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111.
112.
Dariusz Basiak Tomasz Wojciechowski Patryk Rzepiński Łukasz Dobrzycki Anna Wojewódzka Dorota Monikowska Ewa Zygadło-Monikowska Wanda Ziemkowska 《应用有机金属化学》2020,34(9):e5751
Reactions of organomagnesium halides with group 13 metal halides lead to the formation of R3M type compounds (R = alkyl, aryl; M = Al, Ga, In) and are considered as the simplest methods of R3M compound syntheses. These seemingly simple reactions reveal a much more complex chemistry involving mixed magnesium-group 13 metal compounds. To elucidate the reaction course of reactions of organomagnesium halides with group 13 metal halides, we have studied reactions of R3M with organomagnesium halides. The interaction of Et3M with R1MgX led to the formation of following products being mixtures of crystalline ionic complexes with the general composition of [Et4-nR1nM]−[XMg (thf)5]+·(thf): [Et2.2Al(CH=CH2)1.8]−[BrMg (thf)5]+·(thf) ( 1 ), [Et3Ga(CH=CH2)]−[BrMg (thf)5]+·(thf) ( 2 ), [Et4Al]−[BrMg (thf)5]+·(thf) ( 3 ), [Et4Ga]−[BrMg (thf)5]+·(thf) ( 4 ), [Et2.9Al(C6H5)1.1]−[BrMg (thf)5]+·(thf) ( 5 ), [Et2.9Ga(C6H5)1.1]−[BrMg (thf)5]+·(thf) ( 6 ), [Et3.4GaMe0.6]−[IMg (thf)5]+·(thf) ( 7 ) and [Et4In]−[BrMg (thf)5]+·(thf) ( 8 ). A comparison of the production course of group 13 metal trialkyls R3M with a thermal decomposition of 1–8 products showed that reactions of MX3 with RMgX (X = Br, I; R = alkyl, aryl) yield initially intermediate ionic compounds, which must then be thermally decomposed to obtain pure R3M compounds. If group 13 metal bromides and iodides, and alkyl (aryl)magnesium bromides and iodides in thf are used, only intermediate products with the [R4M]−[XMg (thf)5]+·(thf) structure are formed. 相似文献
113.
Solution and Solid State Studies of Urea Derivatives of DITIPIRAM Acting as Powerful Anion Receptors
Patryk Niedbaa Kajetan Dbrowa Agnieszka Cholewiak-Janusz Janusz Jurczak 《Molecules (Basel, Switzerland)》2021,26(6)
Herein, we present the synthesis and anion binding studies of a family of homologous molecular receptors 4–7 based on a DITIPIRAM (8-propyldithieno-[3,2-b:2′,3′-e]-pyridine-3,5-di-amine) platform decorated with various urea para-phenyl substituents (NO2, F, CF3, and Me). Solution, X-ray, and DFT studies reveal that the presented host–guest system offers a convergent array of four urea NH hydrogen bond donors to anions allowing the formation of remarkably stable complexes with carboxylates (acetate, benzoate) and chloride anions in solution, even in competitive solvent mixtures such as DMSO-d6/H2O 99.5/0.5 (v/v) and DMSO-d3/MeOH-d3 9:1 (v/v). The most effective derivatives among the series turned out to be receptors 5 and 6 containing electron-withdrawing F- and -CF3 para-substituents, respectively. 相似文献
114.
Gossypol and its 1: 1 complexes with copper acetate in acetonitrile were studied by FTIR and UV-visible spectroscopy. With the complexation with Cu cation the tautomeric equilibrium of gossypol is completely shifted from the aldehyde-aldehyde to the lactol-lactol tautomer. The acidic character of O11H group in the gossypol-Cu complex led to the selective esterification of the lactol form of gossypol by the acetate group. 相似文献
115.
116.
