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

Carbon dioxide (CO 2 ) capture has attracted considerable attention from both experimental and theoretical chemists. In comparison, carbon disulfide (CS 2 ) activation is less developed. Here, we carry out a thorough comparative density functional theory study to examine the reaction mechanisms of CS 2 activation by five-membered heterocycle-bridged P/N frustrated Lewis pairs (FLPs). Calculations suggest that despite a weaker carbon-sulfur bond, all the CS 2 activations have higher reaction barriers than the CO 2 capture, which could be attributed to electrostatic repulsion between FLPs and CS 2 caused by the reversed polarity of CS in CS 2 rather than the electrostatic attraction in CO 2 capture. In addition, aromaticity is found to play an important role in CS 2 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.