В журнале The Journal of the American Chemical Society (JACS) (IF 15,419) опубликована статья с участием д.ф.-м.н., профессора    Елены Григорьевны Багрянской (Директор института):

Benchmark Test and Guidelines for DEER/PELDOR Experiments on Nitroxide-Labeled Biomolecules

J. Am. Chem. Soc. 2021, 143, 43, 17875-17890 Publication Date:October 19, 2021

https://doi.org/10.1021/jacs.1c07371

ABSTRACT

Distance distribution information obtained by pulsed dipolar EPR spectroscopy provides an important contribution to many studies in structural biology. Increasingly, such information is used in integrative structural modeling, where it delivers unique restraints on the width of conformational ensembles. In order to ensure reliability of the structural models and of biological conclusions, we herein define quality standards for sample preparation and characterization, for measurements of distributed dipole–dipole couplings between paramagnetic labels, for conversion of the primary time-domain data into distance distributions, for interpreting these distributions, and for reporting results. These guidelines are substantiated by a multi-laboratory benchmark study and by analysis of data sets with known distance distribution ground truth. The study and the guidelines focus on proteins labeled with nitroxides and on double electron–electron resonance (DEER aka PELDOR) measurements and provide suggestions on how to proceed analogously in other cases.

 

Abstract

Thermally resistant air-stable organic triradicals with a quartet ground state and a large energy gap between spin states are still unique compounds. In this work, we succeeded to design and prepare the first highly stable triradical, consisting of oxoverdazyl and nitronyl nitroxide radical fragments, with a quartet ground state. The triradical and its diradical precursor were synthesized via a palladium-catalyzed cross-coupling reaction of diiodoverdazyl with nitronyl nitroxide-2-ide gold(I) complex. Both paramagnetic compounds were fully characterized by single-crystal X-ray diffraction analysis, superconducting quantum interference device magnetometry, EPR spectroscopy in various matrices, and cyclic voltammetry. In the diradical, the verdazyl and nitronyl nitroxide centers demonstrated full reversibility of redox process, while for the triradical, the electrochemical reduction and oxidation proceed at practically the same redox potentials, but become quasi-reversible. A series of high-level CASSCF/NEVPT2 calculations was performed to predict inter- and intramolecular exchange interactions in crystals of di- and triradicals and to establish their magnetic motifs. Based on the predicted magnetic motifs, the temperature dependences of the magnetic susceptibility were analyzed, and the singlet–triplet (135 ± 10 cm^–1) and doublet-quartet (17 ± 2 and 152 ± 19 cm^–1) splitting was found to be moderate. Unique high stability of synthesized verdazyl-nitronylnitroxide triradical opens new perspectives for further functionalization and design of high-spin systems with four or more spins.

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Benchmark Test and Guidelines for DEER/PELDOR Experiments on Nitroxide-Labeled Biomolecules   

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An Efficient Access to 3,5-Disubstituted Isoxazoles with Anthranilate Ester Moiety: Alkaloid Lappaconitine – Aryl Conjugates with an Isoxazole Linker

Dr. Kirill P. Cheremnykh, Dr. Victor A. Savelyev, Prof. Elvira E. Shults

Asian Journal of Organic Chemistry, 2021, V. 10, N 10, Pp. 2638-2643

На сайте журнала Applied Organometallic Chemistry   (IF=4,015) 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) 

α,α'-Bis (imino)-2,3:5,6-bis (pentamethylene)pyridines appended with benzhydryl and cycloalkyl substituents: Probing their effectiveness as tunable N,N,N-supports for cobalt ethylene polymerization catalysts

Mingyang Han, Ivan I. Oleynik, Yanping Ma, Irina V. Oleynik, Gregory A. Solan, Tongling Liang, Wen-Hua Sun

Applied Organometallic Chemistry,  
Online Version of Record before inclusion in an issue, e6429

