Diverse Catalytic Systems and Mechanistic Pathways for Hydrosilylative Reduction of CO₂

Abstract

Catalytic hydrosilylation of carbon dioxide has emerged as a promising approach for carbon dioxide utilization. It allows the reductive transformation of carbon dioxide into value‐added products at the levels of formate, formaldehyde, methanol, and methane. Tremendous progress has been made in the area of carbon dioxide hydrosilylation since the first reports in 1981. This focus review describes recent advances in the design and catalytic performance of leading catalyst systems, including transition‐metal, main‐group, and transition‐metal/main‐group and main‐group/main‐group tandem catalysts. Emphasis is placed on discussions of key mechanistic features of these systems and efforts towards the development of more selective, efficient, and sustainable carbon dioxide hydrosilylation processes.

Controlling the Product Platform of Carbon Dioxide Reduction: Adaptive Catalytic Hydrosilylation of CO2 Using a Molecular Cobalt(II) Triazine Complex

“…After hydrolysis of the silylated products by adding 0.05 mL water to the reaction mixture and heating at 80 °C for 12 h, formic acid and methanol were detected by 1 H NMR spectroscopy, while the trimer of formaldehyde trioxane was observed by GC‐MS analysis. No formation of methane was observed in any of these experiments, which is often an undesired side‐product in hydro‐elementation reactions …”

Heterogeneous Organocatalysts for the Reduction of Carbon Dioxide with Silanes

“…using a frustrated Lewis pair organocatalyst. Reports on the homogeneously catalyzed CO 2 hydrosilylation have been summarized in reviews [34–38] . Under a different mechanism of an iridium complex catalyst, silylcarbonate was able to form and further produce methoxysilane and CO 2 at increased temperature [39] …”

“…Reports on the homogeneously catalyzed CO 2 hydrosilylation have been summarized in reviews. [34][35][36][37][38] Under a different mechanism of an iridium complex catalyst, silylcarbonate was able to form and further produce methoxysilane and CO 2 at increased temperature. [39] Motokura et al [40] pointed out that silylformate is a versatile molecule with a high reactivity and electrophilicity that can be converted to various high-value chemicals by hydration, esterification, amide formation, salt production, carbon-carbon bond formation, and metal carbonyl complex formation.…”

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

“…Within the rapidly expanding field of small molecule activation, the reduction and transformation of carbon dioxide has received appreciable attention, not least because it can produce a range of compounds that can be used as simple synthetic building blocks [1–6] . While the hydrogenation of CO 2 can afford a variety of products and is a desirable process in terms of atom economy, the use of silane reductants allows for the use of significantly milder reaction conditions (T<100 °C, P CO2 <3 atm), and benefits thermodynamically from the stability of the generated products featuring Si−O bonds [7–9] . In addition, the use of silanes has allowed for the development of catalytic systems which exercise greater control over selectivity for products with different carbon oxidation levels, including silyl formates, silyl acetals, methoxysilanes and methane (which is formed in conjunction with bis(silyl)ethers) [8–13] …”

“…[1][2][3][4][5][6] While the hydrogenation of CO 2 can afford av ariety of products and is ad esirable process in terms of atom economy,t he use of silane reductantsa llows for the use of significantly milder reaction conditions (T < 100 8C, P CO2 < 3atm), and benefits thermodynamically from the stability of the generated products featuring SiÀOb onds. [7][8][9] In addition, the use of silanesh as allowed for the development of catalytic systemsw hich exercise greaterc ontrolo ver selectivity for products with different carbon oxidationl evels,i ncluding silyl formates,s ilyl acetals, methoxysilanes and methane (which is formed in conjunction with bis(silyl)ethers). [8][9][10][11][12][13] Thus, av arietyo fh omogenousc atalytic systemsb ased on metals (Pd/Pt, [14][15][16][17] Rh, [18] Re, [19,20] Ru, [21][22][23][24][25][26] Ir, [8,[27][28][29][30] Co, [13,31] Mn, [12] Zr, [32,33] Cu, [34][35][36][37][38] Ni, [39]…”