Publications

Abstract In the present work, a combined experimental and computational thermochemical study of nitroimidazole isomers was carried out. The standard (p = 0.1 MPa) molar enthalpy of combustion, in the crystalline phase, for 4-nitroimidazole was determined, at the temperature of 298.15 K, using a static bomb combustion calorimeter. Calvet microcalorimetry experiments were performed to measure its standard molar enthalpy of sublimation. The standard molar enthalpy of formation of 4-nitroimidazole, in the gaseous phase, at T = 298.15 K, (116.9 +/- 2.9) kJ.mol(-1), has been derived from the corresponding standard molar enthalpy of formation in the crystalline phase and the standard molar enthalpy of sublimation. Computational studies for 4-nitroimidazole were performed to complement the experimental work. These were also extended to the 2- and 5-nitroimidazole isomers. The gas-phase enthalpies of formation were estimated from high level ab initio molecular orbital calculations, at the G3 level. Also investigated were the tautomeric equilibrium of 4(5)-nitroimidazole in the gaseous phase and it was concluded that the two tautomers are equally stable. (C) 2016 Elsevier Ltd.

Abstract Thermodynamic properties of 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene for the condensed and gas states were derived from experimental and computational studies. Static-bomb combustion calorimetry, vacuum drop microcalorimetry and the Knudsen effusion techniques were used. Computational calculations of the enthalpies of hypothetical reactions in the gaseous phase, using the G3(MP2)//B3LYP composite method, were performed for the two xanthene derivatives. Natural bond orbital (NBO) calculations were also performed to ascertain the structure and reactivity of these compounds. The energetic effects caused by replacing hydrogen atoms in the xanthene moiety by methyl and tertbutyl groups yielding 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene species were determined from direct comparison of their standard (p degrees = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T=298.15 K. (C) 2016 Elsevier Ltd.

Abstract This article assesses the intention of chemistry teachers to integrate digital media in their classes. The evaluation was performed using a structured questionnaire after participation in two professional development actions. The formative sessions were designed with the aim of training the chemistry teachers for pedagogical integration of digital media in teaching chemistry in high school. The participants were 25 chemistry teachers from different regions of Brazil, who were participating in an international cooperation program for the professional development of teachers in Portugal. Data collection was conducted through questionnaires containing questions about the motivations for innovation in education, attitudes and beliefs in relation to the training actions and face the pedagogical integration of digital media in the chemistry discipline. The data analysis shows a remarkable behavioral intention of adopting the media which is positively correlated with the attitudes and perceptions of control and negatively with subjective norm. These results suggest that interventions focused on technical and pedagogical training centered on subject content are suitable for the professional development of teachers.

Abstract The standard molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, was calculated by combining, for each compound, the standard molar enthalpy of formation, in the crystalline phase, and the standard molar enthalpy of sublimation, yielding -(222.2 +/- 3.5) kJ.mol(-1) and -(234.1 +/- 2.1) kJ.mol(-1) for indole-3-carboxylic acid and 1-methylindole-3-carboxylic acid, respectively. Computational studies, at the G3(MP2) composite level, were conducted for indole-3-carboxylic acid and 1-methylindole-3-carboxylic acid as a complement of the experimental work, and they were also extended to the remaining isomers, indole-2-carboxylic acid, 1-methylindole-2-carboxylic acid, 3-methylindole-2-carboxylic acid, and 2-methylindole-3-carboxylic acid, to provide reliable estimates of the corresponding thermochemical parameters. The agreement of the estimates of the standard gas-phase enthalpy of formation so obtained, indole-2-carboxylic acid -(223.6 +/- 0.8) kJ.mol(-1), 1-methylindole-2-carboxylic acid -(223.7 +/- 0.8) kJ.mol(-1), 3-methylindole-2-carboxylic acid -(251.6 +/- 1.0) kJ.mol(-1), indole-3-carboxylic acid -(227.1 +/- 1.1) kJ.mol(-1), 1-methylindole-3-carboxylic acid -(238.0 +/- 1.0) kJ.mol(-1), and 2-methylindole-3-carboxylic acid -(267.2 +/- 1.0) kJ.mol(-1), with the available experimental data gives us additional confidence for the situations not studied experimentally. The enthalpic effect resulting from the entrance of the carboxyl group into the indole ring was discussed, and an enthalpic stabilization was found for indole and pyrrole derivatives when compared with other similar systems.

