RESONANT IR ABSORPTION IN NANOTHIN MOLECULAR FILMS

This paper presents results of theoretical research in changed optical properties due to the presence of boundaries and changes of boundary parameters in nanofilm-molecular crystals. The energy spectrum of excitons and their spatial distribution along the axis limits (in layers) were found through analytical and numerical calculations. The relative permittivity of these ultrathin dielectric films was determined and the influence of boundary parameters on occurrence of discrete (by frequencies) and selective (per layers) absorption was analyzed. We found conditions for the appearance of the smallest number of resonant absorption peaks (absorption lines) in the border surfaces of the observed film structure

TRANSPORT PROPERTIES OF PENTACENE, HEXACENE AND THEIR BN ANALOGUES

We have investigated transport properties of higher acenes pentacene and hexacene and compared it with the transport properties of their BN analogues. Charge hopping from one structure to another was investigated through calculations of reorganization energies based on DFT and Marcus semiempiric approach, while the investigation of charge transport along the investigated structures was based on DFT calculations and non-equilibrium Green's function (NEGF) method. Attention was also paid to the energy separation between the lowest excited singlet (S1) and triplet (T1) state, which is quantity that is important for the field of thermally activated delayed fluorescence (TADF). The obtained results indicate that both groups of investigated structures have certain advantages and drawbacks. According to the reorganization energies and I-V characteristics, pentacene and hexacene have better properties, while from the aspect of TADF, BN analogues of pentacene and hexacene have better properties

Insights into the reactivity properties, docking, DFT and MD simulations of orphenadrinium dihydrogen citrate in different solvents

Experimental and theoretical investigations of a novel compound, Orphenadrinium dihydrogen citrate (ODC) are reported. Wavenumbers are assigned by means of vibrational spectroscopy. The stability in solvents was tested by adding water, DMSO, and methanol to different solvent models. The solvation energies are −21.65 (acetone), –22.49 (DMSO) and –22.76 (water) kcal/mol and are found to be good solvents for the ODC. ODC is more compact within DMSO and not compact in water and methanol in the period of 100 ns. RMSF analysis shows destabilization of the protein. MD simulations were performed to calculate the radial distribution functions to identify the most critical interactions with water molecules. MD simulations were also applied to obtain the temperature dependence of density. Analyzing the electron density between all atoms, noncovalent interactions between fragments have been identified and quantized

FT-IR, FT-Raman and NMR characterization of 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate and investigation of its reactive and optoelectronic properties by molecular dynamics simulations and DFT calculations

The FT-IR and FT-Raman spectra of the synthesized compound, 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate is recorded and analyzed. Optimized molecular structure, wave numbers, corresponding assignments regarding 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate has become screened tentatively as well as hypothetically using Gaussian09 program package. Natural bonding orbital assessment has been completed with a reason to clarify charge transfer or conjugative interaction, the intra-molecular re-hybridization and delocalization of electron density within the molecule. The NMR spectral assessment had been made choosing structure property relationship by chemical shifts along with the magnetic shielding effects regarding the title compound. The first and second hyperpolarizabilities were calculated. The calculated first order hyperpolarizability is commensurate with the documented worth of very similar derivatives and could be an interesting object for more experiments on nonlinear optics. Local reactivity properties have been investigated using average local ionization energies and Fukui functions. Investigation of optoelectronic properties encompassed calculations of reorganization energies and hopping rates of charge carriers within the framework of Marcus semi-empiric approach. The docked ligand title compound forms a stable complex with CDK inhibitors and gives a binding affinity value of −9.7 kcal/mol and molecular docking results suggest that the compound might exhibit inhibitory activity against CDK inhibitors

Pyridoxylidene aminoguanidine and its copper(II) complexes – Syntheses, structure, and DFT calculations

