Binding CO 2 from Air by a Bulky Organometallic Cation Containing Primary Amines.

The organometallic cation 1 (Fe(bipy-NH2 )3 2+ , 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.