The maximum absorption wavelengths of 31 azo dyes have been calculated by two comprehensive methods using the semiempirical quantum chemical method, PM3, and the weight decay based artificial neural network (WD-ANN) or the early stopping based artificial neural network (ES-ANN). The average absolute errors of WD-ANN and that of ES-ANN are 10.07 nm and 12.40 nm, respectively. These results are m...

The configuration of the gas phase molecule is obtained by density functional theory (DFT) geometry optimization using the generalized gradient approximation (GGA) functional as implemented in the Amsterdam Density Functional (ADF) software [1]. Obtained structures are adapted for adsorption on the surface as explained below. For this purpose we use the semi-empirical Parameterized Model number...

Using semiempirical PM3 method, a comparative quantum chemical estimation has been carried out of the energy of articaine adsorption on the surfaces of the following composite materials: silica-anaesthetic, polymer-anaesthetic, and silica-polymer-anaesthetic. It has been found that adsorption on silica surface takes place due to electrostatic and nonspecific interactions. The data of quantum ch...

The article presents extended computer investigations of various sulfate derivatives of riboflavin. A number of physicochemical parameters such as total energy, binding energy and formation heat were calculated via semi-empirical methods AM1 and PM3 for the different derivatives of riboflavin. Their analysis made it possible to determine the sequence of formation of sulfate derivatives--esterif...

A number of physicochemical parameters were calculated via semi-empirical methods AM1 and PM3 for the molecule of riboflavin at various protonation states. Their analysis made it possible to determine the acidicity of appropriate groups of this compound. The sequence of protons dissociation and accepting by the neutral molecule of riboflavin was determined. This methodology may be used to study...

The title compound, C(15)H(14)N(2)O(2), an azo dye, displays a trans configuration with respect to the N=N bridge. The dihedral angle between the aromatic rings is 0.18 (14)°. There is a strong intra-molecular O-H⋯O hydrogen bond. Geometrical parameters, determined using X-ray diffraction techniques, are compared with those calculated by density functional theory (DFT), using hybrid exchange-co...

The syntheses of novel hydrazono acyclic nucleosides similar to miconazole scaffolds are described. In this series of acyclic nucleosides, pyrimidine as well as purine and other azole derivatives replaced the imidazole function in miconazole and the ether group was replaced with a hydrazone moiety using phenylhydrazine. To interpret the dominant formation of (E)-hydrazone derivatives rather tha...