21 results on '"Nelyubina, Yulia V."'
Search Results
2. Bis(2,6-pyrazolyl)pyridines as a New Scaffold for Coordination Polymers.
- Author
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Nikovskiy, Igor A., Dorovatovskii, Pavel V., Novikov, Valentin V., and Nelyubina, Yulia V.
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COORDINATION polymers ,ABSTRACTION reactions ,TRANSFORMATION groups ,ION sources ,METAL-organic frameworks ,IRON - Abstract
Two coordination polymers, Fe(L
OBF 3 )(CH3 COO)(CH3 CN)2 ]n •nCH3 CN and [Fe(LO− )2 AgNO3 BF4 •CH3 OH]n •1.75nCH3 OH•nH2 O (LO− = 3,3′-(4-(4-cyanophenyl)pyridine-2,6-diyl)bis(1-(2,6-dichlorophenyl)-1H-pyrazol-5-olate)), were obtained via a PCET-assisted process that uses the hydroxy-pyrazolyl moiety of the ligand and the iron(II) ion as sources of proton and electron, respectively. Our attempts to produce heterometallic compounds under mild conditions of reactant diffusion resulted in the first coordination polymer of 2,6-bis(pyrazol-3-yl)pyridines to retain the core N3 (L)MN3 (L). Under harsh solvothermal conditions, a hydrogen atom transfer to the tetrafluoroborate anion caused the transformation of the hydroxyl groups into OBF3 in the third coordination polymer of 2,6-bis(pyrazol-3-yl)pyridines. This PCET-assisted approach may be applicable to produce coordination polymers and metal–organic frameworks with the SCO-active core N3 (L)MN3 (L) formed by pyrazolone- and other hydroxy-pyridine-based ligands. [ABSTRACT FROM AUTHOR]- Published
- 2023
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3. The Role of Non-Covalent Interactions in the Reactions between Palladium Hydrido Complex with Amidoarylphosphine Pincer Ligand and Brønsted Acids.
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Kirkina, Vladislava A., Kulikova, Vasilisa A., Gutsul, Evgenii I., Gafurov, Zufar N., Sakhapov, Ilias F., Yakhvarov, Dmitry G., Nelyubina, Yulia V., Filippov, Oleg A., Shubina, Elena S., and Belkova, Natalia V.
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BRONSTED acids ,FORMIC acid ,PALLADIUM compounds ,NUCLEAR magnetic resonance spectroscopy ,PROTON transfer reactions ,PALLADIUM - Abstract
The interaction between (PNP)PdH (1); PNP = bis(2-diisopropylphosphino-4-methylphenyl)amide and different acids (CF
3 SO3 H, HBF4 ∙Et2 O, fluorinated alcohols and formic acid) was studied in benzene or toluene as well as in neat alcohols by IR and NMR spectroscopies. The structures of hydrogen-bonded complexes were also optimized at the DFT/ωB97-XD/def2-TZVP level. The nitrogen atom of the amidophosphine pincer ligand readily accepts proton not only from strong Brønsted acids but from relatively weak fluorinated alcohols. That suggests that binding to palladium(II) increases the diarylamine basicity, making it a strong base. Nevertheless, H+ can be taken from [(PN(H)P)PdH]+ (2) by pyridine or hexamethylphosphoramide (HMPA). These observations confirm the need for a shuttle base to form [(PN(H)P)PdH]+ (2) as the result of the heterolytic splitting of H2 by [(PNP)Pd]+ . At that, a stoichiometric amount of formic acid protonates a hydride ligand yielding an unstable η2 -H2 complex that rapidly converts into formate (PNP)Pd(OCHO), which loses CO2 to restore (PNP)PdH, whereas the relatively high acid excess hampers this reaction through competitive protonation at nitrogen atom. [ABSTRACT FROM AUTHOR]- Published
- 2023
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4. [3+3]-Annulation of Cyclic Nitronates with Vinyl Diazoacetates: Diastereoselective Synthesis of Partially Saturated [1,2]Oxazino[2,3- b ][1,2]oxazines and Their Base-Promoted Ring Contraction to Pyrrolo[1,2- b ][1,2]oxazine Derivatives.
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Antonova, Yulia A., Nelyubina, Yulia V., Ioffe, Sema L., and Tabolin, Andrey A.
