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

The organometallic cation 1 (Fe(bipy-NH 2 ) 3 2+, bipy-NH 2 = 4,4′-diamino-2,2′-bipyridine), which was constructed in situ in solution, can bind CO 2 from air effectively with a stoichiometric ratio of 1:4 ( 1 /CO 2 ), through the formation of “H-bonded CO 2 ” species: [CO 2 –OH–CO 2 ] − and [CO 2 –CO 2 –OH] − . These two species, along with the captured individual CO 2 molecules, connected 1 into a novel 3D (three-dimensional) architecture, that was crystal 1 ·2(OH – )·4(CO 2 ). 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 CO 2 capture applications. The strategies presented here may provide new hints for the development of new alkanolamine-related absorbents or technologies for CO 2 capture and sequestration.