Guest-Induced Breathing Effect in a Flexible Molecular Crystal.

By introducing a flexible component into a molecular building block, we present an unprecedented alkyl-decorated flexible crystalline material with a breathing behavior. Its selective adsorption is derived from the breathing effect induced by a guest triggered alkyl transformation. This feature allows the crystal to take up 2.5 mmol g(-1) of chloroform with high adsorption selectivity (CHCl3 /EA >2000 for example), implying a potential application in sorption separation and chemical sensors.