A5013325099- Organometallic Complex Synthesis and Catalysis
- Carbon dioxide utilization in catalysis
- Synthetic Organic Chemistry Methods
- biodegradable polymer synthesis and properties
- Catalysis and Oxidation Reactions
- Synthesis and characterization of novel inorganic/organometallic compounds
- Polymer crystallization and properties
- Advanced Polymer Synthesis and Characterization
- Advanced Chemical Physics Studies
- Inorganic and Organometallic Chemistry
- Catalytic Processes in Materials Science
- Carbon Nanotubes in Composites
- Magnetism in coordination complexes
- Polymer Nanocomposites and Properties
- Organoboron and organosilicon chemistry
- Topological Materials and Phenomena
- Asymmetric Hydrogenation and Catalysis
- Inorganic Fluorides and Related Compounds
- Material Properties and Applications
- Metal complexes synthesis and properties
- Catalysis and Hydrodesulfurization Studies
- Radioactive element chemistry and processing
- Advanced NMR Techniques and Applications
- Coordination Chemistry and Organometallics
- Material Properties and Failure Mechanisms
Boreskov Institute of Catalysis
2015-2024
Leiden University
2024
Siberian Branch of the Russian Academy of Sciences
2007-2022
Novosibirsk State University
2004-2021
Skolkovo Institute of Science and Technology
2020-2021
Ioffe Institute
2020
Novosibirsk Tuberculosis Research Institute
2018
The Ministry of Education and Science of the Russian Federation
2017
Russian Academy of Sciences
2001-2017
Federal Agency for Scientific Organizations
2017
Using 1H and 13C NMR spectroscopy, the interaction between Cp2ZrMe2 MAO in toluene solution was investigated a wide range of Al/Zr ratios (10–4 000). Several intermediates (I–IV) were detected reaction. The structures these elucidated from detailed analysis 13C-1H data. Intermediate I is weak complex with MAO. II contact ion-pair [Cp2ZrMe(μ-Me)Cp2ZrMe]+[Me-MAO]– symmetric binuclear cationic part. Species III b are heterodinuclear [Cp2Zr(μ-Me)2AlMe2]+[Me-MAO]– ion-pairs similar separated...
A detailed study of the effect reaction temperature, time, and cocatalyst composition on ethylene polymerization performance 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-(1-mesityliminoethyl)pyridyliron dichloride (1) is reported. In presence modified methylaluminoxane (MMAO), 1 behaves like a highly active, "multisite-like" catalyst, with resulting polyethylenes having time-dependent bimodal-like molecular-weight distributions featuring saturated (n-propyl- i-butyl-terminated) chain...
The activation of 2,6-bis(2,6-diisopropylphenylimino)ethylpyridine iron-based catalysts ethylene polymerization with methylalumoxane (MAO) and aluminum trialkyls has been studied in detail by 1H NMR EPR spectroscopy. Neutral catalytically active species are formed LiPrFeCl2/Al(Alk)3 systems. They complexes [LiPr(−)Fe(+)(μ-Me)2AlMe2] (6) or [LiPr(−)Fe(+)(μ-iBu)(μ-X)Al(iBu)2] (7 8, X = iBu Cl), depending on the activator used (either AlMe3 Al(iBu)3). On contrary, when "AlMe3-free" (PMAO) is as...
Abstract The number of propagation centers ( C p ) and the rate constant K in polymerization ethylene propene presence heterogeneous TiCl 3 derived Ziegler‐Natta catalysts different composition were determined using method quenching by radioactive carbon monoxide 14 CO). values , (1,2±0,3)·10 4 l mol −1 s at 75°C for (90±20) 70°C polymerization, significantly exceed those ones obtained use tritium tagged alcohols as agents. Further, olefins based catalysts, influence catalyst composition,...
The catalyst systems Cr(acac)3/pyrrole/AlEt3/AlEt2Cl and Cr(EH)3/pyrrole/AlEt3/AlEt2Cl in cyclohexane (EH = 2-ethylhexanoate), modeling the Phillips ethylene trimerization catalyst, have been studied by EPR spectroscopy. effect of various components these on concentration Cr(III) Cr(I) species activity has investigated. relationship between data nature chromium present reaction solution studied.
The intermediates of olefin polymerization over homogeneous catalysts based on bis(imino)pyridine iron(II) chloride (LFeCl2, L = 2,6-bis[(1-2,6-dimethylphenylimino)ethyl]pyridine) with different activators (trimethyl-, triisobutyl-, trioctylaluminum and MAO) have been studied by 1H 2H NMR. In conditions approaching real polymerization, neutral species the type [LFe(II)Cl(μ-R)2AlR2] or [LFe(II)R(μ-R)2AlR2] dominate in reaction solution LFeCl2+AlR3 systems, whereas LFeCl2/MAO ion pairs...
