonstrate that the isomerization process is the rate‐determining step of this catalytic transformation. This process would be of value to the chemical industry because mixtures of internal aliphatic olefins are substantially cheaper and more readily available than the pure terminal isomers.

The reaction of [{RhCl(COD)}2] (COD = 1,5-cyclooctadiene) with L = pyrazole (Hpz), 3(5)-methylpyrazole (Hmpz) or 3,5-dimethylpyrazole (Hdmpz) and PPh2(o-C6H4CHO) (Rh : L : P = 1 : 2 : 1) gives hydridoacyl complexes [RhHCl{PPh2(o-C6H4CO)}(L)2] (). Stereoselective formation of and with pyrazoles trans to hydrido and phosphorus and hydrogen bond formation with O-acyl and chlorido occur. is a mixture of two linkage isomers in a 9 : 1 ratio, with two 5-methylpyrazole ligands or with one 3- and one 5-methylpyrazole ligand, respectively. Fluxional undergoes metallotropic tautomerization and is a mixture of equal amounts of and , with hydrido trans to pyrazole or chlorido, respectively. Complexes readily exchange hydrido by chlorido to afford [RhCl2{PPh2(o-C6H4CO)}(L)2] (, and ) as single isomers with cis chloridos and two N-HCl hydrogen bonds. The reaction of with PPh3 or PPh2OH affords static [RhHCl{PPh2(o-C6H4CO)}(PPh3)L] () or [RhHCl{PPh2(o-C6H4CO)}(PPh2OH)L] () respectively with trans P-atoms and pyrazoles forming N-HCl hydrogen bonds. and contain single species with hydrido cis to chlorido, while is a mixture of equal amounts of and . Complexes , with an additional O-HO hydrogen bond, selectively contain only the cis-H,Cl species with all the three ligands. The reaction of [{RhCl(COD)}2] with L and PPh2(o-C6H4CHO) (Rh : L : P = 1 : 1 : 2) led to complexes with trans P-atoms, [RhHCl{PPh2(o-C6H4CO)}{PPh2(o-C6H4CHO)-κP}L] (, and ), at room temperature, and to [RhCl{PPh2(o-C6H4CO)}{PPh2(o-C6H4CHOH)}(Hmpz)] () or [RhCl{PPh2(o-C6H4CO)}2L] () with hydrogen evolution in refluxing benzene. DFT calculations were used to predict the correct isomers, their ratios and the particular intramolecular hydrogen bonds in these complexes. Single crystal X-ray diffraction analysis was performed on , and . Complexes are efficient homogeneous catalysts (0.5 mol% loading) in the hydrolysis of amine- or ammonia-borane (AB) to generate up to 3 equivalents of hydrogen in the presence of air.