Medical and Biomedical Researches

Experimental and Molecular Dynamics Simulation Study of the Sublimation and Vaporization Energetics

Experimental and Molecular Dynamics Simulation Study of the Sublimation and Vaporization Energetics of Iron Metalocenes. Crystal Structures of Fe(eta(5)-C(5)H(4)CH(3))(2) and Fe[(eta(5)-(C(5)H(5))(eta(5)-C(5)H(4)CHO)].

The standard molar enthalpies of sublimation of ferrocene, 1,1\’-dimethylferrocene, decamethylferrocene, ferrocenecarboxaldehyde and alpha-methylferrocenemethanol, and the enthalpy of vaporization of N,N-dimethyl(aminomethyl)ferrocene, at 298.15 K, were determined by Calvet-drop microcalorimetry and/or the Knudsen effusion method. The obtained values were used to assess and refine our previously developed force field for metallocenes. The modified force field was able to reproduce the %@mt;sys@%Delta%@sb@%sub%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@% degrees %@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% and %@mt;sys@%Delta%@sb@%vap%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@% degrees %@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% values of the test-set with an accuracy better than 5 kJ.mol-1, except for decamethylferrocene, in which case the deviation between the calculated and experimental %@mt;sys@%Delta%@sb@%sub%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@% degrees %@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% values was 16.1 kJ.mol-1. The origin of the larger error found in the prediction of the sublimation energetics of decamethylferrocene, and which was also observed in the estimation of structural properties (e.g., density and unit cell dimensions), is discussed. Finally, the crystal structures of Fe(eta5-C5H4CH3)2 and Fe[(eta5-(C5H5)(eta5-C5H4CHO)] at 293 and 150 K, respectively, are reported.

Lousada CM, Pinto SS, Lopes JN, Piedade MF, Diogo HP, Piedade ME.

Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal, and Centro de Química Estrutural, Complexo Interdisciplinar, Instituto Superior Técnico da Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal.