Cooperative effect of “flexible” interaction and “flexible” framework in reversible intake and removal of aromatic guest molecules

Abstract

The metal–organic frameworks of amide based “flexible” ligands has been explored. The reaction of bis-(3-pyridyl)ethanediamide with Cu(PF₆)₂ resulted in a 1D looped chain, where the PF₆⁻ anions interact with the amide groups of the chains. This resulted in unavailability of space for guest inclusion in the loops. The exchange of PF₆⁻ ion with ClO₄⁻ ion resulted in the intake of aromatic guest molecules, which were monitored by IR and UV-Vis spectroscopy. The capability of the flexible ethyl spacer of bis-(3-pyridyl)ethanediamide to adjust the conformation according to the requirements of the other components of the networks is observed in the present study. This resulted in reversible inclusion and removal of guest molecules triggered by the exchange of anions.