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1.
Kirill P. Birin Yulia G. Gorbunova Aslan Yu. Tsivadze 《Magnetic resonance in chemistry : MRC》2010,48(7):505-515
A novel approach for the structural analysis of heteroleptic triple‐decker (porphyrinato)(phthalocyaninato) lanthanides(III) in solutions is developed. The developed approach consists in molecular mechanics (MM+) optimization of the geometry of the complex taking into account the lanthanide‐induced shift (LIS) datasets. LISs of the resonance peaks in 1H NMR spectra of a series of symmetric complexes [An4P]Ln[(15C5)4Pc]Ln[An4P], where An4P2? is 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrinato‐dianion, [(15C5)4Pc]2? is 2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninato‐dianion and Ln = La, Ce, Pr, Nd, Sm, Eu, are analyzed. Analysis of LISs showed two sets of protons in the molecule with opposite signs of shift. Two‐nuclei analysis of LISs testifies isostructurality of the whole series of investigated complexes in solution despite contraction of the lanthanide ions. Model‐free separation of contact and dipolar contributions of LISs was performed with one‐nucleus technique and did not show changes in contact and dipolar terms within the investigated series. MM+ optimization of the molecular structure allowed the interpretation of features of LIS for each particular group of protons. Parameterization of MM + ‐optimized model of molecule with values of structure‐dependent dipolar contributions of LIS allows the development of the precise structural model of the triple‐decker complex in solution. This approach allows the determination of the geometry and structure of the sandwich macrocyclic tetrapyrrolic complexes together with conformational analysis of flexible peripheral substituents in solutions. The developed method can be applied with minor modifications for the determination of structural parameters of other types of lanthanides(III) complexes with tetrapyrrolic ligands and also supramolecular systems based on them. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
2.
Clusters of galaxies are excellent probes of cosmic structure and evolution. X-ray studies of clusters provide some of their
key parameters, viz., temperature of the hot intra-cluster gas, its metallicity, X-ray luminosity and surface brightness giving
mass distribution and mass-flow rate in the case of cooling flows. X-ray measurements for a large sample of clusters have
lead to estimates of the total gravitating mass in them, which can be compared to the virial masses derived from dynamical
considerations and gravitational lensing in some of them. X-ray derived total masses are consistent with masses obtained from
the other methods after the effects due to the presence of cooling flows are taken into account in the analyses. Estimated
virial masses, lack of evolution in X-ray properties, and detection of several very hot clusters at high redshifts indicate
a Universe with a low value (≤ 0.3) for the Ω parameter. 相似文献
3.
M.?V.?Sokolovskaya S.?E.?LyubimovEmail author I.?S.?Mikhel K.?P.?Birin V.?A.?Davankov 《Russian Chemical Bulletin》2018,67(2):260-264
A series of phosphoramidite ligands was tested in the asymmetric hydrogenation of 4-arylsubstituted 1,3-dihydro-2H-benzodiazepine-2-ones and up to 52% ee was achieved. The effects of various factors (solvents, hydrogen pressure, and addition of phosphine ligands) on the hydrogenation were studied. 相似文献
4.
S. L. Selector A. V. Shokurov V. V. Arslanov Yu. G. Gorbunova O. A. Raitman A. A. Isakova K. P. Birin A. Yu. Tsivadze 《Russian Journal of Electrochemistry》2012,48(2):218-233
The spectral and electrochemical properties of Langmuir-Blodgett (LB) films of homoleptic double-decker cerium bis-[tetra-15-crown-5]-phthalocyaninate
Ce[R4Pc]2 and its heteroleptic analog [Pc]Ce[R4Pc] were studied. It was shown that during formation of Langmuir monolayers upon contact of both complexes solutions with
water subphase the metal center with valent state IV in the solution transforms into one with the valent state III in the
monolayer. Upon cyclic compression-expansion of these monolayers, orientation-induced reversible intramolecular transfers
of electron from 4f orbital of cerium ion to the phthalocyanine macrocycle (compression) and in reverse direction (expansion) occur in a planar
supramolecular system. Scheme of reversible electrochemical transformations occurring in ultrathin films of double-decker
cerium crown-phthalocyaninates, one of which is associated with the Ce+3/Ce+4 redox-transition of metal center of the complex, was proposed and substantiated using the results of spectro-electrochemical
investigations. It was shown that one of these transformations is associated with the Ce+3/Ce+4 redox transition of metal center of the complex and upon change of metal center oxidation state its size changes, and, consequently,
the distance between the decks of the complex also changes. This change in the distance can lead to a substantial (13–15%)
modulation of the linear size of molecular assemblies with a large number of molecules in stack. On the basis of this effect
the supramolecular device that can perform mechanical work can be developed. Using surface plasmon resonance technique we
have demonstrated that a step change in electrode potential in region of 200–1000 mV induces a corresponding optical response
reflected in a step change of the resonance angle. High operation speed and reversibility of switching between stable states
can serve as a basis for development of optoelectronic switching systems. 相似文献
5.
Aggregation of methylpyrazinium iodide and its derivatives in chloroform and dichloromethane solutions was studied by EAS and 1H NMR spectroscopy. The isopentylpyrazinium iodide ion quadruple formation constants in solutions were evaluated. Formal extinction coefficient in the outer-sphere charge transfer band maxima does not depend on the degree of aggregation in the system. A model suggested for the formation of ion quadruples in solutions was discussed in terms of the density functional theory and using the X-ray diffraction data for crystalline methylpyrazinium iodides and its derivatives. 相似文献
6.