Abstract

A single-pot method has been utilized to prepare the bis(cycloheptyl)fused N,N,N-cobalt (II) chloride complexes, [2,3:5,6-{C₄H₈C(NAr)}₂C₅H₃N]CoCl₂ (Ar = 2,6-(C₅H₉)₂–4-(CHPh₂)C₆H₂ Co1, 2-(C₅H₉)-4,6-(CHPh₂)₂C₆H₂ Co2, 2-(C₆H₁₁)-4,6-(CHPh₂)₂C₆H₂ Co3, 2-(C₈H₁₅)-4,6-(CHPh₂)₂C₆H₂ Co4, 2-(C₁₂H₂₃)-4,6-(CHPh₂)₂C₆H₂ Co5) in reasonable yields. The molecular structure of Co1 highlights not only the steric shielding of the metal center provided by the N-2,6-dicyclopentyl-4-benzhydrylphenyl groups but also the trans-configuration of the puckered sections of the two fused seven-membered rings. Besides this structural characterization, all complexes have been characterized by elemental analysis and Fourier transform infrared spectroscopy (FT-IR) spectroscopy. In the presence of modified methylaluminoxane (MMAO) or methylaluminoxane (MAO), Co1–Co5 afforded highly linear polyethylenes (T_m′s > 126°C) with dispersities that were influenced by the type of aluminoxane activator [M_w/M_n range: 1.53–1.81 (MMAO) vs. 8.96–15.5 (MAO)]. In common to both co-catalysts, the catalytic activity of the precatalysts fell in the order: Co1 > Co2 > Co5 > Co4 ~ Co3, reflecting the differences in steric/electronic properties of the ortho-cycloalkyl substituents. In terms of thermostability of the catalyst, Co1/MMAO attained optimal performance at 30°C (2.04 × 10⁶ g PE mol⁻¹[Co] h⁻¹), while Co1/MAO reached it at 60°C albeit with lower productivity (0.70 × 10⁶ g PE mol⁻¹[Co] h⁻¹). In general, the polyethylenes were of reasonably high molecular weight (e.g., between 39.9 and 65.8 kg mol⁻¹ using MMAO) which can be linked to the steric hindrance imposed on chain transfer by the cycloalkyl and benzhydryl ortho-substituents.

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На сайте журнала Advanced Functional Materials    (IF 18,808) опубликована статья с участием сотрудников Института  И.П. Коскина  (мнс, ЛОЭ), к.х.н.К.С. Мельниковой-Беккер (снс, ЛОЭ), к.х.н. А.А. Сониной (нс, ЛОЭ), А.Д. Куимова (мнс, ЛОЭ), к.х.н. И.К. Шундриной (снс, ЛАСМ)  и к.х.н. М.С. Казанцева (завлаб ЛОЭ)

Selectively Fluorinated Furan-Phenylene Co-Oligomers Pave the Way to Bright Ambipolar Light-Emitting Electronic Devices

Abstract

Linearly conjugated oligomers attract ever-growing attention as promising systems for organic optoelectronics because of their inherent lucky combination of high charge mobility and bright luminescence. Among them, furan-phenylene co-oligomers (FPCOs) are distinguished by outstanding solubility, very bright luminescence, and good hole-transport properties; however, furan-containing organic semiconductors generally lack electron transport, which makes it impossible to utilize them in efficient light-emitting electronic devices, specifically, ambipolar light-emitting transistors. In this work, 1,4-bis(5-phenylfuran-2-yl)benzene (FP5) derivatives are synthesized with the fully/partially fluorinated central and edge phenyl rings. It is shown that the selective fluorination of FPCOs lowers the energies of frontier molecular orbitals, maintaining the bandgap, solubility, and bright luminescence, dramatically improves the photostability, tunes the π-π stacked packing, and allows the first realization of electron transport in FPCOs. It is found that selectively fluorinated 2,2′-(2,3,5,6-tetrafluoro-1,4-phenylene)bis[5-(3,5-difluorophenyl)furan] demonstrates well-balanced ambipolar charge transport and efficient electroluminescence in an organic light-emitting transistor (OLET) with external quantum and luminous efficiencies as high as 0.63% and 5 cdA⁻¹, respectively, which are among the best reported for OLETs. The findings show that “smart” fluorination is a powerful tool to fine-tune the stability and performance of linearly conjugated small molecules for organic optoelectronics.

