Molecular docking, spectroscopic, and quantum chemical studies on aromatic heterocycle tetrakis(4-pyridyl)cyclobutane regioisomers: potential membrane-permeable inhibitors.

Aromatic heterocyclic compounds are commonly used in pharmaceutical and agrochemical products. The usage has been also extended in the production of corrosion inhibitors and electronic, opto-electronic, and NLO devices. The four regioisomers of the aromatic heterocyclic molecule, tetrakis(4-pyridyl)cyclobutane (tpcb), were optimized, and their chemical, electronic, and biological properties were examined. The rctt and rtct isomers were isolated and further characterized by the infrared and Raman spectroscopic techniques, and their vibrational modes with attention on important functional groups were discussed. The theoretical vibrational data obtained by DFT/B3LYP/6-311++G(d,p) were in very good agreement with the experimental ones. The occupancy, bond polarization, hybridization of the N-C bond, bonding characteristics between the pyridyl carbon and cyclobutane moiety, and distribution of electron density for the four tpcb isomers have been explored through NBO analysis. The inversion barrier of the cyclobutane moiety was obtained based on the optimized structures of the planar and puckered configurations of the isomers. The rccc isomer exhibited the least electrophilic character compared to the other tpcb isomers. The chemical significance of tpcb has been further explained by the wave function analyses. Molecular docking results revealed that the tpcb ligand would possess a potential anti-viral and anti-bacterial activity via a membrane-permeable mechanism.

Spectral characterization, thermochemical studies, periodic SAPT calculations and detailed quantum mechanical profiling various physico-chemical properties of 3,4-dichlorodiuron.

A set of experimental and computational techniques have been applied for the understanding of fundamental spectroscopic and reactive properties of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) compound. Experimental techniques employed in this study encompassed spectroscopic characterization via IR and Raman approaches, while optical properties were studied by measurements of UV/Vis spectra. The thermogravimetric analysis was also studied in order to analyze the stability of diuron. Aside from the determination of reactive properties, DFT calculations on isolated molecules were also used to thoroughly visualize and analyze spectroscopic properties such as IR and UV/Vis. MD simulations were used in order to understand interactions with water, while periodic DFT calculations were used in order to analyze band structure and density of states of the diuron crystal structure. Since the crystal structure of diuron is known, it was used in order to extract the relevant molecular pairs and investigate interactions between them by DFT and symmetry adapted perturbation theory approaches (SAPT).

Conformational profile, vibrational assignments, NLO properties and molecular docking of biologically active herbicide1,1-dimethyl-3-phenylurea.

1,1-Dimethyl-3-phenylurea (known as fenuron) which is a phenyl urea-based widely used herbicide exhibits interesting structural and conformational properties and a notable biological activity. A detailed analysis on the vibrational, molecular and electronic characteristics of fenuron has been carried out. Potential energy scans (PESs) performed at the B3LYP/6-311++G(d,p) level of theory predicted two possible minima corresponding to the optimized anti and synforms resulting from the internal rotation about the N-C bond. The presence of an auxochrome together with the interaction with DMSO solvent exhibited a blue shift corresponding to the C=O orbitals. Delocalization of HOMO and LUMO orbital facilitated the charge transfer effect in the molecule. The calculated HOMO-LUMO energies, chemical potential, energy gap and global hardness suggested a low softness value for the compound while its biological activity was described by the value of electrophilicity. Chlorine substitution in the phenyl ring influenced the orbital delocalization for ortho and para substitutions but that of meta remained unaffected. NLO properties were noticed to increase due to chlorine substitution in the parent molecule. The docking results suggested that the compound exhibits an inhibitory activity against mitochondrial ubiquinol-cytochrome-c reductase and can be developed as a potential anticancer agent.

Principal components analysis of Raman spectral data for screening of Hepatitis C infection.

In the current study, Raman spectroscopy is employed for the identification of the biochemical changes taking place during the development of Hepatitis C. The Raman spectral data acquired from the human blood plasma samples of infected and healthy individuals is analysed by Principal Components Analysis and the Raman spectral markers of the Hepatitis C Virus (HCV) infection are identified. Spectral changes include those associated with nucleic acidsat720 cm-1, 1077 cm-1 1678 (CO stretching mode of dGTP of RNA), 1778 cm-1 (RNA), with proteins at 1641 cm-1(amide-I), 1721 cm-1(CC stretching of proteins) and lipids at 1738 cm-1(CO of ester group in lipids). These differences in Raman spectral features of blood plasma samples of the patients and healthy volunteers can be associated with the development of the biochemical changes during HCV infection.

Facile preparation of g-C3N4 modified BiOCl hybrid photocatalyst and vital role of frontier orbital energy levels of model compounds in photoactivity enhancement.

