Rhodium-Catalyzed Acrylate Synthesis from Carbon Dioxide and Ethylene by using a Guanidine-Based Pincer Ligand: Perturbing Occupied d-Orbitals by pπ-dπ Repulsion Makes a Difference

Abstract

Rhodium-catalyzed acrylate synthesis from CO₂ and ethylene was accomplished by using a guanidine-based NCN pincer ligand. The repulsion between pπ-electron of guanidine sidearms and occupied dπ orbital of rhodium center raised the level of d-electrons close to those of formerly known d⁸ -ruthenium catalyst, thereby promoting the metallalactone formation from carbon dioxide and ethylene. This work fills the absence of group-9 metal based catalyst for the acrylate synthesis and provides a designing approach for pincer-ligated d⁸ -metal catalysts to utilize pπ-dπ interaction for promoting desirable redox processes.

Keywords: acrylate synthesis; carbon dioxide; guanidine sidearm; pincer ligand; rhodalactone.