Chemoselective Alkene Hydrosilylation Catalyzed by Nickel Pincer Complexes.

Chemoselective hydrosilylation of functionalized alkenes is difficult to achieve using base-metal catalysts. Reported herein is that well-defined bis(amino)amide nickel pincer complexes are efficient catalysts for anti-Markovnikov hydrosilylation of terminal alkenes with turnover frequencies of up to 83,000 per hour and turnover numbers of up to 10,000. Alkenes containing amino, ester, amido, ketone, and formyl groups are selectively hydrosilylated. A slight modification of reaction conditions allows tandem isomerization/hydrosilylation reactions of internal alkenes using these nickel catalysts.

Hydrogen Storage in the Carbon Dioxide - Formic Acid Cycle.

This year Mankind will release about 39 Gt carbon dioxide into the earth's atmosphere, where it acts as a greenhouse gas. The chemical transformation of carbon dioxide into useful products becomes increasingly important, as the CO(2) concentration in the atmosphere has reached 400 ppm. One approach to contribute to the decrease of this hazardous emission is to recycle CO(2), for example reducing it to formic acid. The hydrogenation of CO(2) can be achieved with a series of catalysts under basic and acidic conditions, in wide variety of solvents. To realize a hydrogen-based charge-discharge device ('hydrogen battery'), one also needs efficient catalysts for the reverse reaction, the dehydrogenation of formic acid. Despite of the fact that the overwhelming majority of these reactions are carried out using precious metals-based catalysts (mainly Ru), we review here developments for catalytic hydrogen evolution from formic acid with iron-based complexes.