Formate-Catalyzed Selective Reduction of Carbon Dioxide to Formate Products Using Hydrosilanes

Abstract

Formate salts were found to be active and selective homogeneous catalysts for the hydrosilylation of CO2. Counter cations and solvents strongly affected their catalytic activity. The use of toluene as a solvent rendered the recyclable catalyst system. Lewis basic polar solvents such as N-methylpyrrolidone and dimethyl sulfoxide significantly accelerated the reaction. The turnover number approached up to 1800. Analyses of the Fourier-transform infrared spectroscopy and in situ 1H nuclear magnetic resonance spectra suggested that the catalysis proceeds via electron donation from the solvent to hydrosilane, thereby accelerating the hydride transfer step.

Heterogeneous Organocatalysts for the Reduction of Carbon Dioxide with Silanes

“…Regarding the CO 2 reduction with silanes, impressive developments in homogeneous organocatalysis include the application of N-heterocyclic carbenes (NHCs), [45,[51][52][53][54] organic superbases, [55][56][57] triphenylborane, [58] frustrated Lewis pairs, [33,59] and even simple anions such as fluoride [60][61][62][63][64] and formate. [65,66] Recently, numerous studies addressed the development of heterogeneous organocatalysis, which is attractive because of the potential recyclability of the catalyst. This Minireview covers the recent development of heterogeneous organocatalysts for the reduction of CO 2 with hydrosilanes.…”

Diverse Catalytic Systems and Mechanistic Pathways for Hydrosilylative Reduction of CO2

“…The use of polar electron‐donating solvents, such as N ‐methylpyrrolidone (NMP) and dimethyl sulfoxide, accelerate the hydride‐transfer step; thus speeding up the reaction. With NMP as the solvent and tetrabutylammonium (TBA) formate as the catalyst, CO 2 can be hydrosilylated to the formate in a yield of 92 %, with a turnover number (TON) of approaching 1800 in 24 h …”

Partnering a Three‐Coordinate Gallium Cation with a Hydroborate Counter‐Ion for the Catalytic Hydrosilylation of CO2

“…Thus, a variety of homogenous catalytic systems based on metals (Pd/Pt, [14–17] Rh, [18] Re, [19, 20] Ru, [21–26] Ir, [8, 27–30] Co, [13, 31] Mn, [12] Zr, [32, 33] Cu, [34–38] Ni, [39–42] Sc, [43–46] Zn, [47–57] Mg [57, 58] and Sr [59] ), Lewis acids, [60–66] frustrated Lewis pairs (FLPs), [67, 68] organo‐catalysts, [69–75] alkali metal carbonates, [76, 77] and metal borohydrides [78] have been investigated for this process. Many of these catalytic systems feature reactive metal hydride or alkyl groups, which effect the initial activation of CO 2 via insertion.…”