Русский
13 Oct 2017
Acknowledging publications • Publications

Journal of Molecular Structure, 2017, 1146, 554–561

A. M. Afanasenko, D. V. Boyarskaya, I. A. Boyarskaya, T. G. Chulkova, Y. M. Grigoriev, I. E. Kolesnikov, M. S. Avdontceva, T. L. Panikorovskii, A. I. Panin, A. N. Vereshchagin, M. N. Elinson

“Structures and photophysical properties of 3,4-diaryl-1H-pyrrol-2,5-diimines and 2,3-diarylmaleimides”

Journal of Molecular Structure, 2017, 1146, 554–561
DOI: 10.1016/j.molstruc.2017.06.048

source: http://www.sciencedirect.com/science/article/pii/S0022286017308293

Structural features of 3,4-diaryl-1H-pyrrol-2,5-diimines and their derivatives have been studied by molecular spectroscopy techniques, single-crystal X-ray diffraction, and DFT calculations. According to the theoretical calculations, the diimino tautomeric form of 3,4-diaryl-1H-pyrrol-2,5-diimines is more stable in solution than the imino-enamino form. We also found that the structurally related 2,3-diarylmaleimides exist in the solid state in the dimeric diketo form. 3,4-Diaryl-1H-pyrrol-2,5-diimines and 2,3-diarylmaleimides exhibit fluorescence in the blue region of the visible spectrum. The fluorescence spectra have large Stokes shifts. Aryl substituents at the 3,4-positions of 1H-pyrrol-2,5-diimine do not significantly affect fluorescence properties. The insertion of donor substituents into 2,3-diarylmaleimides leads to bathochromic shift of emission bands with hyperchromic effect.

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10 Oct 2017
Daybook

Delegation from Thailand

source: https://spbu.ru/press-center/press-relizy/princessa-tailanda-maha-chakri-sirindon-posetila-nauchnyy-park-spbgu

The delegation led by the Princess Maha Chakri Sirindhorn of Thailand has visited St Petersburg University. The delegation visited some of the Resource Centres. the Director of the Magnetic Resonance Research Centre (CMR) Petr Tolstoy has presented main research methods realized in CMR. Peter Tolstoy also has told about collaboration experience in research with the foreign scientists.
More about visit of the delegation

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04 Oct 2017
Process

September

Total in September 1938 service applications were carried out.
All together measured:

  • 1821  1H spectra
  • 296  13C spectra
  • 72  DEPT spectra
  • 22  COSY spectra
  • 22  NOESY spectra
  • 27  31Р spectra
  • 142  19F spectra

219 applications were carried out.

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25 Sep 2017
Daybook

Processing NMR spectra on mobile devices

source: http://resources.mestrelab.com/mnova-tablet-getting-started-guide/#prettyPhoto/13/
The Mnova NMR tablet application was designed for processing NMR spectra with touch-controlled Android and iPad devices. Free version of this application is available in Google Play store and App Store.

Starting Guide to Mnova tablet

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19 Sep 2017
Acknowledging publications

Tetrahedron Letters, 2017, 58, 3353–3357

S. Miltsov, V. Karavan, A. Misharev, G. Starova, J. Alonso-Chamarro, M. Puyol

“Unprecedented acid-catalyzed Wurtz-type coupling of meso-bromoindodicarbocyanine dyes”

Tetrahedron Letters, 2017,58, 3353–3357
DOI: 10.1016/j.tetlet.2017.07.043

source: http://www.sciencedirect.com/science/article/pii/S0040403917308894

meso-Bromosubstituted indodicarbocyanine dyes produce dimeric molecules, together with the debrominated species, under acid catalysis. The relationship between the dimerization and hydrodebromination routes depends on the aryl substitution of the dyes. A possible reaction mechanism is also proposed.

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05 Sep 2017
Daybook

Photo-session


A photo-session of the working process was held in the CMR.

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28 Aug 2017
Acknowledging publications • Publications

Appl. Magn. Reson., 2017, 48(7), 731-737

D.S. Mazing, A.V. Nikiforova, A.S. Osinin, V.A. Moshnikov, Yu.V. Bogachev, S.M. Sukharzhevskii

“Electron Paramagnetic Resonance Investigations of ZnSe:Mn Nanocrystals”

Appl. Magn. Reson., 2017, 48(7), 731-737
DOI: 10.1007/s00723-017-0898-5

Colloidal nanocrystals of ZnSe doped with Mn2+ were synthesized in non-polar medium using hot-injection technique. Obtained samples were characterized by means of photoluminescence and absorption spectroscopies. To confirm the incorporation of Mn2+ impurity and to reveal its state and localization, electron paramagnetic resonance (EPR) spectroscopy was employed. As a result, EPR spectra were analyzed and hyperfine splitting constant and g-factor for Mn2+ dopant were determined.

