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Free keywords:
Peroxides; Conformers; Structure elucidation; Density functional calculations; Vibrational spectroscopy
Abstract:
Bis(methanesulfonyl)peroxide, CH3S(O)2OOS(O)2CH3, was fully characterized by NMR, UV, and vibrational spectroscopy (ATR, matrix IR, and Raman), mass spectrometry, single‐crystal X‐ray diffraction, and DFT calculations. Three gauche conformers were theoretically predicted, and probably due to the stabilization of intramolecular hydrogen bonding interactions the G+G– conformer was found to be most stable. G+/– designates anticlock/clockwise rotation around the O–S bonds at either end of the O–O linkage. Evidence for this most stable conformer was found for the matrix‐isolated molecules. Two other conformers G+G+ and G–G– were calculated to be 9.0 and 4.0 kJ·mol–1 higher in energy at the B3LYP/6‐311++G(d,p) level of theory. In the crystal structure of CH3S(O)2OOS(O)2CH3 [monoclinic, P21/c, a=8.1214(17)Å, b=8.9443(19)Å, c=10.298(2)Å, α=γ=90°, β=110.815(4)°] the less stable G–G– conformer is stabilized due to strong intermolecular interactions. The crystalline solid explodes at 79 °C with a large enthalpy release of 266 kJ·mol–1 as determined by differential scanning calorimetry (DSC).