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OXAZINES , *PYRROLES , *RHODIUM , *ACETAL resins , *ALKENES , *DIAZO compounds - Abstract
A rhodium(II)-catalyzed reaction of cyclic nitronates (5,6-dihydro-4H-1,2-oxazine N-oxides) with vinyl diazoacetates proceeds as a [3+3]-annulation producing bicyclic unsaturated nitroso acetals (4a,5,6,7-tetrahydro-2H-[1,2]oxazino[2,3-b][1,2]oxazines). Optimization of reaction conditions revealed the use of Rh(II) octanoate as the preferred catalyst in THF at room temperature, which allows the preparation of target products in good yields and excellent diastereoselectivity. Under basic conditions, namely, the combined action of DBU and alcohol, these nitroso acetals undergo ring contraction of an unsaturated oxazine ring into the corresponding pyrrole. Both transformations can be performed in a one-pot fashion, thus constituting a quick approach to oxazine-annulated pyrroles from available starting materials, such as nitroalkenes, olefins, and diazo compounds. [ABSTRACT FROM AUTHOR]
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- 2023
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5. Pyrrolidine-Derived Phenanthroline Diamides: An Influence of Fluorine Atoms on the Coordination of Lu(III) and Some Other f-Elements and Their Solvent Extraction.
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Avagyan, Nane A., Lemport, Pavel S., Evsiunina, Mariia V., Matveev, Petr I., Aksenova, Svetlana A., Nelyubina, Yulia V., Yatsenko, Alexandr V., Tafeenko, Viktor A., Petrov, Vladimir G., Ustynyuk, Yuri A., Bi, Xihe, and Nenajdenko, Valentine G.
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DIAMIDES ,SOLVENT extraction ,PHENANTHROLINE ,LUTETIUM compounds ,STABILITY constants ,FLUORINE ,ATOMS ,CHEMICAL shift (Nuclear magnetic resonance) - Abstract
Three pyrrolidine-derived phenanthroline diamides were studied as ligands for lutetium trinitrate. The structural features of the complexes have been studied using various spectral methods and X-ray. The presence of halogen atoms in the structure of phenanthroline ligands has a significant impact on both the coordination number of lutetium and the number of solvate water molecules in the internal coordination sphere. The stability constants of complexes with La(NO
3 )3 , Nd(NO3 )3 , Eu(NO3 )3 , and Lu(NO3 )3 were measured to demonstrate higher efficiency of fluorinated ligands. NMR titration was performed for this ligand, and it was found that complexation with lutetium leads to an approximately 13 ppm shift of the corresponding signal in the19 F NMR spectrum. The possibility of formation of a polymeric oxo-complex of this ligand with lutetium nitrate was demonstrated. Experiments on the liquid–liquid extraction of Am(III) and Ln(III) nitrates were carried out to demonstrate advantageous features of chlorinated and fluorinated pyrrolidine diamides. [ABSTRACT FROM AUTHOR]- Published
- 2023
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6. Effect of Alkoxy Substituents on the Regioselectivity of Catalytic C-H Activation in Benzoic Acids: Experimental and DFT Study.
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Kharitonov, Vladimir B., Muratov, Dmitry V., Nelyubina, Yulia V., and Loginov, Dmitry A.
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BENZOATES ,METHOXY group ,ANNULATION ,BENZOIC acid ,RHODIUM ,X-ray diffraction ,HOMOGENEOUS catalysis - Abstract
This work demonstrates the influence of the catalyst and alkyne nature on the regioselectivity of rhodium-catalyzed annulation of alkoxy-substituted benzoic acids (such as 3-methoxybenzoic, 3,4-dimethoxybenzoic, and piperonylic acids) with alkynes. Here, X-ray diffraction and DFT calculation data gave evidence that the observed regioselectivity is provided by both steric and coordination effects of methoxy groups. The latter is the result of weak non-covalent C–H⋯O interactions with the supporting ligand rather than with the rhodium atom. We believe that these results are also valid for other reactions of the C-H activation of methoxy-substituted arene compounds. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Chiral Polymers from Norbornenes Based on Renewable Chemical Feedstocks.
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Nazarov, Ivan V., Zarezin, Danil P., Solomatov, Ivan A., Danshina, Anastasya A., Nelyubina, Yulia V., Ilyasov, Igor R., and Bermeshev, Maxim V.
