Exploring reversible reactions between CO2 and amines

The ‘old’ chemistry between CO2 and primary alkylamines has been revisited. Amines and , with appended aromatic fluorophores, reversibly reacted with CO2 in polar aprotic solvent (e.g. DMSO, DMF) with the formation of carbamic acids and . As a result, strong fluorescence occurred, thus directly reporting on the CO2 entrapment. Carbamic acids were studied by 1H and 13C NMR spectroscopy in DMSO-d6. The carbamate bond, despite being covalent, is reversible and can be broken upon heating or simply flashing solutions with inert gases. Synthesis and evaluation of a CO2-sensing amino acid-α-naphthylglycine is also reported for potential CO2 monitoring under biorelevant conditions in aqueous solutions.