Experimental and computational energetic study of 1-R-2-phenylindole (R=H, CH3, C2H5)

• Published in: The Journal of chemical thermodynamics Vol. 85; pp. 129 - 140
• Main Authors: Carvalho, Tânia M.T., Amaral, Luísa M.P.F., Morais, Victor M.F., Ribeiro da Silva, Maria D.M.C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2015
• Subjects: 1-Ethyl-2-phenylindole; 1-Methyl-2-phenylindole; 2-Phenylindole; Combustion calorimetry; Knudsen effusion; Standard molar enthalpy of formation; Theoretical calculations; Knudsen effusion; 1-Methyl-2-phenylindole; Combustion calorimetry; 2-Phenylindole; 1-Ethyl-2-phenylindole; Theoretical calculations; Standard molar enthalpy of formation
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2015.01.012

•Combustion of 1-R-2-phenylindole (R=H, CH3, C2H5) by static bomb calorimetry.•Enthalpies of sublimation of 1-R-2-phenylindole (R=H, CH3, C2H5).•Gaseous enthalpies of formation of 1-R-2-phenylindole (R=H, CH3, C2H5).•Gas-phase enthalpies of formation estimated from G3(MP2)//B3LYP approach.•Experimental energetic study of 1-R-2-phenylindole (R=H, CH3, C2H5). The standard (po=0.1MPa) molar energies of combustion, ΔcUmo, of 2-phenylindole, 1-methyl-2-phenylindole and 1-ethyl-2-phenylindole, in the crystalline state, were determined, at T=298.15K, using a static bomb combustion calorimeter. The vapour pressures as a function of the temperature for these compounds were measured by the Knudsen effusion technique and the standard molar enthalpies of sublimation were derived. From the experimental results, the standard (po=0.1MPa) molar enthalpies of formation in the condensed and gaseous phases, at T=298.15K, of 2-phenylindole, 1-methyl-2-phenylindole and 1-ethyl-2-phenylindole were calculated. Additionally, the gas-phase enthalpies of formation of these compounds and also for 1-ethylindole were estimated by G3(MP2) calculations. Enthalpies of formation, obtained using appropriate working reactions, were calculated and compared with the experimental data. The results were also analysed in terms of structural enthalpic group contributions.