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RING-opening polymerization ,CHIRAL stationary phases ,STATIONARY phase (Chromatography) ,POLYMERS ,GLASS transition temperature ,MOLECULAR weights ,MENTHOL ,ALCOHOL - Abstract
Optically active polymers are of great interest as materials for dense enantioselective membranes, as well as chiral stationary phases for gas and liquid chromatography. Combining the versatility of norbornene chemistry and the advantages of chiral natural terpenes in one molecule will open up a facile route toward the synthesis of diverse optically active polymers. Herein, we prepared a set of new chiral monomers from cis-5-norbornene-2,3-dicarboxylic anhydride and chiral alcohols of various natures. Alcohols based on cyclic terpenes ((-)-menthol, (-)-borneol and pinanol), as well as commercially available alcohols (S-(-)-2-methylbutanol-1, S-(+)-3-octanol), were used. All the synthesized monomers were successfully involved in ring-opening metathesis polymerization, affording polymers in high yields (up to 96%) and with molecular weights in the range of 1.9 × 10
5 –5.8 × 105 (Mw ). The properties of the metathesis polymers obtained were studied by TGA and DSC analysis, WAXD, and circular dichroism spectroscopy. The polymers exhibited high thermal stability and good film-forming properties. Glass transition temperatures for the prepared polymers varied from −30 °C to +139 °C and, therefore, the state of the polymers changed from rubbery to glassy. The prepared polymers represent a new attractive platform of chiral polymeric materials for enantioselective membrane separation and chiral stationary phases for chromatography. [ABSTRACT FROM AUTHOR]- Published
- 2022
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8. New Titanium(IV)-Alkoxide Complexes Bearing Bidentate OO Ligand with the Camphyl Linker as Catalysts for High-Temperature Ethylene Polymerization and Ethylene/1-Octene Copolymerization.
- Author
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Tuskaev, Vladislav A., Gagieva, Svetlana Ch., Kurmaev, Dmitrii A., Nelyubina, Yulia V., Primakov, Petr V., Evseeva, Maria D., Golubev, Evgenii K., Buzin, Mikhail I., Nikiforova, Galina G., Dzhevakov, Pavel B., Privalov, Viktor I., Magomedov, Kasim F., and Bulychev, Boris M.
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COPOLYMERIZATION ,STERIC hindrance ,POLYMERIZATION ,TITANIUM ,ETHYLENE ,THERMAL stability - Abstract
In order to increase the thermal stability of olefin polymerization precatalysts, new titanium(IV) complexes with diolate ligands differing in the degree of steric hindrances were synthesized from readily available precursor (±)camphor. The structures of the complexes 1–2 were established by X-ray diffraction. Complexes 1–4 in the presence of an activator {Et
n AlCl3-n + Bu2 Mg} catalyzed the synthesis of UHMWPE with an Mv up to 10 million and a productivity of up to 3300 kg/molTi ·atm·h. The obtained polymers are obviously characterized by a low density of macromolecular entanglement, which makes it possible to use the solid-phase method for their processing. The mechanical characteristics of the oriented UHMWPE films had a breaking strength up to 2.7 GPa and an elastic modulus of up to 151 GPa. The precatalysts 1–4 were also active in ethylene/1-octene copolymerization. The comonomer content was in the range of 1.4–4.6 mol%. The use of a rigid linker and an increase in the steric load of the diolate complexes ensured the thermal stability of the catalytic system in the range of 50–70 °C. [ABSTRACT FROM AUTHOR]- Published
- 2022
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9. Binuclear Nickel Complexes of a New Di(hydroxyphenyl)imidazolate.
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Nikovskiy, Igor A., Karnaukh, Kseniia M., Aleshin, Dmitry Yu., Spiridonov, Kirill A., Danshina, Anastasia A., Nelyubina, Yulia V., Polezhaev, Alexander V., and Novikov, Valentin V.
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SINGLE molecule magnets ,NICKEL ,RADICAL cations ,MAGNETIC materials ,CYCLIC voltammetry ,INTRAMOLECULAR proton transfer reactions - Abstract
Here, we report a new di(hydroxyphenyl)imidazolate ligand with an N
2 O2 donor set synthesized by a modified Debus–Radziszewski procedure. Its binuclear nickel(II) complexes feature a weak antiferromagnetic interaction with J12 = −3.16 cm−1 between the two nickel(II) ions identified by magnetometry measurements. As follows from cyclic voltammetry experiments and DFT calculations, they undergo ligand-centered oxidation via the formation of cation radicals with short lifetimes that can be potentially stabilized by bulkier t-butyl groups in the ortho-positions of the ligand. The reported ligand widens the range of the building blocks available to molecular magnetism community and thus provides new ways to the design of magnetic materials with switchable properties. [ABSTRACT FROM AUTHOR]- Published
- 2022
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10. On the Isomorphism of Sodium at the M (2) Site in Eudialyte-Group Minerals: The Crystal Structure of Mn-Deficient Manganoeudialyte and the Problem of the Existence of the M (2) Na-Dominant Analogue of Eudialyte.
