Preparation of Multi‐Spin Systems: A Case Study of Tolane‐Bridged Verdazyl‐Based Hetero‐Diradicals

Darya E. Votkina, Pavel V. Petunin, Svetlana I. Zhivetyeva, Irina Yu. Bagryanskaya, Mikhail N. Uvarov, Maxim S. Kazantsev,  Marina E. Trusova,  Evgeny V. Tretyakov,  Pavel S. Postnikov

European Journal of Organic Chemistry, Volume 2020, Issue13, April 7, 2020 Pages 1996-2004

Dear Prof. Bagryanskaya,
I am writing on behalf of the Editorial Board to thank and congratulate you for your recent contribution to PCCP, Photochemistry of Tris(2,3,5,6-tetrathiaaryl)methyl Radicals in Various Solutions, DOI: 10.1039/C9CP06213K.
I am delighted to let you know that this was extremely well received, and has been selected by our Editors as a 2019 HOT PCCP article. Please find the collection, now including your publication, here .
As part of the 2019 HOT articles collection, your article will shortly be made free to access until the end of June 2020, and announced to the PCCP community.
Thank you once again for your excellent contribution, and we look forward to receiving your next submission to PCCP.

Kathryn Gempf M. Sci. MRSC
Development Editor,
Journals Royal Society of Chemistry

В журнале Physical Chemistry Chemical Physics, Vol. 22, Iss. 3, 1019-1026, 2020  (IF 3,567) опубликована статья с участием сотрудников Института:   А.А. Кужелева, В.М. Тормышева,  О.Ю. Рогожниковой, М.В. Еделевой и Е.Г. Багрянской

Photochemistry of tris(2,3,5,6-tetrathiaaryl)methyl radicals in various solutions

Abstract

During the last decades, persistent tris(2,3,5,6-tetrathiaaryl)methyl radicals (TAMs) have attracted much attention due to their applications in oximetry, EPR tomography, and as spin labels in pulsed dipolar EPR spectroscopy. Recently, researchers proposed to use TAM radicals as spin labels and/or a partner for photoinduced spin labels. Thus, the questions of their photochemical stability and mechanism of degradation under UV irradiation have become relevant and important. In this study, steady-state photolysis and flash photolysis of TAM radicals were investigated. A detailed mechanism of TAM phototransformations was proposed and confirmed by NMR, gel permeation chromatography, and mass-spectrometric analyses of the products.

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В журнале Dalton Transactions (IF 4,052) опубликована статья с участием сотрудников Института   д.х.н. И.И. Олейника (внс, ЛЭИСМ ) и к.х.н. И.В. Олейник (снс, ЛЭАСМ):

High molecular weight polyethylenes of narrow dispersity promoted using bis(arylimino)cyclohepta[b]pyridine-cobalt catalysts ortho-substituted with benzhydryl & cycloalkyl groups

Abstract

A one-pot template strategy has been utilized to synthesize sterically enhanced bis(imino)cyclohepta[b]pyridine-cobalt(II) chlorides, [2-{(Ar)NCMe}-9-{N(Ar)}C₁₀H₁₀N]CoCl₂ (Ar = 2-(C₅H₉) -4,6-(CHPh₂)₂C₆H₂ Co1, 2-(C₆H₁₁)-4,6-(CHPh₂)₂C₆H₂  Co2, 2-(C₈H₁₅)-4,6-(CHPh₂) ₂C₆H₂ Co3, 2-(C₁₂H₂₃)-4,6-(CHPh₂ )₂C₆H₂ Co4, 2,6-(C₅H₉)₂ -4-(CHPh₂)C₆H₂ Co5). All five complexes have been characterized by a combination of FT-IR spectroscopy, elemental analysis and single crystal X-ray diffraction. The molecular structures of Co1, Co3 and Co5 highlight the substantial steric hindrance imparted by the 2-cycloalkyl-6-benzhydryl or 2,6-dicyclopentyl ortho-substitution pattern; distorted square pyramidal geometries are exhibited in each case. On activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the complexes (apart from Co4/MAO) were active ethylene polymerization catalysts (up to 3.70 ? 10⁶ g PE per mol (Co) per h for Co5/MMAO), operating effectively at temperatures between 50 °C and 60 °C, producing polyethylenes with high molecular weights (up to 589.5 kg mol^-1 for Co3/MAO). Furthermore, all polymers were highly linear (T_m > 130 °C) with narrow dispersities (M_w/M_n range: 2.0–3.0). The coexistence of two chain termination pathways, β-H elimination and transfer to aluminum, has been demonstrated using ¹³ C/¹H NMR spectroscopy.

