Dimeric structures of ketones and esters in porous adaptive crystals of adamantane-containing macrocycle

Abstract

The assembly of small organic molecules within well-defined spaces in the crystalline state is a fascinating topic in crystal engineering. In this study, we examined the capture of acetylacetone, ethyl acetate, dimethyl malonate, and ethyl pyruvate within the porous adaptive crystals of an adamantane-containing macrocycle bearing pyrazine units through single-crystal-to-single-crystal guest exchange, and confirmed their molecular structures by single-crystal X-ray diffraction analysis. The host : guest stoichiometric ratio was 1 : 2, and several dimeric structures were formed in the macrocycle cavity through intermolecular interactions. The degree and number of atomic disorders and structural restraints of the identified guests were relatively small owing to optimization of the flexible macrocycle-based organic framework.