Abstract By means of 27 Al, 1 H, 17 O and 13 C NMR spectroscopy the structure methylaluminoxane (MAO) cocatalyst Kaminsky‐Sinn catalysts was investigated. We have found that Al resonance line MAO is extremely broad at room temperature (δ ≈ 60, Δω 1/2 50 ± 10 kHz). At elevated temperatures (40–120°C) exhibits an δ 110 10, 15–10 kHz, is, within range reported for aluminoxane clusters [( t ‐Bu)Al(μ 3 ‐O)] 6 9 with cage structures. The 149–153, usually attributed to MAO, belongs AlMe present in...
Abstract The state of Ti 3+ ions formed at various steps preparation and activation highly active titanium‐magnesium catalysts composition (dry milling TiCl 3 with MgCl 2 ; reduction 4 by nonsolvated magnesium dialkyl; interaction the /MgCl system an organoaluminium compound) was studied ESR method. It found that in all systems same three types chlorine environment are formed, differing coordination localization sites . content these depends on conditions catalysts, does not exceed 20% total...
All types of chemical reactions (reduction, alkylation, and complexation Ti species by organoaluminum compounds) leading to formation active sites in heterogeneous Ziegler−Natta catalysts have been studied within density functional theory. A generally accepted mechanism site was found be less preferable as compared the alternative ways considered. Based on calculation implemented, a whole scenario postulated for different center precursors MgCl2 surface. The proposed allows us rationalize...
Abstract Most superconductors are thermal insulators. A disordered chiral p -wave superconductor, however, can make a transition to metal phase. Because heat is then transported by Majorana fermions, this phase referred as metal. Here we present numerical evidence that the mechanism for with increasing electrostatic disorder percolation of boundaries separating domains different Chern number. We construct network domain walls using spectral localizer “topological landscape function”, and...
Abstract The effect of Ti content on the activity titanium–magnesium catalysts (TMC) and molecular weight distribution (MWD) polyethylene (PE) produced has been studied. It was found that enhances sharply as decreases from 0.6 to 0.07 wt %, shows no significant changes in range 0.6–5.0 %. maximum (36 kg PE/mmol × h bar C 2 H 4 ) observed for TMC with lowest content. catalyst low titanium (∼ 0.1 % Ti) PE narrower MWD ( M w / n = 3.1–3.5) compared higher (3–5 Ti; 4.8–5.0). New data hydrogen...
A systematic consideration of different Ti(IV) and Ti(III) species on the (104) (110) MgCl2 surfaces has been implemented within DFT using cyclic boundary conditions. Some new mononuclear dinuclear surface complexes were obtained due to implication zip coordination mode. possible spin state was thoroughly studied: antiferromagnetic (ESR silent) proved be most preferable in a number cases. The Ti2Cl6 residing dominant make it rationalize fact that part incorporated activated is ESR silent....
Adsorption species of ethyl benzoate (EB) on the (104) and (110) MgCl2 surfaces have been studied within DFT. As a result, monodentate bidentate complexes EB were obtained both surfaces. The structures surface proved to be stabilized by decreased distance between neighboring adsorption sites (surface Mg cations). different affinity for five- four-coordinated cations predicted was suggested cause changing equilibrium shape crystals upon growing in presence EB: chemisorption seems stabilize...
Abstract The data on the effects of polymerization duration, cocatalyst, and monomer concentrations upon ethylene in absence hydrogen, effect an additional chain transfer agent (hydrogen) molecular weight (MW), distribution (MWD), content vinyl terminal groups for polyethylene (PE) produced over supported titanium‐magnesium catalyst (TMC) are obtained. these parameters nonuniformity active sites different reactions analyzed by deconvolution experimental MWD curves into Flory components. It...
Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. The chloro-bridged heterodinuclear ansa-zirconocenium cation [(SBI)Zr(μ-Cl)2AlMe2](+) (SBI = rac-dimethylsilylbis(1-indenyl)), present in toluene solution as its B(C6F5)4(-) salt, thus gives rise an signal the complex (SBI)Zr(III)(μ-Cl)2AlMe2, while (SBI)Zr(III)-Me and (SBI)Zr(III)(μ-H)2Al(i)Bu2 are formed by reduction [(SBI)Zr(μ-Me)2AlMe2](+)...
We calculate theoretically the transverse magneto-optical Kerr effect (TMOKE) in periodically patterned waveguide made from a diluted magnetic semiconductor. It is demonstrated that TMOKE resonantly enhanced when incident wave resonance with bound state continuum, arising quality factor of mode increases due to far-field interference. Our results uncover potential all-dielectric and semiconductor nanostructures for resonant magneto-optics.
Several of the recently discovered 2D layered quantum materials host higher-order Van Hove singularities near charge neutrality point. The authors develop here a universal description for magnetic breakdown different types singularities. observation such via measurement oscillations or longitudinal bulk conductance in Hall bar allows reconstruction Fermi surface and classification corresponding saddle point dispersion.