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The formation and extraction of ion-associate complexes between the vanadium(V)-4-(2-thiazolylazo)resorcinol (TAR) anionic chelate and the cations of some mono-and ditetrazolium salts {3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (Thiazolyl blue, MTT), 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (Tetrazolium violet), 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (Iodonitrotetrazolium chloride), 3,3′-[3,3′-dimetoxy(1,1′-biphenyl)-4,4′-diyl]-bis[2,5-diphenyl-2H-tetrazolium] chloride (Tetrazolium blue chloride) and 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride] (Nitro blue tetrazolium chloride)} have been studied. The optimum extraction conditions have been found. The composition of the V-TAR-monotetrazolium and V-TAR-ditetrazolium complexes extracted into chloroform has been determined to be 1:2:3 and 2:4:3 respectively. The extraction, distribution and association constants, and the recovery factors have been calculated. The relationship between the molecular weight of tetrazolium cations, and the association constants of their complexes has been discussed. The special behavior of the tetrazolium cations, containing-NO2 groups has been noticed. The effects of foreign ions and reagents on the extraction of vanadium with TAR and the best tetrazolium salt-MTT have been studied. A sensitive, selective, simple and fast method for the determination of vanadium has been developed. [...]
Tetrazole and its 1- and 5-monosubstituted derivatives are found to react with tert-butyl alcohol in 72% perchloric acid media, yielding selectively 1,3-di- and 1,3,5-trisubstituted tetrazolium salts. 1,3-Disubstituted salts are slowly converted under the same conditions into the corresponding 1,4-disubstituted salts. This transformation may be used for selective synthesis of the latter.
Synthesis of some new N-substituted bistetrazoles is described. 1,5-Bis(2-tert-butyl- 5-tetrazolyl)-3-oxopentane (btop) is obtained by regioselective alkylation of 1,5-bis(5- tetrazolyl)-3-oxopentane with tert-butyl alcohol in 96% sulphuric acid media. 1,5-Bis(1- methyl-5-tetrazolyl)-3-oxopentane (mtop) is synthesized by exhaustive methylation of 1,5-bis(2-tert-butyl-5-tetrazolyl)-3-oxopentane followed by the removal of tert-butyl group from the formed tetrazolium methyl sulphate in acidic conditions. Isomeric tetrazolium perchlorate is converted in analogous conditions to perchlorate of 1,5-bis(1- methyl-5-tetrazolyl)-3-oxopentane. Synthesized bistetrazoles are found to react with copper(II) chloride in ethyl alcohol or acetone solutions giving solid [Cu(mtop)Cl2] and [Cu(btop)Cl2] complexes. Perchlorate of 1,5-bis(1-methyl-5-tetrazolyl)-3-oxopentane reacts with copper(II) chloride in ethyl alcohol leading to formation of complex [Cu(mtop)Cl2], whereas in aqueous solution complex [Cu(mtop)2](ClO4)2 is formed. According to X-ray study of chloride complexes, Cu(II) is surrounded by a tridentate chelating ligand and two halide anions resulting in distorted square pyramidal geometry.
Content available remote A Method of 1D UVC Radiation Dose Measurement using a Novel Tablet Dosimeter
In this work, a method for the measurement of one-dimensional (1D) UV radiation dose is described. It comprises a new tablet dosimeter that measures the dose using reflectance spectrophotometry. The tablet dosimeter elaborated is a solid structure with a cylindrical form and has been manufactured with polycaprolactone (PCL) doped with a representative of tetrazolium salts: 2,3,5−triphenyltetrazolium chloride (TTC). The PCL used makes the dosimeter biodegradable and therefore proecological. The TTC dopant is distributed uniformly in the whole PCL tablet, and the whole tablet changes color to red under UVC irradiation. The intensity of this color increases if the PCL–TTC tablet absorbs higher doses. The color of the tablet is stable for at least 30 days after irradiation. It is proposed that the PCL-TTC tablet be used for measurement with reflectance spectrophotometry in order to determine the reflectance of light versus the absorbed dose in a fast and easy manner. On this basis, the PCL-TTC tablet could be characterized by providing information on its dose range, which amounted to 0–2 J/cm2. Moreover, other parameters were derived, such as dose sensitivity, quasilinear dose range, and dose threshold. The morphology of the tablets studied using scanning electron microscopy revealed their high porosity, which however did not influence the reflectance measurements with the aid of the chosen instrument. UVC irradiation at a dose (15 J/cm2) much above the PCL-TTC tablets’ dose range did not alter the morphology of the tablets. The PCL-TTC tablet read with reflectance spectrophotometry is shown to be a promising and fast method for 1D UV dose measurements.
Synthesis and some new transformations of 1-aryltetrazoles into other heterocycles through 1,4-disubstituted tetrazolium salts are described. 1-Aryltetrazoles, quaternized with tert-butanol and diacetone alcohol in perchloric acid media, gave pure 1,3- or 1,4-disubstituted tetrazolium salts or their mixtures. 1,3-Disubstituted tetrazolium salts are slowly converted into the corresponding 1,4-salts under dissolving in perchloric acid. 1,4-Disubstituted tetrazolium salts are recyclized to 2-alkylaminobenzoxazoles, 3-monosubstituted 2,4-quinazolinediones and mixtures of di- and tetrahydropyrimidin-2(1H)- ones in basic conditions.
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