A novel hybrid photocatalyst (g-C3N4/BiOCl) using g-C3N4 series modified with BiOCl having controllable mass ratios among the g-C3N4 and BiOCl molecules was prepared through hydrolysis process of Bi(3+) onto g-C3N4, using NaBiO3 and g-C3N4 produced from pyrolysis of melamine as the starting materials. The microstructure, morphology and optical properties of the synthesized g-C3N4/BiOCl were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflection spectroscopy (DRS) and photoluminescence (PL) emission spectroscopy. The photoactivity of the g-C3N4/BiOCl was evaluated by photodegradation of Rhodamine B(RhB) from water as a model toxic contaminant. The RhB photodegradation results revealed that the photocatalytic activity of g-C3N4/BiOCl hybrid photocatalyst (mass ratio of g-C3N4/BiOCl equals to 2:8) exhibits superior activity as compared with pure BiOCl under visible light irradiation. The effects of pH, initial concentration of the model contaminant as well as the catalyst recycling on the photoactivity (or photostability) of g-C3N4/BiOCl were investigated in depth as well. Quantum chemical calculations revealed that the photoactivity enhancement is strongly dependent on the active role played by the frontier orbital energy levels of dye molecules and a probable correlation of "structure-activity" relationship was established.

Photodegradation of Rhodamine B over unexcited semiconductor compounds of BiOCl and BiOBr.

This study reported, for the first time systematically, photodegradation of Rhodamine B (RhB) in aqueous solution over BiOCl and BiOBr semiconductors. Under visible light irradiation (λ>400 nm, λ>420 nm and λ=550±15 nm), RhB adsorbed on the surface of BiOCl and BiOBr was photosensitized and decomposed effectively over unexcited BiOCl and BiOBr. The degradation of Methyl Orange (MO) and Methylene Blue (MB) over BiOCl and BiOBr was investigated as well, and the results were compared with RhB photodegradation. It was found that MB molecules having the lowest LUMO could not be degraded by this process. Utilizing the quantum chemical calculation (Gaussian 03 program), the relationship between frontier orbital energy of selected dye molecules and photodegradation rate was established for the first time in this study.

Potential energy scans and vibrational assignments of cyclopropanecarboxylic acid and cyclopropanecarboxamide.

The structural stability and internal rotations in cyclopropanecarboxylic acid and cyclopropanecarboxamide were investigated by the DFT-B3LYP and the ab initio MP2 calculations using 6-311G** and 6-311+G** basis sets. The computations were extended to the MP4//MP2/6-311G** and CCSD(T)//MP2/6-311G** single-point calculations. From the calculations the molecules were predicted to exist predominantly in the cis (C=O group eclipses the cyclopropane ring) with a cis-trans barrier of about 4-6kcal/mol. The OCOH torsional barrier in the acid was estimated to be about 12-13kcal/mol while the corresponding OCNH torsional barrier in the amide was calculated to be about 20kcal/mol. The equilibrium constant k for the cis<-->trans interconversion in cyclopropanecarboxylic acid was calculated to be 0.1729 at 298.15K that corresponds to an equilibrium mixture of about 85% cis and 15% trans. The vibrational frequencies were computed at the DFT-B3LYP level. Normal coordinate calculations were carried out and potential energy distributions were calculated for the low energy cis conformer of the molecules. Complete vibrational assignments were made on the basis of normal coordinate calculations and comparison with experimental data of the molecules.

A family study of renal dysplasia.

A family study was undertaken to investigate genetic involvement in renal dysplasia, which is defined as abnormal metanephric differentiation. Probands were ascertained through the retrospective examination of necropsy records and the reevaluation of available material, which included microscopic examinations of the kidneys, gross descriptions of organs, and gross photographs. We obtained family histories and performed physical examinations and renal ultrasonography on parents and sibs of the 21 probands. In only one family a sibling with renal dysplasia was discovered; both the proband and the previous stillborn sib had renal dysplasia in association with posterior urethral values. Renal dysplasia could have resulted from urinary tract obstruction secondary to the urethral valves, with inheritance of the valves as the primary abnormality. However, we cannot exclude primary inheritance of the renal abnormality, perhaps with multifactorial determination with a threshold. The empiric recurrence risk of 2.1%, calculated from this family study, was statistically not significantly different from zero. We can assume, therefore, that the multicystic and aplastic types of renal dysplasia, which predominated in this study, are sporadic or rarely familial, but certain other types of renal dysplasia, identified in the literature as familial, probably carry a higher recurrence risk.

Effect of anthelmintic treatment on the development of resistance in sheep vaccinated or experimentally infected with Dictyocaulus filaria.

This investigation was undertaken to study the immune response of Iraqi sheep vaccinated with Dictyocaulus filaria larvae (Filiraq) and to determine the effect of tetramisole on the development of resistance to reinfection. The findings confirm the effectiveness of Filiraq in conferring protection against experimental infection with D filaria. However, the administration of anthelmintic four weeks after each vaccination interfered with the development of immunity. Termination of D filaria infection at 28 days by tetramisole treatment also prevented the immune response.