A series of substituted 2-(2-hydroxyphenylimino) phenolic (salen) derivatives (1-4) have been synthesized and their structures of obtained compound were characterized by analytical, FT-IR, UV-Vis and C{H}-NMR experimentally. The geometry structure optimization, frequencies (IR), NMR, electronic character, frontier molecular orbital (HOMO-LUMO) and first static hyperpolarizability (βtot) studies...

Quantum mechanical calculations are performed on 116 conformers of the protein ubiquitin (Lange et al., Science 2008, 320, 1471–1475). The results indicate that the heat of formation (HOF), dipole moment, energy of the frontier orbitals HOMO and LUMO, and HOMO-LUMO gap fluctuate within their corresponding ranges. This study thus provides a link between the conformational dynamics of a protein a...

The geometric and electronic structures of all-trans polyacetylene (PA) molecule in neutral, cationic, and anionic states have been studied theoretically by density functional theory method at the B3LYP/6-31+G* level. The results show that both the geometric and electronic structures of the PA molecule are sensitive to the external electric field (EF). For neutral PA molecule, with the increase...

The stability,optimized structure,binding energy,dipole moment and electronic gap of adamantane, C10H16,incorporating cage-centered small atoms and ions (X@cage, where X = Li, Be, Na, Mg, He, and Ne) have been studied at the B3LYP hybrid level of theory. A wide variety of atoms and ions can be encapsulated by adamantane. The complexes are more stable for smaller and more highly charged metallic...

The synthesis and characterization of 1, 3-bis [(furan-2-yl) methylene] urea (BFMU) and 1, 3-bis [furan-2-yl) methylene] thiourea (BFMT) have been reported by our research team. The effects of solvents polarity on their electronic transition energies (HOMO-LUMO) and associated qualitative structure activity relationship parameters (i.e. log P, ionization energies and global hardness) were inves...

The influence of the insertion/addition of a benzene ring to the natural nucleic acid bases on the local aromaticity of the so-called size-expanded (xN, with N being adenine, guanine, cytosine, and thymine) bases is examined. To this end, the local aromaticity of the six- and five-membered rings in both the natural bases and their benzoderivatives is determined using HOMA, NICS, aromatic fluctu...