A Cryptand Metal–Organic Framework as a Platform for the Selective Uptake and Detection of Group I Metal Cations

Abstract The metal–organic framework (MOF) complex (H 3 O) 2 [Zn 4 (ur)(Hfdc) 2 (fdc) 4 ] ( 1 , ur=urotropine, H 2 fdc=furan‐2,5‐dicarboxylic acid) incorporates cryptand‐like cavities, which can be used to separate and detect Rb + and Cs + optically. This is the first example of the effective employment of a MOF material for optical detection of these cations.