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Mutual diffusion of sodium hyaluranate in aqueous solutions
Veríssimo, Luís M. P.; Valada, Teresa I. C.; Sobral, Abilio J. F. N.; Azevedo, Eduarda E. F. G.; Azevedo, Maria L. G.; Ribeiro, Ana C. F.The Taylor dispersion technique has been used for measuring mutual diffusion coefficients of sodium hyaluronate in aqueous solutions at T = 298.15 K, and concentrations ranging from (0.00 to 0.50) g · dm−3. The results are interpreted on the basis of Nernst, and Onsager and Fuoss theoretical equations. From the diffusion coefficient at infinitesimal concentration, the limiting ionic conductivity and the tracer ...
Experimental and theoretical studies of the second- and third-order NLO propert...
Silva, Pedro S. Pereira; Ouazzani, Hasnaa El; Pranaitis, Mindaugas; Silva, Manuela Ramos; Arranja, Cláudia T.; Sobral, Abilio J. F. N.A new semi-organic compound, 6-aminoquinolinium iodide monohydrate (I), has been synthesized and characterized by single crystal X-ray diffraction, UV–vis absorption and fluorescence spectroscopy and nonlinear optical (NLO) measurements. The second- and third-order NLO responses were investigated with the second- and third-harmonic Maker fringes techniques, carried out on thin films at a fundamental wavelength ...
Interaction between lactose and cadmium chloride in aqueous solutions as seen b...
Verissimo, Luis M. P.; Gomes, Joselaine C. S.; Romero, Carmen; Esteso, Miguel A.; Sobral, Abilio J. F. N.; Ribeiro, Ana C. F.Diffusion coefficients of an aqueous system containing cadmium chloride 0.100 mol · dm−3 and lactose at different concentrations at 25 °C have been measured, using a conductimetric cell and an automatic apparatus to follow diffusion. The cell relies on an open-ended capillary method and a conductimetric technique is used to follow the diffusion process by measuring the resistance of a solution inside the capill...
Conformational Studies of Poly(9,9-dialkylfluorene)s in Solution Using NMR Spec...
Justino, Licínia L. G.; Ramos, M. Luísa; Abreu, Paulo E.; Carvalho, Rui A.; Sobral, Abilio J. F. N.; Scherf, Ullrich; Burrows, Hugh D.Relationships have been obtained between intermonomer torsional angle and NMR chemical shifts (1H and 13C) for isolated chains of two of the most important poly(9,9-dialkylfluorenes), poly[9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (PF2/6) and the copolymer poly(9,9-dioctylfluorene-co-[2,1,3]benzothiadiazole-4,7-diyl) (F8BT), using DFT calculations. The correlations provide a model for NMR spectral data interpreta...
Mean distance of closest approach of ions: Lithium salts in aqueous solutions
Ribeiro, Ana C. F.; Lobo, Victor M. M.; Burrows, Hugh D.; Valente, Artur J. M.; Amado, Ana M.; Sobral, Abílio J. F. N.; Teles, Ana S. N.Numerical values for the mean distance of closest approach of ions, "a", for lithium salts in aqueous solutions are presented and discussed. These values were obtained from both experimental activity and diffusion coefficients, and estimated by using different theoretical approaches. ; http://www.sciencedirect.com/science/article/B6TGR-4RR1NKM-1/1/b8d3cdac33991c5424d567940bc0c3a6
Self-aggregation of free base porphyrins in aqueous solution and in DMPC vesicles
Andrade, Suzana M.; Teixeira, Raquel; Costa, Sílvia M.B.; Sobral, Abílio J.F.N.Free base porphyrin (PPhe), derivatized with aminosulfonyl groups linked to the aromatic amino acid phenylalanine at the meso-positions, was mixed with DMPC vesicles. The resulting interaction was studied by absorption, steady-state and transient state fluorescence, at different pHs. ; http://www.sciencedirect.com/science/article/B6TFB-4R68NKV-2/1/aca6e255f297903981898ccea264a386
Diffusion coefficients and electrical conductivities for calcium chloride aqueo...
Ribeiro, Ana C. F.; Barros, Marisa C. F.; Teles, Ana S. N.; Valente, Artur J. M.; Lobo, Victor M. M.; Sobral, Abílio J. F. N.; Esteso, M. A.http://www.sciencedirect.com/science/article/B6TG0-4T7XGV2-6/2/9f2789c31efbabbadc8d9358c079cafe
Oxoperoxo Vanadium(V) Complexes of l-Lactic Acid: Density Functional Theory Stu...
Justino, Licínia L. G.; Ramos, M. Luísa; Nogueira, Fernando; Sobral, Abilio J. F. N.; Geraldes, Carlos F. G. C.; Kaupp, Martin; Burrows, Hugh D.Various combinations of density functionals and pseudopotentials with associated valence basis-sets are compared for reproducing the known solid-state structure of [V2O2(OO)2l-lact2]2−cis. Gas-phase optimizations at the B3LYP/SBKJC level have been found to provide a structure that is close to that seen in the solid state by X-ray diffraction. Although this may result in part from error compensation, this optimi...
Oxoperoxo Vanadium(V) Complexes of l-Lactic Acid: Density Functional Theory Stu...
Justino, Licínia L. G.; Ramos, M. Luísa; Nogueira, Fernando; Sobral, Abilio J. F. N.; Geraldes, Carlos F. G. C.; Kaupp, Martin; Burrows, Hugh D.Various combinations of density functionals and pseudopotentials with associated valence basis-sets are compared for reproducing the known solid-state structure of [V2O2(OO)2l-lact2]2−cis. Gas-phase optimizations at the B3LYP/SBKJC level have been found to provide a structure that is close to that seen in the solid state by X-ray diffraction. Although this may result in part from error compensation, this optimi...
Synthesis of flexible dimeric meso-tetrakis-porphyrins
Sobral, Abilio J.F.N.; Melo, Susana M.; Ramos, M. Luísa; Teixeira, Raquel; Andrade, Susana M.; Costa, Silvia M.B.Monofunctionalisation of meso-tetrakis-porphyrins through introduction of a carboxylic group in the meso position of the phenyl group confers the necessary characteristics to anchor them through stable amide bonds to functionalised supports or to molecules. In this Letter we describe the synthesis, characterisation and photophysical evaluation of such a functionalised flexible dimeric porphyrin, bis-(meso-tetra...
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