• Mohammad Kassem, Maria Bokova, Andrey S. Tverjanovich, Daniele Fontanari, David Le Coq, Anton Sokolov, Pascal Masselin, Shinji Kohara, Takeshi Usuki, Alex C. Hannon, Chris J. Benmore and Eugene Bychkov*, Bent HgI2 Molecules in the Melt and Sulfide Glasses: Implications for Nonlinear Optics, Chem. Mater. 2019. DOI: 10.1021/acs.chemmater.9b00860

    Nonlinear optical (NLO) crystals are widely used in advanced photonic technologies for second harmonic and difference frequency generation (SHG and DFG, respectively), producing coherent light at frequencies where existing lasers are unavailable. Isotropic glasses do not exhibit SHG or DFG, except temporarily induced anisotropy under external stimuli. However, recent reports on glasses with chiral structural motifs show promising permanent NLO properties. We propose an alternative solution: hybrid molecular/network glasses with noncentrosymmetric HgI2 monomers. Mercury(II) iodide consists of linear HgI2 triatomic molecules in the vapor phase and in the yellow orthorhombic polymorph stable above 400 K. At lower temperatures, the tetragonal red form is composed of corner-sharing HgI4/2 tetrahedra forming a layered extended framework...

  • Dan Wang, Lihui Xiao, Peixia Yang,* Zhengrui Xu, Xiangyu Lu, Lei Du,* Oleg Levin, Liping Ge, Xiaona Pan, Jinqiu Zhang and Maozhong An, Dual-nitrogen-source engineered Fe–Nx moieties as a booster for oxygen electroreduction, J. Mater. Chem. A, 2019, 7, 11007-11015. DOI: 10.1039/C9TA01953G

    Metal–air batteries, particularly Zn–air batteries, have triggered considerable enthusiasm of communities due to their high theoretical power density. Developing highly active, cost-effective and alternative non-precious metal catalysts for the oxygen reduction reaction (ORR) is pivotal for popularizing zinc–air batteries. The rational design and synthesis of this type of catalyst are therefore critical, but it is still challenging to control the well-defined active sites as expected. Herein, we report a dual-nitrogen-source mediated route for synergistically controlling the formation of active Fe–Nx moieties that are embedded in the carbon matrix...

  • Maartje J.Levels, Cynthia M.Fehres, Lisa G.M. van Baarsen, Nathalie O.P. van Uden, Kristine Germar, Tom G.O'Toole, Iris C.J.Blijdorp, Johanna F.Semmelink, Marieke E.Doorenspleet, Arjen Q.Bakker, Mikhail Krasavin, Alexey Tomilin, Sophie Brouard, Hergen Spits, Dominique L.P.Baeten, Nataliya G.Yeremenko, BOB.1 controls memory B-cell fate in the germinal center reaction, J. Autoimmun. 2019. DOI: 10.1016/j.jaut.2019.04.011

    During T cell-dependent (TD) germinal center (GC) responses, naïve B cells are instructed to differentiate towards GC B cells (GCBC), high-affinity long-lived plasma cells (LLPC) or memory B cells (Bmem). Alterations in the B cell-fate choice could contribute to immune dysregulation leading to the loss of self-tolerance and the initiation of autoimmune disease. Here we show that mRNA levels of the transcription regulator BOB.1 are increased in the lymph node compartment of patients with rheumatoid arthritis (RA), a prototypical autoimmune disease caused by the loss of immunological tolerance. Investigating to what extent levels of BOB.1 impact B cells during TD immune responses we found that BOB.1 has a crucial role in determining the B cell-fate decision. High BOB.1 levels promote the generation of cells with phenotypic and functional characteristics of Bmem. Mechanistically, overexpression of BOB.1 drives ABF1 and suppresses BCL6, favouring Bmem over LLPC or recycling GCBC. Low levels of BOB.1 are sufficient for LLPC but not for Bmem differentiation...

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Репрезентативные публикации за июнь 2018 г.

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I.O. Koshevoy, V. Sivchik, Rajib Sarker, Zong-Ying Liu, Kun-You Chung, E.V. Grachova, A.J. Karttunen, and Pi-Tai Chou, Improvement of the photophysical performance of platinum cyclometalated complexes in halogen bonded adducts, Chem. Eur. J., 2018, 24, 11475–11484, doi: 10.1002/chem.201802182

Три группы люминесцирующих платиновых комплексов [Pt(C^N)(L)(Y)] были исследованы как акцепторы галогенной связи в отношении иодфторбензолов (IC6F5 и I2C6F4). Производные фосфиноцианида (L/Y = PPh3/CN) кристаллизуются совместно как с IC6F5, так и с I2C6F4. В то время как нативные комплексы являются довольно плохими люминофорами в твердом состоянии (Φ = 0,02-0,09), аддукты проявляют до 10-кратного увеличения интенсивности свечения с незначительным изменением энергии эмиссии. Наблюдаемое усиление квантовой эффективности объясняется главным образом совместным влиянием нековалентных взаимодействий, которые регулируют режим кристаллической упаковки.

