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Synthesis, molecular structure and catalytic performance of heterocycle-fused cyclopentadienyl-amido CGC of Ti (IV) in ethylene (co)polymerization: The formation and precision rheometry of long-chain branched polyethylenes
European Polymer Journal. 2022. Vol. 176. Article 111397.
Ilya E.Nifant'ev, Vinogradov A., Vinogradov A., Guzelia I.Sadrtdinova, Komarov P., Minyaev M., Ilyin S., Artem V. Kiselev, Samurganova T., Ivchenko P.
Long-chain branching is an efficient tool to design and produce polyolefins with enhanced mechanical characteristics, physical properties, and processability. In the synthesis of long-chain branched polyethylene (LCB PE), constrained geometry complexes (CGCs) of Ti (IV) [(η5-C5Me4)SiMe2NtBu]TiX2 (X = Cl, Ti1; X = alkyl) are highly effective at elevated temperatures. However, further development of polyolefin technologies requires new catalytic approaches to provide LCB formation in broad temperature interval. In the present study, a series of CGCs of Ti (IV) of general formula [Cp#SiMe2NtBu]TiCl2 derived from heterocycle-fused cyclopentadienes Cp# (Ti2–Ti5) were synthesized and characterized by NMR spectroscopy and by X-ray diffraction analysis (XRD). New complexes Ti2–Ti5 along with benchmark precatalysts (n-BuC5H4)2ZrCl2 (Zr1) and Ti1 were supported on MMAO-12/silica and investigated in ethylene homopolymerization and ethylene/hex-1-ene copolymerization. In contrast to benchmark complexes Ti1 and Zr1, Ti2–Ti5 catalyzed formation of LCB PEs even at 80 °C, as confirmed by precision rheology studies of ethylene/hex-1-ene copolymers. The complex Ti2, derivative of 5-methyl-5,10-dihydroindeno[1,2-b]indole, demonstrated the best set of properties.
Nazarov Alexey A., Dudarova N., Zhidkova O. et al., Journal of Photochemistry and Photobiology A: Chemistry 2026 Vol. 483 Article 117654
Сyclocondensation of phenyl, ortho-bromophenyl, para-phenylphenyl, para-methoxycarbonylphenyl, para-tolyl and para-methoxyphenyl boronic acid with curcumin in the presence of K3PO4 upon refluxing in 1,4-dioxane for 24 h leads to the formation of curcumin-based 2,2-diaryl-1,3,2-dioxaborines in good yields. The absorption-emission spectra of the synthesized fluorescent conjugates and 1,3,2-dioxaborine with para-biphenyl boronic substituent demonstrated the highest quantum yield. Among the compounds studied, conjugate curcumin with para-methoxycarbonylphenyl boronic substituent ...
Added: September 9, 2026
Chemical Papers 2026
Benzenoid hydrocarbons are structurally regular aromatic compounds, which makes them well suited for quantitative structure–property relationship (QSPR) studies. This study presents a QSPR analysis of nineteen benzenoid hydrocarbon species using degree-based topological co-indices. We developed a Python program to compute eleven degree-based topological co-indices from molecular graphs and evaluated their ability to explain variations in ...
Added: September 8, 2026
Gurina D., Fashchevsky K. A., Oparin R. D. et al., Surfaces and Interfaces 2026 Vol. 98 Article 110545
In this work, we combine experimental characterization and molecular dynamics (MD) simulations to elucidate the molecular mechanisms governing the impregnation of mefenamic acid (MFA) into nanocrystalline cellulose (NCC) aerogels. NCC aerogels were impregnated with MFA in scCO2, and low-temperature nitrogen adsorption revealed a concentration-dependent decrease in surface area, pore volume, and pore size, with an ...
Added: September 8, 2026
Budkov Y., Journal of Chemical Physics 2026 Vol. 165 No. 9 Article 094902
We derive the stress tensor of a flexible polymer solution within the Gaussian-chain self-consistent field theory (SCFT) without invoking the ground-state dominance (GSD) approximation. Starting from a covariant formulation of the single-chain partition function in a background metric, we obtain the symmetric stress tensor expressed through the full Edwards propagators. The result contains the local ...
Added: September 2, 2026
Novikov A., Polyhedron 2026 Vol. 299 Article 118358
Two new supramolecular halometalate hybrid complexes, (H2bpen){[MCl5](I2)} (M = Sb(III) (1) and Bi(III) (2); bpen – 1,2-Bis(4-pyridyl)ethylene, have been prepared. Despite very close similarity of the nature of cations, they reveal significant structural difference from the (H2bpe){[MCl5](I2)} (bpe – 1,2-bis(4-pyridil)ethane) reported earlier. We discuss these features, along with thermal stability, optical properties as well as Raman spectra ...
Added: September 2, 2026
Meng K., Vasenko A., Chulkov E. et al., The Journal of Physical Chemistry Letters 2026 Vol. 17 No. 36 P. 10546–10554
Data-driven discovery of sodium-ion cathodes is often limited by small data sets and the poor interpretability of graph neural networks (GNNs). Here, we developed Symbol_ETR, an interpretable framework combining symbolic regression with ensemble learning. By constructing explicit nonlinear descriptors, symbolic regression extra trees regression (Symbol_ETR) achieves a test R2 of 0.90 for average voltage prediction ...
