In situ Raman spectroscopic measurements of water in the region of OH vibration were conducted up to 0.4 GPa at 23 and 52 degrees C. The frequencies of the decomposed OH stretching bands initially decreased with increasing pressure, reached a minimum at 0.15 GPa and increased up to 0.3 GPa and then decreased, which corresponds to the variations of the strength of hydrogen bonding. This variatio...

The interfacial structure of water in contact with TiO2 is the key to understand the mechanism of photocatalytic water dissociation as well as photoinduced superhydrophilicity. We investigate the interfacial molecular structure of water at the surface of anatase TiO2, using phase-sensitive sum frequency generation spectroscopy together with spectra simulation using ab initio molecular dynamic t...

Four complementary hydrogen bonds between sulfamides and ureas link adjacent hydrogen-bonded ribbons to form sheets in the solid-state; this interaction is investigated in solution using model urea and sulfamide compounds.

Four series of hydrogen bonded complexes of formamide and substituted benzoic acids and benzoates were studied in the light of substituent effect on intermolecular interactions. The analysis based on energy of interaction, geometry, QTAIM-derived properties of hydrogen bond critical point and energy of hydrogen bonds were made and discussed. The opposite effect of the substituent on hydrogen bo...

The bonding interaction between non-hydrogen-bonded (NHB) hydrogen atoms and the non-nuclear attractor (NNA) observed in cavity-bound anionic water clusters has been investigated using ab initio methods. The clusters range in size from four to ten water molecules and generally consist of several water molecules hydrogen-bonded in a ring, with two of these rings stacked such that the NHB hydroge...

Acting as hydrogen bond acceptors, heterocyclic compounds could interact with a hydrogen bond donor, where either the heteroatom or the p system is the bonding site. The hydrogen bonded complexes of heterocyclic compounds with methanol (MeOH) were studied using matrix isolation FTIR spectroscopy and theoretical calculations based on density functional theory. Four heterocyclic compounds, furan ...

BACKGROUND Trimethoprim [2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidine] is an antifolate drug. It selectively inhibits the bacterial dihydrofolate reductase (DHFR) enzyme. RESULTS In the crystal structures of trimethoprim (TMP)-hydrogen phthalate (1) and trimethoprim-hydrogen adipate (2), one of the N atoms of the pyrimidine ring is protonated and it interacts with the deprotonated carb...

Chromatography is a tool to measure molecular interactions, and computational chemistry is a tool to explain molecular interactions. Therefore, reversed-phase liquid chromatography of acidic drugs using a pentyland an octyl-bonded silica gels was quantitatively analyzed in silico. A model pentyland an octyl-bonded silica gel and a methanol phases were constructed for docking with acidic drugs. ...

The influence of ion dissolution in water is still controversial. The challenge posed to the existing concept of dissolved ions acting as water structure makers and structure breakers through recent studies calls for more experimental evidence. The temperature-dependent relaxation dynamics of water in bulk and in ionic salt solutions can give an idea about the hydrogen-bonded network and hence ...