- Author
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Aksenov, Sergey M., Chukanov, Nikita V., Pekov, Igor V., Nelyubina, Yulia V., Varlamov, Dmitry A., and Kogarko, Lia N.
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ISOMORPHISM (Mathematics) ,MINERALS ,CRYSTAL structure ,SPACE groups ,SODIUM - Abstract
Sodium plays an important role in the crystal structures of eudialyte-group minerals given that it can occupy different crystallographic sites. Predominantly, it distributes between the N(1–5) sites situated in the large cavities of the heteropolyhedral framework. Rarely, Na occupies split sites of the M(2) microregion where it can predominate over other elements (predominantly Mn, Fe
2+ , and Fe3+ ). The crystal structure of the Mn-deficient manganoeudialyte from the Lovozero alkaline complex (Kola Peninsula, Russia) has been refined. The trigonal unit–cell parameters are: a = 14.1848(2) Å, c = 30.4726(3) Å, V = 5309.90(11) Å3 . The sample is a rare example of a high-sodium and high-calcium representative of the eudialyte group with Fe + Mn < 2 apfu. The idealized formula is Na14 Ca6 [(Mn,Fe)2 Na]Zr3 Si2 [Si24 O72 ]O(OH)·2H2 O with bivalent components, Mn2+ and Fe2+ , dominating at the M(2) site. The regularities of isomorphism involvingM (2) Na in EGMs and the problem of the existence of theM (2) Na-dominant analogue of eudialyte are discussed. The new data obtained in this work confirm the previous conclusion that the complete isomorphism between Ca-deficient and Ca-rich members of the eudialyte group cannot be realized in frames of a single-space group (R3m, R-3m or R3). Thus, the existence of theM (2) Na analogue of eudialyte remains questionable. [ABSTRACT FROM AUTHOR]- Published
- 2022
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11. New Co-Crystals/Salts of Gallic Acid and Substituted Pyridines: An Effect of Ortho-Substituents on the Formation of an Acid–Pyridine Heterosynthon.
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Denisov, Gleb L. and Nelyubina, Yulia V.
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GALLIC acid ,HYDROGEN bonding ,ZWITTERIONS ,X-ray diffraction ,CRYSTALLIZATION ,MECHANICAL properties of condensed matter - Abstract
Co-crystallization of gallic acid with pyridines and their polyaromatic analogue, quinoline, ortho-substituted by various proton-donating groups able to form hydrogen bonds, produced the only reported co-crystal of gallic acid with an ortho-substituted pyridine, 2-hydroxypyridine, as its preferred pyridone-2 tautomer, and four new crystalline products of gallic acid. These co-crystals, or gallate salts depending on the choice of the pyridine-containing compound, as predicted by the pKa rule, were identified by X-ray diffraction to feature the popular acid–pyridine heterosynthon found in most of the two-component systems of gallic acid that lack ortho-substituents in the pyridine-containing compound. This single-point heterosynthon is, however, modified by one or two proton-donating ortho-substituents, which sometimes may transform into the proton acceptors in an adopted tautomer or zwitterion, to produce its two- or other multi-point variants, including a very rare four-point heterosynthon. The hydrogen bonds they form with the gallic acid species in the appropriate co-crystals/salts strongly favors the formation of the acid–pyridine heterosynthon over the acid–acid homosynthon. In the competitive conditions of multi-component systems, such a modification might be used to reduce supramolecular-synthon-based polymorphism to produce new pharmaceuticals and other crystalline materials with designed properties. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. Stereoselective Alkane Oxidation with meta-Chloroperoxybenzoic Acid (MCPBA) Catalyzed by Organometallic Cobalt Complexes.
- Author
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Shul’pin, Georgiy B., Loginov, Dmitriy A., Shul’pina, Lidia S., Ikonnikov, Nikolay S., Idrisov, Vladislav O., Vinogradov, Mikhail M., Osipov, Sergey N., Nelyubina, Yulia V., and Tyubaeva, Polina M.
