В журнале The Journal of Physical Chemistry Letters   (IF=6,71) опубликована статья  с участием сотрудников Института к.х.н. О.И. Рогожниковой (с.н.с, ГИТР), Д.В. Трухина (снс, ГИТР),  к.х.н. А.А. Кужелева (нс, ЛОЭ), д.ф.-м.н., проф. Е.Г. Багрянской (Директор НИОХ), к.х.н. В.М. Тормышева (снс, рук. группы ГИТР)

Multiquantum Counting of Trityl Radicals

J. Phys. Chem. Lett. 2020, 11, 15, 6286–6290
Publication Date:July 15, 2020

Abstract

We demonstrate a series of multitrityl radical compounds where accurate spin-counting by pulsed electron paramagnetic resonance (EPR) can be achieved at X-band (9 GHz) frequencies, even for molecules with very short and flexible linkers. Multiquantum filter experiments, well-known from NMR, were used to count the number of coupled electron spins in these compounds. The six pulse double quantum filter sequence used in EPR for distance determinations in biradicals was used. Precise phase settings to separate higher quantum coherences were achieved by an arbitrary waveform generator. The trityl radicals have narrow spectral width so that homogeneous excitation of all spins by the pulses is possible. The transversal relaxation times of higher quantum coherences of trityl radicals are sufficiently long to allow their detection. Our results on model compounds show the potential of this approach to determine oligomeric states in protein complexes in their native environment using functionalized trityl spin labels.

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В  журнале Crystal Growth & Design   (IF=4,089) опубликована статья  с участием сотрудников Института к.х.н. Е.А. Чулановой н.с, ЛГеТС), Е.А. Радюш (мнс, ЛОЭ),  к.х.н. И.К. Шундриной (снс, ЛЭАСМ), д.х.н. И.Ю. Багрянской (внс, рук. группы ГРСА), к.х.н. Н.А. Семёнова (снс, ЛГеТС) и д.х.н. А.В. Зибарева (завлаб, ЛГеТС) 

Lewis Ambiphilicity of 1,2,5-Chalcogenadiazoles for Crystal Engineering: Complexes with Crown Ethers

Cryst. Growth Des. 2020, 20, 9, 5868–5879
Publication Date:July 13, 2020

Abstract

The cocrystallization of 1,2,5-chalcogenadiazoles (chalcogen E = S, Se, and Te) with cyclic polyethers 18-crown-6 (18-c-6) and dibenzo-18-crown-6 (db-18-c-6) yielded the molecular complexes characterized by X-ray diffraction and thermogravimetry/differential scanning calorimetry techniques together with density functional theory (DFT) calculations and quantum theory of atoms in molecule and natural bond orbitals analysis. The complexes are bound by multiple secondary bonding interactions, the most important of which reflects the Lewis ambiphilicity of 1,2,5-chalcogenadiazoles and includes charge transfer from O atoms of the ethers onto E atoms of the chalcogenadiazoles (i.e., chalcogen bonding), and the back-donation from E to O. For complexes of 18-c-6, the DFT-calculated energies of bonding interactions correlate with the melting temperatures of the complexes, as well as with the atomic number of E and the size of the E-associated σ-holes but not with the maximum of molecular electrostatic potential at the σ-holes. Taking into account the previous results, the Lewis ambiphilicity of 1,2,5-chalcogenadiazoles may be used for applications in crystal engineering.

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В журнале Applied Organometallic Chemistry   (IF=3,14) опубликована статья  с участием сотрудников Института д.х.н. И.И. Олейника (в.н.с, ЛЭАСМ) и  к.х.н. И.В. Олейник (с.н.с, ЛЭАСМ) 

Achieving strictly linear polyethylenes by the NNN‐Fe precatalysts finely tuned with different sizes of ortho‐cycloalkyl substituents