Reductive amination of the macrolide antibiotic josamycin with alkyl amines, using three different reducing agents: NaBH3CN, NaBH4 and NaBH(OAc)3, yields surprisingly different major products which are identified as either Lewis complexes, aminoalkyl derivatives or α,β-unsaturated derivatives of josamycin by 1H and 13C NMR, FT-IR and ESI MS methods. 相似文献
117.
Patryk Brzezinski 《Mathematische Nachrichten》2013,286(17-18):1726-1743
This paper deals with volume estimates for hyperplane sections of the simplex and for m‐codimensional sections of powers of m‐dimensional Euclidean balls. In the first part we consider sections through the centroid of the n‐dimensional regular simplex. We state a volume formula and give a lower bound for the volume of sections through the centroid. In the second part we study the extremal volumes of m‐codimensional sections “perpendicular” to of unit balls in the space for all . We give volume formulas and use them to show that the normal vector (1, 0, …, 0) yields the minimal volume. Furthermore we give an upper bound for the ‐dimensional volumes for natural numbers . This bound is asymptotically attained for the normal vector as . 相似文献
118.
Jacek Szczepkowski Patryk Jasik Anna Grochola Włodzimierz Jastrzȩbski Józef E. Sienkiewicz Paweł Kowalczyk 《The European physical journal. Special topics》2013,222(9):2329-2333
The 41Σ+ state of LiCs molecule is observed experimentally for the first time. The inverted perturbation approach (IPA) method is used to derive the potential energy curve of the state from the measured spectra. The experiment is accompanied by theoretical calculations of adiabatic potentials for excited states in LiCs including 41Σ+, performed with the MOLPRO program package. The irregular shape of the 41Σ+ state potential predicted by theory is confirmed in the experiment. 相似文献
119.
Christiansen SC Hedin N Epping JD Janicke MT del Amo Y Demarest M Brzezinski M Chmelka BF 《Solid state nuclear magnetic resonance》2006,29(1-3):170-182
The robustness and sensitivities of different polarization-transfer methods that exploit heteronuclear dipole-dipole couplings are compared for a series of heterogeneous solid systems, including polycrystalline tetrakis(trimethylsilyl)silane (TKS), adamantane, a physical mixture of doubly (13)C,(15)N-enriched and singly (13)C-enriched polycrystalline glycine, and a powder sample of siliceous marine diatoms, Thalossiosira pseudonana. The methods were analyzed according to their respective frequency-matching spectra or resultant signal intensities. For a series of (13)C{(1)H} cross-polarization experiments, adiabatic passage Hartmann-Hahn cross-polarization (APHH-CP) was shown to have several advantages over other methods, including Hartmann-Hahn cross-polarization (HHCP), variable-amplitude cross-polarization (VACP), and ramped-amplitude cross-polarization (RACP). For X-Y systems, such as (13)C{(15)N}, high and comparable sensitivities were obtained by using APHH-CP with Lee-Goldburg decoupling or by using the transferred-echo double resonance (TEDOR) experiment. The findings were applied to multinuclear (1)H, (13)C, (15)N, and (29)Si CP MAS characterization of a powder diatom sample, a challenging inorganic-organic hybrid solid that places high demands on NMR signal sensitivity. 相似文献
120.
Chemical shifts of H-bonded protons in tetrabutylammonium hydrogen maleate and 14-substituted picolinic acid N-oxides have been measured in a number of dry solvents, of different activity, in order to distinguish between symmetrical single minimum and asymmetrical hydrogen bonds. In tetrabutylammonium hydrogen maleate the resonance was observed at 20.70 ppm and its was independent of the nature of the solvent used. The chemical shift value of picolinic acid N-oxide varies with the solvent. These observations suggest that the hydrogen bond is symmetrical in tetrabutylammonium hydrogen maleate but that it is asymmetrical in picolinic acid N-oxide. The chemical shifts of substituted picolinic acid N-oxides were correlated with σp, σm and ΔpKa. The substituent and solvent effects are compared and the position of the intramolecular H-bonded protons in picolinic acid N-oxides are estimated and discussed. 相似文献