Abstract

Three groups of luminescent platinum complexes [Pt(C^N)(L)(Y)] [C^N=benzothienyl‐pyridine (1), bezofuryl‐pyridine (2), phenyl‐pyridine (3); L/Y=DMSO/Cl (a), PPh3/Cl (b), PPh3/CN (c)] have been probed as halogen‐bond (XB) acceptors towards iodofluorobenzenes (IC6F5 and I2C6F4). Compounds 1 a and 2 a (L/Y=DMSO/Cl) afford the adducts 1 a⋅⋅⋅I2C6F4 and 2 a⋅⋅⋅I2C6F4, which feature I⋅⋅⋅Sbtpy/I⋅⋅⋅πbtpy and I⋅⋅⋅ODMSO/I⋅⋅⋅Cl short contacts, respectively. The phosphane‐cyanide derivatives 1 c and 2 c (L/Y=PPh3/CN) co‐crystallise with both IC6F5 and I2C6F4. None of the phpy‐based species 3 a3 c participated in XB interactions. Although the native complexes are rather poor luminophores in the solid state (Φem=0.023–0.089), the adducts exhibit an up to 10‐fold increase of the intensity with a minor alteration of the emission energy. The observed gain in the quantum efficiency is mainly attributed to the joint influence of non‐covalent interactions (halogen/hydrogen bonding, π–π stacking), which govern the crystal‐packing mode and diminish the radiationless pathways for the T1→S0 transition by providing a rigid environment around the chromophore.


Koronatov A.N., Rostovskii N.V., Khlebnikov A.F., Novikov M.S. Rh(II)-Catalyzed Ring Expansion of Pyrazoles with Diazocarbonyl Compounds as a Method for the Preparation of 1,2-Dihydropyrimidines, J. Org. Chem., 2018, doi: 10.1021/acs.joc.8b01228

В работе описана новая Rh(II)-катализируемая реакция диазокарбонильных соединений с 1,4-ди- и 1,4,5-тризамещенным пиразолами как первый пример внедрения карбеноида в простую связь N-N. Эта новая реакция представляет собой новый подход к 4-незамещенным 1,2-дигидропиримидинам, позволяющий осуществлять широкое варьирование функциональных групп в целевом гетероцикле. Согласно DFT расчетам, расширение пиразольного цикла протекает через последовательное образование связанного с металлом пиразолиевого илидая, свободного пиразолиевого илида и 1,5-диазагексатриена,претерпевающего 1,6-циклизацию на последней стадии домино процесса.

Abstract

A high yield synthesis of 1,2-dihydropyrimidines by the Rh(II)-catalyzed reaction of diazocarbonyl compounds with 1,4-di- and 1,4,5-trisubstituted pyrazoles is reported. This reaction represents the first example of a carbenoid insertion into a N–N bond and provides a novel approach to 4-unsubstituted 1,2-dihydropyrimidines with a broad range of functional group tolerance. According to DFT calculations, the pyrazole ring expansion proceeds via the sequential formation of the metal-bound pyrazolium ylide, metal-free pyrazolium ylide, and 1,5-diazahexatriene followed by 1,6-cyclization.).


Maria P. Sokolova, Michael A. Smirnov, Artemiy A. Samarov, Natalya V. Bobrova, Vitaly K. Vorobiov, Elena N. Popova, Elizaveta Filippova, Pavel Geydt, Erkki Lahderanta, Alexander M. Toikka Plasticizing of chitosan films with deep eutectic mixture of malonic acid and choline chloride, Carbohydrate Polymers, V. 197, 548–557, 2018, doi: 10.1016/j.carbpol.2018.06.037

Получены и исследованы пленки хитозана, содержащие глубокий эвтектический растворитель (DES) на основе малоновой кислоты и хлориде холина. Содержание DES варьировалось от 0 до 82 вес%. Анализ изотерм сорбции воды, данные атомно-силовой микроскопии и результаты Фурье ИК-спектроскопии подтвердили сильное взаимодействие хитозана с компонентами ДЭС. Пластифицирующий эффект DES отражают проведенные статические объемные механические измерения, термический анализ и количественное наномеханическое картирование (QNM). Введение DES в пленки хитозана приводит к температуре стеклования в области +2 - 2.3 °C. Результаты QNM подтверждают однородность пленок, содержащих до 75 мас.% DES.

Abstract

Chitosan (CS) films containing deep eutectic solvent (DES) based on malonic acid (MA) and choline chloride (ChCl) were successfully prepared by solution casting method by using DES content ranging from 0 to 82 wt%. A strong interaction of CS with the components of DES was demonstrated by analyses of water sorption isotherms, atomic force microscopy and FTIR results. The plasticizing effect of the MA and ChCl mixture on the CS matrix was shown by static bulk mechanical measurements, thermal analysis and quantitative nanomechanical mapping (QNM). Elongation at break increased from 3 to 62% at increase of DES content from 0 to 67 wt%, while further increase of DES content led to the decreasing of maximal elongation. Introduction of DES into CS films led to the appearance of glass transition temperature in the region +2 - -2.3 °C. QNM results indicated homogeneity of the films containing up to 75 wt% of DES.

Ответственный за содержание сайта Института химии: Роман Зумберов, r.zumberov@spbu.ru