Applied Organometallic Chemistry 
Volume34, Issue11, November 2020, e5937

Abstract

Six examples of newly synthesized α,α’‐bis (aryl)‐2,3:5,6‐bis (pentame thylene)pyridyliron complexes [2,3:5,6‐{C₄H₈C(NAr)}₂C₅HN]FeCl₂ (Ar = 2‐(c‐C₅H₉)‐6‐MeC₆H₃ Fe1 , 2‐(c‐C₆H₁₁)‐6‐MeC₆H₃ Fe2 , 2‐(c‐C₈H₁₅)‐6‐MeC₆H₃ Fe3 , 2‐(c‐C₅H₉)‐4,6‐Me₂C₆H₂ Fe4 , 2‐(c‐C₆H₁₁)‐4,6‐Me₂C₆H₂ Fe5 , 2‐(c‐C₈H₁₅)‐4,6‐Me₂C₆H₂ Fe6 ; c refers as cyclic), on activation with methylalumoxane (MAO) or modified MAO (MMAO), exhibit high activities towards ethylene polymerization, producing strictly linear polyethylenes with terminal vinyl groups. The catalytic performances are systematically investigated along with various polymerization parameters as well as the microstructures of resultant polyethylenes. The steric hindrances of ortho‐cycloalkyl substituents of N_imino‐aryl groups significantly affect the activities of the corresponding iron precatalysts as well as the microstructures of resultant polyethylenes: higher steric hindrance the ortho‐cycloalkyl substituents, higher activity the iron precatalyst, lower molecular weight the resultant polyethylenes. Experimental observations are additionally supported by the computational study. The resultant polyethylenes exhibited excellent hydrophobicity.

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Funding Information

• Bureau of International Cooperation of Chinese Academy of Sciences. Grant Numbers: 121111KYSB20190005, No. 121111KYSB20190005
• Russian Foundation for Basic Research. Grant Numbers: 18‐53‐80031, No. 18‐53‐80031
• Russian State funded budget project. Grant Numbers: 0302‐2019‐0007, No. 0302‐2019‐0007
• National Natural Science Foundation of China. Grant Number: No. 21871275 and 51861145303

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В журнале Polymers   (IF=3,426) опубликован обзор  с участием  д.х.н., проф. Е.Г. Багрянской

Gérard Audran , Elena G. Bagryanskaya , Sylvain R. A. Marque and Pavel Postnikov

Polymers, 2020, 12 (7), 1481;

https://doi.org/10.3390/polym12071481

 

Abstract

Nitroxide-mediated polymerization is now a mature technique, at 35 years of age. During this time, several variants have been developed: electron spin capture polymerization (ESCP), photoNMP (NMP2), chemically initiated NMP (CI-NMP), spin label NMP (SL-NMP), and plasmon-initiated NMP (PI-NMP). This mini-review is devoted to the features and applications of these variants. 
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Keywords: nitroxide mediated polymerization; CI-NMP; SLNMP; PI-NMP; NMP2; ESCP

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New Variants of Nitroxide Mediated Polymerization   

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В журналк Dyes and Pigments (IF 4,018) опубликована статья с участием сотрудников
Института: к.х.н. А.Д. Куимова (мнс, ЛОЭ), к.х.н. К.С. Беккер (снс, ЛОЭ), И.Р. Коскина (мнс ЛОЭ), А.С. Сониной (нс, ЛОЭ), к.х.н. И.К. Шундриной (снс, ЛЭАСМ), к.х.н. М.С. Казанцева (зав.лаб, с.н.с ЛОЭ)

2-((9H-fluoren-9-ylidene)methyl)pyridine as a new functional block for aggregation induced emissive and stimuli-responsive materials

Abstract

Highly-emissive mechanofluorochromic (MFC) organic solids changing their emission colors upon exposure to mechanical stimuli are highly demanded for various practical applications. In this work we introduced a planarizable by intramolecular N⋯H bond 2-((9H-fluoren-9-ylidene)methyl)pyridine fragment featuring an Aggregation-Induced Emission Enhancement and, particularly, MFC property for its bithiophene derivative. A two compounds, 2-((9H-fluoren-9-ylidene)methyl)-5-(5-phenylthiophen-2-yl)pyridine (FTP) and 2-((9H-fluoren-9-ylidene)methyl)-5-([2,2′-bithiophen]-5-yl)pyridine (FTT) were synthesized and fully characterized. In liquid solution both compounds are low emissive, however in the solid state they exhibit the photoluminescence quantum yield of 33% and 13% for FTP and FTT, respectively. Remarkably, the powder of FTT demonstrates a self-reversible mechanofluorochromism: the emission spectrum red-shifts after the grinding or pressurization and it recovers during one-day of storage without any treatment. The powder X-ray diffraction and differential scanning calorimetry revealed the reversible phase transition under temperature and mechanic stimuli. Analysis of molecular structure shows that in the gas phase FTT has a planar geometry while in the solid state it loses the flatness due to the crystal environment. Our results speak in favor of the increase of FTT planarity under the pressure to be responsible for the observed mechanofluorochromism.

