Oxo-dipeptides and thio-dipeptides are built via condensation between couples of amino acids and amino thioacids, the latter with the carbonyl oxygen replaced by an sp(2) sulfur. We explored via in silico methods (PBE0/6-31G(d,p) and PBE0/6-311G(d,p)) all the possible combinations and built 800 dipeptides, whose structures were fully optimized. Maps of condensation energies are presented to hig...

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...

The inhibiting effect of methionine and tyrosine on the corrosion of iron is researched electrochemically in 0.1M HCl, Quantum chemical calculations were performed. The level of HF with the 6–311G(d,p) basis set for methionine and tyrosine. Corrosion current density has been determined by polarization measures and the inhibition effect was calculated. With an increase in the concentration of in...

In this paper we study the small Na+N (N 12) cationic clusters fragmentation channels, with all electronic calculations performed at the B3LYP/6–311G+(d,p) DFT level of theory. For these cluster sizes, we obtain for all neutral, cationic, bi-cationic and anionic species the optimized geometries, total energies and electronic properties such as the adiabatic ionization potentials, electron affin...

The structures of the D(3h)-symmetric molecules dodecafluoro-1,6-distibatriptycene and dodecafluoro-1,6-dibismatriptycene [Z2(C6F4)3 (Z = Sb, Bi)] have been determined in the gas phase by electron diffraction, using the SARACEN method, with restraints obtained from quantum chemical calculations. Several methods of ab initio and density functional theory geometry calculations have been performed...

In this article we provide a data package containing the topology files and parameters compatible with the CHARMM22 force field for thirteen non-natural amino acids. The force field parameters were derived based on quantum mechanical (QM) calculations involving geometry optimization and potential energy surface scanning at the HF 6-31G(d) and HF 6-311G(d,p) levels of theory. The resulting energ...

3-(3-Dimethylammonio)propylammonio propanoate bromide (1), 4-(3-dimethylammonio)propylammonio butanoate bromide (2), and 5-(3-dimethylammonio)propylammonio pentanoate bromide (3) have been obtained in reaction of 1,1-dimethyl-1,3-propylenediamine with 3-bromopropionic acid, ethyl 4-bromobutyrate and 5-bromovaleric acid, respectively. The products have been characterized by FTIR, Raman and NMR s...

A one-step synthetic procedure using the reaction of potassium bis(oxalato)platinate(II) with the corresponding N6-benzyladenosine derivative (nL) provided the [Pt(ox)(nL)₂]∙1.5H₂O oxalato (ox) complexes 1-5, involving the nL molecules as monodentate coordinated N-donor ligands. The complexes were thoroughly characterized by elemental analysis, multinuclear (¹H, ¹³C, ¹⁵N, 1¹⁹⁵Pt) and two dimens...

Theoretical calculations have been performed on three model reactions representing the reduction of hydrogen peroxide by ebselen, ebselen selenol, and ebselen diselenide. The reaction surfaces have been investigated at the B3PW91/6-311G(2df,p) level, and single-point energies were calculated using the 6-311++G(3df,3pd) basis set. Solvent effects were included implicitly with the conductor-like ...

The fabrication of a non-doped red organic light-emitting device (OLED) has been developed using naturally occurring curcumin as an emissive layer of OLED. In this research, the electroluminescent spectrum (EL) of curcumin as a donor-acceptor-donor (D-A-D) chromophore was obtained at wavelength of 612 nm. Also, the maximum external quantum efficiencies (EQE) for this device was measured and fou...