Yu. Yu. Enakieva

Nonlinear Optical Properties of Systems Based on Ruthenium(II) Tetra-15-crown-5-phthalocyaninate

The third-order nonlinear optical properties of the ruthenium (II) complex with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules (R4Pc)Ru(TED)2 were analyzed by means of the z-scanning technique. A solution of (R4Pc)Ru(TED)2 in tetrachloroethane was exposed to nanosecond laser pulses at a wavelength of 1064 nm. It was found that the third-order molecular polarizability of the Ru(II) complex is 4.5 × 10−32 cm4/C (esu). The polarizability per molecule increases by a factor of 3.6 when the single molecule occurs in a supramolecular assembly of (R4Pc)Ru(TED)2 complexes. The photoelectric and photorefractive properties at 1064 nm of polymer composites, determined by the supramolecular assemblies that exhibits optical absorption and photoelectric sensitivity in the near IR region, are reported.

Photorefractive IR-range composites on the basis of poly(vinyl carbazole) and ruthenium (II) tetra-15-crown-5-phthalocyanines

The photoelectric sensitivity and photorefractive properties at 1064 nm of composites consisting of poly(vinyl carbazole) (PVC), complexes of ruthenium(II) with tetra-15-crown-5-phthalocyanine and axially coordinated CO and CH3OH molecules (R4Pc)Ru(CO)(CH3OH), R4Pc2− is tetrakis-(1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion in the presence and absence of ferrocene were studied. The nature of the optical absorption within the near IR region in composites prepared from PVC and (R4Pc)Ru(TED)2 (TED is triethylenediamine) and (R4Pc)Ru(CO)(CH3OH) is discussed. It was established that the photoelectric, non-linear optical, and photorefractive properties of the polymer composite are determined by supramolecular ensemble composed of Ru(II) crown-phthalocyanines.

Photoelectric and photorefractive properties of composites based on poly(vinylcarbazole) and ruthenium(II) tetra-15-crown-5-phthalocyanine with axially coordinated pyrazine molecules

The photoelectric and photorefractive characteristics of composites based on poly(vinylcarbazole) containing crown-substituted ruthenium phthalocyanine with axially coordinated pyrazine molecules, (R4Pc)Ru(pyz)2 (where R4Pc−2 is [4,5,4′,5′,4″,5″,4″′,5″′-tetrakis-(1,4,7,10,13-pentaoxatridecamethylene)phthalocyanine ion], pyz is pyrazine), have been studied. Supramolecular ensembles of these complexes are responsible for optical absorption and photoelectric and photorefractive sensitivity in the near IR region. It has been found that under the action of a 1064-nm laser, the quantum efficiency of formation of mobile charge carriers, estimated from the photocurrent, corresponds to the Onsager equation when the quantum yield of formation of thermalized electron-hole pairs φ0 = 0.35 and the separation distance is 9.8 Å, irrespective of the (R4Pc)Ru(pyz)2 content. The kinetic curves of amplification of the information laser beam are bellshaped. This suggests that the photorefractive characteristics are underestimated owing to lowering to zero of the field E0 inside the layer as a result of buildup of space charge in the near-electrode space upon passing the dark current. The two-beam gain coefficient at an (R4Pc)Ru(pyz)2 content of 7 wt % is Γ = 62 cm−1 as estimated from the maximum of the bell-shaped curve.

Cation-promoted supramolecular assembly of bivalent metal tetra-15-crown-5-phthalocyaninates: Controlling the architecture of supramolecular aggregates

Cation-promoted supramolecular assembly of cobalt(II) and ruthenium(II) tetra-15-crown-5-phthalocyaninates is comparatively studied using the electronic absorption and infrared spectroscopy. The effects of the nature of the receptor and substrate on the architecture of the supramolecular aggregates formed are discovered. By contrast to Cu(II), Zn(II), and Ni(II) tetra-15-crown-5-phthalocyaninates, Co(II) and Ru(II) complexes are found to demonstrate sodium-potassium selectivity determined by the peculiarities of supramolecular structures formed upon the interaction with the cations.