- Abstract
Cobalt pi-complexes, previously described in the literature and specially synthesized and characterized in this work, were used as catalysts in homogeneous oxidation of organic compounds with peroxides. These complexes contain pi-butadienyl and pi-cyclopentadienyl ligands: [(tetramethylcyclobutadiene)(benzene)cobalt] hexafluorophosphate, [(C
4 Me4 )Co(C6 H6 )]PF6 (1); diiodo(carbonyl)(pentamethylcyclopentadienyl)cobalt, Cp*Co(CO)I2 (2); diiodo(carbonyl)(cyclopentadienyl)cobalt, CpCo(CO)I2 (3); (tetramethylcyclobutadiene)(dicarbonyl)(iodo)cobalt, (C4 Me4 )Co(CO)2 I (4); [(tetramethylcyclobutadiene)(acetonitrile)(2,2′-bipyridyl)cobalt] hexafluorophosphate, [(C4 Me4 )Co(bipy)(MeCN)]PF6 (5); bis[dicarbonyl(B-cyclohexylborole)]cobalt, [(C4 H4 BCy)Co(CO)2 ]2 (6); [(pentamethylcyclopentadienyl)(iodo)(1,10-phenanthroline)cobalt] hexafluorophosphate, [Cp*Co(phen)I]PF6 (7); diiodo(cyclopentadienyl)cobalt, [CpCoI2 ]2 (8); [(cyclopentadienyl)(iodo)(2,2′-bipyridyl)cobalt] hexafluorophosphate, [CpCo(bipy)I]PF6 (9); and [(pentamethylcyclopentadienyl)(iodo)(2,2′-bipyridyl)cobalt] hexafluorophosphate, [Cp*Co(bipy)I]PF6 (10). Complexes 1 and 2 catalyze very efficient and stereoselective oxygenation of tertiary C–H bonds in isomeric dimethylcyclohexanes with MCBA: cyclohexanols are produced in 39 and 53% yields and with the trans/cis ratio (of isomers with mutual trans- or cis-configuration of two methyl groups) 0.05 and 0.06, respectively. Addition of nitric acid as co-catalyst dramatically enhances both the yield of oxygenates and stereoselectivity parameter. In contrast to compounds 1 and 2, complexes 9 and 10 turned out to be very poor catalysts (the yields of oxygenates in the reaction with cis-1,2-dimethylcyclohexane were only 5%–7% and trans/cis ratio 0.8 indicated that the oxidation is not stereoselective). The chromatograms of the reaction mixture obtained before and after reduction with PPh3 are very similar, which testifies that alkyl hydroperoxides are not formed in this oxidation. It can be thus concluded that the interaction of the alkanes with MCPBA occurs without the formation of free radicals. The complexes catalyze oxidation of alcohols with tert-butylhydroperoxide (TBHP). For example, tert-BuOOH efficiently oxidizes 1-phenylethanol to acetophenone in 98% yield if compound 1 is used as a catalyst. [ABSTRACT FROM AUTHOR]- Published
- 2016
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13. 3D-Printed Porous Magnetic Carbon Materials Derived from Metal–Organic Frameworks.
- Author
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Cherevko, Anton I., Nikovskiy, Igor A., Nelyubina, Yulia V., Skupov, Kirill M., Efimov, Nikolay N., and Novikov, Valentin V.
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MAGNETIC materials ,METAL-organic frameworks ,POROUS materials ,MANUFACTURING processes ,MAGNETIC particles ,NICKEL ,MESOPOROUS materials - Abstract
Here we report new porous carbon materials obtained by 3D printing from photopolymer compositions with zinc- and nickel-based metal–organic frameworks, ZIF-8 and Ni-BTC, followed by high-temperature pyrolysis. The pyrolyzed materials that retain the shapes of complex objects contain pores, which were produced by boiling zinc and magnetic nickel particles. The two thus provided functionalities—large specific surface area and ferromagnetism—that pave the way towards creating heterogenous catalysts that can be easily removed from reaction mixtures in industrial catalytic processes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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14. New Low-Dimensional Hybrid Perovskitoids Based on Lead Bromide with Organic Cations from Charge-Transfer Complexes.
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Nikovskiy, Igor A., Isakovskaya, Kseniya L., and Nelyubina, Yulia V.
