Molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (IHB) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (nPBD) (n = 2, 3, or 4) have been investigated by means of density functional theory (DFT) calculations. Energy differences for all possible nPBD cis-enol forms of isomers with respect to the most stable form of the correspondin...

background and aims. studies have shown decreased bond strength of composite resin to human and bovine bleached enamel. this study evaluated the effect of sodium ascorbate and delayed bonding on the bond strength of two adhesive systems to bleached enamel. materials and methods. the labial surfaces of 150 sound bovine incisor teeth were abraded with abrasive paper. the teeth were randomly divid...

molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (ihb) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (npbd) (n = 2, 3, or 4) have been investigated by means of density functional theory (dft) calculations. energy differences for all possible npbd cis-enol forms of isomers with respect to the most stable form of the corresponding isomer have been...

abstract statement of problem: bleaching systems with different concentrations and applications are widely used to improve the visual appearance of the teeth, but one of the complications of these materials is reduction of bond strength for immediately bonding to the bleached enamel. objectives: the aim of this study was to evaluate the influence of using different modified hydrogen peroxide bl...

the solvatochromism of fluoresceine and its derivatives was studied in solvents of different hydrogen bond donor (hbd), hydrogen bond acceptor (hba), donor number (dn) and acceptor number (an) by their uv-vis spectra. results showed that position, intensity and shape of absorption bands change with type of solvent. these changes can be rationalized by solvatochromic parameters such as α, β, et ...

in this work, a molecular dynamics simulation of the transport of water - methanol mixture through the single wall carbon nanotube (swcnt) is reported. methanol and water are selected as fluid molecules since water represents a strongly polar molecule while methanol is as an intermediate between polar and strongly polar molecules. some physical properties of the methanol-water mixture such as r...

Heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by Pt/A1203, was carried out in thirteenvarious solvents (four alcoholic solvents, six aprotic polar solvents and three non polar solvents) at 25 °C.Single-parameter correlations of logk vs. normalized polarity parameter (ETN), hydrogen-bond acceptorbasicity (p), hydrogen-bond donor acidity (a) and dipolarity/polarizibility (it*) d...