Theoretical studies on anthracene and a series of its derivatives were performed using the AM1 method and DFT. Based on B3LYP/6-31G(d) optimized geometries, the electronic, IR and NMR spectra of anthracene oligomers were calculated using the Indo/Cis, AM1 and B3LYP/6-31G(d) methods, respectively. The energy gaps of the oligomers decreased and the main absorptions in the electronic spectra of th...

A series of some novel 1,2,4-triazol-5(4H)-one derivatives were designed and synthesized under microwave irradiation via multistep reaction. The structures of 1,2,4-triazoles were confirmed by (1)H NMR, MS, FTIR, and elemental analysis. The antifungal activities of 1,2,4-triazoles were determined. The antifungal activity results indicated that the compounds 5c, 5f, and 5h exhibited good activit...

The Fourier transform gas phase (5000-400 cm), solid phase (4000-400 cm) infrared spectra as well as Raman spectra (3500-50 cm) of 1,3-dimethylbarbituric acid have been recorded. Quantum chemical calculations of energies, geometrical structure and vibrational wave numbers of 1,3-dimethylbarbituric acid have been made by density functional method with 6-31G(d,p) as basis set. The best level of t...

A neural-network-based approach was applied to correct the systematic deviations of the calculated heats of formation for 180 organic molecules and led to greatly improved calculation results compared to the first-principles methods [J. Chem. Phys. 119 (2003) 11501]. In this work, this neural network approach has been improved by using new descriptors obtained from natural bond orbital analysis...

Conformational analyses on 2-substituted (methoxy, vinyloxy, and acetoxy) methylenecyclohexanes have been performed computationally with HF, B3LYP, PBE0, and MP2 and the 6-31G(d) basis set. The global minimum for the methoxy substituent is an axial conformer. For the vinyloxy substituent, except with PBE0, an axial conformer is determined as the global minimum. The acetoxy substituent prefers t...

Condensation of 16-silatripyrrane with pentafluorobenzaldehyde under catalytic conditions followed by DDQ oxidation leads to 31,34-disilahexaphyrinoid--a four times reduced derivative of 31,34-disilahexaphyrin which contains two built-in silole units flanked by four tetrahedrally hybridized meso carbons. In the preferred folded macrocyclic conformation the silole rings remain perpendicular to e...

In order to investigate the biological activity of novel 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing pyridine moiety were synthesized under microwave assistant condition by multi-step reactions. The structures were characterized by 1H NMR, MS and elemental analyses. The target compounds were evaluated for their fungicidal activities against Stemphylium lycope...