Energetics of 1-(aminophenyl)pyrroles: A joint calorimetric and computational study

Static bomb calorimetry and the Knudsen effusion mass-loss technique were used to derive, respectively, the standard (p° = 0.1 MPa) molar enthalpy of formation, in the crystalline phase, ΔfHm∘(cr), and the standard molar enthalpy of sublimation, at T = 298.15 K, ΔcrgHm∘, of 1-(2-aminophenyl)pyrrole. These experiments allowed the determination of its standard (p° = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, ΔfHm∘(g), at T = 298.15 K, as (224.1 ± 2.4) kJ · mol−1.The gas-phase enthalpy of formation of 1-(2-aminophenyl)pyrrole was also estimated by G3(MP2)//B3LYP calculations, which were further extended to the (aminophenyl)pyrroles that were not studied experimentally. Experimental and theoretical results are in very good agreement.

► Enthalpy of formation of crystalline 1-(2-aminophenyl)pyrrole was determined by combustion calorimetry. ► Vapor pressures of 1-(aminophenyl)pyrrole were measured as function of temperature by the Knudsen effusion technique. ► Enthalpies of formation of the three gaseous isomers of 1-(aminophenyl)pyrrole were obtained by G3(MP2)//B3LYP calculations.