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В журнале Polymer Chemistry (IF 4,760) опубликована статья с участием сотрудников Института   Д.С. Одинцова (мнс ЛЭАСМ) , к.х.н. И.К. Шундриной (с.н.с. ЛЭАСМ), к.х.н. И.А. Оськиной (с.н.с. ЛГетС), к.х.н. И.В. Олейник (с.н.с. ЛЭАСМ)  и д.х.н. Л.А. Шундрина (зав.лаб. ЛЭАСМ):

Ambipolar polyimides with pendant groups based on 9H-thioxanthene-9-one derivatives: synthesis, thermostability, electrochemical and electrochromic properties

Abstract

New electro-active polyimides (PI) with pendant groups based on 9H-thioxanthene-9-one (Th(O)S) and its S,S-dioxide derivative (Th(O)SO₂) have been synthesized on the basis of 2-{bis(4-aminophenyl)aminomethyl}-9H-Th(O)S/Th(O)SO₂ by the route including the synthesis of the corresponding polyamidoacids followed by their chemical imidization. The synthesized polyimides demonstrated thermal stability up to 400 °C without a noticeable weight loss. Thin-layer cyclic voltammetry showed the polyimides to be capable of reversible electron transfer at low negative potentials, their values depending on the nature of the pendant groups. The electrochromic behavior of the polyimides showed absorption bands at 363, 409, 683 nm for the PI with the Th(O)S pendant group and 355, 644 nm for the PI with the Th(O)SO₂ in the potential sweep range 0 > E > −2.1 V. Optical absorption bands under electrochemical reduction conditions are associated with the formation of radical anion states of the pendant groups inside the PI layer as well as reversible electron transfer to the electron-acceptor moiety of the polymer chain. It was confirmed by comparison with 3D UV-VIS-NIR spectroelectrochemical studies of the corresponding 2-methyl-9H-thioxanthene-9-ones used as precursors of the pendant groups.

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На сайте журнала ACS Applied Materials & Interfaces   (IF=8,456) опубликована статья  с участием сотрудника Института к.х.н. М.С. Казанцева

Fluorinated thiophene-phenylene co-oligomers for optoelectronic devices

ACS Appl. Mater. Interfaces, 2020, 12, 8,  9507-9519
Publication Date:February 3, 2020

Abstract

Organic optoelectronics requires materials combining bright luminescence and efficient ambipolar charge transport. Thiophene-phenylene co-oligomers (TPCOs) are promising highly emissive materials with decent charge-carrier mobility; however, they typically show poor electron injection in devices, which is usually assigned to high energies of their lowest unoccupied molecular orbitals (LUMOs). A widely used approach to lower the frontier orbitals energy levels of a conjugated molecule is its fluorination. In this study, we synthesized three new fluorinated derivatives of one of the most popular TPCOs, 2,2'-(1,4-phenylene)bis[5-phenylthiophene] (PTPTP), and studied them by cyclic voltammetry, absorption, photoluminescence and Raman spectroscopies. The obtained data reveal a positive effect of fluorination on the optoelectronic properties of PTPTP: LUMO levels are finely tuned, photoluminescence quantum yield and absorbance are increased. We then grew crystals from fluorinated PTPTPs, resolved their structures, and showed that fluorination dramatically affects the packing motif and facilitates π-stacking. Finally, we fabricated thin-film organic field-effect transistors (OFETs) and demonstrated a strong impact of fluorination on charge injection/transport for both types of charge carriers, electrons and holes. Specifically, balanced ambipolar charge transport and electroluminescence were observed only in the OFET active channel based on the partially fluorinated PTPTP. The obtained results can be extended to other families of conjugated oligomers and highlight the efficiency of fluorination for rational design of organic semiconductors for optoelectronic devices.

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В журнале Polymer   (IF=8,456) опубликована статья  с участием сотрудника Института д.х.н. Е.Е. Шульц

Pyrocatechol borates: Synthesis, reaction with formaldehyde, and solvent effect on polycondensation process

Polymer

Abstract

Pyrocatechol (I) and dipyrocatechol (II) borates were synthesized by esterification between pyrocatechol (1,2-dihydroxybenzene) and boric acid in о-xylene with azeotropic distillation of water. The co-esterification between pyrocatechol and boric acid with added equimolar quantities of phenol or 2,6-di-tert-butylphenol was studied, and pyrocatechol phenyl (III) and pyrocatechol-(2,6-di-tert-butyl)phenyl (IV) borates were prepared. The reaction of the resultant esters with formaldehyde in the presence of boron trifluoride etherate as a catalyst was examined. The coupling of the methylene moiety in several position of moleculeIII was found to be dependent on the solvent used. The electrophilic substitution on the phenol substituent took place in о-xylene, while the reaction in either benzene or molten monomer proceeded to substitute the methylene moiety for the proton on the catechol moiety. The molecular weights of the compounds were measured. Some properties of the synthesized oligomers were determined and thermal and thermooxidative destruction was examined.

