Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• . In addition, the zwitterion adduct 2 and bicarbonate salt 3 were selectively prepared from 1 under dry (in anhydrous CH3CN) and wet (in CH3CN containing an equimolar amount of water for 1) conditions, respectively. Both compounds 2 and 3 were isolated as white solids and their structures were

• characterized in detail by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculation. These analytical results obviously revealed the formation of a zwitterion adduct and bicarbonate salt from N-benzyl cyclic guanidine and CO2. Especially, the zwitterion adduct of the monocyclic guanidine

• derivative and CO2 was isolated and characterized for the first time. Keywords: bicarbonate salt; carbon dioxide adsorption; cyclic guanidine; repeatable capture and release; zwitterion adduct; Introduction Recently, various reactions with CO2 as a cheap and green carbon reagent have been developed not