Mikherdov A. S., Novikov A. S., Kinzhalov M. A., Boyarskiy V. P., Starova G. L., Kukushkin V. Yu., Halides Held by Bifurcated Chalcogen-Hydrogen Bonds. Effect of µ_(S,N-H)Cl Contacts on Dimerization of Cl(carbene)PdII Species, Inorg. Chem. 2018, 57 (6), pp 3420–3433

В работе описан новый тип нековалентных взаимодействий — бифуркатные халькогенные/водородные связи µ(Сhal,E-H)X. Изучено влияния данного типа взаимодействий на димеризацию диамикарбеновых комплексов палладия.

Abstract

The reaction of cis-[PdCl₂(CNCy)₂] (1) with thiazol-2-amines (2–10) leads to the C,N-chelated diaminocarbene-like complexes [PdCl{C(N(H)4,5-R₂-thiazol-2-yl)NHCy}(CNCy)] (11–14; 82–91%) in the case of 4,5-R₂-thiazol-2-amines (R, R = H, H (2), Me, Me (3), −(CH₂)₄– (4)) and benzothiazol-2-amine (5) or gives the diaminocarbene species cis-[PdCl₂{C(N(H)Cy)N(H)4-R-thiazol-2-yl}(CNCy)] (15–19; 73–93%) for the reaction with 4-aryl-substituted thiazol-2-amines (R = Ph (6), 4-MeC₆H₄ (7), 4-FC₆H₄ (8), 4-ClC₆H₄ (9), 3,4-F₂C₆H₃ (10)). Inspection of the single-crystal X-ray diffraction data for 15–17 and 19 suggests that the structures of all these species exhibit previously unrecognized bifurcated chalcogen–hydrogen bonding μ_(S,N–H)Cl and also Pd^II···Pd^II metallophilic interactions. These noncovalent interactions collectively connect two symmetrically located molecules of 15–17 and 19, resulting in their solid-state dimerization. The existence of the μ_(S,N–H)Cl system and its strength (6–9 kcal/mol) were additionally verified/estimated by a Hirshfeld surface analysis and DFT calculations combined with a topological analysis of the electron density distribution within the formalism of Bader’s theory (AIM method) and NBO analysis. The observed noncovalent interactions are jointly responsible for the dimerization of 15–19 not only in the solid phase but also in CHCl₃ solutions, as predicted theoretically by DFT calculations and confirmed experimentally by FTIR, HRESI-MS, ¹H NMR, and diffusion coefficient NMR measurements. Available CCDC data were processed under the new moiety angle, and the observed μ_(S,E–H)Cl systems were classified accordingly to E (E = N, O, C) type atoms.

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Nikolay Solovyev, Evgenii Drobyshev, Geir Bjørklund, Yaroslav Dubrovskii, Roman Lysiuk, Margaret P. Rayman Selenium, selenoprotein P, and Alzheimer's disease: is there a link? Free Radical Biology and Medicine, 2018

Обзор о роли селена и селенопротеина Р в патологии болезни Альцгеймера.

Abstract

The essential trace element, selenium (Se), is crucial to the brain but it may be potentially neurotoxic, depending on dosage and speciation; Se has been discussed for decades in relation to Alzheimer's disease (AD). Selenoprotein P (SELENOP) is a secreted heparin-binding glycoprotein which serves as the main Se transport protein in mammals. In vivo studies showed that this protein might have additional functions such as a contribution to redox regulation. The current review focuses on recent research on the possible role of SELENOP in AD pathology, based on model and human studies. The review also briefly summarizes results of epidemiological studies on Se supplementation in relation to brain diseases, including PREADViSE, EVA, and AIBL. Although mainly positive effects of Se are assessed in this review, possible detrimental effects of Se supplementation or exposure, including potential neurotoxicity, are also mentioned. In relation to AD, various roles of SELENOP are discussed, i.e. as the means of Se delivery to neurons, as an antioxidant, in cytoskeleton assembly, in interaction with redox-active metals (copper, iron, and mercury) and with misfolded proteins (amyloid-beta and hyperphosphorylated tau-protein).

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Nikita Kuznetsov, Peixia Yang, Georgy Gorislov, Yuri Zhukov, Vladimir Bocharov, Valery Malev, Oleg Levin Electrochemical transformations of polymers formed from nickel (II) complexes with salen-type ligands in aqueous alkaline electrolytes, Electrochimica Acta, 2018

В работе изучен метод получения наноструктурированного гидроксида никеля из плёнок полимерных комплексов. Полученные материалы демонстрируют высокую каталитическую активность по отношению к реакциям электроокисления спиртов в щелочных растворах.

Abstract

The polymeric nickel complexes with salen-type ligands can serve as useful materials for a range of applications, including catalytic systems and energy storage devices. Despite the fact that electrochemical properties of such complexes were investigated in detail in non-aqueous solutions, there has still remained scarce information about their behavior in aqueous systems. This work is devoted to studying such properties of poly[Ni(salen)] films in aqueous alkaline electrolytes. By combination of electrochemical methods with X-ray photoelectron and Raman spectroscopy it was shown that the redox transformations observed result in ligand exchange and formation of nickel hydroxide thin films deposited on the working electrodes. The obtained material consists of uniformly distributed nanoparticles with the characteristic size of about 10 nm. Catalytic activity of the produced modified electrodes in reactions of ethanol and methanol oxidation, as well as their ability to be charged and discharged reversibly for more than 1000 cycles, makes them promising materials for applications in catalytic and energy storage devices.