Added: August 29, 2026
Belousov Y., Кискин М. А., Sidoruk A. et al., Australian Journal of Chemistry 2022 Vol. 75 No. 9 P. 572–580
Four new complexes [Ln(pfaa)3(H2O)2]n (Ln = Eu (1), Tb (2)) and [Ln2Cd2(pfaa)10 (phen)2(EtOH)2]·2MeCN (Ln = Eu (3), Tb (4), phen = 1,10-phenanthroline) based on pentaphorphenylacetic acid (Hpfaa) have been prepared and completely investigated. The structures of compounds 1 and 3 were studied by single crystal X-ray diffraction analysis: the isostructural complexes 1 and 2 represent ...
Added: August 26, 2026
Mazur D., Petr E. Brandyshev, Doronin S. et al., Electrochimica Acta 2026 Vol. 577 Article 149729
The electric double layer (EDL) at a single-crystal metal surface is controlled not only by the electrolyte composition and the electrode potential, but also by the atomic structure of the surface itself. This makes the Ag(hkl)/NaF interface a stringent test for continuum theories of the EDL. In the third part of our series, we examine ...
Added: August 20, 2026
Budkov Y., Kalikin N., Journal of Chemical Physics 2026 Vol. 165 Article 064506
A self-consistent statistical-mechanical theory of the Hall effect in electrolyte solutions is developed by extending the self-consistent Debye–Hückel–Onsager (SCDHO) framework to crossed electric and magnetic fields. The theory incorporates non-local ionic charge distributions via Slater-type form factors, regularizing the Coulomb interaction at short range, and accounts for dielectric friction through ion-specific coefficients, employing experimental values ...
Added: August 12, 2026
Obijiofor O., Alexander S. Novikov, New Journal of Chemistry 2026 Vol. 50 No. 33 P. 13931–13957
The rational design of coinage metal nanocarriers requires a mechanistic understanding of metal-drug binding and predictive descriptors that translate molecular interactions into design rules. Using DFT (B3LYP-D3BJ/def2-TZVP, SMD water), we systematically investigated the binding of 5-fluorouracil (5-FU) and levodopa (l-DOPA) to neutral and cationic homo- and heteronuclear dimers of Au, Ag, and Cu (Au2, Ag2, ...
Added: August 12, 2026
Voropaeva D., S. Novikova, I. Stenina et al., Solid State Ionics 2026 Vol. 445 Article 117288
Composite gel polymer electrolytes based on a perfluorinated sulfonic acid cation-exchange MF-4SC membrane
containing surface-sulfonated nanoparticles of aluminum oxide, cerium (IV) oxide, and titanium oxide (sAl2O3,
sCeO2, and sTiO2, respectively) were prepared by casting from a dispersion in N,N-dimethylformamide and
plasticized with a 1,3-dioxolane/1,2-dimethoxyethane mixture. The influence of the filler nature on ionic conductivity,
solvent uptake, activation energy, lithium ...
Added: July 30, 2026
Korogod D., Shapeev A., Ivan S. Novikov, Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 2 Article 024104
We present two models with explicit long-range electrostatics in the form of Coulomb interactions. Both models include point charges depending on their local atomic environments, and the second model also conserves a total charge of an atomic system. We combine the proposed long-range models with the local moment tensor potential (MTP) and demonstrate that they ...
Added: July 22, 2026
Moshkina E., Molokeev M., Zolotov A. et al., Journal of Alloys and Compounds 2026 Vol. 1077 Article 189412
A wide series of substitutions in a subsystem of small radii cations M = Al, Cr, Fe, Ga, Sc is possible in rare-earth borates ReM3(BO3)4 with the huntite structure. However, the existence of these compounds where M = Mn still raises doubts. The study presents a synthetic approach developed in the framework of the flux method allowing for the required ...
Added: June 29, 2026
Schneider M., Zaripov D., Dokin R. et al., Journal of Chemical Theory and Computation 2026 Vol. 22 No. 9 P. 4405–4414
Density functional theory (DFT) is the workhorse of modern reactions and materials modeling. While the exact functional remains unknown, many approximations to it have been constructed either by hand-crafting functional forms to satisfy exact constraints or by machine learning. In this work, we show how both of these approaches can be fused to build both ...
Added: June 26, 2026
Laurinavichyute V., Levin E. E., Mironkova A. A. et al., Surfaces and Interfaces 2026 Vol. 81 Article 108389
In this work we characterize mixed Mo-W acidic deposition solutions with Mo content ranging from 0 to 100 mol.% by Raman and UV–Vis spectroscopy. The obtained distribution diagram of mixed isopolyanions allows one to explain the observed change in film deposition rate with increase in Mo content. It was found that the initial decrease in ...
