[Show abstract][Hide abstract] ABSTRACT: An intensely emitting crystalline europium(III) complex with cinnamic acid [Eu(Cin)3]n and exhibiting triboluminescent properties is synthesized. It is established that the measured photo- and triboluminescence spectra are identical for the above polymeric non-centrosymmetric complex and are determined by the characteristic f-f luminescence of the europium(III) ion.
[Show abstract][Hide abstract] ABSTRACT: We have synthesized heterometallic complexes based on a copolymer of acrylic acid with butyl methacrylate (BMAC) with a composition [Eu x Bi(1 - x)-BMAC]. These complexes have several emission bands in the visible range. At room temperature, in complexes with a content of Eu(III) of 30-40%, intense white luminescence appears.
Optics and Spectroscopy 02/2014; 116(3). · 0.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Crystalline and strongly luminescent complexes of europium hexafluoroacetylacetonate and trifluoroacetate with triphenylphosphine oxide of Eu(HFAA)3 · 2TPPO and [Eu(TFA)3 · 2TPPO(H2O)]2 composition are synthesized that demonstrating triboluminescent properties. It is established that the measured photoluminescence and triboluminescence spectra of these noncentrosymmetric complex compounds are identical, due to the characteristic f- f-luminescence of the europium(III) ion.
[Show abstract][Hide abstract] ABSTRACT: Interaction between Eu(III) tris(β-diketonates) and ammonia vapors increases the luminescence of Eu(III). A mechanism for the effect of analyte molecules on the intensification of Eu(III) luminescence is proposed. The mechanism includes the displacement of water molecules from the coordination sphere of europium(III).
[Show abstract][Hide abstract] ABSTRACT: Electronic structure of guanidine, diphenylguanidine, their protonated forms, and guanidinium chloride have been studied by X-ray photoelectron spectroscopy and quantum-chemical modeling. From the derived geometry parameters and electronic structure, the effect of protonation on localization of the electron density has been revealed. The lines in the valence region of the X-ray photoelectron spectra have been assigned.
Russian Journal of General Chemistry 01/2014; 84(1). · 0.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The yttrium, lanthanum (III), and terbium (III) chelates, Y(NO 3 ) 3 (OP(N(CH 3 ) 2 ) 3 ) 3 ,
Y(C 6 H 5 COCHCOCF 3 ) 2 NO 3 (OP(C 6 H 5 ) 3 ) 2 , La(NO 3 ) 3 (OP(N(CH 3 ) 2 ) 3 ) 3 , Tb(NO 3 ) 3 (OP(N(CH 3 ) 2 ) 3 ) 3 were studied by theoretical and experimental physical chemical methods in order to describe spectral and structural features, characteristics of the electronic structure. The structure and spectral properties of these complexes were simulated in the vacuum approximation within the cluster approach by quantum-chemical methods of the density functional theory DFT/TDDFT with the hybrid exchange-correlation functional PBE0, the Stuttgart pseudopotential ECP-MWB with the appropriate basis sets as well as with a number of the standard basis sets. A description of features of the obtained experimental electronic absorption and luminescence spectra, vibrational and X-ray photoelectron spectra was performed on basis of the simulation results. Conclusions were done about the most probable centers of ionization in these molecular systems. The effects of structure changes on the spectral characteristics of these chelates were determined. Assumptions were suggested on the relationship between the ligand electronic structure, the main vibration modes and parameters of the X-ray photoelectron spectra of these chelate complexes. An explanation of the luminescence mechanism was done, a possibility of the luminescence control was discussed in nanostructured materials based on the studied rare earth chelates. To determine effects of mechanical stress, the simulated displacement of molecular layers was performed in the cluster (La(NO 3 ) 3 (OP(N(CH 3 ) 2 ) 3 ) 3 ) 4 , an assessment was done of the dislocation effects on the electronic, spectral and thermodynamic properties of this molecular system.
