Mechanistic insights on CO2 utilization using sustainable catalysis

We reported on sustainable, one-pot synthesized caffeine-based compounds as effective, bifunctional, heterogenous, hydrogen-bond-donor organocatalysts for the cycloaddition of CO2 with several epoxides, supported by a mechanistic study and verified by density functional theory calculations. Two reaction intermediates were isolated during the catalytic cycle: the first involving hydrogen bonding between caffeinium bromide and epichlorohydrin upon exchanging Br- with PF6-, and the second comprising of the nucleophilic attack of Br- followed by ring opening, as deduced from the appearance of a peak corresponding to the C-Br bond in the ATR-FTIR spectrum in the absence of CO2. In this respect, most of the literature is based on postulated mechanisms, racing to achieve lower working conditions, urging us to dig deeper to understand the aforementioned reaction.

Automated summary

This study reported sustainable and efficient caffeine-based compounds as catalysts for the cycloaddition of epoxides with CO2, supported by experimental and computational evidence. The study identified two reaction intermediates, shedding light on the mechanistic details of the reaction process.