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41.
E. V. Ivanov E. Yu. Lebedeva V. K. Abrosimov N. G. Ivanova 《Russian Chemical Bulletin》2004,53(4):751-757
Densities of Bun
4NBr solutions in MeOH, MeOD, and CD3OH were measured at salt concentrations of up to 1.5 solvomolality units (nearly 2.63·10–2 mole fraction) at 278.15, 288.15, 298.15, 308.15, and 318.15 K. The limiting partial molar volumes of Bun
4NBr dissolved in these alcohols were calculated. The isotope effects in the volume characteristics of the stoichiometric mixture of ions, [Bun
4N+ + Br–], are mainly due to the vibrational changes in the solvent structure upon deuteration of different molecular fragments. Structural transformations in infinitely dilute solution of Bun
4NBr in methanol are governed by non-specific solvation of the symmetrical Bun
4N+ cation. 相似文献
42.
Polymer-supported DABCO–palladium complex was observed as to be efficient and reusable catalytic system for the Suzuki–Miyaura cross-coupling reaction. In the presence of 0.25 mol % of the polymer-supported DABCO–palladium complex, a variety of aryl bromides were coupled with arylboronic acids efficiently in an aqueous ethanol at room temperature under air. Moreover, the reaction was very rapid, and the catalyst could be recovered readily from the reaction by simple filtration and could be reused at least five times. 相似文献
43.
在吡啶溶剂中氯化镍催化的溴代芳烃自身偶联反应 总被引:1,自引:0,他引:1
Pyridine was used as a solvent for homocoupling of aryl bromides catalyzed by nickel chloride/triarylphosphinein the presence of zinc and recycled easily.Triphenylphosphine was the best ligand for nickel in this coupling reac-tion. 相似文献
44.
A new kind of multilayer of didodecyldimethylammonium bromide (DDAB) and 1:12 phosphomolybdic anions (PMo12) was achieved on the surface of a wax-impregnated graphite (WIG) electrode by ion exchange and electrostatic interaction.
The characterization and electrochemical behavior of the multilayer films of DDAB/PMo12 is described in detail. The chemically modified electrode was shown to exhibit an excellent electrocatalytic activity toward
the reduction of BrO3
– anion in 0.5 M H2SO4 and possesses several attractive features, such as simple preparation, fast response, good stability, etc.
Electronic Publication 相似文献
45.
46.
On the Chemical Transport and Sublimation of CrBr3 — Experiments and Model Calculations The migration of CrBr3 in the presence of high concentrations of bromine (for example D(Br2) = 0,05 mmol/ml; closed silica ampoules) in the investigated temperature range (T? = 625°C to 875°C; T? = 50°C) is a result from the endothermic reaction The chemical transport of CrBr3 is superimposed with the sublimation. With low concentrations of D(Br2) and high temperatures T? is the sublimation decisive participated. This is a result of the homogenous equilibrium between CrBr3,g and CrBr4,g (2a) The reaction (2a) in comparison with the chemical transport of CrCl3 with Cl2 (Gl. (2b)) is more shifted to CrBr3,g. 相似文献
47.
Kh. Polvonov Q. Sabirov Kh. M. Shakhidoyatov 《Chemistry of Heterocyclic Compounds》2003,39(2):228-232
The reaction of 5-anilino(toluidino-, morpholino)-1,3,4-thiadiazoline-2-thiones at 80°C with allyl bromide and benzyl chloride in alcohol, acetonitrile or DMF in the presence of KOH and also with phenoxymethyloxirane in alcohol in the absence of base gives the corresponding novel allyl-, benzyl-, and 2-hydroxy-3-phenoxypropyl products substituted at the exocyclic S atom. Alkylation of the indicated thiones with benzyl chloride at 150-153°C in DMF in the presence of KOH occurs similarly. Under these conditions, allyl bromide forms alkylation products at the endocyclic N(3) atom as a result of an SN thio-Claisen rearrangement of the initially formed product which is allyl substituted at the exocyclic S atom. 相似文献
48.
The reaction of acetone-4-chlorophenylhydrazone (6) with bromine in the presence of acetamide yields 2-bromo-2-(4-chlorophenylazo)-propane (7) and 2,2-bis(4-chlorophenylazo)propane (8). The unstable heteroallylic bromide7 was subjected without isolation to nucleophilic displacements with a series of heteronucleophiles thereby affording the corresponding 2-(4-chlorophenylazo)-2-propane derivatives9 with the azo- and heteroelement-functions in a geminal position to each other.
Herrn Prof. Dr. Dr. h. c.K. Kratzl mit den besten Wünschen zum 70. Geburtstag gewidmet. 相似文献
49.
Arbuzov reaction of bromo-substituted benzyl bromides and trialkyl phosphites in benzene gave high yields of dialkyl bromo-substituted benzyl phosphonates, and —CH2CH2CH2CH3). The structural assignments of these phosphonates were confirmed by 1H nmr, 13C nmr, ir and mass spectral analysis. 相似文献
50.
The interaction of ethidium bromide (2,7-diamino-10-ethyl-9-phenylphenanthridinium bromide; EB) with double stranded (ds) calf thymus DNA and thermally denatured single stranded (ss) DNA was studied in solution and at the electrode surface by means of transfer voltammetry using a carbon paste electrode (CPE) as working electrode in 0.2 M acetate buffer, pH 5.0. As a result of intercalation of this dye between the base pairs of dsDNA, the characteristic peak of dsDNA, due to the oxidation of guanine residues, decreased and after a particular concentration of EB a new peak at +0.81 V appeared, probably due to the formation of a complex between dsDNA and EB. The non-intercalated EB gives another peak, but at an increased concentration of the dye. A similar behaviour was observed during the interaction of the dye with ssDNA.Furthermore, the interaction of EB with ds, ss and supercoiled (sc) DNA was studied at the hanging mercury drop electrode (HMDE) surface by means of alternating current voltammetry in 0.3 M NaCl and 50 mM sodium phosphate buffer (pH 8.5) as supporting electrolyte. dsDNA yields a smaller peak at −1.42 V (peak III) compared to the one yielded by ssDNA, since the latter is a relaxed and more accessible form. By addition of EB into the buffer solution an increase of peak III was observed in the dsDNA form as well as in ssDNA resulting from their interaction with EB. Furthermore, the appearance of peak III in covalently closed circular scDNA after exposure to increasing concentrations of EB is a result of the introduction of ‘free ends’ in DNA affecting its structural integrity. 相似文献