2021/03/18 by Manoj Trivedi, Abhinav Kumar, Ahmad Husain +1 · 30 citations
Chemical Engineering · Chemistry · Energy · #Asymmetric Hydrogenation and Catalysis #CO2 Reduction Techniques and Catalysts #Carbon dioxide utilization in catalysis #Catalysis #Chemistry #Copper #Crystal structure #Crystallography #Cubane #Formate #Inorganic chemistry #Ligand (biochemistry) #Medicinal chemistry #Organic chemistry #Stereochemistry #Thiocyanate #Turnover number
paper · doi:10.1021/acs.inorgchem.0c01937
published in Inorganic Chemistry 60(7), 4385-4396 (American Chemical Society)
openalex publication_date 2021/03/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
The five new copper(I) complexes [Cu 2 (μ-Cl) 2 (κ 1 -PCP t -Bu )] ( 1 ), [Cu 2 (μ-Br) 2 (κ 1 -PCP t -Bu )] ( 2 ), [Cu 2 (μ-I) 2 (κ 1 -PCP t -Bu )] ( 3 ), [Cu 2 (μ-CN) 2 (κ 1 -PCP t -Bu )] ( 4 ), and [Cu 4 (μ 3 -SCN) 4 (κ 1 -PCP t -Bu ) 2 ]·CH 2 Cl 2 ( 5 ) bearing a 1,3-bis[(di- tert -butylphosphino)methyl]benzene ligand were synthesized and characterized spectroscopically, and the molecular structures of 1, 3, and 5 were determined by single-crystal X-ray diffraction techniques. Structural studies for 1 and 3 revealed their binuclear structures with Cu···Cu separations of 2.609(3) and 2.6359(19) Å, respectively. However, 5 has a tetranuclear cubane structure with an 18-electron configuration at each copper without any metal–metal bonds. The two copper centers in 1 and 3 are bonded to one bridging PCP t -Bu ligand in a κ 1 -manner and two bridging (pseudo)halido ligands in a μ 2 -bonding mode to generate a nonplanar Cu 2 (μ-X) 2 framework. The four copper centers in 5 are at the vertices of a tetrahedron. Each copper center has pseudo-tetrahedral coordination provided by two bridging PCP t -Bu ligands in a κ 1 -manner and the four bridging thiocyanate groups in a μ 3 -manner. These complexes were used as catalysts for the hydrogenation of CO 2 to formate in the presence of DBU as a base to produce valuable energy-rich chemicals, and therefore it is a promising, safe, and simple strategy to conduct reactions under ambient pressure at room temperature. Among all of the five copper(I) complex based catalysts, 3 displayed the best catalytic performance with turnover number (TON) values of 38–8700 in 12–48 h of reaction at 25–80 °C. The outstanding catalytic performance of [Cu 2 (μ-I) 2 (κ 1 -PCP t -Bu )] ( 3 ) makes it a potential candidate for realizing the large-scale production of formate by CO 2 hydrogenation.