The ring-current aromaticity of the bicalicene molecule arises, in spite of the 16 π carbon perimeter, from strong local diatropic circulations on the two pentagonal rings, as shown by current-density maps computed at the ipsocentric RHF/6-311G** and DFT/6-311G** levels of theory. Conjugated-circuit models cannot capture this pattern of circulation as it arises from 'ionic' contributions in a v...

Cálculos B3LYP usando bases até 6-311G(3d2f,3p2d) foram utilizados para a previsão acurada de propriedades termoquímicas relacionadas à reação de dissociação trans-HONO(XA’) HO(XP) + NO(X P). Um estudo sistemático da influência da base foi realizado e resultados B3LYP foram comparados a dados experimentais e a outros resultados teóricos, calculados usando os métodos G2, G2MP2, CBS e métodos ab ...

Fourier transform Raman and infrared spectra of 4-hydroxy-2,6-dimethyl pyrimidine (HDMP) were recorded and interpreted by comparison with respective theoretical spectra calculated using HF and B3LYP methods. The HDMP equilibrium geometry with Cs symmetry, harmonic vibrational frequencies, infrared and Raman intensities were determined using HF/6-311G and B3LYP/6-311G level of theories. The band...

3-Phenylamino-4-phenyl-1,2,4-triazole-5-thione was synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. Density functional theory calculations of the structure, natural bond orbitals, atomic charge distributions and thermodynamic functions of the title compound were performed at B3LYP/ 6-311G** and PBE1PBE/6-311G**levels of theory, respectively. NPA atom...

Application of topological properties and graph theory to benzenoid hydrocarbons allowed us to construct an effective approach interpreting ring current formation in molecules when exposed to an external magnetic field. Transformation of unexcited canonical structures for molecules of 34 benzenoid hydrocarbons into circuit structures and then to directed circuit structures allowed us to define ...

Some new N-benzyl phosphoramidic acid (4-methylphenyl)ester derivatives were synthesized and characterized by 1H, 13C, 31P NMR and IR spectroscopy and elemental analysis. The structure of [(C6H5)(CH3)CH-NH]P(O)(p-OC6H4CH3)2 (2) was investigated. This compound exists in polymeric zigzag chains in the crystalline lattice produced by hydrogen bonding built from two alternating independent molecule...

An X-ray and a theoretical study of the structure of the isoniazid derivative N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate (1) are reported. In this work, we will report a combined experimental and theoretical study on the molecular structure, vibrational spectra and energies of N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate. The calculated parameters are i...

enaminones are those structures made up three various functional groups including carbonyl, alkeneand amine groups which arelocated along with each other in a conjugate fashion. these compoundsare of much attention due to special characteristics and numerous applications. in the paper, sixvarious enaminone structures were theoretically optimized and after concluding, were compared withequivalen...

In the current work, chemical reactivity of some trivalent phosphorus derivatives R2PR? towards polyhaloalkanes CCl3POR ? ?2 was studied by quantum method DFT/B3LYP/6-311G(d,p). The introduction substituents for derivative and polyhaloalkane allowed us to have more information on these reactions. On one hand, calculation indices derived from DFT/B3LYP/6-311G(d,p) gapLUMO ? HOMO show that organo...

A computational modeling of the protonation of corannulene at B3LYP/6-311G(d,p)//B3LYP/6-311G(d,p) and of the binding of lithium cations to corannulene at B3LYP/6-311G(d,p)//B3LYP/6-31G(d,p) has been performed. A proton attaches preferentially to one carbon atom, forming a sigma-complex. The isomer protonated at the innermost (hub) carbon has the best total energy. Protonation at the outermost ...