Reversible uptake of sulfur-containing gases by single crystals of a Cr8 metallacrown

Abstract

The exposure of green crystals of the [CrF(O₂C^tBu)₂]₈Cr8 metallacrown to SO₂ and H₂S gases results in the binding of the gas molecules in the internal molecular cavity, despite the absence of any pores or channels in the structure. Single crystal X-ray diffraction studies show that the gas molecules bind weakly to the bridging fluoride ligands. The desorption process was followed by TGA, DSC and in situ variable temperature single crystal X-ray diffraction, obtaining the gas binding energies for the gas guest molecules. These results are supported by DFT calculations.