Molecular nitrogen (N2) is abundant in the atmosphere and nitrogen, found in many biomolecules, is an essential element of life. The Haber–Bosch process, developed over 100 years ago, requires relatively harsh conditions to activate N2 on the iron surface and generate ammonia for use as fertilizer or to produce other chemicals, leading to consumption of more than 2% of the world’s annual energy supply. Thus, developing approaches for N2 activation under mild conditions is particularly important and urgent.
Recent progress in frustrated Lewis pairs (FLPs) has attracted increasing attention. However, most of the FLPs are composed of Lewis basic phosphines and Lewis acidic boranes. In 2015, Kinjo and co-workers reported the first intramolecular boron–boron FLP, namely, 1,3,2,5-diazadiborinine (1), which showed high regioselectivity in the reactions with methyl trifluoromethansulfonate, phenylacetylene, and CO2. More interestingly, the activation of CO2 was found to be reversible when the temperature was elevated to 90 °C.
The sequestration of carbon disulfide (CS2), a common pollutant in environmental systems, is of great importance due to its physical harm to human beings. Compared with CO2 capture, that of CS2 is much less developed. The use of P/N-based frustrated Lewis pairs (FLPs) has been proven, both experimentally and theoretically, to be an alternative strategy to efficiently sequestrate CO2. Therefore, we pose the question of whether the analogue CS2 could also be sequestrated by the same FLPs, given that the C═S bond in CS2 is weaker than the C═O bond in CO2.