Local dynamics in a hydrogen-bonded organic framework for adaptive guest accommodation with programmable luminescence

Flexible hydrogen-bonded organic frameworks (FHOFs) have attracted great attention due to their unique dynamics and versatile applications; however, designing FHOFs remains a challenge. Herein, we report the first example of a flexible HOF (named 8PZ) with local dynamics for adaptive guest accommodation through incorporating soft ethyl-ester chains. Single-crystal X-ray diffraction (SXRD) analyses reveal that, in response to various external stimuli, local motions of ethyl-ester chains occur with unaltered molecular assembling forms of 8PZ, which can efficiently regulate pore sizes but allow for stable luminescence performances. 8PZ can adapt to a series of 3-alkylthiophenes with large-scale alkyl-chain-length variation through its local dynamics. Host-guest cocrystals amenable to SXRD analyses are produced, which present programmable temperature-dependent luminescence behaviors and show potential for various crucial applications. This work provides a promising avenue to engineer future multifunctional HOFs, thus enriching the types and applications of existing porous materials.