[Show abstract][Hide abstract] ABSTRACT: We have studied the filamentation of femtosecond laser pulses (λ = 800 nm, ~42 fs pulse duration) in poly(methyl methacrylate) doped with 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2- dioxaborine and the associated photomodification of the material. The results demonstrate that multiple filamentation occurs at pulse energies above 5 μJ. At a pulse energy of 1.5 mJ, it is accompanied by supercontinuum generation. The average filament length in PMMA is 9 mm and the filament diameter is ~10 μm. An incident power density of ~1012 W cm-2 ensures inscription of the filament pattern owing to two-photon photochemical processes. Preliminary exposure to continuous light at λ = 400 nm enables an ordered filament pattern to be written.
[Show abstract][Hide abstract] ABSTRACT: The concentration dependence of spectral-luminescence properties of solutions boron difluoride dibenzoylmethanate (DBMBF2) in benzene and chloroform has been studied through stationary and time-resolved emission spectroscopy methods. The formation of J-aggregates in the solution of DBMBF2 in chloroform has been revealed and a crystalline adduct of DBMBF2 with benzene has been obtained. A bright blue adduct luminescence is due only to the luminescence of J-aggregates, unlike the crystals of DBMBF2, for which the luminescence of excimers and J-aggregates has been observed. The quantum chemistry simulation of geometric and electronic structure of the DBMBF2 С6Н6 solvate has been performed, and the absorption spectra of DBMBF2 and it is adduct have been calculated.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 10/2013; 120C:119-125. · 1.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In order to research features of the excited singlet and triplet electronic states and the luminescence mechanism of the chelate yttrium complexes Y(NO3)3(HMPA)3 and Y(BТFА)2NO3(ТPPО)2 (HMPA – hexamethylphosphotriamide, BТFА – benzoyltrifluoroacetonate-anion, ТPPО – triphenylphosphine oxide), the electronic structure of the complexes in the ground and excited states was studied by quantum chemical methods. The structure and spectral properties of the complexes were simulated by the density functional methods DFT and TDDFT with the hybrid exchange-correlation functional PBE0, and the Stuttgart pseudopotential and basis ECP-MWB in the vacuum approximation. The explanation was done of features of the experimental electronic absorption and luminescence spectra. The studied molecular systems are shown to be polar, their dipole moment is 9,6 and 5,10 D, respectively. According to the simulations, the conclusions were done on the mechanism of luminescence, possibility of the luminescence control in nanostructured materials was discussed.
[Show abstract][Hide abstract] ABSTRACT: Nonlinear optical properties of dibenzoylmethanate boron difluoride crystals have been discovered. The optical properties of bulk crystals and microcrystals are different. The bands observed in the luminescence spectrum of the bulk crystals can be interpreted as follows: the narrow band at 530 nm is ascribed to second harmonic generation; the wide band at 460 nm is caused by multiphoton excitation processes. A specific difference in nonlinear optical properties of the bulk crystals and microcrystals is the absence of the band related to the multiphoton excitation processes in the luminescence spectrum of microcrystals. Therefore, in the case of dibenzoylmethanate boron difluoride crystals, a size dependence of not only luminescent, but also of nonlinear optical properties, is discovered for the first time, which is promising for the development of new optical materials.
Optics and Spectroscopy 04/2013; 114(4). · 0.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In order to explain features of the excited singlet and triplet electronic states and the luminescence mechanism of the lanthanum (III) complex La(NO3)3(HMPA)3 (HMPA - hexamethylphosphortriamide), the electronic structure of the complex in the ground and excited states was studied by quantum chemical methods. The structure and spectral properties of the complex were simulated by the density functional methods DFT and TDDFT with hybrid exchange-correlation functional PBE0, and the Stuttgart pseudopotential and basis ECP-MWB in the vacuum approximation. The explanation was done of features of the experimental electronic absorption and luminescence spectra. To determine an effect of mechanical stress, the simulated shift of the molecular layers was performed in the (La(NO3)3(HMPA)3)4 cluster. The estimation was given for the effect of dislocation on electronic structure of the molecular system. According to the simulations, the conclusions were done on the mechanism of luminescence, possibility of the luminescence control in nanostructured materials was discussed.
