Epoxide activation by a silver phosphonate for heterogeneous catalysis of CO2 cycloaddition

Hydrothermal reaction of silver nitrate and a tetraphosphonic acid (H8L) affords a novel coordination polymer, with the general formula, [Ag-10(H3L)(2)(H2O)(2)(4,4 & PRIME;-bipy)], denoted as compound 1. It is built from extended MIDLINE HORIZONTAL ELLIPSISAg-O-P-OMIDLINE HORIZONTAL ELLIPSIS chains and organic linkers to form a 3D network. In its structure, three of four phosphonyl groups of the organic ligand are protonated, endowing compound 1 with rich Bronsted acid sites. With Bronsted and Lewis acidic sites, the catalytic activity of 1 was investigated through cycloaddition reaction of CO2 and epoxides, and the results displayed an excellent performance. Besides, the heterogeneous nature of compound 1 was proved by five cycle experiments with no significant compromise on the activity, indicating the silver phosphonate as an excellent catalyst for CO2 chemical fixation.

Automated summary

A novel coordination polymer was synthesized by the hydrothermal reaction of a tetraphosphonic acid and silver nitrate. The resulting polymer showed a 3D network structure and possessed abundant acid sites. It exhibited excellent catalytic activity in the cycloaddition reaction of CO2 and epoxides. The cyclic experiments verified its good stability, making it a promising catalyst for CO2 chemical fixation.