Abstract A carbon quantum dots (CQDs) based ratiometric nanosensor exhibiting dual emission fluorescence was developed. The spherical fluorescent carbon nanoparticles were obtained from lactose using a hydrothermal method. Under a single excitation at 355 nm they showed the typical blue emission at 417 nm and a red emission at 550 nm attributed to the coating effect of vitamin B-12. The latter is explained by the fluorescence resonance energy transfer (FRET) and it consists of 61% of total emission. Upon the presence of carbofuran phenol 3-Keto, a phenolic metabolite of carbofuran, the red emission was quenched, resulting in a ratiometric fluorescence response in the blue range. This ratiometric nanosensor exhibited a good selectivity to carbofuran phenol 3-Keto. The ratio of I-412/I-550 linearly decreased with an increasing carbofuran phenol 3-Keto concentration in the range 9.8 mu M-1.40 x 10(-4) M. A detection limit for carbofuran phenol 3-Keto pesticide was 12.2 mu M. The pesticide tested was extracted from soy sauce. Recovery values ranged from 98% to 114% with RSD values from 1.50% to 6.50%.

Abstract A thermochemical study of N-methylmorpholine and N-ethylmorpholine compounds was performed with the purpose of evaluating and understanding the energetic effects inherent to the replacement of the hydrogen of the amino group by an alkyl group in the morpholine scaffold. Calorimetric techniques complemented by computational calculations were used to determine the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of the two morpholine derivatives. Static bomb combustion calorimetry and vacuum drop microcalorimetric techniques were used. Computational calculations of the enthalpies of hypothetical reactions in the gaseous phase, using the G3(MP2)//B3LYP composite method, were performed for the two morpholine derivatives. The values of the experimental and computational gas-phase enthalpy of formation obtained for N-alkylmorpholine compounds will be compared and discussed. The energetic effect and the structural changes resulting from the substitution of the hydrogen of the amino group by an alkyl group in the morpholine scaffold are analyzed.

Abstract The project 'Multimedia in science teaching: five years of research and teaching in Portugal' was successful in featuring the national research on multimedia in science education and in providing the community with a simple reference tool - a repository of open access scientific texts. The current work aims to describe the theoretical background that may allow creating and sustainably developing an online community on science teaching. The community should be capable of appropriating and generating scientific peer review and validation processes, which would allow reflections on teaching practices in science areas using information and communication technologies (ICT) and improvements from a participatory science perspective. Through an action-research process, the current platform is being adjusted in the sense of implementing strategies able to attract and engage an interested public and progressively to create a community of peers. The project is particularly relevant with respect to the gap between academic production and pedagogical practice and the avenues that it opens for comparing affinity spaces across different locations and domains of interest.

Abstract The purpose of this research was to determine the energetic and reactivity properties of diphenylamine and 9,10-dihydroacridine using computational methodologies. The equilibrium geometries in the gaseous phase of the studied compounds were analysed in detail and the structural effects on the aforementioned properties were assessed. The values of the gas-phase standard molar enthalpies of formation of diphenylamine (217.7 +/- 1.8) kJ.mol(-1) and 9,10-dihydroacridine (198.7 +/- 4.4) kJ.mol(-1) were estimated by hypothetical gas-phase reactions using the G3(MP2)//B3LYP composite method. These data were compared with the ones available in the literature, including the gas-phase enthalpy of formation of 9,10-dihydroacridine derived from the assumption of comparability of the enthalpies of hydrogenation in the liquid and gas phases. Other gas-phase thermodynamic properties, namely the bond dissociation enthalpies (NAH and CAH) and the gas-phase acidities were also determined. The electrostatic potential surfaces and the frontier molecular orbitals were determined for both compounds, allowing us to infer about its reactivity. Other derived properties include the HOMO-LUMO energy gap and the ionization potential. (C) 2017 Elsevier Ltd.

Abstract The possibility to preserve perspectives of reality with spontaneous creations allowed by the web tools that now empower common users with content production skills highlights the numerous opportunities for the present and future of cultural identity maintenance. Our research approaches digital storytelling during intergenerational dynamics as a stage for a participatory contribution to the maintenance of cultural identity. With an ethnographic approach and with partnerships with existing senior movements, we seek to (a) understand the storytelling processes during intergenerational dynamics, (b) develop a framework for the participative creation of narratives in the context of intergenerational cultural identity maintenance, (c) support the participatory maintenance of cultural identity through a set of workshops for intergenerational storytelling, (d) understand the challenges and opportunities promoted by digital affinity spaces for the maintenance of cultural identity. Our contribution proposes to develop the understanding of the role that interactive narratives can have in the context of cultural identity maintenance, by developing new usage strategies to enhance cultural mediation through social and ubiquitous storytelling strategies.