Hydroboration of CO₂ to Methyl Boronate Catalyzed by a Manganese Pincer Complex: Insights into the Reaction Mechanism and Ligand Effect

Abstract

The conversion of carbon dioxide to fuels, polymers, and chemicals is an attractive strategy for the synthesis of high-valueadded products and energy-storage materials. Herein, the density functional theory method was employed to investigate the reaction mechanism of CO 2 hydroboration catalyzed by manganese pincer complex, [Mn(Ph 2 PCH 2 SiMe 2 ) 2 NH(CO) 2 Br]. The carbonyl association and carbonyl dissociation mechanisms were investigated, and the calculated results showed that the carbonyl association mechanism is more favorable with an energetic span of 27.0 kcal/mol. Meanwhile, the solvent effect of the reaction was explored, indicating that the solvents could reduce the catalytic activity of the catalyst, which was consistent with the experimental results. In addition, the X ligand effect (X = CO, Br, H, PH 3 ) on the catalytic activity of the manganese complex was explored, indicating that the anionic complexes [Mn I − Br] − and [Mn I − H] − have higher catalytic activity. This may not only shed light on the fixation and conversion of CO 2 catalyzed by earth-abundant transition-metal complexes but also provide theoretical insights to design new transition-metal catalysts.

A theoretical study on the hydrogenation of CO2to methanol catalyzed by ruthenium pincer complexes

“…That is to say, the solvent could play a different role in the CO 2 hydrogenation to methanol catalyzed by Ru-PNP complexes. 58…”

“…That is to say, the solvent could play a different role in the CO 2 hydrogenation to methanol catalyzed by Ru-PNP complexes. 58 The RuH The HUMO-LUMO gap analysis (Table S2 in the ESI †) and NBO charge analysis (Fig. S10 in the ESI †) for intermediate A2 of three catalytic systems show that the HOMO-LUMO gaps and the NBO charges on the Ru center of the pincer complexes are similar.…”

“…Over the past few years, we have investigated the mechanism of CO 2 conversion and transformation catalyzed by transition-metal complexes using the DFT method. [26][27][28][29][30][31][32] In 2021, inspired by Leitner's work, 17 we studied the mechanism of CO 2 hydrogenation by Mn-PNP [Mn(Ph 2 PCH 2 SiMe 2 ) 2 N(CO) 2 ], predicting that CO 2 could be converted into MeOH in THF solvent at 100-150 °C. 22 Based on previous studies, in this work, we proposed a catalytic strategy for CO 2 hydrogenation catalyzed by ruthenium pincer complex [RuH 2 (Me 2 PCH 2 SiMe 2 ) 2 NH (CO)] (abbreviated to Ru-PNP) which has not been synthesized experimentally.…”

Combined Computational and Experimental Investigation on the Mechanism of CO2 Hydrogenation to Methanol with Mn-PNP-Pincer Catalysts

“…The same main intermediates were previously confirmed for reduction reactions of cobalt catalysts in the hydrosilylation of CO 2 51,52 and with a manganese catalyst in the hydroboration of CO 2 . 53,54 Additionally, these steps were also followed by other, purely computational studies on CO 2 hydrogenation 49 or methanol dehydrogenation 55 with manganese catalysts.…”

Density Functional Theory Study on the H2-Acceptorless Dehydrogenative Boration of Alkenes Catalyzed by a Zirconium Complex

“…If not specified, all energies described in the following parts are free energy relative to complex 1 . The NBO analyses were performed using NBO7.0, and visual molecular dynamics, Muliwfn, and CYLview were also used in the orbital analyses and the presentation of geometric structures of stationary points. − The computational and analytical methods have shown some reliability in previous theoretical studies. − …”