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31.
合成了纳米尺度氧化石墨烯(NGO)层,用作碳催化剂高效催化苄醇与芳香醛的氧化反应.对于醇氧化反应,当80℃时H2O2存在下,NGOs(20 wt%)可高效催化醇选择性生成醛,其反应速率和产率取决于醇上取代基的性质.对于4-硝基苄醇,反应24 h后,只有10%可转换为相应羧酸.相反,4-甲氧基苄醇和二苯基甲醇分别反应仅9和3h则可完全转化为对应的羧酸和酮.NGO碳催化剂上芳香醛氧化速率高于醇氧化速率.对于所有的醛,采用7 wt% NGO作催化剂,在70℃反应2-3 h后,就可完全转化为相应羧酸.我们讨论了NGO催化剂结构对苄醇和芳香醛氧化反应影响的可能机理. 相似文献
32.
Hamid Beyzaei Mohammadreza Moghaddam-Manesh Reza Aryan Behzad Ghasemi Alireza Samzadeh-Kermani 《Chemical Papers》2017,71(9):1685-1691
Pyrazolo[3,4-d]pyrimidines are one of the most important classes of fused heterocyclic compounds which exhibit a broad range of biological and medicinal properties. They are known as anticancer, antifungal, antibacterial, antiviral and anti-inflammatory agents. In this study, some new 6-substituted 4-amino-pyrazolo[3,4-d]pyrimidine derivatives were prepared via reaction of 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile with various nitriles in the presence of sodium ethoxide as catalyst. The inhibitory properties of synthesized compounds were studied according to CLSI guidelines against some pathogenic bacteria including four gram-positive strains (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis subsp. spizizenii) and three gram-negative strains (Pseudomonas aeruginosa, Shigella flexneri and Salmonella enterica subsp. enterica). The antibacterial effects of all derivatives were compared with those of antibiotics belonging to different classes. The values were reported as inhibition zone diameter (IZD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The effect of substituents on the biological activity of derivatives was discussed as well. The inhibitory effect of compound 6a, was shown to be the most, with MIC values in the range of 32–4096 μg/mL. Since most of the synthesized compounds were effective against Streptococcus pyogenes and Pseudomonas aeruginosa, they can be considered as inhibitors of these two bacteria. 相似文献
33.
34.
Alireza Abdollahi Edwin R. van Dam Mojtaba Jazaeri 《Designs, Codes and Cryptography》2017,84(1-2):73-85
We classify the distance-regular Cayley graphs with least eigenvalue \(-2\) and diameter at most three. Besides sporadic examples, these comprise of the lattice graphs, certain triangular graphs, and line graphs of incidence graphs of certain projective planes. In addition, we classify the possible connection sets for the lattice graphs and obtain some results on the structure of distance-regular Cayley line graphs of incidence graphs of generalized polygons. 相似文献
35.
Hassan Y. Aboul-Enein Garshasb Rigi Mohsen Farhadpour Alireza Ghasempour Gholamreza Ahmadian 《Chromatographia》2017,80(11):1633-1639
Staphylococcal protein A (protein A) is an important protein frequently used in research studies within the fields of biomedicine and biotechnology. Due to some limitations in available protein purification methods which can hold the native structure of the protein A without changing the folding or adding histidine to structure of this protein, its separation in the native form is difficult. In this study, a new cost-effective and powerful technique was introduced for separation of the full-length and truncated forms of recombinant protein A, without any alteration in their 3D structures. Per aqueous liquid chromatography with bare silica gel stationary phase and water:acetonitrile as the mobile phase was proved to be an attractive choice among the range of separation methods. Similar to hydrophilic liquid chromatography, this method employs high percentage of water in mobile phase. The effects of mobile phase composition, pH, and salt concentration on the retention behavior of protein A on bare silica gel stationary phases were investigated. In this method, applying high amounts of aqueous solvent accompanied by a minimum percentage of organic solvent could successfully separate protein A with preservation of folding, and any affinity-tagged group such as histidine has not occurred on its structure. Purity of the fractions obtained by the proposed method was confirmed using SDS-PAGE, western blotting, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. According to the results of ELISA, separated proteins retained their ability of binding to antibody. 相似文献
36.
