Marina Yu. Balakina

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. These results are in a good agreement with the electron density distribution in the complexes. Additionally, ESR data obtained for the complexes upon oxidation is reported.

The Account of Molecular Multipole Moments in the Study of the Effect of Locally Anisotropic Polarizable Deformable Medium on the Nonlinear Optical Response of Incorporated Chromophore

The model suggested earlier by the author and allowing to describe the effect of locally anisotropic polarizable polymer matrix on the nonlinear optical response of incorporated chromophore is generalized to the case when a chromophore charge distribution is approximated by the multipole expansion including the terms up to octupole. The analytical formula for the local electric field, affecting the chromophore in a polymer electret, is obtained as a solution of electrostatic problem for a molecule in an ellipsoidal cavity, with corresponding boundary conditions taken into account. The approach exploits the special cavity ansatz according to which the cavity ellipsoid is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the medium. Using a self-consistent procedure, analytical formulas for induced dipole and quadrupole moments and the macroscopic frozen-in polarization are obtained. The relashionship of the microscopic molecular characteristics (electric moments and polarizabilities) with macroscopic electret polarization, as well as with external macroscopic parameters (applied electric field and permittivity of the medium) is established.

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. Analytical expressions for the dynamic electric moments of dipole chromophores and macroscopic polarization of a polymer electret at fundamental and second harmonic frequencies are obtained by using a computational scheme based on two self-consistency procedures. On the basis of the expressions for dynamic macroscopic polarization, the analytical formulas for linear, chi(j)(i(1)) (omega), and quadratic, chi(jk)(i(2)) (2omega), electric susceptibilities are obtained. The presented expressions establish the relationship between the molecular polarizabilities of chromophores and the macroscopic electrical properties of the polymer electret.

The Study of Electronic and Spatial Structure of Some Derivatives of 5-Phosphoranylidenbarbituric Acid and 5-Phosphoranylidenthiobarbituric Acid

Abstract Barbituric acid derivatives are known to participate in fortnation of ordered supramolecular structures with other pyrimidine dcrivatives. The properties of such species are dctumined by the structure and specific features of molecules which are the building blocks of such arrangements. Here, the results of MNDO study of spatial and electronic structure of a number of derivatives of 5-phosphoranylidenbarbituric acid (I) and S-phosphoranylidenthiobarbituric acid(11) arc presented (the substituents at P are: H, Me, Et, Ph; the substituents at N are: H, t-Bu, OH).