Energetic studies of two oxygen heterocyclic compounds Xanthone and tetrahydro-γ-pyrone
- 101 Downloads
The present work reports an experimental thermochemical study supported by state of the art calculations of two heterocyclic compounds containing oxygen in the ring: xanthone and tetrahydro-γ-pyrone. The standard (pº = 0.1 MPa) molar enthalpies of formation in the condensed phase, at T = 298.15 K, were derived from the measurements of the standard molar energies of combustion in oxygen atmosphere, using a static bomb calorimeter. The standard molar enthalpies of sublimation or vaporization, at T = 298.15 K, of the title compounds were obtained from Calvet microcalorimetry measurements. These values were used to derive the standard enthalpies of formation of the compounds in the gas-phase at the same temperature, which were compared with estimated data from G3(MP2)//B3LYP computations.
KeywordsCalvet microcalorimetry Combustion calorimetry Enthalpy of formation Enthalpies of transition G3(MP2)//B3LYP calculations Heat capacities
Thanks are due to Fundação Para a Ciência e Tecnologia (FCT), Lisbon, Portugal, for financial support to Centro de Investigação em Química - UP and to CICECO. V. L. S. Freitas thanks FCT and European Social Fund for the award of a Ph.D. Research Grant SFRH/BD/41672/2007.
- 1.http://webbook.nist.gov. Accessed Sept 20 2008.
- 3.Castanheiro RAP, Pinto MMM, Silva AMS, Cravo SMM, Gales L, Damas AM, et al. Dihydroxyxanthones prenylated derivatives: Synthesis, structure elucidation, and growth inhibitory activity on human tumor cell lines with improvement of selectivity for MCF-7. Bioorg Med Chem. 2007;15:6080–8.CrossRefGoogle Scholar
- 10.Sabbah R, El Watik L. Etude thermodynamique de deux molecules simples rencontrées dans les produits issus de la pyrolyse du charbon: chromone et xanthene. Bull Soc Chim. 1998;4:626–30.Google Scholar
- 11.Onuma BS, Iijima K, Oonishi I. Structure of xanthone. Acta Cryst. 1990;C46:1725–7.Google Scholar
- 12.Aldrich. Handbook of fine chemicals. 2007/2008, España, Portugal.Google Scholar
- 17.Sousa EA. Ph D Dissertation, Faculty of Science, University of Porto; 2005.Google Scholar
- 18.Wagman DD, Evans WH, Parker VB, Schumm RH, Halow I, Bailey SM, Churney KL, Nuttal RL. The NBS tables of chemical thermodynamics properties. J Phys Chem Ref Data 1982;II:Suppl 2.Google Scholar
- 19.Washburn EN. Standard states for bomb calorimetry. J Res Nat Bur Stand (US). 1933;10:525–58.Google Scholar
- 20.Hubbard WN, Scott DW, Waddington G. Standard states and corrections for combustions in a bomb at constant volume. In: Rossini FD, editor. Experimental thermochemistry, vol. 1. New York: Interscience; 1956. p. 75–128.Google Scholar
- 27.Gaussian 03 Revision C.01. Gaussian Inc., Wallingford CT; 2004.Google Scholar
- 29.Cox JD, Wagman DD, Medvedev VA. CODATA key values for thermodynamics. New York: Hemisphere; 1989.Google Scholar
- 30.Irikura KK. THERMO.PL National Institute of Standards and Technology; 2002.Google Scholar
- 32.Sousa CCS. Ph. D. Dissertation, Faculty of Science, University of Porto; 2008.Google Scholar
- 33.Pedley JB. Thermochemical data and structures of organic compounds. Texas, College Station: Thermodynamics Research Centre; 1994.Google Scholar
- 34.Cox JD, Pilcher G. Thermochemistry of organic & organometallic compounds. London and New York: Academic Press; 1970.Google Scholar