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В журнале New Journal of Chemistry, 2019, Vol. 43, N 41, Pp. 16331-16-337,  (IF 3,069) опубликована статья с участием сотрудников Института:   к.х.н. Н.А. Семёнова, Е.А. Радюш, Е.А. Чулановой, д.х.н. И.Ю. Багрянской, к.х.н. Иртеговой, д.х.н. Л.А. Шундрина и д.х.н. А.В. Зибарева

Design, synthesis and isolation of a new 1,2,5-selenadiazolidyl and structural and magnetic characterization of its alkali-metal salts

Abstract

5,6-Dicyano[1,2,5]selenadiazolo[3,4-b]pyrazine 1 was synthesized and electrochemically and chemically reduced into its radical anion [1]˙−, which was characterized by EPR spectroscopy and DFT calculations, and isolated in the form of homospin salts [K(18-crown-6)]+[1]˙− (2) and [Na(18-crown-6)]+[1]˙− (3). The crystal structure of 2 revealed π-dimers of [1]˙− featuring a shortened interplanar separation of 3.18 Å, and that of 3 showed chains of alternating cations and anions. DFT and CASSCF calculations on the π-dimers of [1]˙− suggest a closed-shell singlet ground state with a noticeable contribution of diradical character. According to EPR and SQUID magnetometry, salt 2 is diamagnetic in the range of 2–300 K, whereas salt 3 is paramagnetic and reveals weak antiferromagnetic exchange interactions.

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В журнале The Journal of Supercritical Fluids, Vol. 158, 1 April 2020, 104748,  (IF 3,481) опубликована статья с участием сотрудника Института:   д.х.н. И.А. Григорьева

Paramagnetic bioactives encapsulated in poly(D,L-lactide) microparticules: Spatial distribution and in vitro release kinetics

Abstract

Poly(D,L-lactide) microparticles impregnated with a number of bioactive paramagnetic compounds have been fabricated using two SCF techniques: 1). PGSS (Particles from Gas Saturated Solution) and 2). polymer plasticization and swelling by supercritical carbon dioxide followed by its cryomilling. Electron paramagnetic resonance (EPR) spectroscopy manifested homogeneous spatial distribution for the most of these substances encapsulated into the polymer. Irreversible relaxation processes in the prepared polymer structures and formulations were not observed. The qualitative difference in the release kinetics of paramagnetic molecules of different structure from the polymer microparticles into the phosphate-buffered saline (PBS, pH = 7.4) was demonstrated. pH-sensitive ATI spin probe proved the decrease (up to ≤ 4.5) of local pH inside the microparticles during the first 9 days after its immersion in PBS.

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В журнале Chemical Communications, Vol. 56, Iss. 7, 1113-1116, 2020  (IF 6,29) опубликована статья с участием сотрудника Института:   А.В. Зибарева

Bis(2,1,3-benzotelluradiazolidyl)2,1,3-benzotelluradiazole: a pair of radical anions coupled by Te...N chalcogen bonding

Abstract

Reduction of 2,1,3-benzotelluradiazole (3) yielded a crystalline solid that features a trimeric dianion formally composed of two [3]˙− and one 3 bridged by unusually asymmetric Te⋯N chalcogen bonds. The solid is diamagnetic due to strong antiferromagnetic coupling, as revealed by CASSCF/CASPT2 and BS-DFT.

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В журнале Physical Chemistry Chemical Physics, Vol. 22, Iss. 3, 1019-1026, 2020  (IF 3,567) опубликована статья с участием сотрудников Института:   А.А. Кужелева, В.М. Тормышева,  О.Ю. Рогожниковой, М.В. Еделевой и Е.Г. Багрянской

Photochemistry of tris(2,3,5,6-tetrathiaaryl)methyl radicals in various solutions

Abstract

During the last decades, persistent tris(2,3,5,6-tetrathiaaryl)methyl radicals (TAMs) have attracted much attention due to their applications in oximetry, EPR tomography, and as spin labels in pulsed dipolar EPR spectroscopy. Recently, researchers proposed to use TAM radicals as spin labels and/or a partner for photoinduced spin labels. Thus, the questions of their photochemical stability and mechanism of degradation under UV irradiation have become relevant and important. In this study, steady-state photolysis and flash photolysis of TAM radicals were investigated. A detailed mechanism of TAM phototransformations was proposed and confirmed by NMR, gel permeation chromatography, and mass-spectrometric analyses of the products.

Альметрики: 

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