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В журнале Computational and Structural Biotechnology Journal (IF 7,271) опубликована статья  с участием директора Института   д.ф.-м..н. проф. Е.Г. Багрянской :

Two alternative conformations of mRNA in the human ribosome during elongation and termination of translation as revealed by EPR spectroscopy

Abstract

The conformation of mRNA in the region of the human 80S ribosome decoding site was monitored using 11-mer mRNA analogues that bore nitroxide spin labels attached to the terminal nucleotide bases. Intramolecular spin–spin distances were measured by DEER/PELDOR spectroscopy in model complexes mimicking different states of the 80S ribosome during elongation and termination of translation. The measurements revealed that in all studied complexes, mRNA exists in two alternative conformations, whose ratios are different in post-translocation, pre-translocation and termination complexes. We found that the presence of a tRNA molecule at the ribosomal A site decreases the relative share of the more extended mRNA conformation, whereas the binding of eRF1 (alone or in a complex with eRF3) results in the opposite effect. In the termination complexes, the ratios of mRNA conformations are practically the same, indicating that a part of mRNA bound in the ribosome channel does not undergo significant structural alterations in the course of completion of the translation. Our results contribute to the understanding of mRNA molecular dynamics in the mammalian ribosome channel during translation.

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В журнале International Journal of Pharmaceutics  (IF 5,875) опубликована статья  с участием научных сотрудников Института   к.б.н. С.В. Анькова (нс ЛФИ) и д.б.н. проф. Т.Г. Толстиковой (завлаб ЛФИ) :

Aerosol Inhalation Delivery of Cefazolin in Mice: Pharmacokinetic Measurements and Antibacterial Effect

Abstract

Aerosol inhalation delivery of cefazolin, a broad-spectrum first-generation cephalosporin antibiotic, was investigated. Inhalation system based on ultrasonic nebulizer was developed for the generation of dry cefazolin aerosol within mean particle diameter range 0.5–3.0 μm and mass concentration 0.01–3 μg/cm³. Pharmacokinetic measurements were carried out for the aerosolized form of cefazolin delivered in mice using nose-only chamber. Cefazolin concentrations in blood serum and in the lungs of mice were measured as a function of time by means of high performance liquid chromatography. Body-delivered dose depending on particle size, concentration and inhalation time as well as other pharmacokinetic parameters were determined. The antibacterial effect of aerosolized cefazolin was assessed through the aerosol inhalation treatment of mice infected with Klebsiella pneumoniae. Survival rate for infected mice after the treatment with cefazolin aerosol demonstrated high antibacterial efficiency of the inhalation delivery of cefazolin in comparison with intraperitoneal delivery.

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В  журнале Physical Chemistry Chemical Physics,   (IF 3,676) опубликована статья с участием сотрудников Института:  к.х.н. Т.А. Вагановой (снс, ЛГеТС) и д.х.н. Е.В. Малыхина (гнс, ЛГеТС)

Impact of fluorination and chlorination on the electronic structure, topology and in-plane ring normal modes of pyridines

Abstract

Seven partially and fully fluorinated/chlorinated pyridines were investigated by means of FT-IR and Raman spectroscopy combined with quantum chemical calculations, mainly aiming to detect how the nature and position of F and Cl substituents affect the in-plane ring normal modes (RNMs) of pyridines in terms of vibrational wavenumbers, force constants, IR intensities and Raman activities. Taking pyridine as the reference, the RNMs and some derived RNMs through coupling with related C–X (X = F, Cl) stretching vibrations were identified on the basis of their composition in terms of internal coordinates. The impact of fluorination and chlorination on these RNMs was also discussed from the perspective of frontier molecular orbitals (MOs), maps of the molecular electrostatic potential (MEP) and the molecular topology. Natural bond orbital (NBO) analysis revealed the consequences of substitutions on the intramolecular charge delocalisation and consequently the ring bond strength. Moreover, the effects of anharmonicity of the potential on vibrational frequencies were presented and discussed.