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HYBRID solar cells ,ANTHRACENE derivatives ,ANTHRACENE ,OPTOELECTRONIC devices ,BROMIDES ,CATIONS ,X-ray diffraction - Abstract
We have obtained a series of low-dimensional hybrid perovskitoids (often referred to as perovskites) based on lead bromide. As organic cations, the derivatives of polyaromatic and conjugated molecules, such as anthracene, pyrene and (E)-stilbene, were chosen to form charge-transfer complexes with various organic acceptors for use as highly tunable components of hybrid perovskite solar cells. X-ray diffraction analysis showed these crystalline materials to be new 1D- and pseudo-layered 0D-perovskitoids with lead bromide octahedra featuring different sharing modes, such as in unusual mini-rods of four face- and edge-shared octahedra. Thanks to the low dimensionality, they can be of use in another type of optoelectronic device, photodetectors. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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15. Spin-Crossover in Iron(II) Complexes of N,N′-Disubstituted 2,6-Bis(Pyrazol-3-yl)Pyridines: An Effect of a Distal Substituent in the 2,6-Dibromophenyl Group.
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Nikovskiy, Igor A., Polezhaev, Alexander V., Novikov, Valentin V., Aleshin, Dmitry Yu., Aysin, Rinat R., Melnikova, Elizaveta K., Carrella, Luca M., Rentschler, Eva, and Nelyubina, Yulia V.
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SPIN crossover ,NUCLEAR magnetic resonance spectroscopy ,IRON ,COMPUTER storage devices ,METHYL groups ,X-ray diffraction ,BROMINE - Abstract
A series of new bis(pyrazol-3-yl)pyridines (L
R ) N,N′-disubstituted by 4-functionalized 2,6-dibromophenyl groups have been synthesized to study the effect of a distal substituent on the spin-crossover (SCO) behaviour of the iron(II) complexes [Fe(LR )2 ](ClO4 )2 by variable-temperature magnetometry, NMR spectroscopy, and X-ray diffraction. The SCO-assisting tendency of the substituents with different electronic and steric properties (i.e., the bromine atom and the methyl group) in the para-position of the 2,6-dibromophenyl group is discussed. Together with earlier reported SCO-active iron(II) complexes with N,N′-disubstituted bis(pyrazol-3-yl)pyridines, these new complexes open the way for this family of SCO compounds to emerge as an effective 'tool' in revealing structure–function relations, a prerequisite for successful molecular design of switchable materials for future breakthrough applications in sensing, switching, and memory devices. [ABSTRACT FROM AUTHOR]- Published
- 2021
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16. Synthesis, Photophysical, and Computational Studies of a Bridged Ir ΙΙΙ -Pt ΙΙ Heterodimetallic Complex.
- Author
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Wu, Si-Hai, Ma, Dian-Xue, Gong, Zhong-Liang, Ma, Junjie, Shao, Jiang-Yang, Yang, Rong, Zhong, Yu-Wu, Sanmartín-Matalobos, Jesús, and Nelyubina, Yulia V.
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ABSORPTION spectra ,PLATINUM ,ELECTRONIC structure ,BRIDGING ligands ,TRANSITION metal complexes ,PYRAZINES - Abstract
An Ir
III -PtII heterodimetallic complex [(ppy)2 Ir(dapz)PtCl2 ]Cl (4), together with the corresponding monometallic complexes [(dapz)PtCl2 ] (2) and [(ppy)2 Ir(dapz)]Cl (3) was designed and prepared, where dapz is 2,5-di(N-methyl-N′-(pyrid-2-yl)amino)pyrazine and ppy is 2-phenylpyridine, respectively. Single-crystal X-ray analysis was carried out for complex 4, displaying the intermolecular Pt∙∙∙Pt and aromatic plane∙∙∙plane distances of 3.839 and 3.886 Å, respectively. The monometallic complex 2 exhibits a single emission maximum at 432 nm with a shorter excited-state lifetime (τ) of 6 ns, while complex 3 exhibits an emission band at 454 nm with a longer excited-state lifetime of 135 ns in CH3 CN (N2 -saturated) under ambient conditions. In contrast, the heterodimetallic complex 4 displays intriguing excitation wavelength-dependent dual singlet and triplet emissions. Theoretical calculations of the electronic structures and absorption spectra of these complexes were carried out to assist the interpretation of these experimental findings. [ABSTRACT FROM AUTHOR]- Published
- 2021
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17. Synthesis, Structure and In Vitro Anticancer Activity of Pd(II) Complex of Pyrazolyl- s -Triazine Ligand; A New Example of Metal-Mediated Hydrolysis of s -Triazine Pincer Ligand.
