Selective CO2 gas adsorption in the narrow crystalline cavities of flexible peptide metallo-macrocycles

Abstract

Crystalline peptide Ni(II)-macrocycles (BF₄⁻ salt) exhibited moderate CO₂ gas adsorption (ca. 6–7 CO₂ molecules per macrocycle) into very narrow cavities (narrowest part <2 Å), accompanied by the expansion of the cavities. The BF₄⁻ salt demonstrated selective uptake of CO₂ gas in preference to CH₄ and N₂ gases.