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61.
Evgen V. Govor Andrey B. Lysenko Alexander N. Chernega Judith A.K. Howard Andriy A. Mokhir Joachim Sieler Konstantin V. Domasevitch 《Polyhedron》2008
Reaction of copper(II) acetate, lanthanium(III) or gadolinium(III) nitrate (1/5 equiv.) with pyrazinohydroxamic acid (H2Pyzha) in DMF led to a series of new heterobimetallic 15-metallacrown-5 complexes. In a MeOH/H2O solution the complexes exist as molecular unassociated metallacrowns. In solid state their structures are more complicated as it has been confirmed by X-ray analysis: discrete molecular metallacrowns [Gd(NO3)2{Cu(pyzha)}5(DMF)4(NO3)] · 0.5C6H6 · H2O (1), [Gd(NO3)2{Cu(pyzha)}5(DMF)5](NO3) · 1.5DMF · 0.5H2O (2), [La(NO3)2{Cu(pyzha)}5(DMF)5]NO3 · 1.5DMF · 2C6H6 (3) are solvates, whereas compound [{La(NO3)2{Cu(pyzha)}5(DMF)5}2(μ2-NO3)](NO3) · 3DMF (4) is a dimer, where μ-bridged nitrate links two copper centres of the adjacent metallamacrocycles. Complex [Gd(NO3)2{Cu(pyzha)}5(DMF)2(H2O)(NO3)] · CH2Cl2 · DMF (5) self-associates into a polymer chain by means of one pyrazine moiety and the copper ring atom. Reaction of the molecular metallacrowns with excess of inorganic salts CdBr2 or Cu(OAc)2 proceeds as anion methathesis process affording heteroanionic metallacrowns: molecular [Gd(NO3)2{Cu(pyzha)}5(DMF)5] [Gd(NO3)2{Cu(pyzha)}5(DMF)4(H2O)][CdBr4] · 1.5DMF (6), and 3D hydrogen bonded polymer [La(μ2-OAc)(H2O)3{Cu(pyzha)}5 (H2O)4(NO3)](NO3) · 4H2O (7). 相似文献
62.
Dr. Igor L. Dalinger Dr. Irina A. Vatsadze Dr. Tatyana K. Shkineva Dr. Alexandr V. Kormanov Dr. Marina I. Struchkova Dr. Kyrill Yu. Suponitsky Dr. Anatoly A. Bragin Dr. Konstantin A. Monogarov Dr. Valery P. Sinditskii Dr. Aleksei B. Sheremetev 《化学:亚洲杂志》2015,10(9):1987-1996
A new family of energetic compounds, nitropyrazoles bearing a trinitromethyl moiety at the nitrogen atom of the heterocycle, was designed. The desirable high‐energy dense oxidizers 3,4‐dinitro‐ and 3,5‐dinitro‐1‐(trinitromethyl)pyrazoles were synthesized in good yields by destructive nitration of the corresponding 1‐acetonylpyrazoles. All of the prepared compounds were fully characterized by multinuclear NMR and IR spectroscopy, as well as by elemental analysis. Single‐crystal X‐ray diffraction studies show remarkably high density. Impact sensitivity tests and thermal stability measurements were also performed. All of the pyrazoles possess positive calculated heats of formation and exhibit promising energetic performance that is the range of 1,3,5‐trinitroperhydro‐1,3,5‐triazine and pentaerythritol tetranitrate. The new pyrazoles exhibit positive oxygen balance and are promising candidates for new environmentally benign energetic materials. 相似文献
63.
Dr. Christin Kirst Jonathan Tietze Dr. Peter Mayer Prof. Dr. Hans-Christian Böttcher Prof. Dr. Konstantin Karaghiosoff 《ChemistryOpen》2022,11(3):e202100224
The different coordination behavior of the flexible yet sterically demanding, hemilabile P,N ligand bis(quinoline-2-ylmethyl)phenylphosphine ( bqmpp ) towards selected CuI, AgI and AuI species is described. The resulting X-ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN)4]BF4, compound 1 [Cu2(bqmpp)2](BF4)2 is obtained, wherein the copper(I) atoms display a distorted square planar and square pyramidal geometry. The steric demand and π-stacking of the ligand allow for a short Cu⋅⋅⋅Cu distance (2.588(9) Å). CuI complex 2 [Cu4Cl3(bqmpp)2]BF4 contains a rarely observed Cu4Cl3 cluster, probably enabled by dichloromethane as the chloride source. In the cluster, even shorter Cu⋅⋅⋅Cu distances (2.447(1) Å) are present. The reaction of Ag[SbF6] with the ligand leads to a dinuclear compound ( 3 ) in solution as confirmed by 31P{1H} NMR spectroscopy. During crystallization, instead of the expected phosphine complex 3 , a tris(quinoline-2-ylmethyl)bisphenyl-phosphine ( tqmbp ) compound [Ag2(tqmbp)2](SbF6)2 4 is formed by elimination of quinaldine. The Au(I) compound [Au2(bqmpp)2]PF6 ( 5 ) is prepared as expected and shows a linear arrangement of two phosphine ligands around AuI. 相似文献
64.