<p>Two nitrate salts of the well-known, and due to its significant biological activity very important, compound pyridoxylidene aminoguanidine (PLAG) were obtained in the form of single crystals. Thus this ligand is structurally characterized for the first time. In addition, the first data on the structure of a Schiff base of aminoguanidine with the active form of vitamin B₆, i.e. pyridoxal-phosphate, of the formula PLPAG·HCl·2H₂O, are presented. Two new square-pyramidal Cu(II) complexes of PLAG were synthesized and their physicochemical and structural properties analyzed. In these complexes, PLAG is coordinated as a zwitter-ion, in a tridentate <i>ONN</i> manner, via the oxygen atom of the deprotonated phenolic OH-group and nitrogen atoms of the azomethine and imino group of the aminoguanidine moiety. For the first time it was possible to make a comparative analysis of the structural properties of ligand salts and the coordinated ligand, so the effects of coordination could be unequivocally pointed out. Common fragments encountered in ligand structures were compared by half-normal probability plots. Density functional theory calculations have been conducted in order to gain insight into reactive properties of the investigated molecules. Molecular electrostatic potential, average local ionization energy surfaces, and Fukui functions have been calculated in order to obtain further information on the reactive properties.</p

4-[(4-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid, a newly synthesized amide with hydrophilic and hydrophobic segments: Spectroscopic characterization and investigation of its reactive properties

The FT-IR and FT-Raman spectra of 4-[(4-acetylphenyl)amino]-2- -methylidene-4-oxobutanoic acid were recorded. The vibrational wave numbers were computed by DFT quantum chemical calculations and the vibrational assignments were realized using the potential energy distribution. The theoretically predicted geometrical parameters were in agreement with the XRD data. Determination and visualization of molecule sites prone to electrophilic attacks were performed by mapping the average local ionization energies (ALIE) to the electron density surface. Furthermore, determination of possible reactive centres of title molecule was realized by calculation of the Fukui functions. Intramolecular non-covalent interactions were also determined and visualized. In addition, prediction of molecule sites possibly prone to autoxidation was performed by calculation of the bond dissociation energies (BDE), while the stability of the title molecule in water was assessed by calculation of radial distribution functions (RDF) obtained after molecular dynamics (MD) simulations. The docked title ligand compound forms a stable complex with insulin receptor kinase and gives a binding affinity of –10.2 kcal* mol-1

Spectroscopic characterization of 4-2-(5-Ethylpyridin-2-yl)ethoxybenzaldehyde oxime and investigation of its reactive properties by DFT calculations and molecular dynamics simulations

The molecular structure, vibrational wave numbers, NLO, NBO, MEP and HOMO, LUMO analysis of 4-2-(5-Ethylpyridin-2-yl)ethoxybenzaldehyde oxime were reported. The theoretically predicted geometrical parameters are in agreement with the XRD data. Using NBO analysis the change in the electron density in the anti-bonding orbital and stabilization energies have been calculated to give clear evidence of stabilization in the hyper-conjugation of hydrogen bonded interactions. The calculated first hyperpolarizability is 46.761 times that of the standard NLO material urea. From molecular electrostatic potential plot, phenyl ring, pyridine ring and oxygen atoms are the most electronegative regions and the hydrogen atom in the OH group is the most electropositive region. ALIE surfaces and Fukui functions have been calculated in order to obtain information related to the local reactivity properties of the title molecule. Intra-molecular non-covalent interactions have also been searched for. In order to investigate autoxidation and degradation properties we have calculated bond dissociation energies for all single acyclic bonds. To determine which atoms have the most pronounced interactions with water molecules we have conducted molecular dynamics simulations and calculated radial distribution functions. Molecular docking studies suggest that the title compound can be a lead compound for developing new anti-cancerous drug

HEAT CONDUCTIVITY OF SOME LAYERED STRUCTURES

Callaway model with Debye’s approximation of phonon states density is used to determine heat conductivity of some layered structures of Nb1-x Snx Se2 type. In total relaxation time, a term proportional to squared frequency, typical for layered structures, is kept. Electronic heat conductivity is determined by Wiedemann–Franz law and BRT model for superconductors. In both cases, heat conductivity is determined numerically in the range of 2 – 200 K. Results correlate well with experimental data.Callaway model with Debye’s approximation of phonon states density is used to determine heat conductivity of some layered structures of Nb1-x Snx Se2 type. In total relaxation time, a term proportional to squared frequency, typical for layered structures, is kept. Electronic heat conductivity is determined by Wiedemann–Franz law and BRT model for superconductors. In both cases, heat conductivity is determined numerically in the range of 2 – 200 K. Results correlate well with experimental data

Interactions of Schiff base compounds and their coordination complexes with the drug cisplatin

There is a complex interplay between the structural and other physicochemical properties of new compounds and the molecules in living organisms.</p