Zahra Jafari Chermahini Alireza Najafi Chermahini Hossein A. Dabbagh Behzad Rezaei Neda Irannejad 《Journal of the Iranian Chemical Society》2017,14(7):1549-1556
Di(1H-tetrazol-5-yl)methane is employed as a new electron acceptor group in the synthesis of two metal-free organic dyes containing triphenylamine donor group. Dye-sensitized nanocrystalline TiO2 solar cell (DSSC) applying these novel dyes is constructed for consideration of their photovoltaic properties. The electronic properties of the dyes are also considered with the aid of theoretical calculations. The DSSC constructed from 4-(2,2-di(1H-tetrazol-5-yl)vinyl)-N,N-diphenylaniline (T1) shows a short-circuit photocurrent density of 13.38 mA cm?2, an open circuit voltage of 578 mV, and a fill factor of 0.54, with a resulted solar energy-to-electricity conversion efficiency of 4.18% under simulated 1 sun irradiation (100 mW cm?2). This result reveals that the dye with the di(1H-tetrazol-5-yl)methane anchoring group injects more electrons to the conduction band of TiO2 in comparison with its analogs with single tetrazole ring in their anchoring group. It is found that in spite of a red-shift of the absorption spectrum resulted from the lengthening of the molecule, the dye with two di(1H-tetrazol-5-yl)methane groups gives lower performance than the dye with a single electron acceptor. 相似文献
37.
This paper considers a novel formulation of the multi-period network interdiction problem. In this model, delivery of the maximum flow as well as the act of interdiction happens over several periods, while the budget of resource for interdiction is limit. It is assumed that when an edge is interdicted in a period, the evader considers a rate of risk of detection at consequent periods. Application of the generalized Benders decomposition algorithm considers solving the resulting mixed-integer nonlinear programming problem. Computational experiences denote reasonable consistency with expectations. 相似文献
38.
Olga Koba-Ucun Tuba
lmez Hanci Idil Arslan-Alaton Samira Arefi-Oskoui Alireza Khataee Mehmet Kobya Yasin Orooji 《Molecules (Basel, Switzerland)》2021,26(2)
The application of layered double hydroxide (LDH) nanomaterials as catalysts has attracted great interest due to their unique structural features. It also triggered the need to study their fate and behavior in the aquatic environment. In the present study, Zn-Fe nanolayered double hydroxides (Zn-Fe LDHs) were synthesized using a co-precipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption analyses. The toxicity of the home-made Zn-Fe LDHs catalyst was examined by employing a variety of aquatic organisms from different trophic levels, namely the marine photobacterium Vibrio fischeri, the freshwater microalga Pseudokirchneriella subcapitata, the freshwater crustacean Daphnia magna, and the duckweed Spirodela polyrhiza. From the experimental results, it was evident that the acute toxicity of the catalyst depended on the exposure time and type of selected test organism. Zn-Fe LDHs toxicity was also affected by its physical state in suspension, chemical composition, as well as interaction with the bioassay test medium. 相似文献
39.
Mohammadi Ziarani Ghodsi Khademi Mahdieh Mohajer Fatemeh Anafcheh Maryam Badiei Alireza Ghasemi Jahan B. 《Research on Chemical Intermediates》2022,48(5):2111-2133
Research on Chemical Intermediates - The synthesis of 4-Aryl-(3,5-dimethyl-1,4,7,8-tetrahydro-dipyrazolo[3,4b:4′,3′e]pyridine derivatives was accomplished using Fe3O4@SiO2@(BuSO3H)3... 相似文献
40.
Alireza Najafi Chermhini Hossein Farrokhpour Abbas Teimouri Fatemah Pourmoghaddas 《Structural chemistry》2013,24(4):1215-1227
The tautomerism of all possible forms of imidazole selenone (ISe1–ISe6), induced by proton transfer was studied theoretically in different environments including gas phase, continuum solvent, and microhydrated environment with one explicit water molecule. The calculations were performed at the MP2 and CAM-B3LYP levels of theory, separately. It was found that the imidazole selenone, in the form of ISe3, is the most stable isomer in both gas phase and solvent. The activation energy for conversion of ISe3 to imidazole selenol (ISe6), as the second stable form, is 41.72 and 43.0 kcal/mol in the gas phase and water, respectively. The infrared spectral frequencies as well as the vibrational frequency shifts were reported and assigned to their corresponding vibrational modes. In addition, the variation of dipole moments and charges on the atoms with change of solvent was studied. The energies of HOMO, LUMO, and HOMO–LUMO gap were calculated in both gas phase and solvent. Specific solvent effects with addition of water molecule near the electrophilic centers of tautomers and the transition states of proton transfer, assisted by water molecule, were investigated. It was found that the water molecule can form different hydrogen bonds with the molecule. Aggregation of the isomers with water molecule does not change the order of stability of isomers, but proton transfer reaction assisted by a water molecule needs less energy than when the proton shifts through the intramolecular process. 相似文献