Ionic liquids (ILs) play a key role in many chemical applications. As regards the theoretical approach, ILs show added difficulties in calculations due to the composition of the ion pair and to the fact that they are liquids. Although density functional theory (DFT) can treat this kind of systems to predict physico-chemical properties, common versions of these methods fail to perform accurate predictions of geometries, interaction energies, dipole moments, and other properties related to the molecular structure.
View Article and Find Full Text PDFThe molecular structure of novel ionic liquids based on cholinium amino acids (ChAA-ILs) has been analyzed. The polarization charge density for all ion pairs has been examined as a function of the hydrophobicity of the anion. The COnductor-like Screening MOdel σ-profiles and σ-potentials have been obtained and used to interpret the chemical behavior of ChAA-ILs.
View Article and Find Full Text PDFMolecular structure of the conformers of 1-C n -3-methylimidazolium chloride (n = 1 to 4) ionic liquids has been explored and the relationships with density and viscosity have been studied using COSMO related methodologies. Effects of the number of conformers, ionic character, anion-cation relative positions and the alkyl chain length of the cation on predictions of properties have been analyzed. The quality of the predictions has been tested by comparing with experimental results.
View Article and Find Full Text PDFThe density functional theory (DFT) was used to investigate the chemical behavior of C60 hosting neutral guest molecules (NGM). The deformed atoms in molecules (DAM) allowed identifying the regions of electron density depletion and accumulation. The studied NGM are CH4, NH3, H2O, and HF.
View Article and Find Full Text PDFAn analysis of the electron density of different conformers of the 1-butyl-3-methylimidazolium chloride (bmimCl) ionic liquid by using DFT through the BVP86 density functional has been obtained within the framework of Bader's atom in molecules (AIM), localized orbital locator (LOL), natural bond orbital (NBO), and deformed atoms in molecules (DAM). We also present an analysis of the reduced density gradients that deliver the non-covalent interaction regions and allow to understand the nature of intermolecular interactions. The most polar conformer can be characterized as ionic by AIM, LOL, and DAM methods while the most stable and the least polar shows shared-type interactions.
View Article and Find Full Text PDFAims: The aim of this work is to investigate the accuracy of the urea breath test (UBT) performed immediately after emergency endoscopy in peptic ulcer bleeding (PUB).
Methods: Urea breath test was carried out right after emergency endoscopy in patients with PUB. The accuracy of this early UBT was compared to a delayed one after hospital discharge that was considered the gold standard.
Background: Selective serotonin reuptake inhibitors (SSRIs) have been associated with upper gastrointestinal (GI) bleeding. Given their worldwide use, even small risks account for a large number of cases. This study has been conducted with carefully collected information to further investigate the relationship between SSRIs and upper GI bleeding.
View Article and Find Full Text PDFObjective: We investigated the effects of dietary fiber on symptoms of irritable bowel syndrome.
Methods: A single-blind randomized clinical trial was designed. Fifty-six subjects with irritable bowel syndrome were prospectively and randomly assigned to one of two groups: group 1 received a diet containing 10.
Objective: The aim of our work was to carry out a randomized clinical trial with two diets, one enriched in fiber (total fiber 30 g and soluble fiber 4 g) to investigate the effect on lipid and glucose levels in healthy subjects.
Research Design And Methods: Fifty-three subjects were prospectively randomized to two groups (see Table 1). Group I received a diet with 10.
© LitMetric 2025. All rights reserved.