Chromium-catalyzed transfer hydrogenation of CO 2 to formate using isopropanol under ambient pressure

• Published in: Catalysis science & technology 2025
• Main Authors: Singh, Tushar, Chakraborty, Subrata
• Format: Article
• Language: English
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/D4CY01329H

Herein, we present the first example of earth-abundant 3d metal-catalyzed ambient pressure carbon dioxide transfer hydrogenation to formate using isopropanol as an inexpensive and environmentally benign hydrogen source. The bidentate phosphine bis(diphenylphosphino)propane (DPPP, β n = 91°)-derived low-valent Cr(0) complex Cr(DPPP)(CO) 4 C- 3 emerged as the most efficient catalyst yielding sodium formate with a TON of up to 1974 under 1 bar CO 2 and 2231 under 5 bar CO 2 in the presence of NaOH in a THF : H 2 O mixture after 24 h at 130 °C. The catalyst was also found to be active in the transfer hydrogenation of sodium bicarbonate and carbonate to produce their corresponding formates in low yields. Mechanistic experiments revealed formation of an anionic hydride complex, which is believed to be an active catalyst for CO 2 transfer hydrogenation.