Pavel D. Komarov Kirill P. Birin Alexander A. Vinogradov Evgenia A. Varaksina Lada N. Puntus Konstantin A. Lyssenko Andrei V. Churakov Ilya E. Nifantev Mikhail E. Minyaev Dmitrii M. Roitershtein 《Molecules (Basel, Switzerland)》2022,27(22)
A series of potassium salts of di- and tri-arylsubstituted cyclopentadienes has been obtained by the metalation of the corresponding cyclopentadienes with benzylpotassium in THF media. Crystals of all compounds, afforded by recrystallization from THF/hexane, diglyme-THF/hexane and toluene/hexane mixtures, have been studied by X-ray diffraction. All studied potassium cyclopentadienides exhibit the luminescence at room temperature and overall quantum yield of photoluminescence for potassium salt of diarylsubstituted cyclopentadiene is 18%. 相似文献
7.
K. P. Birin Yu. G. Gorbunova A. Yu. Tsivadze 《Russian Journal of Inorganic Chemistry》2007,52(2):191-196
Praseodymium(III) complexes with tetra-15-crown-5-phthalocyanine—the neutral radical [(R4Pc?·)Pr3+(R4Pc2?)]0 and one-electron reduced [(R4Pc2?)Pr3+(R4Pc2?)]? forms of the sandwich double-decker complex and the triple-decker complex Pr2(R4Pc)3 (R4Pc2? is [4,5,4′,5′,4″,5t",4″′,5″′-tetrakis(1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion])—have been synthesized and spectrally characterized. These compounds have been obtained by direct interaction of tetra-15-crown-5-phthalocyanine with praseodymium(III) acetate or acetylacetonate. The salt anion has an effect on the yield and structure of the reaction products. The complexes have been obtained in high yields, isolated, and characterized by different physicochemical methods: UV and visible electronic absorption spectroscopy, 1H NMR, and MALDI-TOF mass spectrometry. The double-decker complex is stable in the solid state and in solutions. The triple-decker complex is stable only in the solid state. In a chloroform-methanol (10 vol %) solution, it slowly decomposes. 相似文献
8.
S. L. Selektor A. V. Shokurov O. A. Raitman L. S. Sheinina V. V. Arslanov K. P. Birin Yu. G. Gorbunova A. Yu. Tsivadze 《Colloid Journal》2012,74(3):334-345
The spectral, electrochemical, and optical properties of Langmuir-Blodgett films (LBFs) and cast films from a solution of new double-decker cerium bis[tetra-(15-crown-5)-phthalocyaninate] (Ce(R4Pc)2) are studied. Based on analysis of compression isotherms and quantum-chemical calculations, schemes of the organization of Ce(R4Pc)2 molecules at different states of its monolayers are proposed. Correlation dependences are determined in order to relate the optical and electrochemical characteristics of monolayers and LBFs of sandwich-type lanthanide phthalocyaninates to the ionic radii of their metal centers. The valent state of Ce ions in a monolayer-forming complex is determined, and a sequence of redox transformations occurring in LBF uppon appliance of a potential is proposed, one of the transformations being associated with the Ce3+/Ce4+ redox transition. Orientation-induced intramolecular electron transfer is revealed in the planar supramolecular system. It is shown that, during the formation of a monolayer from a Ce(R4Pc)2 solution, a tetravalent metal center passes to a trivalent state. Monolayer compression to a high surface pressure reverts the complex to the electronic state typical of the solution. The reversible transformations observed upon the monolayer compression result from intramolecular electron transfer from the 4f-orbital of Ce to the phthalocyanine ring and backwards. The high operation rate and the reversibility of switching between the stable states, which are determined by means of the surface plasmon resonance technique, upon a stepwise change in the electrode potential within the range of 200?C850 mV may underlie the development of optoelectronic systems. With a large number of molecules in a stacking aggregate, changes in the distance between the decks of the complex that occur with changes in the oxidation level of the metal center can substantially modulate the sizes of molecular ensembles. A supramolecular device capable of performing mechanical work can be developed based on this effect. 相似文献
9.
Lyubimov S. E. Sokolovskaya M. V. Mikhel I. S. Birin K. P. Davankov V. A. 《Russian Chemical Bulletin》2019,68(7):1429-1434
Russian Chemical Bulletin - A novel chiral phosphoramidite ligand, (Sa)-2-[N-ethyl-N-(1-naphthylmethyl)amino]-dinaphtho[2,1-d:1´,2´-f][1,3,2]dioxaphosphepane, was obtained and tested in... 相似文献
10.
P. S. Koroteev Zh. V. Dobrokhotova A. B. Ilyukhin K. P. Birin M. S. Motornova V. M. Novotortsev 《Russian Chemical Bulletin》2012,61(6):1069-1078
New rare-earth cymantrenecarboxylate complexes [Ln2(μ,η2-O2CCym)2(μ2-O2CCym)2-(η2-O2CCym)2(DMSO)4] (Cym = (η5-C5H4)Mn(CO)3, Ln = Ce (1), Nd (2), Eu (3), Gd (4)) were synthesized and characterized by X-ray diffraction. In dimeric structures 1–4, two of four bridging carboxylates are chelating-bridging, and Ln atoms have coordination number 9. The catalytic activity of complex 2 in the polymerization of 2,3-dimethyl-1,3-butadiene was investigated. The thermal decomposition of the synthesized compounds was studied by DSC and TGA. According to the X-ray powder diffraction data, the final thermal decomposition product of 1 in air consists of CeO2 and Mn3O4. Under the same conditions, complexes 2–4 afford mixtures of LnMn2O5 and Mn2O3. 相似文献