Standard molar enthalpy of formation of monothiodibenzoylmethane by rotating-bomb calorimetry

The standard (p0=0.1 MPa) molar enthalpies of formation of crystalline thianthrene and monothiodibenzoylmethane, HDBMS, at T=298.15 K were measured by rotating-bomb calorimetry and the standard molar enthalpies of sublimation at T=298.15 K of dibenzoylmethane (HDBMO) and monothiodibenzoylmethane (HDBMS) were measured by microcalorimetry. From the present results it could be shown that, in these molecules, the intramolecular hydrogen bond energy (O-H···O), is ca. 20 kJ · mol-1 larger than for (S-H···O)