New Chiral Hydrogen-Bonded Organic Framework Based on Substituted Diarylacetylene Dicarboxylic Acid

A new chiral hydrogen-bonded organic framework (HOF) denoted as ZIOC-1 based on a l-prolineamide substituted diarylacetylene dicarboxylic acid (3,3′-ethyne-1,2-diylbis[6-(l-prolylamino)benzoic acid]) has been synthesized and structurally characterized. Crystal structures of two forms of ZIOC-1, i.e., anhydrous and dihydrate phases, were identified by powder X-ray analysis. It was found that the novel HOF material demonstrated a framework flexibility: its crystalline phases transform reversibly into each other by a change in either humidity or ambient temperature. This fact in conjunction with the retention of crystal identity to the temperature as high as 265 °C indicates a robustness of the framework formed by a hydrogen bonding system. The catalytic performance of the synthesized HOF was probed in aldol condensation and Michael reaction.