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排序方式: 共有195条查询结果,搜索用时 31 毫秒
91.
Shahnavaz Zohreh Khaligh Nader Ghaffari Mihankhah Taraneh Johan Mohd Rafie 《Research on Chemical Intermediates》2020,46(10):4645-4658
Research on Chemical Intermediates - A new ionic liquid is synthesized, and its chemical structure is characterized by FTIR, 1D NMR and 2D NMR, and mass analyses. The thermal behavior and thermal... 相似文献
92.
An easy, efficient, and simple one-pot approach for the synthesis of 1,3-thiazolidine-2-thiones via multicomponent reaction is reported. The reaction of a primary amine with carbon disulfide in the presence of dibenzoylacetylene or bis(4-methyl-1-benzoyl)acetylene in a mixture of CH2Cl2 and H2O after 5 h, afforded the title compound as alkene diastereomers. 相似文献
93.
94.
Hamid Saeidian Seyed Mahdi Mortazavi Asadabad Dariusz W. Szczepanik Noorhan Jasim Mohammed Al-Juaifari Zohreh Mirjafary 《International journal of quantum chemistry》2024,124(1):e27271
Due to the insufficient interaction of the phosphorus lone pair with the butadiene moiety, the aromaticity of the phosphole ring is lower than that of its counterpart's pyrrole, furan, and thiophene. Considering the high importance of phosphole core in organic chemistry, increasing its stability through reinforcement its aromaticity can be very valuable. In the present work, the aromaticity of the phosphole on the anomeric carbon in both the axial and equatorial conformers of the unsaturated six-membered heterocycles, using structural, electronic, energetic, and magnetic indices were investigated by the DFT-B3LYP/6-311++G(d,p) computational method. Electron pumping through anomeric and then Schleyer hyperconjugative interaction increase the aromaticity of the phosphole ring in axial conformer of compounds 1–11 . Based on various types of aromaticity indices, the results showed that the phosphole ring in the axial position has far higher aromaticity than the equatorial position. The phosphole ring containing cyano groups shows an efficient anomeric effect and, as a result, higher aromaticity. Excellent correlations were observed between aromaticity indices with different backgrounds. 相似文献
95.
Nowroozi-Nejad Zohreh Bahramian Bahram Hosseinkhani Saman 《Research on Chemical Intermediates》2019,45(4):2489-2501
Research on Chemical Intermediates - Stabilization and immobilization on a proper support is essential in processing and production of enzymes. Luciferase is an unstable, thermally sensitive, and... 相似文献
96.
Crystallography Reports - A new co-crystal compound of 4,4'-bipyridine and phenylsuccinic acid was synthesized and characterized by elemental analysis, infrared and ultraviolet–visible... 相似文献
97.
Highly ordered mesoporous molecular sieves AlMCM‐41 and a new NiO/AlMCM‐41 nanocomposite were synthesized using a sol–gel method. Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), and N2 adsorption desorption analyses were used to examine the structure, morphology, size and phase composition of the synthesized NiO/AlMCM‐41 nanocomposites. AlMCM‐41 embedded with NiO nanoparticles was subsequently prepared using different nickel loadings in a direct synthetic route. The results show the successful deposition of NiO nanoparticles onto the framework of AlMCM‐41. AlMCM‐41 provides enormous benefits such as environmentally safe, economic viability and porosity when used as support for NiO nanoparticles. The excellent catalytic activities of AlMCM‐41 and NiO/AlMCM‐41 were investigated for the reduction of nitrophenols (4‐NP, 2‐NP) to aminophenols (4‐AP, 2‐AP) in water at ambient temperature. The best observed performance of reduction of NP with 100% conversion into analogous amino derivatives occurred within 6 min with an estimated rate constant of 0.46 min?1. The efficiency of reduction was observed to increase as a function of NiO enrichment. The NiO/AlMCM‐41 nanocomposite could be recycled and reused up to five times without noticeable change in its structure and activity. These properties make NiO/AlMCM‐41 nanocomposite an ideal platform to study various heterogeneous catalytic processes which can have application in purification, catalysis, sensing devices, and green chemistry. 相似文献
98.