- Author
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Lasri, Jamal, Haukka, Matti, Al-Rasheed, Hessa H., Abutaha, Nael, El-Faham, Ayman, Soliman, Saied M., and Nelyubina, Yulia V.
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TRIAZINE derivatives ,TRIAZINES ,HYDROGEN bonding interactions ,HYDROLYSIS ,PYRAZOLES ,CELL lines ,CRYSTAL structure - Abstract
The square planar complex [Pd(PT)Cl(H
2 O)]*H2 O (HPT: 6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4(1H,3H)-dione) was obtained by the reaction of 2-methoxy-4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine (MBPT) pincer ligand with PdCl2 in a molar ratio (1:1) under thermal conditions and using acetone as a solvent. The reaction proceeded via C-N cleavage of one C-N moiety that connects the pyrazole and s-triazine combined with the hydrolysis of the O-CH3 group. The reaction of the chloride salt of its higher congener (PtCl2 ) gave [Pt(3,5-dimethyl-1H-pyrazole)2 Cl2 ]. The crystal structure of [Pd(PT)Cl(H2 O)]*H2 O complex is stabilized by inter- and intra-molecular hydrogen bonding interactions. Hirshfeld analysis revealed that the H...H (34.6%), O...H (23.6%), and Cl...H (7.8%) interactions are the major contacts in the crystal. The charges at Pd, H2 O, Cl and PT are changed to 0.4995, 0.2216, −0.4294 and −0.2917 instead of +2, 0, −1 and −1, respectively, using the MPW1PW91 method. [Pd(PT)Cl(H2 O)]*H2 O complex has almost equal activities against MDA-MB-231 and MCF-7 cell lines with IC50 of 38.3 µg/mL. [ABSTRACT FROM AUTHOR]- Published
- 2021
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18. Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy.
- Author
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Melnikova, Elizaveta K., Aleshin, Dmitry Yu., Nikovskiy, Igor A., Denisov, Gleb L., and Nelyubina, Yulia V.
- Subjects
X-ray diffraction ,ANALYTICAL chemistry ,IRON ,ELECTRON paramagnetic resonance spectroscopy ,ION traps ,METAL ions ,CHEMICAL shift (Nuclear magnetic resonance) ,NUCLEAR magnetic resonance spectroscopy - Abstract
A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing 'molecular' design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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19. Steric and Electronic Effect of Cp-Substituents on the Structure of the Ruthenocene Based Pincer Palladium Borohydrides.
- Author
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Safronov, Sergey V., Osipova, Elena S., Nelyubina, Yulia V., Filippov, Oleg A., Barakovskaya, Irina G., Belkova, Natalia V., and Shubina, Elena S.
- Subjects
POLAR effects (Chemistry) ,PALLADIUM ,RUTHENIUM ,DATA analysis - Abstract
Ruthenocene-based PCP
tBu pincer ligands were used to synthesize novel pincer palladium chloride RcF [PCPtBu ]PdCl (2a) and two novel palladium tetrahydroborates RcF [PCPtBu ]Pd(BH4 ) (3a) and Rc* [PCPtBu ]Pd(BH4 ) (3b), where RcF [PCPtBu ] = κ3 -{2,5-(tBu2 PCH2 )2- C5 H2 }Ru(CpF ) (CpF = C5 Me4 CF3 ), and Rc*[PCPtBu ] = κ3 -{2,5-(tBu2 PCH2 )2 C5 H2 }Ru(Cp*) (Cp* = C5 Me5 ). These coordination compounds were characterized by X-ray, NMR and FTIR techniques. Analysis of the X-ray data shows that an increase of the steric bulk of non-metalated cyclopentadienyl ring in 3a and 3b relative to non-substituted Rc[PCPtBu ]Pd(BH4 ) analogue (3c; where Rc[PCPtBu ] = κ3 -{2,5-(tBu2 PCH2 )2 C5 H2 }Ru(Cp), Cp = C5 H5 ) pushes palladium atom from the middle plane of the metalated Cp ring in the direction opposite to the ruthenium atom. This displacement increases in the order 3c < 3b < 3a following the order of the Cp-ring steric volume increase. The analysis of both X-ray and IR data suggests that BH4 ligand in both palladium tetrahydroborates 3a and 3b has the mixed coordination mode η1,2 . The strength of the BH4 bond with palladium atom increases in the order Rc[PCPtBu ]Pd(BH4 ) < Rc*[PCPtBu ]Pd(BH4 ) < RcF [PCPtBu ]Pd(BH4 ) that appears to be affected by both steric and electronic properties of the ruthenocene moiety. [ABSTRACT FROM AUTHOR]- Published
- 2020
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20. Special Issue Editorial: Chemical Bonding in Crystals and Their Properties.
