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111.
Hu Y Kazemian H Rohani S Huang Y Song Y 《Chemical communications (Cambridge, England)》2011,47(47):12694-12696
ZIF-8 as a promising storage material was investigated at high pressures up to ~39 GPa by in situ FTIR spectroscopy for the first time. Structural modifications are found to be reversible in a low-pressure region but irreversible in a high-pressure region. Overall, the ZIF-8 framework exhibits an unusual chemical stability even under extreme compression. 相似文献
112.
Tahereh Harsij Sani Mohammadreza Hadjmohammadi Mohammad Hossein Fatemi 《Journal of separation science》2020,43(7):1224-1231
Extraction and determination of three flavonoids (morin, quercetin, and kaempferol) were performed by dispersive magnetic solid phase extraction based on mixed hemi/ad‐micelles and high‐performance liquid chromatography with UV detection. The Fe3O4/SiO2 nanoparticles were synthesized and characterized by X‐ray diffraction, FTIR, scanning electron microscopy, and thermogravimetric analysis. Fe3O4/SiO2 nanoparticles coated with mixed hemi/ad‐micelles cetyltrimethyl ammonium bromide was applied as a sorbent and used for extraction of flavonoids. Effective parameters on the extraction recovery such as amount of magnetic nano particles, volume of cetyltrimethyl ammonium bromide solution with specific concentration, pH of sample solution, adsorption equilibrium time, volume of desorption solvent, and desorption times were evaluated and optimized using fractional factorial design and central composite design. Under the optimum condition limit of detection and linearity were 0.83, 2.7–500.0 for morin, 0.18, 0.7–500.0 for quercetin and, 0.37, 1.3–500.0 µg/L for kaempferol. The extraction recovery with relative standard deviation were 97.88, 1.94 for morin, 95.77, 0.80 for quercetin, and 93.35, 1.45 for kaempferol. The proposed method was applied for simultaneous extraction and determination of flavonoids in several fruit juices and vegetable samples. 相似文献
113.
114.
An efficient and multicomponent method has been developed for the synthesis of functionalized tricarboxamides at room temperature using CuI nanoparticles as catalyst. This method involved fivecomponent coupling reactions of Meldrum's acid, isocyanides with aromatic aldehydes and amines at room temperature. Atom economy, wide range of products, excellent yields in short time and mild reaction conditions are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for several times without significantly decreasing the catalytic activity. 相似文献
115.
Tahereh Sedaghat Azam Golalzadeh Hossein Motamedi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):1694-1702
Abstract The organotin(IV) complexes, SnPh2La (1), SnMe2La (2), SnBu2La (3), SnPh2Lb (4), SnMe2Lb (5), SnPh2Lc (6), SnMe2Lc (7), and SnBu2Lc (8) were obtained by reaction of SnR 2Cl2 (R = Ph, Me, and Bu) with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H2La), 1-((2-hydroxynaphthalen-1-yl)methylene)-4-phenylthiosemicarbazide (H2Lb), and 1-(2-hydroxy-3-methoxybenzylidene)-4-phenylthiosemicarbazide (H2Lc). The synthesized complexes have been investigated by elemental analysis, IR, 1H NMR, and 119Sn NMR spectroscopy. The data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination number of tin is 5. The in vitro antibacterial activities of the ligands and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and compared with the standard antibacterial drugs. [Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures and tables] 相似文献
116.
George Argiropoulos Robert W. Cattrall Ian C. Hamilton Rohani Paimin 《Analytica chimica acta》1998,360(1-3):167-169
A procedure is described for the identification and determination of the quaternary ammonium ion components of the commercial solvent extraction reagent Aliquat 336 using Electro Spray Mass Spectrometry (ESMS). The procedure is extremely rapid when compared with an existing procedure based on gas chromatography and produces comparable results in terms of accuracy and precision. 相似文献
117.
118.
A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multisite phase-transfer catalyst,α,α′,α″-N-hexakis(triethylammoniummethylene chloride)-melamine,is developed.A variety ofβ-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 相似文献
119.
Tahereh Ahmadi Ghodsi Mohammadi Ziarani Parisa Gholamzadeh Hoda Mollabagher 《Tetrahedron: Asymmetry》2017,28(5):708-724
Asymmetric multicomponent reactions (AMCRs) include the reaction of three or more reactants simultaneously to produce chiral products that they have some advantages containing simple procedures, saving time and energy, and being environmentally friendly processes. AMCRs have seen much development and their potent synthetic approaches are discussed in this review. 相似文献
120.
The formation constants of the species formed in the systems H+ + thallium(I) + AMP and H+ + AMP have been determined in aqueous solutions of methanol at 25 degrees C and constant ionic strength 0.1 mol dm(-3) sodium perchlorate, using spectrophotometric and potentiometric techniques. Thallium(I) forms two mononuclear 1:1 complexes with AMP of the type TlHL and TlL- in the pH range of study (1-11), where L2- represents the fully dissociated ligand. The formation constants in various media were analyzed in terms of Kamlet and Taft's parameters. Single-parameter correlation of the formation constants, beta111, and beta101, versus alpha (hydrogen-bond donor acidity), beta (hydrogen-bond accepter basicity), and for pi* (dipolarity/polarizability) are relatively poor in all solutions, but multi-parameter correlation represents significant improvement with regard to the single-parameter models. Finally, the results are discussed in terms of the effect of the solvent on complexation. 相似文献