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В журнале Chemistry - A European Journal   (IF=5,16) опубликована статья  с участием сотрудника Института к.х.н. А.М. Агафонцева (с.н.с, ЛТС)

Ratiometric detection of ATP by fluorescent cyclophanes with bellows‐type sensing mechanism

Aleksandr M. Agafontsev, Tatiana A. Shumilova, Aleksandr S. Oshchepkov, Frank Hampel, Evgeny A Kataev

Chemistry - A European Journal, 

Volume 26 , Issue 44 Special Issue: Young Chemists 2020

August 6, 2020, Pages 9991-9997

This article also appears in:

• Young Chemists 2020

Abstract

Pyrene‐based cyclophanes have been synthesized with the aim to realize a bellows‐type sensing mechanism for the ratiometric detection of nucleotide concentrations in a buffered aqueous solution. The sensing mechanism involves the encapsulation of a nucleobase between two pyrene rings, which affects the monomer‐excimer equilibrium of the receptor in the excited state. The nature of the spacer and its connection pattern to pyrene rings have been varied to achieve high selectivity for ATP. The 1,8‐substituted pyrene‐based cyclophane with the 2,2′‐diaminodiethylamine spacer demonstrates the best selectivity for ATP showing a 50‐fold increase in the monomer‐excimer emission ratio upon saturation with the nucleotide. The receptor can detect ATP within the biological concentrations range over a wide pH range. NMR and spectroscopic studies have revealed the importance of hydrogen bonding and stacking interactions for achieving a required receptor selectivity. The probe has been successfully applied for the real‐time monitoring of creatine kinase activity.

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В журнале Biomedical Optics Express (IF 3,91) опубликована статья с участием сотрудника
Института: к.х.н. А.Ю. Воробьева (зав.лаб, с.н.с ЛФ)

Optical uncaging of ADP reveals the early calcium dynamics in single, freely moving platelets

Abstract

Platelet activation is considered to be a cornerstone in pathogenesis of cardiovascular disease. The assessment of platelet activation at the single-cell level is a promising approach for the research of platelet function in physiological and pathological conditions. Previous studies used the immobilization of platelets on the surface, which significantly alters the activation signaling. Here we show that the use of photolabile “caged” analog of ADP allows one to track the very early stage of platelet activation in single, freely moving cells. In this approach, the diffusion step and ADP receptor ligation are separated in time, and a millisecond-timescale optical pulse may trigger the activation. The technique allows us to measure the delay (lag time) between the stimulus and calcium response in platelets. We also propose a simple model function for calcium peaks, which is in good agreement with the measured data. The proposed technique and model function can be used for in-depth studies of platelet physiology.

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В журнале Dalton Transactions (IF 4,052) опубликована статья с участием сотрудников Института   д.х.н., проф.  А.В. Ткачева (завлаб, ЛТС) и к.х.н. А.М. Агафонцева (снс, ЛТС):

Luminescent Zn(II) and Cd(II) complexes with chiral 2,2′-bipyridine ligands bearing natural monoterpene groups: synthesis, speciation in solution and photophysics

Abstract

Mononuclear zinc(II) and cadmium(II) complexes, ZnLCl₂ (1), CdLCl₂ (2), ZnL¹Cl₂·2H₂O (3), and CdL¹Cl₂·2H₂O (4), with chiral ligands containing a 2,2′-bipyridine moiety and natural terpene (+)-limonene (L) or (+)-3-carene (L¹) moieties were synthesized. In these complexes the L and L¹ ligands are shown to coordinate Zn²⁺ and Cd²⁺ ions through the 2,2′-bipyridine moiety. The acetamide group of the ligands interacts with M²⁺ ions by forming N⋯M>²⁺> and CO⋯M²⁺contacts and N–H⋯Cl hydrogen bonds with coordinated Cl⁻ ions. In solutions the complexes have several conformers differing by the degree of the turn of the acetamide moiety relative to the ligand core and the type of its interaction with the coordination core. The ligands and complexes exhibit luminescence with the quantum yield increasing in the order: ligand < cadmium(II) complex < zinc(II) complex. The complexes 3 and 4 demostrate excitation wavelength independent single-channel fluorescence. As opposed to 3 and 4, the complexes 1 and 2 demonstrate excitation wavelength dependent emission with nanosecond and microsecond lifetimes of the excited states. According to our TD-DFT calculations, an interplay of ligand centered and halide to ligand transitions facilitates two deactivation channels in 1 and 2: S₁–S₀ and T₁–S₀.