65.
Dr. Alexey S. Kiryutin Dr. Grit Sauer Dr. Daniel Tietze Martin Brodrecht Stephan Knecht Prof. Dr. Alexandra V. Yurkovskaya Prof. Dr. Konstantin L. Ivanov Dr. Olga Avrutina Prof. Dr. Harald Kolmar Prof. Dr. Gerd Buntkowsky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4025-4030
Two-dimensional NMR spectroscopy is one of the most important spectroscopic tools for the investigation of biological macromolecules. However, due to the low sensitivity of NMR spectroscopy, it takes usually from several minutes to many hours to record such spectra. Here, the possibility of detecting a bioactive derivative of the sunflower trypsin inhibitor-1 (SFTI-1), a tetradecapeptide, by combining parahydrogen-induced polarization (PHIP) and ultrafast 2D NMR spectroscopy is shown. The PHIP activity of the inhibitor was achieved by labeling with O-propargyl-l -tyrosine. In 1D PHIP experiments a signal enhancement of a factor of approximately 1200 compared to standard NMR was found. This enhancement permits measurement of 2D NMR correlation spectra of low-concentrated SFTI-1 in less than 10 seconds, employing ultrafast single-scan 2D NMR detection. As experimental examples PHIP-assisted ultrafast single-scan TOCSY spectra of SFTI-1 are shown. 相似文献
66.
Dr. Yulia Y. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Y. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10552-10556
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity). 相似文献
67.
Galia Pozina Elizaveta I. Girshova Konstantin M. Morozov Konstantin A. Ivanov Anton Yu. Egorov Mikhail A. Kaliteevski 《Annalen der Physik》2019,531(6)
Enhancement of spontaneous emission in a resonant Bragg quantum well (QW) structure with 60 periods of triple InAs monolayers embedded in a GaAs matrix is studied experimentally and theoretically. From measurements of the time‐resolved photoluminescence, besides the QW exciton at 1.47 eV, a specific super‐radiant (SR) emission demonstrating nonlinear properties is found. The SR mode shows a near‐quadratic dependence of intensity on excitation power, while its energy position follows the Bragg condition. It is revealed that the SR mode shows a peculiar non‐monotonic dependence of intensity on direction, with a maximum observed at approximately 40°. The enhancement in the SR emission at a specific direction is correlated well with suggested theoretical consideration of the modal Purcell factor for periodic quantum well structures. 相似文献
68.
69.
Marco Reichel Mara Egenhöfer Burkhard Krumm Konstantin Karaghiosoff 《无机化学与普通化学杂志》2020,646(6):328-331
Fluoromethylating agents are a highly studied and controversely discussed class of compounds. New fluoromethyl pseudohalides FCH2N3, FCH2SCN, and FCH2SeCN were prepared for the first time and their physical and spectroscopic properties investigated. Their synthesis is performed conveniently by fluoromethylation of the respective silver or potassium pseudohalogenides with fluoroiodomethane. 相似文献
70.
Dr. Konstantin I. Galkin Bogdan Ya. Karlinskii Dr. Alexander Yu. Kostyukovich Dr. Evgeniy G. Gordeev Prof. Dr. Valentine P. Ananikov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8567-8571
This work reveals ambident nucleophilic reactivity of imidazolium cations towards carbonyl compounds at the C2 or C4 carbene centers depending on the steric properties of the substrates and reaction conditions. Such an adaptive behavior indicates the dynamic nature of organocatalysis proceeding via a covalent interaction of imidazolium carbenes with carbonyl substrates and can be explained by generation of the H-bonded ditopic carbanionic carbenes. 相似文献