Publications

Abstract The gas-phase standard molar enthalpies of formation of the three monoiodoanilines were derived from the enthalpies of combustion in the condensed phases. measured by rotating-bomb calorimetry and their enthalpies of sublimation/vaporization obtained by Calvet microcalorimetry at T = 298.15 K. The standard enthalpies of formation for these compounds and for the diiodoaniline isomers were determined by DFT calculations. The theoretical calculations were performed with the B3LYP/6-31G(d):SBKJ-VDZ and B3LYP/6-311G(2d, 2p):SBKJ-VDZ approaches. Estimated values are in excellent agreement with the reported experimental numbers derived in the present Letter.

Abstract The enthalpies of combustion, heat capacities, enthalpies of sublimation and enthalpies of formation of 2-tert-butylbenzimidazole (2tBuBIM) and 2-phenylimidazole (2PhIM) are reported and the results compared with those of benzene derivatives and a series of azoles (imidazoles, pyrazoles, benzimidazoles and indazoles). Theoretical estimates of the enthalpies of formation were obtained through the use of atom equivalent schemes. The necessary energies were obtained in single-point calculations at the B3LYP/6-311++G(d,p) on B3LYP/6-31G* optimized geometries. The comparison of experimental and calculated values of all studied compounds bearing H (unsubstituted), methyl (Me) ethyl (Et), propyl (Pr), isopropyl (iPr), tert-butyl (tBu), benzyl (Bn) and phenyl (Ph) groups show remarkable homogeneity. The remarkable consistency of both the calculated and experimental results allows us to predict with reasonable certainty the missing experimental values. The crystal and molecular structure of the 2-benzylbenzimidazole (2BnBIM) has been determined by X-ray analysis. The observed molecular conformation permits the crystal being built up through N-H...N hydrogen bonds and van der Waals contacts between the molecules. An attempt has been made to relate the crystal structure to the enthalpies of sublimation.

Abstract The standard (p degrees = 0.1 MPa) molar energies of combustion in oxygen of N-(diethylaminothiocarbonyl)-N'-monoethylbenzamidine, PhCNHEtNCSNEt2 (DATMB), and N-(diethylaminothiocarbonyl)benzimido ethylester, PhCOEtNCSNEt2 (DATBE), were measured, at T = 298.15 K, by rotating-bomb calorimetry. The standard molar enthalpies of sublimation of these compounds were determined using Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the title compounds, in their crystalline and gaseous phases, respectively. Compounds -Delta U-c degrees(m) (cr)/ -Delta H-f degrees(m)(cr)/ Delta H-g(cr)degrees(m)/ (kJ center dot mol(-1)) (kJ center dot mol(-1)) (kL center dot mol(-1)) N-(Diethylaminothiocarbonyl)-N'-monoethylbenzamidine (DATMB) 9053.6 +/- 3.9 45.7 +/- 4.4 141.2 +/- 1.2 N-(Diethylaminothiocarbonyl)benzimido ethylester (DATBE) 8780.9 +/- 4.0 176.2 +/- 4.4 135.6 +/- 2.6 The standard molar enthalpies of formation for the two title compounds, in the gaseous state, were also calculated based on density functional theory at the B3LYP/6-311++G(2dfp)//6-31+G(d,p)-level of theory, anchored on previous experimental data for the standard molar enthalpy of formation of N-(diethylaminothiocarbonyl)-benzamidine.

Abstract The standard (p degrees = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-bromoaniline, 2,4-, 2,5-, and 2,6-di-bromoaniline, and 2,4,6-tribromoaniline were derived from the standard molar enthalpies of combustion, in oxygen, which yields CO2(g), N-2(g), and HBr center dot 600H(2)O(1), at T = 298.15 K, measured by using rotating-bomb calorimetry. The standard molar enthalpies of sublimation, or vaporization, of these compounds at 1 298.15 K were measured by using Calvet microcalorimetry, and so their standard molar enthalpies of formation in the gaseous state were derived. The enthalpies of fusion of the solid compounds were determined by DSC. The gas-phase enthalpies of formation were also estimated by density functional theory calculations performed at the BP86/6-31 +G* level. As a result it is confirmed that thermodynamic data is consistent with intramolecular N-(HBr)-Br-... hydrogen bonding.

Abstract Drug abuse is associated with brain dysfunction and neurodegeneration, and various recreational drugs induce apoptotic cell death. This study examined the role of the mitochondrial apoptotic pathway in psychostimulant-induced neuronal dysfunction. Using primary neuronal cultures, we observed that amphetamine (IC50 = 1.40 mM) was more potent than cocaine (IC50 = 4.30 mM) in inducing cell toxicity. Apoptotic cell death was further evaluated using cocaine and amphetamine concentrations that moderately decreased cell reduction capacity but did not affect plasma membrane integrity. Compared to cocaine, amphetamine highly decreased the mitochondrial membrane potential, as determined using the fluorescent probe rhodamine-123, whereas both drugs decreased mitochondrial cytochrome c. In contrast to amphetamine, cocaine cytotoxicity was partly mediated through effects on the electron transport chain, since cocaine toxicity was ameliorated in mitochondrial DNA-depleted cells lacking mitochondrially encoded electron transport chain subunits. Cocaine and amphetamine induced activation of caspases-2, -3 and -9 but did not affect activity of caspases-6 or -8. In addition, amphetamine, but not cocaine, was associated with the appearance of evident nuclear apoptotic morphology. These events were not accompanied by differences in the release of the apoptosis-inducing factor (AIF) from mitochondria. Our results demonstrate that although both amphetamine and cocaine activate the mitochondrial apoptotic pathway in cortical neurons, amphetamine is more likely to promote apoptosis.

Abstract An extensive monitoring programme of pesticides was carried out in soil samples from an intensive horticulture area in north of Portugal, putting into practice the needs for increased control of soil quality as far as organic pollution is concerned. The area under investigation was additionally defined as vulnerable to nitrates due to local soil and aquifer characteristics, which might be extended to pesticides contamination. Five sampling sites were selected and soils analysed at three depths in eight sampling campaigns, for the period of 2 years. A stepwise multivariate statistical approach was selected to uncover most relevant patterns inside a complex environmental data matrix. Cluster analysis was applied both to group pesticides and samples, giving a primary and unsupervised overlook of privileged relationships. Clusters of persistent pesticides and selected herbicides were identified, whereas sample classes were also formed and disposed geographically. Thirty eight percent of analysed soils samples fell into one class characterized by low contamination (class 1 in cluster analysis), which is entirely representative of the sampling site no. 1. Afterwards, linear discriminant analysis was applied to identify those pesticides, which had a higher impact in the definition of classes. Finally, factor analysis using a five component model was implemented in order to bring to light the constitution and data variance explained by each of the five main principal components, as well as, their relation to pest management practices. A factor was identified (PC1- 22% variance) composed of chlorinated pesticides, which was representative of one of the investigated sites indicating its high contamination status. Qualitative main findings and class average concentration values were obtained through this multivariate statistical approach.