Theory-guided development of homogeneous catalysts for the reduction of CO to formate, formaldehyde, and methanol derivatives

• Published in: Chemical science (Cambridge) Vol. 14; no. 11; pp. 2799 - 287
• Main Authors: Cramer, Hanna H, Das, Shubhajit, Wodrich, Matthew D, Corminboeuf, Clémence, Werlé, Christophe, Leitner, Walter
• Format: Journal Article
• Published: 15.03.2023
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d2sc06793e

The stepwise catalytic reduction of carbon dioxide (CO 2 ) to formic acid, formaldehyde, and methanol opens non-fossil pathways to important platform chemicals. The present article aims at identifying molecular control parameters to steer the selectivity to the three distinct reduction levels using organometallic catalysts of earth-abundant first-row metals. A linear scaling relationship was developed to map the intrinsic reactivity of 3d transition metal pincer complexes to their activity and selectivity in CO 2 hydrosilylation. The hydride affinity of the catalysts was used as a descriptor to predict activity/selectivity trends in a composite volcano picture, and the outstanding properties of cobalt complexes bearing bis(phosphino)triazine PNP-type pincer ligands to reach the three reduction levels selectively under different reaction conditions could thus be rationalized. The implications of the composite volcano picture were successfully experimentally validated with selected catalysts, and the challenging intermediate level of formaldehyde could be accessed in over 80% yield with the cobalt complex 6 . The results underpin the potential of tandem computational-experimental approaches to propel catalyst design for CO 2 -based chemical transformations. Computational volcano plots are used to predict selectivity in the context of (first-row) transition metal-catalyzed CO 2 reduction. The expected trends were tested experimentally and allowed for systematic improvement of the catalyst.