Energetics of 6-methoxyquinoline and 6-methoxyquinoline N-oxide: The dissociation enthalpy of the (N-O) bond

Article abstract of DOI:10.1016/S0021-9614(03)00052-1

The standard (p° = 0.1MPa) molar enthalpies of formation, at T = 298.15K, were determined using static-bomb calorimetry for crystalline 6-methoxyquinoline N-oxide (6MeOQUINO), as -(85.6 ± 3.7) kJ·mol^-1 and liquid 6-methoxyquinoline (6MeOQUI), -(25.8 ± 2.2)kJ·mol^-1. The standard molar enthalpies of sublimation/vaporization, at T = 298.15K, were measured by microcalorimetry and from the enthalpies of formation of the gaseous compounds, the dissociation enthalpy D_m⁰ of the (N⁺-O^-) dative covalent bond was derived, as (269.2 ± 5.0)kJ·mol^-1.