Modern Problems of Science and Education. 03/2013;
[Show abstract][Hide abstract] ABSTRACT: The optical properties of a new photorecording polymer based on 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2-dioxaborine have been investigated. This material is found to change its absorption coefficient and refractive index in the visible range under illumination with a wavelength λ = 405.9 nm. This circumstance makes it possible to record static holograms with a spatial frequency up to 2500 lines/mm, a diffraction efficiency above 60%, and a lifetime more than 6 months. A dynamic change in the effective refractive index of this material under 405.9-nm irradiation is found, due to which one can form control optical elements of the light-light type with a modulation frequency up to 50 Hz in it.
Optics and Spectroscopy 04/2012; 112(4). · 0.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The atomic structure of ((C2H5)4N)2TeBr6 crystals (a = 17.930(8) Å, b = 11.133(5) Å, c = 15.022(7) Å, β = 109.28(9)°, space group C2/c, Z = 4, ρcalcd = 2.036 g/cm3) has been studied by X-ray diffraction. The ((C2H5)4N)2TeBr6 crystal structure consists of isolated [TeBr6]2− anions and ((C2H5)4N)+ cations. The electronic and geometric aspects that influence the luminescence and thermochromic properties of the complex
have been considered.
[Show abstract][Hide abstract] ABSTRACT: The electronic absorption spectra and electronic structure of yttrium quinaldinates with an island and polymer structure were
studied. A comparative analysis of the energies of the singlet and triplet excited states, the total energies of complex compounds
in the ground state, and Mulliken’s bond overlap populations was performed by the TD-DFT method with the B3LYP density functional.
For yttrium quinaldinate with a polymer structure, the distance between the highest occupied and lowest unoccupied orbitals
was found to be longer than for the compound with an island structure. The transition energies were shifted to the blue region,
which accounts for the higher stability of the polymer compound.
[Show abstract][Hide abstract] ABSTRACT: Using the tellurium(IV) complex compounds as an example, we study the interrelation between the geometric structure and spectral luminescence properties. We find that, in the series of compounds of Te(IV), which are characterized by the island octahedral coordination of Te(IV) ions, the luminescence intensity depends on the degree of distortion of the Te(IV) coordination polyhedron, the Stokes shift, and the energy of the luminescence transition. We revealed that the considered series of Te(IV) compounds possess reversible thermochromic properties.
Optics and Spectroscopy 01/2011; 110(5). · 0.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It has been shown that difluoro(dibenzoylmethanato)boron ((dbm)BF2) can be absorbed on silica gel in the form of fluorescent monomers and dimers with the emission properties that change in
the presence of vapors of volatile organic compounds, such as ethanol, acetone, toluene, and meta-xylene. Fluorescence quenching was observed for the (dbm)BF2 monomers and dimers in the case of ethanol and acetone, whereas the formation of fluorescent exciplexes with monomers and
enhancement of the dimer fluorescence were observed in the case of toluene and meta-xylene. Results of the quantum-chemical calculations of the structure of the (dbm)BF2 monomer complex with the matrix and toluene and (dbm)BF2 dimers with matrix are presented.
High Energy Chemistry 01/2011; 45(4):315-319. · 0.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The crystal structure of 2,2-difluoro-4-(9H-fluorene-2-yl)-6-methyl-1,3,2-dioxaborine (C13H9COCH × COCH3BF2) (1) is determined. The structural and spectral luminescent characteristics of 1 are compared to those of its electron analogue:
2,2-difluoro-4-(4-phenylphenyl)-6-methyl-1,3,2-dioxaborine (C6H5C6H4 × COCHCOCH3BF2).
Journal of Structural Chemistry 01/2011; 52(1):221-225. · 0.58 Impact Factor