Inclusion and reactivity of main group radicals in the porous framework MIL-53(Al)

Abstract

Inclusion of the dithiadiazolyl and diselenadiazolyl radicals PhCNEEN (E = S, Se) into the porous framework, Al(bdc)(OH) [MIL-53(Al); bdc = 1,4-benzenedicarboxylate] was achieved by vacuum sublimation. PXRD studies reveal the inclusion complexes adopt the orthorhombic space group Imma. Variable temperature PXRD studies coupled with thermal analysis reveal that for PhCNSSN@MIL-53(Al), radical elimination from the pores at elevated temperatures is accompanied by an opening of the pore channels. Radicals can also be extracted from the framework using an appropriate solvent. Oxidation of the radical guest within the host framework has been achieved with Cl₂ or Br₂ and led to complete radical oxidation (based on EPR studies) whereas the milder oxidant I₂ leads to incomplete oxidation.