Artigos científicos, teses e dissertações
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In the present work, solvatochromic probes were employed in the study of pure solvents, binary mixtures of water with protic and aprotic solvents, ionic liquids and their aqueous binary mixtures The probes studied are classified in two series: (i) RPMBr2; where R = methyl to 1-oc...

Acid catalyzed decomposition of C5 and C6 sugars has been considered an important source of biomass derived chemicals. An essential step in this process is the extraction of furfural, hydroxymethylfurfural and levulinic acid from aqueous phase. In this work, a computational scree...

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Aqueous two-phase systems (ATPSs) have found wide application in the separation of biological molecules such as amino acids, peptides and proteins. Most of the research in this area has been dedicated to experimental determination and less effort has been devoted to the proper th...

In this Thesis are presented studies by Molecular Dynamics simulations on some molecular systems presenting complex dynamics behavior (i.e., relaxation process caracterized by multiple time scales), including saccharides aqueous solutions, double helix DNA systems, air/water inte...

The DNA-intercalating chromophore [Ru(phen)2dppz]2+ has unique photophysical properties, the most striking of which is the “light-switch” characteristic when binding to DNA. As a dimer, it acts as a molecular staple for DNA, exhibiting a remarkable double-intercalating topology. ...

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The solvation energies of salt bridges formed between the terminal carboxyl of the host pentapeptide AcWL- X-LL and the side chains of Arg or Lys in the guest (X) position have been measured. The energies were derived from octanol-to-buffer transfer free energies determined betwe...

The effect of a solvation on the thermodynamics and kinetics of polyalanine (Ala12) is explored on the basis of its energy landscapes in vacuum and in an aqueous solution. Both energy landscapes are characterized by two basins, one associated with α-helical structures and the...

Equilibrium binding free energies of 14 benzo-, naphtho-, and anthraquinone cofactors have been determined at the QA redox catalytic site of the purified photosynthetic reaction center protein from Rhodobacter sphaeroides solubilized in water (delta G degrees B,w), in hexane solu...

Molecular dynamic simulation was performed for the first time to Li2C4O4 aqueous solution with the objective of studying solvation of squaric anion in the microscopic level and get a better understanding of the behavior of this anion in solution. Through an analysis of the simula...

A systematic molecular mechanics study of the alamethicin molecule was made to determine a set of low-energy conformers in vacuo and in aqueous environment. The behavior of these conformers was investigated at the phase boundary which was modeled as a plane dividing two compartme...

Intra-dinucleoside dimer conformational energy calculations were performed on a series of conformations corresponding to the unwinding of a dinucleoside dimer from the B-form type structure. Conformational states were characterized in terms of the distance, d, between parallel ba...

The gas phase and aqueous thermochemistry and reactivity of nitroxyl (nitrosyl hydride, HNO) were elucidated with multiconfigurational self-consistent field and hybrid density functional theory calculations and continuum solvation methods. The pKa of HNO is predicted to be 7....

Computer simulation methods were used to characterize the structure and molecular properties of natural and synthetic biopolymers in aqueous solution. The polysaccharides chitin and chitosan, and aliphatic polypeptides were studied. The interest on the chitin and chitosan biopoly...

ABSTRACT Physical extraction studies of pyruvic acid from dilute aqueous solutions (0.025 kmol·m-3 to 0.200 kmol·m-3) using several pure solvents (tri-n-butylphosphate (TBP), 1-decanol, 1-octanol, toluene, Methyl-isobutylketone (MIBK), and n-heptane) and their binary mixtures are...

We have carried out free energy perturbation calculations on DNA double-stranded hexanucleotides. The sequence d(CGCGCG)2 has been "mutated" into d(CGTGCG).d(CGCACG) with the oligonucleotide in the A, B, and Z structural forms, both in vacuo and in aqueous solution. In addition, ...

Forces between type I collagen triple helices are studied in solvents of varying hydrogen-bonding ability. The swelling of collagen fibers in reconstituted films is controlled by the concentration of soluble polymers that are excluded from the fibers and that compete osmotically ...

We use molecular dynamics to simulate recent neutron scattering experiments on aqueous solutions of N-acetyl-leucine-amide and N-acetyl-glutamine-amide, and break down the total scattering function into contributions from solute-solute, solute-water, water-water, and intramolecul...

Abstract Biodegradable polymers have become part of the realm of polymer science with specially when associated to renewable sources. Unraveling the plasticizer effect of natural occurring fatty acids in the Brazilian Cerrado on amylose oligomers was aimed in this work in an aqu...

Density functional theory calculations (ωB97X-D/6-311++G(d,p)) are employed to investigate an alternative pathway for Prins-like cyclization. Although strong acids usually catalyze this reaction, 4-amino-1,3-dioxanes are rapidly obtained in high yields without catalyst when benze...