Energetics of the N-O bonds in 2-hydroxyphenazine-di-N-oxide

• Autor(a) principal: Gomes, JRB
• Data de Publicação: 2005
• Outros Autores: Sousa, EA, Goncalves, JM, Monte, MJS, Gomes, P, Pandey, S, Acree, WE, da Silva, MDMCR
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10216/82109

The standard enthalpy of formation and the enthalpy of sublimation of crystalline 2-hydroxyphenazine-diN-oxide, at T = 298.15 K, were determined from isoperibol static bomb combustion calorimetry and from Knudsen effusion experiments, as -76.7 +/- 4.2 kJ center dot mol(-1) and 197 5 kJ center dot mol(-1), respectively. The sum of these two quantities gives the standard enthalpy of formation in the gas-phase for this compound, Delta(f)H(m)degrees(g) = 120 6 KJ center dot mol(-1). This value was combined with the gas-phase standard enthalpy of formation for 2-hydroxyphenazine retrieved from a group estimative method yielding the mean (N-O) bond dissociation enthalpy, in the gas-phase, for 2-hydroxyphenazine-di-N-oxide. The result obtained with this strategy is < DHmdegrees (N - O)> = 263 +/- 4 KJ center dot mol(-1), which is in excellent agreement with the B3LYP/6-311+G(2d,2p)// B3LYP/6-31G(d) computed value, 265 KJ center dot mol(-1).