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15 Aug 2017
Acknowledging publications • Publications

J Therm Anal Calorim, 2017

M. Brusnikina, O. Silyukov, M. Chislov, T. Volkova, A. Proshin, A. Mazur, P. Tolstoy, I. Terekhova

“Effect of cyclodextrin complexation on solubility of novel anti-Alzheimer 1,2,4-thiadiazole derivative”

J Therm Anal Calorim, 2017
DOI: 10.1007/s10973-017-6252-1

source: https://link.springer.com/journal/10973

New 1,2,4-thiadiazole derivative displaying neuroprotective potential and high activity in the treatment of Alzheimer’s disease has been synthesized. The objective of this study was to improve the aqueous solubility of this drug-like compound by means of complex formation with native and hydroxypropylated β-cyclodextrins. To this end, aqueous solubility of 1,2,4-thiadiazole derivative was investigated in the presence of β-cyclodextrins. It was shown that the phase solubility diagrams are of Bs type demonstrating the initial increase in thiadiazole solubility in solutions of cyclodextrins (concentration up to 0.01 mol kg−1) followed by a solubility decrease due to the precipitation of the complexes formed. In comparison with β-cyclodextrin, hydroxypropyl-β-cyclodextrin displays more pronounced solubilizing action since it forms more stable complexes with thiadiazole. Solid complexes of 1,2,4-thiadiazole derivative with β-cyclodextrins were prepared by grinding and freeze-drying methods. DSC, TG, hot-stage microscopy, solid-state 13C MAS CP/TOSS NMR, powder X-ray diffractometry and FTIR spectroscopy were used to prove the existence of complexes in the solid state. Solubility of the obtained formulations was also examined. It was found that complexes of thiadiazole with hydroxypropyl-β-cyclodextrin exhibited higher solubility in phosphate buffer (pH 7.4) compared with pure thiadiazole and its complexes with β-cyclodextrin.

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09 Aug 2017
Acknowledging publications

Czech Polar Reports, 2017, 7, 1-10

E. Abakumov

“Characterisation of humic acids, isolated from selected subantarctic soils by 13C-NMR spectroscopy”

Czech Polar Reports, 2017, 7(1), 1-10
DOI: 10.5817/CPR2017-1-1

Soils of Antarctic considered as underestimated in terms of soils organic matter polls, organic remnants humification/mineralization rates and biogenic-abiogenic interactions. Humic acids of selected Sub Antarctic soils were investigated in terms of elemental and structural composition with special reference to evaluation of organic matter stabilisation degree and assessment of carbon species distributions in the molecules with use of solid state 13C-NMR spectroscopy. It was shown, that the prevailing of aliphatic compounds on the aromatic one is more pronounced in Antarctic soils than in Arctic ones. Average portion of the aromatic compounds is about 20% in humic acids, extracted from soils with evident ornitogenic effect from Fildes Peninsula (Norh-West Antarctic peninsula). This indicates that the role of humification precursors composition is the leading in the humification process. The stabilisation rate of the Antarctic HAs can be assessed as low and the potential risk of biodegradation of their molecules are high.

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28 Jul 2017
Acknowledging publications • Publications

Applied Catalysis: A, 2017, 542, 350-358

P.Mäki-Arvela, J.Zhu, N.Kumar, K. Eränen, A.Aho, J.Linden, J.Salonen, M.Peurla, A.Mazur, V.Matveev, D.Y.Murzin

“Solvent-free “green” amidation of stearic acid for synthesis of biologically active alkylamides over iron supported heterogeneous catalysts”

Applied Catalysis: A, 2017, 542, 350-358
DOI: 10.1016/j.apcata.2017.06.006

Stearoyl ethanolamine was synthesized by amidation of stearic acid with ethanolamine in solventless conditions. Iron containing heterogeneous catalysts supported on SiO2, Al2O3, Beta (BEA), ZSM-12 (MTW) and Ferrierite (FER) were used in this work. Sn-modified Ferrierite and H-Ferrierite were also studied for comparison. Fe-modified catalysts synthesized using solid state ion-exchange and evaporation impregnation methods, were thoroughly characterized with X-ray powder diffraction, scanning electron microscope, FTIR with pyridine, nitrogen adsorption, energy dispersive X-ray microanalysis and Mössbauer spectroscopy. The highest conversion was obtained with Fe-H-FER-20 at 140 °C in 1 h giving 61% conversion and 98% selectivity towards the desired amide. The catalytic performance in terms of turnover frequency per mole of iron was achieved with the catalyst exhibiting the largest amount of Fe3+ species, optimum acidity and a relatively low Brønsted to Lewis acid site ratio.

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