title: The experimental and calculational thermochemistry of 1,2,4,5-benzenetetracarboxylic dianhydride: is this 10 pi multiring species aromatic?
abstract: The standard (p degrees = 0.1 MPa) molar enthalpy of formation of 1,2,4,5-benzenetetracarboxylic dianhydride in the gaseous phase, -826.8 +/- 3.1 kJ mol-1, was derived from the standard molar enthalpy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry and the standard molar enthalpy of sublimation, at T = 298.15 K, measured by Calvet microcalorimetry. In addition, density functional theory calculations have been performed with the B3LYP, MPW1B95, and B3PW91 density functionals and the cc-pVTZ basis set for 1,2,4,5-benzenetetracarboxylic dianhydride and 1,2,4,5-benzenetetracarboxylic diimide. Nucleus-independent chemical shifts calculations show that the aromaticity is restricted to the benzenic ring in both compounds even though they are formally 10 pi polynuclear species.
authors.affiliation: Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, P-4169-007 Porto, Portugal. marmatos@fc.up.pt
authors.forename: M Agostinha R
authors.initials: MA
authors.lastname: Matos
authors.forename: Margarida S
authors.initials: MS
authors.lastname: Miranda
authors.forename: Susana M M
authors.initials: SM
authors.lastname: Pereira
authors.forename: Victor M F
authors.initials: VM
authors.lastname: Morais
authors.forename: Joel F
authors.initials: JF
authors.lastname: Liebman
mesh_terms: D000465:Algorithms; D000812:Anhydrides / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry*; D002151:Calorimetry; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D013816:Thermodynamics
chemical_list: D000812:Anhydrides; D001565:Benzoates; D006841:Hydrocarbons, Aromatic; D007094:Imides; C012019:pyromellitic dianhydride