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В журнале  Успехи химии/Russian Chemical Reviews  (IF 4.612) опубликован обзор сотрудников Института

Ю.А. Тена, к.х.н. Н.М. Трошковой и д.х.н. Е.В. Третьякова

От спин-меченых конденсированных полиароматических соединений к магнитно-активным графеновым наноструктурам

From spin-labelled fused polyaromatic compounds to magnetically active graphene nanostructuresFrom spin-labelled fused polyaromatic compounds to magnetically active graphene nanostructures

Анотация

Молекулярный дизайн магнитно-активных графеновых наноструктур - формирующаяся область науки. Основная цель таких исследований - получение графеновых нанолент и графеновых квантовых точек с заданными электронными, оптическими и магнитными свойствами. В обзоре рассмотрены методы синтеза спин-меченых полициклических ароматических углеводородов - гомологических предшественников графеновых наноструктур. Обсуждены достижения и перспективы развития дизайна магнитно-активных графеновых материалов. Библиография - 134 ссылки.

Abstract

Molecular design of magnetically active graphene nanoscale structures is an emerging field of research. The key goal of this research is to produce graphene nanoribbons and graphene quantum dots with specified electronic, optical and magnetic properties. The review considers methods for the synthesis of spin-labelled polycyclic aromatic hydrocarbons, the homologous precursors of graphene nanostructures and discusses the achievements and prospects of the design of magnetically active graphene materials. Bibliography — 134 references

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Just add water! A range of heterogeneous ‐SO₃H functionalized catalysts were investigated for the first time using the Prins‐Ritter (−)‐isopulegol reaction with benzaldehyde and acetonitrile as a model producing 4‐amido derivatives of octahydro‐2H‐chromenes (as S‐ and R‐diastereomers). A strong effect of water addition prior the reaction on the overall selectivity and the ratio of isomers was found.

На сайте  журнала ChemCatChem (IF 4,495) опубликована статья с участием сотрудников Института:  Н.С. Ли-Жуланова (мнс, ЛНТПС),  д.х.н., проф. РАН К.П. Волчо (гнс, ЛФАФ) и д.х.н., член.-корр. РАН, поф. Н.Ф. Салахутдинова (зав .отделом медицинской химии)

Stereoselectivity Inversion by Water Addition in the −SO₃H‐catalyzed Tandem Prins‐Ritter Reaction for Synthesis of 4‐amidotetrahydropyran Derivatives

Dr. Alexander Yu. Sidorenko,  Nikolai S. Li‐Zhulanov, Päivi Mäki‐Arvela, Thomas Sandberg, Anna V. Kravtsova, Andreia F. Peixoto, Cristina Freire, Konstantin P. Volcho, Nariman F. Salakhutdinov, Vladimir E. Agabekov, Prof. Dmitry Yu. Murzin

Abstract

A range of heterogeneous ‐SO₃H functionalized catalysts including carbon and halloysite nanotubes, commercial K10 clay, Amberlyst‐15 etc. was investigated for the first time using as a model the Prins‐Ritter reaction of (−)‐isopulegol with benzaldehyde and acetonitrile producing 4‐amido derivatives of octahydro‐2H‐chromenes (as (S)‐ and (R)‐diastereomers). A strong effect of water addition prior the reaction on the overall selectivity and the ratio of isomers in the case of heterogeneous and homogeneous (p‐toluenesulfonic acid) catalysis was found for the first time. The yield of the (R)‐diastereomer sharply increased with increasing amount of added water, while the S‐isomer prevailed with a minimum amount of added water. Experimental results and DFT calculations clearly indicate a kinetic control for R‐amide formation. Typically synthesis of 4‐amidooctahydro‐2H‐chromenes requires subzero temperatures and toxic catalysts, which were avoided in the current work. Nevertheless, the yield of the desired products (up to 83 %) at 30 °C after water addition exceeded the values reported previously. Thus, adding water is a simple and a very effective method for controlling both the yield and stereoselectivity of the Prins‐Ritter reaction products under mild conditions.

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