The organometallic cation 1 (Fe(bipy-NH2)32+, bipy-NH2 = 4,4'-diamino-2,2'-bipyridine), which was constructed in situ in solution, can bind CO2 from air effectively with a stoichiometric ratio of 1:4 (1/CO2), through the formation of "H-bonded CO2" species: [CO2-OH-CO2]- and [CO2-CO2-OH]-. These two species, along with the captured individual CO2 molecules, connected 1 into a novel 3D (three-dimensional) architecture, that was crystal 1·2(OH-)·4(CO2). The adsorption isotherms, recycling investigations, and the heat capacity of 1 have been investigated; the results revealed that the organometallic cation 1 can be recycled at least 10 times for the real-world CO2 capture applications. The strategies presented here may provide new hints for the development of new alkanolamine-related absorbents or technologies for CO2 capture and sequestration.
Keywords: CO2 capture; amine-functionalized; organometallic cation; recycling potential; “H-bonded CO2”.