Photorefractive polymer composites based on ruthenium (II) tetra-15-crown-5-phthalocyanate axially coordinating ethylisonicotinate molecules photosensitive in telecommunication range

Polyvinylcarbazole layers containing ruthenium (II) tetra-15-crown-5-phthalocyanate axially coordinating ethylisonicotinate molecules are found to have photoelectric and photorefractive sensitivity at 1550 nm. The effect is determined by the formation of supramolecular ensembles with the electronic optical absorption and photoelectric sensitivity in the near IR range up to 1600 or 1700 nm and nonlinear optical properties. A photorefractive two-beam coupling gain coefficient Γ measured at 1550 nm increases with an increase in the Ru(II) complex content in the polymer layer and equals 25 cm−1 at 6 wt %. The difference between the coupling gain and absorption coefficients (the actual gain coefficient) is Γ − α = 19 cm−1. Additionally introducing 3 wt % C60 fullerene into the layer does not change the characteristics, but the subsequent preirradiation (irradiation of the whole layer with a 633-nm laser beam in a range of the optical absorption of C60 before recording photorefractive curves) results in an increase in the gain coefficient at 1550 nm up to Γ = 48.3 cm−1 and, hence, in Γ − α = 42.3 cm−1. A time constant of the diffraction grating formation is about τ = 0.8 s.

Synthesis of meso -substituted porphyrins as precursors in creating highly ordered electroluminescent polymer materials

Methods of obtaining porphyrin-containing polymer materials that have electroluminescent properties are analyzed. Based on the data, a strategy for producing the most effective porphyrin precursors for the further synthesis of highly ordered polymer materials is developed. Synthetic approaches are found and two meso-substituted porphyrins, i.e., 5,15-diphenyl-10,20-dibromoporphyrin (1a) and 5,15-diethynylphenylporphyrin (2a), are synthesized.

Photorefractive IR-spectrum composites prepared from polyimide and ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated triethylenediamine molecules

It is established that supramolecular ensembles on the basis of the complex of ruthenium(II) with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules (R4Pc)Ru(TED)2, where R4Pc2− and TED denote 4,5,4′,5′,4″,5″4‴,5‴-tetraksis-(1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion and triethylenediamine molecule, respectively) make an aromatic polyamide layer photoelectrically sensitive to 1064-nm Nd:YAG laser radiation, exhibit third-order susceptibility, and, consequently, impart photorefractive properties to the polymer layer at this wavelength.

The influence of a solvent on the aggregation of ruthenium(II) tetra-15-crown-5-phthalocyaninate

The images of ensembles of ruthenium(II) complexes with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules, (R4Pc)Ru(TED)2, obtained on an atomic force microscope were analyzed. A comparison with the X-ray structure analysis data was performed to estimate the number and mutual arrangement (architecture) of molecules in supramolecular aggregates depending on the nature of the solvent and the temperature of solutions before casting. Storage at room temperature or heating of a solution of the complex in tetrachloroethane caused the formation of stable supramolecular “wires” 600 nm or more long. The z-scanning method was used to study the third-order nonlinear optical characteristics of solutions of the (R4Pc)Ru(TED)2 complex in tetrachloroethane.

Electrochemical Behavior of Complex Based on Ruthenium(II) Phthalocyaninate

The electrochemical reactions of ruthenium(II) bis(triethylenediamine)tetra-tret-butyl-phthalocyaninate in dimethylformamide are studied. Two reversible redox reactions on the platinum amalgam electrode are revealed at the potentials of −0.73 and −1.16 V (Ag/AgCl). Similarly to several other phthalocyanines, these redox reactions correspond to the successive transfer of two electrons to phthalocyanine ring. A new phenomenon, which has not been reported in the literature for phthalocyanines, namely, the cathodic polymerization, is discovered. Thus formed polymer is redox-active, and only one cathodic reaction at the potentials from −0.78 to −0.84 V (a shift in the cathodic direction takes place as the film thickness increases) is observed in the polymer. In addition, the polymer exhibits also considerable electron conductivity that enables one to perform various electrochemical reactions in a wide potential range on the electrode modified with the polymer.