27.07.2017 Публикация пользователей

Chemistry - A European Journal Volume 23, Issue 47, Pages 11301–11311

Kristina S. Kisel, Alexei S. Melnikov, Elena V. Grachova, Pipsa Hirva, Sergey P. Tunik, IgorO. Koshevoy

Linking Re(I) and Pt(II) chromophores with aminopyridines: a simple route to achieve a complicated photophysical behavior

Chemistry - A European Journal Volume 23, Issue 47, Pages 11301–11311

DOI: 10.1002/chem.201701539

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The bifunctional aminopyridine ligands H2N–(CH2)n–4–C5H4N (n = 0, L1; 1, L2; 2, L3) have been utilized for the preparation of rhenium complexes [Re(phen)(CO)3(L1L3)]+ (13). 2 and 3 with NH2-coordinated L2/L3 were coupled with cycloplatinated motifs {Pt(ppy)Cl} and {Pt(dpyb)}+ to give the bimetallic species [Re(phen)(CO)3(μ-L2/L3)Pt(ppy)Cl]+ (4, 6) and [Re(phen)(CO)3(μ-L2/L3)Pt(dpyb)]2+ (5, 7). In solution, complexes 4 and 6 show 3MLCT{Re}-based emission at 298 K, which changes the parentage to 3IL(ppy) state at 77 K. The photophysical properties of compounds 5 and 7 display a pronounced concentration dependence presumably due to the formation of bimolecular aggregates. Analysis of the spectroscopic data, combined with TD-DFT simulations, suggest that the unconventional heteroleptic {Re(phen)}…{Pt(dpyb)} π-π stacking operates as a driving force for the ground state association. The latter, together with intra- and intermolecular energy transfer processes, determines the appearance of multiple emission bands and results in nonlinear relaxation kinetics of the excited states.

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24.07.2017 Публикация пользователей

Glass Physics and Chemistry Volume 43, August 2017, Issue 4, Pages 298–301

A. A. Razumtsev, Yu. S. Tver’yanovich, Fahd S. Khan, I. E. Kolesnikov, A. V. Kurochkin

Spectral properties of glass (15Ga2S3 · 85GeS2) doped with erbium

Glass Physics and Chemistry Volume 43, August 2017, Issue 4, Pages 298–301

DOI: 10.1134/S1087659617040137

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For chalcogenide glasses in the system (1 – x)[0.15Ga2S3 · 0.85GeS2xEr2S3, the absorption and luminescence spectra are investigated and the X-ray diffraction analysis is performed. A small shift in the position of the erbium absorption band with the increase of its content in the glass indicates the decrease of the effective charge on it, while the negligible changes in the angle position of the first sharp diffraction peak points to the constancy of the glass’s intermediate-order parameter. The possibility of describing the dependence of the intensity of erbium luminescence on its concentration using the earlier suggested equation has been discussed.

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04.07.2017 Публикация пользователей

Journal of Luminescence Volume 187, July 2017, Pages 26-32

I.E. Kolesnikov, D.V.Mamonova, E.Lähderanta , A.V.Kurochkin, M.D.Mikhailov

The impact of doping concentration on structure and photoluminescence of Lu2O3:Eu3+ nanocrystals

Journal of Luminescence Volume 187, July 2017, Pages 26-32

DOI: 10.1016/j.jlumin.2017.03.006

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Cubic Eu3+-doped Lu2O3 nanocrystals were synthesized via combined Pechini foaming method. Doping concentration effect on the structural and luminescence properties was studied. It was found that the increase of Eu3+ concentration leads to the growth of unit cell parameters and red shift of Raman lines. The optimal doping concentration and shape of emission lines were studied upon different excitation mechanism. Radiative and nonradiative transition rates and Judd-Ofelt parameters were calculated using the model of 4f–4f intensity theory. The type of multipolar interaction resulting in luminescence concentration quenching was determined.

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30.06.2017 Публикация пользователей

Vestnik SPbSU. Physics and Chemistry Volume 4 (62), issue 1, Pages 34–40

Unksov I.N., Bakulev V.M., Kasyanenko N.A.

Interaction of triethanolamine with high molecular DNA and its influence on formation of surfactant—DNA complexes

Vestnik SPbSU. Physics and Chemistry Volume 4 (62), issue 1, Pages 34–40

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Effect of triethanolamine (TEA) on high molecular calf thymus DNA in aqueous solution was studied by fluorescent spectroscopy and viscometry. It was shown that TEA prevents the interaction of the fluorescent dye DAPI with phosphate groups, but does not affect binding of the dye to the minor groove of DNA. The presence of TEA in solution does not induce any changes in the secondary structure of DNA. We estimated the decrease of the volume of DNA molecular coil in solution, which is induced by TEA. The destruction of DNA—surfactant complexes formed in solution was observed after the addition of TEA.

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12.06.2017 Публикация пользователей

Journal of Luminescence 192 (2017) 40–46

I.E. Kolesnikov, A.A. Kalinichev, M.A. Kurochkin, D.V. Mamonova, E.Yu. Kolesnikov, A.V. Kurochkin, E. Lähderanta, M.D. Mikhailov

«New strategy for thermal sensitivity enhancement of Nd3+-based ratiometric luminescence thermometers»

Journal of Luminescence 192 (2017) 40–46

DOI: 10.1016/j.jlumin.2017.06.024

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Accurate luminescence thermal sensing using nanophosphors that operate within biological windows is of great interest in bio- and nanomedicine. Here, we show that Nd3+-doped YVO4 NPs can act as nanothermometers in the second biological window upon 808 nm excitation. Significant enhancement of thermal sensitivity and temperature resolution was achieved by optimal choice of wavelengths for ratiometric thermal calibration. It was concluded that thermal calibration should be calculated using integral intensities. The obtained temperature uncertainty together with the emission and excitation lying in the biological windows open the venue to the possible application of Nd3+-doped YVO4 NPs for real time sub-tissue luminescence thermal sensing with a subdegree resolution.

 

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