- Author
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Vologzhanina, Anna V. and Nelyubina, Yulia V.
- Subjects
CRYSTAL chemical bonds ,MOLECULAR volume ,MATERIALS science ,MOLECULAR shapes ,SCIENCE education - Abstract
Relations between physicochemical properties of chemical compounds exploited in many modern applications (including optical, magnetic, electrical, mechanical, and others) and interatomic interactions that operate in their crystals are the key to the successful design of new crystalline materials, in which X-ray crystallography has proved to be an invaluable tool. Among other experimental techniques, Raman spectroscopy was found to be useful for understanding the bonding features of the triiodide anion [[5]]; however, weak intermolecular interactions can also be identified by other spectroscopic tools. [Extracted from the article]
- Published
- 2020
- Full Text
- View/download PDF
21. Stereoselective Alkane Oxidation with meta-Chloroperoxybenzoic Acid (MCPBA) Catalyzed by Organometallic Cobalt Complexes.
- Author
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Shul'pin GB, Loginov DA, Shul'pina LS, Ikonnikov NS, Idrisov VO, Vinogradov MM, Osipov SN, Nelyubina YV, and Tyubaeva PM
- Subjects
- Catalysis, Molecular Structure, Oxidation-Reduction, Stereoisomerism, Alkanes chemistry, Chlorobenzoates chemistry, Cobalt chemistry, Organometallic Compounds chemistry
- Abstract
Cobalt pi-complexes, previously described in the literature and specially synthesized and characterized in this work, were used as catalysts in homogeneous oxidation of organic compounds with peroxides. These complexes contain pi-butadienyl and pi-cyclopentadienyl ligands: [(tetramethylcyclobutadiene)(benzene)cobalt] hexafluorophosphate, [(C₄Me₄)Co(C₆H₆)]PF₆ ( 1 ); diiodo(carbonyl)(pentamethylcyclopentadienyl)cobalt, Cp*Co(CO)I₂ ( 2 ); diiodo(carbonyl)(cyclopentadienyl)cobalt, CpCo(CO)I₂ ( 3 ); (tetramethylcyclobutadiene)(dicarbonyl)(iodo)cobalt, (C₄Me₄)Co(CO)₂I ( 4 ); [(tetramethylcyclobutadiene)(acetonitrile)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [(C₄Me₄)Co(bipy)(MeCN)]PF₆ ( 5 ); bis[dicarbonyl(B-cyclohexylborole)]cobalt, [(C₄H₄BCy)Co(CO)₂]₂ ( 6 ); [(pentamethylcyclopentadienyl)(iodo)(1,10-phenanthroline)cobalt] hexafluorophosphate, [Cp*Co(phen)I]PF₆ ( 7 ); diiodo(cyclopentadienyl)cobalt, [CpCoI₂]₂ ( 8 ); [(cyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [CpCo(bipy)I]PF₆ ( 9 ); and [(pentamethylcyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [Cp*Co(bipy)I]PF₆ ( 10 ). Complexes 1 and 2 catalyze very efficient and stereoselective oxygenation of tertiary C-H bonds in isomeric dimethylcyclohexanes with MCBA: cyclohexanols are produced in 39 and 53% yields and with the trans / cis ratio (of isomers with mutual trans - or cis -configuration of two methyl groups) 0.05 and 0.06, respectively. Addition of nitric acid as co-catalyst dramatically enhances both the yield of oxygenates and stereoselectivity parameter. In contrast to compounds 1 and 2 , complexes 9 and 10 turned out to be very poor catalysts (the yields of oxygenates in the reaction with cis -1,2-dimethylcyclohexane were only 5%-7% and trans / cis ratio 0.8 indicated that the oxidation is not stereoselective). The chromatograms of the reaction mixture obtained before and after reduction with PPh₃ are very similar, which testifies that alkyl hydroperoxides are not formed in this oxidation. It can be thus concluded that the interaction of the alkanes with MCPBA occurs without the formation of free radicals. The complexes catalyze oxidation of alcohols with tert -butylhydroperoxide (TBHP). For example, tert -BuOOH efficiently oxidizes 1-phenylethanol to acetophenone in 98% yield if compound 1 is used as a catalyst.
- Published
- 2016
- Full Text
- View/download PDF
Catalog
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