Selective and reversible acetone inclusion in crystals of a π-deficient tetraoxa[4]arene via hydrogen bonding

A π-deficient tetraoxa[4]arene derivative bearing bromo and dinitrophenylene units was prepared and found to co-crystallize with acetone in a 1:2 host–guest ratio. Single-crystal X-ray diffraction revealed acetone inclusion through pseudo-hydrogen bonds (CH···O) driven by enhanced electropositive host protons, further supported by Hirshfeld surface analysis and DFT calculations. Thermogravimetric and pXRD studies also confirmed the stoichiometric ratio and reversibility of the included acetone molecules. These results highlight the potential of electron-deficient macrocycles in the selective recognition of volatile polar guests.