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В журнале Gels  (IF 5,875) опубликована статья  с участием сотрудника Института   к.х.н. И.А. Кирилюка (завлаб ЛАС) :

Acidic and Electrosurface Properties of Binary TiO₂–SiO₂ Xerogels Using EPR of pH-Sensitive Nitroxides

Abstract

The binary xerogels TiO₂-SiO₂ are widely used as catalysts and their carriers in organic synthesis. Characterization and adjustment of the electrostatic properties of the surface and the local acidity inside the pores, are necessary for the further development of TiO₂-SiO₂ xerogels applications. This research investigates acid–base equilibria in the pores, and the surface electrostatic potential (SEP) of binary TiO₂-SiO₂ xerogels, by the EPR of stable pH-sensitive nitroxide radicals. These radicals are small enough to penetrate directly into the pores, and to be adsorbed onto the surface of the material under study. This makes it possible to obtain valuable information on the acidic and electrosurface properties of the studied system. The highest negative surface electrical charge associated with surface electrical potential (SEP) was equal to −196 ± 6 mV. It was induced by the surface of the sample with a 7% TiO₂ content. The local acidity inside the pores of this sample was found to be higher, by approximately 1.49 pH units, as compared to that in the external bulk solution. View Full-Text

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На сайте журнала Applied Organometallic Chemistry   (IF=4,015) 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) 

Boosting activity, thermostability, and lifetime of iron ethylene polymerization catalysts through gem-dimethyl substitution and incorporation of ortho-cycloalkyl substituents

Randi Zhang, Mingyang Han, Irina V. Oleynik, Gregory A. Solan, Ivan I. Oleynik, Yanping Ma, Tongling Liang, Wen-Hua Sun

Applied Organometallic Chemistry,  
Online Version of Record before inclusion in an issue, e6376

Abstract

Six types of ferrous chloride complex, [2-(ArN=CMe)-8-(ArN)-7,7-Me₂C₉H₆N]FeCl₂ (Ar=2-(C₅H₉)-6-MeC₆H₃ Fe1, 2-(C₆H₁₁)-6-MeC₆H₃ Fe2, 2-(C₈H₁₅)-6-MeC₆H₃ Fe3, 2-(C₅H₉)-4,6-Me₂C₆H₂ Fe4, 2-(C₆H₁₁)-4,6-Me₂C₆H₂ Fe5, 2-(C₈H₁₅)-4,6-Me₂C₆H₂ Fe6), each bearing a gem-dimethyl-substituted N,N,N-chelating ligand that differs in the ortho-cycloalkyl ring size and para-substituent of the N-aryl groups, are disclosed. All complexes have been prepared by a straightforward one-flask route and characterized by FT-IR spectroscopy and elemental analysis. In the case of Fe1, oxidation to form the oxo-bridged diferric species [2-(2-(C₅H₉)-6-MeC₆H₃N=CMe)-8-(2-(C₅H₉)-6-MeC₆H₃N)-7,7-Me₂C₉H₆N]FeCl(μ-O)FeCl₃ (Fe1') has been demonstrated and its structural identity confirmed by single crystal X-ray diffraction. Following treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), Fe1–Fe6 exhibited optimal catalytic activities at 60°C for ethylene polymerization [up to 2.35 × 10⁷ g of PE (mol of Fe)⁻¹ h⁻¹ for Fe1/MMAO] producing linear polyethylene; even over prolonged run times, high activities were maintained. Moreover, this family of iron catalysts exhibited remarkable thermostability by displaying appreciable activity at temperatures as high as 100°C [activity up to 7.8 × 10⁶ g of PE (mol of Fe)⁻¹ h⁻¹]. By varying the ring size of the ortho-cycloalkyl and para-R² group (R² = H, Me), excellent control over molecular weight of the polyethylenes could be achieved with values in the range 1.4–67.8 kg mol⁻¹ obtainable. In addition, end-group analysis of the polymers generated with Fe/MAO or Fe/MMAO revealed that both β-H elimination and chain transfer to aluminum are competitive processes during chain termination.

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В журнале CrystEngComm, 2021, V. 23, N 7, Pp 4767-4781   (IF 3,545) опубликована статья с участием сотрудников Института  к.х.н. Т.А. Вагановой (снс ЛГетС), д.х.н. Ю.В. Гатилова (внс  ГРСА) М. Сухова (лаборант ЛГетС) и д.х.н. Е.В. Малыхина (гнс ЛГетС)

Co-crystals of polyhalogenated diaminobenzonitriles with 18-crown-6: effect of fluorine on the stoichiometry and supramolecular structure

