Experimental and computational thermochemistry of 1,4-benzodioxan and its 6-R derivatives

The derivatives of 1,4-benzodioxan are found widely spread in nature and have great biomedical importance. The present work reports an experimental and computational study on the thermochemistry of 1,4-benzodioxan and several of its 6-R derivatives in the gaseous phase, at T -298.15 K. Our current results were obtained from measurements of combustion energies, at T = 298.15 K, using a static bomb calorimeter. The standard molar enthalpies of vaporization/ sublimation were measured by Calvet microcalorimetry and corrected to T = 298.15 K. Additionally, estimates were performed of the enthalpies of formation of all the studied compounds in the gas phase, using DFT and other more accurate correlated calculations, together with appropriate isodesmic or homodesmic reactions. There is a reasonable agreement between computational and experimental results.