Improving Light-Responsive Efficiency of Type II Porous Liquid by Tailoring the Functionality of Host

Light-responsive porous liquids (LPLs) attract significant attention for their controllable gas uptake under light irradiation, while their preparation has remained a great challenge. Here we report the fabrication of type II LPLs with enhanced light-responsive efficiency by tailoring the host's functionality for the first time. The functionality of light-responsive metal-organic cage (MOC-RL, constructed from dicopper and responsive ligands) is modified by introducing the second long-chain alkyl ligand, producing MOC-RL-AL as a new host. A spatially hindered solvent based on polyethylene glycol, IL-NTf₂, is designed and can dissolve MOC-RL-AL due to the suitable interaction, creating a type II LPL (PL-RL-AL). Under light irradiation, the variation in propylene adsorption for PL-RL-AL increases by 58.0 % compared to PL-RL. The enhanced light-responsive efficiency is caused by easier control in accessibility of internal cavities within MOCs and increased number of external cavities between MOCs and IL-NTf₂. This makes PL-RL-AL the first LPL with the probability for propylene/propane separation.