Added: June 24, 2026
Filippova A. V., Yurchenko N. Y., Smirnov S. A. et al., Journal of Alloys and Compounds 2026 No. 1074 Article 189162
This study investigates the effects of post-processing heat treatment at 300–500 °C on the microstructure, hardness, and tensile properties of laser powder bed fusion (PBF-LB) processed Al-bronze processed with energy densities (ED) in the range of 125–938 J/mm3. In the as-printed state, sharp needle-like α + β′ laths form at lower ED whereas with increasing ED, the β′ ...
Added: June 12, 2026
Ilya Nifant’ev, Komarov P., Guzelia Sadrtdinova et al., Polymers 2024 Vol. 16 No. 5 Article 681
Silica-supported chromium oxide catalysts, also named Phillips chromium catalysts (PCCs), provide more than half of the world’s production of high- and medium-density polyethylenes. PCCs are usually prepared in the Cr(VI)/SiO2 form, which is subjected to reductive activation. It has been explicitly proven that CO reduces Cr(VI) to Cr(II) species that initiate ethylene polymerization; ethylene activates ...
Added: May 12, 2026
Roitershtein D., Puntus L., Varaksina E. et al., Russian Journal of Coordination Chemistry/Koordinatsionnaya Khimiya 2025 Vol. 51 No. 3 P. 218–225
The reaction of europium dibenzoylmethanate complex Na+[Eu(Dbm)4]– with 1-alkyl-4-dimethylaminopyridinium
salts gives compounds [RNC5H4NMe2]+[Eu(Dbm)4]– (Dbm = [PhC(O)CHC(O)–
Ph]), where R = C10H21 (I) or a set of oligomers CnH2n+1, (n is even) ([(R-NC5H4NMe2)]I) with a weightaverage
molecular weight Mw = 1520 (II). The molecular structure of complex I was established by X-ray diffraction
analysis (CCDC no. 2405293). Compounds I and ...
Added: November 9, 2025
D.E. Roshchin, Torkunov M. K., Shiyanova K. A. et al., Polymer Engineering and Science 2025 Vol. 65 No. 1 P. 290–298
The influence of cavitation-generated free radicals on the suspension polymerization of n-butyl methacrylate under ultrasonic irradiation was investigated experimentally and by kinetic modeling. A kinetic model of radical polymerization was proposed, considering the interaction of free radicals generated in cavitation bubbles with both monomer molecules and free radicals formed within the monomer droplets. It was found ...
Added: February 2, 2025
Guzelia I. Sadrtdinova, Daniil A. Bardonov, Konstantin A. Lyssenko et al., Mendeleev Communications 2023 Vol. 33 No. 3 P. 357–359
Mononuclear [CpNd(BH4)2L] borohydrides comprising
L = 1,3,5-trimethyl-1,3,5-triazacyclohexane (Me3tach) and
L = 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) were
obtained and structurally characterized. Their catalytic
activity in coordination–insertion ring-opening polymerization
of e-caprolactone was studied. ...
Added: January 18, 2024
D. E. Roshchin, Patlazhan S. A., Berlin A. A., European Polymer Journal 2023 Vol. 190 Article 112002
The free-radical polymerization inside monomer droplets surrounded by an immiscible liquid of the initiator solution is studied before the gel effect by means of the generalized method of moments taking into account diffusion of radicals and polymer chains. The influence of the droplet radius and initiator concentration in the surrounding phase on the polymerization kinetics ...
Added: January 8, 2024
Serkhacheva N. S., Ryzhikov K. A., Prokopov N. et al., Polymer Science - Series B 2022 Vol. 64 No. 2 P. 124–136
The regularities of the seeded polymerization of styrene in an aqueous-alcoholic medium in the presence of the seed particles of the triblock copolymer of acrylic acid and butyl acrylate, containing the trithiocarbonate group within the chain and acting as a reversible chain transfer agent, were studied for the first time. The influence of the composition ...
Added: October 27, 2022
Roitershtein D., Minyaev M., Komarov P. et al., Organometallics 2019 Vol. 38 No. 15 P. 2892–2901
Complexes [(1,2,4-Ph3C5H2)2NdCl2K(THF)2]2 (Nd1), {[1,2-Ph2-4-(4-MeOC6H4)C5H2]2NdCl2K(THF)2}2 (Nd2), {[1,2-Ph2-4-(2-MeOC6H4)C5H2]2NdCl2[K(THF)4]}(THF)0.5 (Nd3), and [(1,2,4-Ph3C5H2)2TbCl2K]2 (Tb1) have been synthesized, studied by X-ray diffraction analysis, and used in coordinative chain transfer polymerization (CCTP) of ethylene upon activation by alkyl magnesium derivatives. The complexes Nd1 and Tb1 exhibiting similar molecular structures and the same core type have demonstrated similar catalytic activities. Two types ...
Added: August 13, 2019
Roitershtein D., Savchenko M., Lyssenko K. et al., New Journal of Chemistry 2017 Vol. 41 P. 13663–13672
Luminescent composite materials based on linear polyethylene doped by well dispersed tetrakis dibenzoylmethanate europium complex have been developed. The anion of the latter serves as an efficient light harvesting antenna and possesses the desired photophysical properties. The targeted modification of the Eu complex, namely introduction of a long hydrocarbon chain into the tetraalkylammonium cation [RNEt3]+, ...
Added: October 19, 2018