A Porous Framework as a Variable Chemosensor: From the Response of a Specific Carcinogenic Alkyl-Aromatic to Selective Detection of Explosive Nitroaromatics.

Selective probing of one molecule from one class of similar molecules is highly challenging due to their similar chemical and physical properties. Herein, a novel metal-organic framework FJI-H15 with flexible porous cages has been designed and synthesized, which can specifically recognize ethylbenzene with ultrahigh enhancement efficiency from a series of alkyl-aromatics, in which an unusual size-dependent interaction has been found and proved. It can also selectively detect phenolic-nitroaromatics among a series of nitroaromatics based on energy transfer and electrostatic interactions. Such unusual specificity and variable mechanisms responding to different types of molecules have not yet been reported, which will provide a new strategy for the development of more effective chemosensors based on MOFs for probing small structural differences in molecules.