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101.
Sadjadi Samahe Heravi Majid M. Zadsirjan Vahideh Farzaneh Vahid 《Research on Chemical Intermediates》2018,44(11):6765-6785
Research on Chemical Intermediates - SBA/hydrotalcite/heteropolyacid nanocomposite is synthesized via a novel procedure in which the as-prepared heteropolyacid-loaded SBA-15 was impregnated with... 相似文献
102.
Abdollah Rahimi Davood Habibi Amin Rostami Mohammad Ali Zolfigol Shadpour Mallakpour 《Tetrahedron letters》2018,59(4):383-387
The direct aerobic oxidation of 4-substituted urazoles using the laccase enzyme from Trametes versicolor in a phosphate buffer solution at ambient temperature, and subsequent cross-coupling with sodium benzenesulfinates was investigated to afford arylsulfonyl-1,2,4-triazolidine-3,5-dione derivatives in good to high yields. 相似文献
103.
Behrouz Notash Hamid Reza Khavasi Vahid Amani Anita Abedi 《Journal of organometallic chemistry》2008,693(24):3553-3557
Two novel organometallic complex of 2,2′-dimethyl-4,4′-bithiazole (dm4bt) ligand (L) with formula [Tl(dm4bt)2(NO3)(H2O)] (1) and [Tl(dm4bt)2(NO3)(DMSO)] (2) have been synthesized and structurally characterized by elemental analysis, FT-IR, 1H NMR spectra and X-ray crystallography. These complexes also display the first transoid conformation in bithiazole ligands in which C-H bond activation in bithiazole ring is observed with Tl(III) ion. 相似文献
104.
Saeed Rayati Saeed Zakavi Somayeh H. Motlagh Vahid Noroozi Maryam Razmjoo Andrzej Wojtczak Anna Kozakiewicz 《Polyhedron》2008
X-ray crystallographic studies have shown that the free base β-tetra-brominated meso-tetraphenylporphyrin (H2TPPBr4) has a slightly ruffled structure with the dihedral angles of 70.1–79.2° between the phenyl groups and the porphyrin mean plane. The N(pyrrole)–N(pyrrolenine) distance is very similar to that of the standard planar porphyrins. The decreased N–H bond length of H2TPPBr4 with respect to that of meso-tetraphenylporphyrin (H2TPP) seems to be due to the weaker intramolecular hydrogen bond of the former relative to the latter caused by the electron-withdrawing effects of the β-bromine substituents. The large red shifts of the Soret and Q(0,0) bands of H2TPPBr4 in comparison with those of H2TPP, in spite of the nearly planar porphyrin core of the compound, also may be explained on the basis of the electron-withdrawing effects of the bromine atoms. Oxidation of styrene, the para-substituted derivatives and cyclooctene with tetrabutylammonium oxone in the presence of catalytic amounts of β-tetra-brominated meso-tetraphenylporphyrinatomanganese(III) acetate immediately gives the epoxide as the sole product. Terminal double bonds and unconjugated ones are less reactive than the conjugated double bonds and show lower selectivities. Catalytic activity of the electron-deficient Mn(H2TPPBr4)OAc dramatically depends on the Co-catalytic activity of the nitrogen donors as the axial base. The best axial bases are the nitrogenous donors with mixed σ- and π-donor ability to the metal centre. 相似文献
105.
Upon improving and extending the concept of redundancy of frames, we introduce the notion of redundancy of fusion frames, which is concerned with the properties of lower and upper redundancies. These properties are achieved by considering the minimum and maximum values of the redundancy function which is defined from the unit sphere of the Hilbert space into the positive real numbers. In addition, we study the relationship between redundancy of frames (fusion frames) and dual frames (dual fusion frames). Moreover, we indicate some results about excess of fusion frames. We state the relationship between redundancy of local frames and fusion frames in a particular case. Furthermore, some examples are also given. 相似文献
106.
Seyed Mehrdad Jalilian Hassan Farhadnejad Farshid Ziaee Behrouz Furughi Nia Hossein Abdollahi Vahid Najafi 《Polymer Science Series B》2016,58(6):675-680
The free radical solution polymerization of n-octyl methacrylate has been studied in benzene-d 6 in the presence of 2,2′-azobisisobutyronitrile as thermal initiator. An on-line nuclear magnetic resonance spectroscopy was applied to record the reaction data and to determine the monomer conversion at different times during the polymerization reaction. Effect of monomer and initiator concentration as well as reaction temperature on polymerization rate was studied. The order of the reaction with respect to initiator (0.45) was consistent with the classical kinetic rate equation, while the order of reaction with respect to monomer (1.87) was much greater than unity. An overall activation energy (E a = 53.8 kJ/mol) was obtained over the temperature range 328?338 K. Also, the efficiency of the synthesized poly(n-octyl methacrylate) for improving the viscosity index of the lube oil was investigated. 相似文献
107.
A. A. Ensafi H. Rahimi Mansour K. Zarei 《Fresenius' Journal of Analytical Chemistry》1999,363(7):646-650
A novel method for the determination of cobalt(II) by stripping voltammetry is described. It involves an adsorptive accumulation
of the cobalt(II)-2-aminocyclopentene-1-dithiocarboxylic acid complex on a hanging mercury drop electrode, followed by a stripping
voltammetric measurement of the catalytic reduction current of the complex at –1.4 V at pH = 9 (vs. Ag/AgCl). The effects
of various experimental parameters on the catalytic current were investigated. An accumulation time of 60 s results in a low
experimental limit of detection of 0.1 ng/mL of Co(II), and 0.50 to 40.0 ng/mL of cobalt can be determined. The relative
standard deviation at 0.50 ng/mL is 2.8%. Possible interferences from co-existing ions were also investigated.
Received: 17 August 1998 / Revised: 16 November 1998 / Accepted: 20 November 1998 相似文献
108.
109.
Microchimica Acta - A highly porous fiber coated polyaniline/montmorillonite clay was prepared for solid-phase microextraction. The nanocomposite was synthesized by in-situ polymerization. The... 相似文献
110.