Synthesis of D-π-A'-π-A Chromophores with Quinoxaline Core as Auxiliary Acceptor and Effect of Various Silicon-Substituted Donor Moieties on Thermal and Nonlinear Optical Properties at Molecular and Material Level.

Novel D-π-A'-π-A chromophores with quinoxaline cores as auxiliary acceptors and various donor moieties (aniline, carbazole, phenothiazine, tetrahydroquinoline) containing bulky -butyldimethylsilyloxy (TBDMSO) groups and tricyanofuranyl (TCF) acceptors with bulky cyclohexylphenyl substituents were synthesized via eight- to nine-step procedures, and their photo-physical and thermal properties were investigated. The values of the chromophores' first hyperpolarizabilities were calculated in the framework of DFT at the M06-2X/aug-cc-pVDZ computational level; the effect of the introduction of the TBDMSO group into the donor fragment is shown to be inessential, as this group is not coupled to the π-conjugated system of the chromophore. The chromophore with the tetrahydroquinoline donor has a first hyperpolarizability value of 937 × 10 esu, which is the highest for the studied chromophores.

Composing NLO Chromophore as a Puzzle: Electrochemistry-based Approach to Design and Effectiveness.

A series of D-π-A, D-π-D'-π-A, D-π-A'-π-A nonlinear optical chromophores with vinylene π-electron bridges or bridges with π-deficient/π-excessive heterocyclic moieties along with the corresponding precursors D-vinylene, D-π-D', D'-π-A, D-π-A' and A'-π-A are synthesized and studied both experimentally and computationally. The effect of the heterocycle in the π-electron bridge on the oxidation/reduction potentials and the energy gap (ΔE ) is investigated in detail. The properties of the D-π-A'(D')-π-A chromophores are shown to correlate with those of building blocks: the oxidation potential is determined by the D-vinylene, and the reduction potential is determined by A'(D')-π-A truncated compounds.

Redox trends in cyclometalated palladium(ii) complexes.

A series of diverse binuclear and mononuclear cyclometalated palladium(ii) complexes of different structure was investigated by electrochemical techniques combined with density functional theory (DFT) calculations. The studies including cyclic and differential pulse voltammetry, X-ray structure analysis and quantum chemical calculations revealed a regularity of the complexes oxidation potential on the metal-metal distance in the complexes: the larger Pd-Pd distance, the higher oxidation potentials. The reduction potentials feature unusually high negative values while no correlation depending on the structure could be observed.

Nonlinear optical response of a polymer electret with incorporated organic chromophores.

An analytical approach aimed at modeling the nonlinear optical (NLO) response of a polymer electret with incorporated organic dipole chromophores is extended to the dynamic case. The approach allows the effect of the locally anisotropic, polarizable, deformable polymer matrix on the chromophore NLO response to be accounted for. The method exploits the original cavity ansatz according to which the virtual cavity occupied by the chromophore in the polymer matrix is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor.

Scaling law for second-order hyperpolarizability in poly(triacetylene) molecular wires.

Poly(triacetylenes) are rodlike molecules with electrons delocalized over a one-dimensional path. We show that they exhibit a power-law dependence of the second-order hyperpolarizability gamma on the monomer unit n for short molecules and a smooth saturation toward a linear increase in longer molecules. The power law of gamma?n(a) with a approximately 2.

Polymer matrix effects on the nonlinear optical response of incorporated chromophore: new analytical models.

A new approach aimed at the modeling of the nonlinear optical (NLO) response of a dipole chromophore incorporated into a locally anisotropic, deformable, polarizable polymer matrix is suggested. The general continuum methodology is used with a specific cavity ansatz being employed; the cavity is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the polymer medium. The suggested ansatz allows the electrostatic boundary value problem to be solved analytically, and the local field experienced by the chromophore in the polymer electret to be found.

[Inhibitory effect of lead ions on cells of some strains of Pseudomonas species bacteria].

The inhibition effect of ionic lead on membrane ATPase activity, transmembrane potential (delta psi) and permeability level of the Pb-sensitive P. fluorescens B894 and Pb-resistant P. fluorescens B4252 bacteria cells have been studied.

[Inducible surface proteins from some strains of Pseudomonas species bacteria while adapting to cobalt].

The possibility of increasing resistance of some Pseudomonas strains to cobalt at adaptation to monotonous increasing its concentration was studied. Strains Pseudomonas fluorescens B5242 and Pseudomonas fluorescens B894 are capable to increase its resistance in such conditions via inducible synthesis of protective surface proteins. The molecular masses of such proteins were 55.

Monodisperse poly(triacetylene) oligomers extending from monomer to hexadecamer: joint experimental and theoretical investigation of physical properties.

A series of monodisperse Et3-Si-end-capped poly(triacetylene) (PTA) oligomers ranging from monomer to hexadecamer was prepared by a fast and efficient statistical deprotection-oxidative Hay oligomerization protocol. The PTA oligomers exhibit an increasingly deep-yellow color with lengthening of the pi-conjugated backbone, feature excellent solubility in aprotic solvents, and exhibit melting points up to > 22 degrees C for the hexadecameric rod. This new dramatically extended oligo(enediyne) series now enables to investigate the evolution of the physico-chemical effects in PTAs beyond the linear 1/n versus property regime into the higher oligomer region where saturation becomes apparent.

[Effect of thallium of ATP-ase activity and transmembrane potential in bacteria].

Effect of thallium (TlNO3) on the ATPase activity and transmembrane potential (Dj) of bacteria with different levels of resistance to this metal has been studied. The hypothesis has been made that the resistance biochemical mechanism is based on the energy transformation systems in the cell.

[Transmembrane potential and ATP-ase activity of the plasma membrane of bacteria exposed to heavy metals].

Effect of heavy metals (gold, zinc and cadmium) on the ATPase activity and transmembrane potential (delta psi) as integral index of bacterial cells membrane processes intensity has been studied. It was shown that studied membrane systems of bacteria are very sensitive to the action of heavy metals and they can serve as indicators of resistance of bacterial cultures.

[Bacterial cell membrane ATPase in assessing heavy metal toxicity].

Sensitivity of membrane ATPase to heavy metals was studied in bacterial stains Bacillus cereus ATCC 14579, Bacillus cereus B4368, and Alcaligenes eutrophus CH34 was studied. The inhibition effects of metals on membrane ATPase ranged in the same order (Au > Cu > Zn > Co > Mn) as their effects on the growth of cultures. It is suggested that membrane ATPase is one of the targets for the action of heavy metal ions within the microbial cell and, therefore, its activity may serve as an indicator of their toxicity.