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The new heterocyclic derivative LQFM048 (3) (2,4,6-tris ((E)-ethyl 2-cyano-3-(4-hydroxy-3-methoxyphenyl)acrylate)-1,3,5-triazine) was originally designed through the molecular hybridization strategy from Uvinul® T 150 (1) and (E)-ethyl 2-cyano-3-(4hydroxy-3-methoxyphenyl)acrylate (2) sunscreens, using green chemistry approach. This compound was obtained in global yields (80%) and showed an interesting redox potential. In addition, it is thermally stable up to temperatures around 250°C. It was observed that LQFM048 (3) showed a low degradation after 150min of sunlight exposure at 39°C, whereas the extreme radiation conditions induced a considerable photodegradation of the LQFM048 (3), especially when irradiated by VIS and VIS+UVA. During the determination of sun protection factor, LQFM048 (3) showed interesting results, specially as in association with other photoprotective compounds and commercial sunscreen. Additionally, the compound (3) did not promote cytotoxicity for 3T3 fibroblasts. Moreover, it was not able to trigger acute oral systemic toxicity in mice, being classified as a compound with low acute toxicity hazard (2.000mg/kg>LD50<5.000mg/kg). Therefore, this compound synthesized using green chemistry approach is promising showing potential to development of a new sunscreen product with advantage of presenting redox potential, indicating antioxidant properties.

In this work, we examined how photoluminescence in poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is affected by morphology, dictated by the mode of preparation. For that, MEH-PPV dilute solutions in good and non-solvents, thick cast films with poly[methylmethacrylate] (PMMA) as inert matrix and spin-coated thin films were prepared. These systems were studied by steady-state and time-dependent fluorescence spectroscopy and electronic microscopy. Unexpected photoluminescent behavior was detected in solutions and films and it was related to different excitons modulated by MEH-PPV conformation. By semi empirical calculations we obtained the singlet and triplet state energies of an MEH-PPV model system and, from time-resolved fluorescence spectroscopy, the existence of short-lived excited states was revealed, enabling us to infer on possible singlet fission in MEH-PPV-based systems.Keywords: photoluminescence, morphology, thin films, time-resolved fluorescence, computational calculations IntroductionSince poly(phenylene-vinylene) (PPV) derivatives were found to be electroluminescent, 1 the search for a systematic method to determine their applications has been of great interest. Their mechanical, morphological and optical properties have been widely discussed and findings related these properties to preparation methods. Although there are many aspects regarding the effects of preparation methods on optical response, authors seem to agree that preparation method influences molecular conformation, enabling or inhibiting aggregation and, consequently, affecting inter and intrachain interactions. Processing parameters are believed to modify the conformation and assembling mechanisms of polymeric materials, resulting in a memory effect of the structural information that is replicated from solutions to solid films. Therefore, to understand the role of chain conformation in solution is of major importance for applications such as device fabrication, since properties can be tuned, enhancing the desired characteristics and suppressing the undesired ones. 2,3 For instance, it is well known that photoluminescence of PPV derivatives show prominent red-shift due to the enhancement of energy transfer as the π-electron delocalization increases. 4 As pointed out in an earlier work, 5 this red-shift indicates aggregation driven by π-π interactions as the conjugation length increases.In polymeric systems, several occurrences are responsible for chain torsions that impose limits to the length of conjugated segments, affecting the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps. They are interpreted as stabilization and/or destabilization of HOMO and LUMO levels. 6 These occurrences may be related to the presence of impurities, molecules of solvent that strongly interact with the polymer chains and a distribution of torsion angles promoted by molecular interactions of any nature. 6 In this situation, the densities of excited states (DOS) available for electronic chan...

RESUMO:  Esta pesquisa teve como objetivo avaliar o efeito da adição dos pigmentos inorgânicos nas cores vermelha, amarela e verde em blocos destinados à construção modular. Os blocos foram fabricados com o traço 1:5 (cimento: agregados totais), em massa, utilizando como agregados areia artificial, fíler e micro fíler; todos, subprodutos de britagem. Foram incorporados 0% (traço de referência), 5%, 10% e 15% dos pigmentos em relação à massa do cimento e em substituição parcial ao fíler. Para a confecção dos blocos, utilizou-se uma prensa hidráulica com capacidade de prensagem de 8,0 tf. Foram determinadas as densidades dos blocos e realizados os ensaios de absorção total de água e de resistência à compressão. Além disso, com o fim de analisar os efeitos dos pigmentos sobre a porosidade dos blocos, foram realizados ensaios de Microscopia Eletrônica de Varredura (MEV), que indicaram uma microestrutura mais densa para os blocos que apresentaram menor absorção total de água. Verificou-se ainda que o efeito da adição dos pigmentos varia conforme o formato dos grãos e porcentagem de pigmento. Os blocos que tiveram melhores desempenhos mecânicos foram os com 5% de pigmento amarelo, 10% e 15% de pigmento verde e 15% de pigmento vermelho, todos estes com desempenhos superiores ao desempenho dos blocos de referência, sem pigmento. ABSTRACT: This research aimed to evaluate the effect of the addition of inorganic pigments in red, yellow, and green colors in blocks intended for modular construction. The blocks were manufactured with the mix 1:5 (cement: total aggregates), in mass, using artificial sand, filler and micro filler as aggregates; all crushing by-products. Reference mix (0%) and 5%, 10% and 15% of the pigments were incorporated in relation to the cement mass and in partial replacement of the filler. To make the blocks, a hydraulic press with a pressing capacity of 8.0 ton was used. Block densities were determined, and total water absorption and compressive strength tests were performed. Furthermore, to analyze the effects of pigments on the porosity of the blocks, Scanning Electron Microscopy (SEM) tests were carried out, which indicated a denser microstructure for the blocks that showed lower total water absorption. It was also found that the effect of adding pigments varies according to the shape of the grains and the percentage of pigment. The blocks that had the best mechanical performance were those with 5% of yellow pigment, 10% and 15% of green pigment and 15% of red pigment, all of which performed better than the reference blocks without pigment.