Ресурсный центр «Магнитно-резонансные методы исследования»

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.

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

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.

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.

A.S. Smirnov, D.N. Nikolaev, V.V. Gurzhiy, S.N. Smirnov, V.S. Suslonov, A.V. Garabadzhiu, P.B. Davidovich

“Conformational stabilization of isatin Schiff bases – biologically active chemical probes”

RSC Adv., 2017, 7, 10070-10073
DOI: 10.1039/c6ra26779c

Isatin Schiff base derivatives have a wide range of biological effects. Unfortunately, these compounds possess a serious topological shortcoming: the conformational E ⇆ Z interconversion. Two ways of conformation stabilization are reported here: complexation with metals that stabilize the E-conformer and substitution in the 4th position of the isatin core stabilizing the Z-form.