Abstract

A series of polyhalogenated diaminobenzonitriles and 18-crown-6 ether were used to reveal the dependence of the stoichiometry and supramolecular structure of co-crystals on various factors. 2,6-Diamino-3,5-difluoro-, 2,6-diamino-4-chloro-3,5-difluoro-, and 2,6-diamino-4-chloro-3-fluorobenzonitriles, as well as 2,4-diamino-3,5-difluorobenzonitrile give 1 : 1 co-crystals regardless of the diamine : crown ratio in the crystallization solution (from 2.5 : 1 to 1 : 2.5) and the nature of the solvent. According to X-ray diffraction data, the supramolecular structures of these co-crystals can be considered as 1D assemblies with the only structure-forming N–H⋯O_cr hydrogen bond. 2,4-Diamino-3,5,6-triflurobenzonitrile forms no 1 : 1 co-crystal, but yields co-crystals of 4 : 3 (under most of the studied conditions) and 2 : 1 (in CCl₄ solution) stoichiometry. The N–H⋯NC hydrogen bond and p⋯π electron interactions, along with the N–H⋯O_cr H-bond, participate in the formation of the 3D supramolecular structures of these co-crystals. The effect of the number of F atoms on the co-crystallization behaviour of difluoro- and trifluoro-2,4-diaminobenzonitriles was rationalized using quantum-chemical computations of the interaction energies of N–H⋯NC bonded pairs of these diamines in the experimental crystals and DFT simulated models. The DSC curves of each co-crystal contain a single peak corresponding to a crystal-to-liquid phase transition (melting), which does not change in melting–crystallization cycles, indicating that the stoichiometry and crystal structure are reproducible.

• This article is part of the themed collections: Supramolecular & Polymorphism and CrystEngComm HOT articles

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В журнале Chemosphere (IF 7,086) опубликована статья с участием сотрудника Института   к.х.н. С. В. Морозова (завлаб ЛЭИиХА) 

Supercritical water oxidation of chlorinated waste from pulp and paper mill

Chemosphere,  2021, V. 238, November 2021, 131239

https://doi.org/10.1016/j.chemosphere.2021.131239

 

Abstract

The article presents the research results of the oxidation of watered toxic waste from the pulp and paper industry (sludge-lignin, the empirical formula of organic matter CH_1.51N_0.05S_0.03Cl_0.01O_0.54) in supercritical water-oxygen (SCW/O₂) fluid. The experiments were carried out using a flow tube reactor at a pressure of 25 MPa, temperature gradient along its vertical axis (from top to bottom: 390–600 °C), sludge-lignin flow rate of 9.5–14.5 g/min, oxygen ratio OR = 0.73–2.52, using NaOH (1.6 wt%) as a catalyst. Employing gas chromatography – mass spectrometry, polychlorophenols were identified in the composition of sludge-lignin, in which 2,4,6-trichlorophenol was the main component. The total yield of extracted phenols and chlorophenols per sludge-lignin organic matter was 20.82 and 2.88 μg/g, respectively. It is revealed that the conversion rate of sludge-lignin in SCW/O₂ fluid is limited by heterogeneous oxidation of the carbonized residue, and is determined by the O₂ content in the reaction mixture. At OR ≥ 1.16, only CO₂, CO, N₂, and N₂O were detected in the volatile oxidation products. An increase in OR from 0.73 to 2.52 leads to a decrease in the total content of phenols (from 45540.1 to 129.3 μg/dm³) and chlorophenols (from 51.4 to 2.2 μg/dm³) in the water collected at the reactor outlet. It is shown that 2,6-dichlorophenol and 2-chlorophenol are the most resistant to oxidation. From the analysis of the initial sludge-lignin and mineral residues, it follows that the bulk of the chlorine contained in its organic matter is converted into NaCl in the course of oxidation.

Keywords: Waste disposal, Phenols, Chlorophenols, Supercritical water oxidation, Alkali catalyst

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Supercritical water oxidation of chlorinated waste from pulp and paper mill   

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В журнале Pharmaceuticals (IF 5,863) опубликована статья с участием сотрудников Института   д.х.н., проф. Э. Э. Шульц (завлаб ЛМХ) и Т.В. Рыбаловой (нс ГРСА) 

Calcium Chelidonate: Semi-Synthesis, Crystallography, and Osteoinductive Activity In Vitro and In Vivo