title: Energetics of the N-O bonds in 2-hydroxyphenazine-di-N-oxide.
abstract: The standard enthalpy of formation and the enthalpy of sublimation of crystalline 2-hydroxyphenazine-di-N-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.mol(-1) and 197 +/- 5 kJ.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.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 (DH(m)degrees (N - O)) = 263 +/- 4 kJ.mol(-1), which is in excellent agreement with the B3LYP/6-311+G(2d,2p)//B3LYP/6-31G(d) computed value, 265 kJ.mol(-1).
authors.affiliation: Centro de Investigação em Química, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007, Porto, Portugal.
authors.forename: José R B
authors.initials: JR
authors.lastname: Gomes
authors.forename: Emanuel A
authors.initials: EA
authors.lastname: Sousa
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Gonçalves
authors.forename: Manuel J S
authors.initials: MJ
authors.lastname: Monte
authors.forename: Paula
authors.initials: P
authors.lastname: Gomes
authors.forename: Siddharth
authors.initials: S
authors.lastname: Pandey
authors.forename: William E
authors.initials: WE
authors.lastname: Acree
authors.forename: Maria D M C
authors.initials: MD
authors.lastname: Ribeiro da Silva