Aromaticity-promoted CS 2 activation by heterocycle-bridged P/N-FLPs: a comparative DFT study with CO 2 capture

Carbon dioxide (CO ) capture has attracted considerable attention from both experimental and theoretical chemists. In comparison, carbon disulfide (CS ) activation is less developed. Here, we carry out a thorough comparative density functional theory study to examine the reaction mechanisms of CS activation by five-membered heterocycle-bridged P/N frustrated Lewis pairs (FLPs). Calculations suggest that despite a weaker carbon-sulfur bond, all the CS activations have higher reaction barriers than the CO capture, which could be attributed to electrostatic repulsion between FLPs and CS caused by the reversed polarity of CS in CS rather than the electrostatic attraction in CO capture. In addition, aromaticity is found to play an important role in CS capture as it stabilizes both the transition states and products in heterocycle-bridged FLPs. All these findings could be useful for experimentalists to realize small molecule activations by FLPs.