Vahideh Mahdavi Zohreh Garshasbi Mahdi Moridi Farimani Mohsen Farhadpour Hassan Y. Aboul-Enein 《Biomedical chromatography : BMC》2020,34(3):e4747
There is an increasing need to address the potential risks arising from combined exposures to multiple residues from pesticides in the diet. Pesticide residue-related pollution is a problem that arises because of the increased use of pesticides in agriculture to meet the growing demands of food production. In this study, pesticide residue data were obtained based on an optimized extraction method. For this purpose, we established a method based on qu ick, e asy, ch eap, e ffective, r ugged, and s afe (QuEChERS) extraction for simultaneous determination of imidacloprid (IMI) and acetamiprid (ACT) in pistachio nuts. The parameters influencing the QuEChERS method were the sample-to-water ratio and adsorbent amounts. As a result, both were optimized to improve the recovery of the analytes as well as the clean-up efficiency of the pistachio matrix. Our results indicated that a freeze-out step and use of primary and secondary amines as an adsorbent led to much cleaner chromatograms with lower baseline drift, without using graphitized carbon black and C18-based adsorbent, which reduced both cost and time of analysis. Following extraction, the pesticide residues were separated and quantified by reverse-phase HPLC. For validation purposes, recovery studies were carried out using a concentration range from 20 to 2500 μg/L at nine levels. The suitable linearity, precision, and accuracy were obtained with HPLC–UV with recoveries of 70.37%–89.80% for IMI and 81.05%–113.57% for ACT, with relative standard deviations <12%. The validated method was successfully applied to the analysis of pistachio samples collected from a field trial to estimate maximum residue limits. There was no significant health risk for consumers via pistachio consumption. 相似文献
99.
The first general method for the Suzuki-type cross-coupling of phenols with aryl boronic acids using dichloroimidazolidinedione (DCID) as a new reagent is presented. In the presence of DCID and Pd/metal–organic framework (MOF), coupling of aryl boronic acids with a wide range of phenols, was carried out smoothly in tetrahydrofuran (THF) at reflux conditions to afford the cross-coupling products in good to excellent yields. The structures of all compounds were corroborated by 1H- and 13C-NMR. A plausible mechanism for this type of reaction is proposed. 相似文献
100.
A copper (II) supramolecular coordination complex formulated as [Cu2(μ‐ox)2(pyz)3]n ( 1 ), (pyz = pyrazine and ox = oxalate) has been synthesized under ultrasound irradiation. 1 was characterized using various techniques such as elemental analyses, Fourier‐transform infrared spectroscopy (FT‐IR), ultraviolet–visible spectroscopy (UV–Vis), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and single crystal X‐ray diffraction (SC‐XRD). A detailed magnetic characterization of complex 1 has been carried by vibrating sample magnetometer (VSM). The M‐H hysteresis loop of 1 revealed a weak ferromagnetic behavior with the highest magnetization of 0.0123 emu/g at room temperature. Compound 1 was used as an inorganic precursor to prepare Cu2O nanoparticles through thermal decomposition at 600 °C. The obtained Cu2O has been characterized using Fourier transform infrared spectroscopy (FT‐IR), X‐ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The results of SEM showed octahedron Cu2O nanoparticles with the edge lengths from 5–80 nm. Also, the adsorption ability and the photocatalytic activity of octahedral Cu2O nanoparticles in the removal of rhodamine B (RB) have been investigated. The results showed that the obtained octahedral Cu2O nanoparticles are effective in adsorption and degradation of rhodamine B from contaminated water sources. The maximum adsorption capacity and degradation efficiency of Cu2O nanoparticles were 83.3 mg/g and 91.7%, respectively. It was also found that in comparison with the commercial Cu2O, our fabricated Cu2O nanoparticles exhibit higher catalytic activity. 相似文献