T. N. Kopylova

Photonics of zinc complexes of 3,3′-bis(dipyrrolylmethenes)

We measure the spectral luminescence characteristics (absorption, fluorescence, lasing, phosphorescence, and luminescence excitation spectra; fluorescence and phototransformation quantum yields; lifetimes of long-lived radiation) and estimate the fluorescence radiation constants and lifetimes for new synthesized binuclear bihelical complexes of zinc(II) with 3,3′-bis(dipyrrolylmethenes) of different structure in liquid and solid solutions. We discuss possible applications of these compounds.

Spectral, luminescent, photochemical, and laser properties of a series of boron fluoride complexes of dipyrrolylmethenes in solutions

We have studied the spectroscopic and lasing characteristics of active media based on two synthesized boron fluoride complexes of alkyl-substituted dipyrrolylmethenes and the photostability of the complexes in comparison with complexes of this kind that were previously studied in the literature under identical excitation conditions. We have determined and analyzed conditions under which new compounds have either merits or drawbacks as compared to the known dye with respect to both lasing efficiency and resource characteristics.

Photolysis of Phenol and para -Chlorophenol by UV Laser Excitation

The photolysis of phenol and para-chlorophenol by irradiation with the fourth harmonic of a neodymium laser was examined using electronic absorption spectroscopy, fluorescence, and quantum-chemical techniques. It was found that the introduction of a chlorine atom into the phenol molecule increases the efficiency of photolysis of para-chlorophenol by excitation in the long-wavelength absorption band. The O–H and C–Cl bonds in the test compounds are ruptured via a predissociation mechanism in triplet states localized at the breaking bonds.

Theoretical and experimental investigation of photophysical properties of Zn(DFP SAMQ)2.

Theoretical calculations and experimental measurements were carried out for the investigation of spectroscopic and photophysical properties of Zn(DFP SAMQ)2 complex. The rate constant of intersystem crossing and the radiative rate constant were calculated using ab initio method. The rate constant of the internal conversion was estimated using the received calculated values and the experimental fluorescence quantum yield. It was shown that the main mechanism for the deactivation of the excited electronic energy of the first singlet excited state is the process of internal conversion.

Experimental and Theoretical Investigation of the Spectral and Luminescent Properties of Some Acridine Compounds

Complex (experimental and quantum-chemical) investigation of the spectral and luminescent properties of acridine, 9-aminoacridine, 2,7-dimethyl-9-ditolylaminoacridine, and their protonated forms was performed. The electronic absorption and fluorescence spectra of the acridine dyes were studied at room temperature in ethanolic solutions at different pH values and in other solvents of different chemical nature and polarity. The energies of the excited states, the deactivation rate constants for the excited states, and the dipole moments are presented, which were obtained by calculations using the method of intermediate neglect of the differential overlap with special spectroscopic parameterization.

Spectroscopic and laser characteristics of new efficient luminophores for a wide spectral range based on complexes of dipyrrolylmethene derivatives with difluorine borate

We have studied the spectral-luminescent, lasing, photochemical, and endurance characteristics of a series of new efficiently emitting difluorine borate complexes with dipyrrolylmethenes of different structures. Experimental data have been obtained in polar and nonpolar organic solvents and in solid polymer films involving the participation of silicate structures. We have discussed relations of the structure of investigated compounds and formed solvates with their optical characteristics, and have given guidelines on the use of particular compounds as active media of tunable lasers for determining spectral ranges.

Study of Structure and Spectral Characteristics of the Binuclear Zinc Complex with (E)-2-({2-(3-(pyridin-2-yl)-1H-1,2,4-triazol- 5-yl)phenylimino}methyl)phenol

A study of the structure and spectral properties of the compound (E)-2-({2-[3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl]phenylimino}methyl)phenol and its binuclear complex with zinc was carried out by the quantum-chemical calculations at a level of density functional theory. Within the framework of the time-dependent density functional theory were calculated electron spectra of both compounds, which gave good agreement with experiment, and was revealed the nature of the absorption bands in the visible and near UV region taking into account the solvent effect. Complete interpretation of the absorption bands in the infrared spectra of the complex and protonated ligand was given, and the frequency shift and changes in the intensities of IR bands of the ligand at the complex formation were analyzed.

Computational and experimental investigation of the optical properties of the chromene dyes.

Absorption and fluorescence spectra of the chromene 3 and chromene 13 dyes are studied experimentally and by density functional theory (DFT) including vibronic structure analysis. Vertical electronic absorption spectra are also calculated with the ab initio multiconfiguration method XMC-QDTP2. The vibronic progression for the S0 → S1 electronic transition is calculated within the Franck-Condon approximation including Dushinsky effect and promoting modes are analyzed. The laser-active solid-state media with high efficiency and long operation time are created implementing the studied dyes. The results of investigation indicate that the studied compounds can be used as effective laser dyes in the red range of visible light.

Polarization characteristics of stimulated emission of organic molecules when excited by intense XeCl laser radiation

We study the influence of the molecular structure, medium, and exciting-radiation parameters on the polarization, energy, and spectral characteristics of the emission of laser-active media based on the dicarboxylic derivative of p-terphenyl, rhodamine 101, and phenalemine 512. We found that the polarization of the stimulated emission of molecules when strongly excited under the conditions studied significantly depends on their structure, the pumping mode, the intensity and polarization of the exciting radiation, the shape and dimensions of the excited volume, and the phase state of the medium.

Spectral, luminescent, and lasing properties of 3-(benzothiazolyl-2)-7-hydroxy-and-8-hydroxycoumarins

The spectral and luminescent properties of 3-(benzothiazolyl-2)-7-hydroxy-and-8-hydroxycoumarins and their protolytic forms are studied experimentally and with the help of quantum-chemical calculations using the method of intermediate neglect of differential overlap with spectroscopic parameterization. The photophysical processes in these compounds are analyzed. The fluorescence of 3-(benzothiazolyl-2)-8-hydroxycoumarin is shown to be extremely weak due to intercombination conversion of the excitation energy. The introduction of a proton-accepting substituent next to the hydroxy group of the molecule (at position 8) leads to intramolecular proton transfer, resulting in formation of a zwitterion, with the probability of the proton transfer increasing in the excited S1 state. The lasing ability of the protolytic forms of the molecules under excitation with a XeCl excimer laser is studied. It is shown that the compounds have the highest lasing efficiency in the anionic form.