abstract
The energetic effects caused by replacing one of the methylene groups in the 9,10-dihydroanthracene by ether or ketone functional groups yielding xanthene and anthrone species, respectively, were determined from direct comparison of the standard (p degrees = 0 1 MPa) molar enthalpies of formation in the gaseous phase, at T = 298.15 K. of these compounds. The experimental static-bomb combustion calorimetry and Calvet microcalorimetry and the computational G3(MP2)//B3LYP method were used to get the standard molar gas-phase enthalpies of formation of xanthene. (41 8 +/- 3 5) kJ mol(-1), and anthrone, (31 4 +/- 3 2) kJ mol(-1) The enthalpic increments for the substitution of methylene by ether and ketone in the parent polycyclic compound (9,10-dihydroanthracene) are -(1179 +/- 5 5) kJ mol(-1) and -(1283 +/- 5.4) kJ mol(-1), respectively (C) 2010 Elsevier Ltd All rights reserved
keywords
O BOND; ENTHALPIES; THERMOCHEMISTRY; CALORIMETRY; COMBUSTION; ANTHRONE; SUBLIMATION; COUMARIN; EFFUSION; DESIGN
subject category
Thermodynamics; Chemistry
authors
Freitas, VLS; Gomes, JRB; da Silva, MDMCR
our authors
José R. B. Gomes
Principal Researcheracknowledgements
Thanks are due to Fundacao para a Ciencia e Tecnologia (FCT), Lisbon, Portugal, for financial support to Centro de Investigacao em Quimica - UP and CICECO. V. L. S. Freitas thanks FCT and European Social Fund for the award of a Ph. D. Research Grant (SFRH/BD/41672/2007).