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41.
Searching new light‐absorbing materials to replace toxic lead halide in solar cells is very important and highly desirable. In this research, we firstly demonstrated that tellurium iodide (TeI4) could be used as a light‐absorbing material in solar cells due to its suitable optical band gap and the active lone‐pair electron orbital in Te4+. The best power conversion efficiency (PCE=3.56%) was achieved with a concentration of 0.9 M TeI4 in DMF:DMSO (4 : 1, v,v) without any heat treatment or antisolvent dripping. Our study indicates the promising potential of TeI4 for photovoltaic and optoelectronic applications. 相似文献
42.
Response surface methodology (RSM),based on five‐level, four variable Box‐Benkhen technique was investigated for modeling the average fiber diameter of electrospun polyacrylonitrile (PAN) nanofibers. The four important electrospinning parameters were studied including applied voltage (kV), Berry's number, deposition distance from nozzle to collector (cm), and spinning angle (? in degree). The measured fiber diameters were in a good agreement with the predicted results by using RSM technique. High‐regression coefficient between the variables and the response (R2 = 87.74%) indicates excellent evaluation of experimental data by second‐order polynomial regression model. The optimum PAN average fiber diameters of 208 and 37‐nm standard deviation were collected at 19 kV, Berry's number = 10, 25° spinning angle, and 16‐cm deposition distance. The PAN/N,N‐dimethylformamide (DMF) polymer solution with the optimum weight concentration (10 wt.%) was selected to study the effect of dispersing exfoliated graphite nanoplatelets (EGNPs) in PAN/DMF solution on the electrospun EGNP/PAN fibril composite diameter. Five different EGNPs weight concentrations (2, 4, 6, 8, and 10 wt.%) were dispersed in the optimized PAN/DMF polymer solution. Morphology of EGNPs/PAN fibril composites and its distribution were investigated by scanning electron microscopy (SEM) to show the minimum fiber diameter for the above‐mentioned 5 wt. % of EGNPs. A minimum fibril composite diameter of 182 nm was obtained at 10 wt.% of EGNPs. Morphological characteristics of electrospun fibers and their distribution were tested by Raman spectroscopy, SEM, differential light scattering, and high‐resolution transmission electron microscopy. 相似文献
43.
Three natural basaltic samples were collected and used as efficient catalysts for the liquid‐phase synthesis of n‐butyl acetate. The samples were characterized by X‐ray fluorescence analysis (XRF), X‐ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DTA), Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), and N2 sorption. The acidity of the samples was determined using isopropanol dehydration, and the strength of the acid sites was measured using chemisorption of basic probes. The catalytic activity of the samples towards the esterification of acetic acid with n‐butanol was extensively examined. The influence of different parameters, such as the reaction refluxing time, molar ratio, catalyst loading, reusability, and calcination temperature, on the esterification reaction was studied in detail. The results revealed that all samples had high catalytic activity with a selectivity of 100% to n‐butyl acetate formation. In addition, the sample obtained from the top hill of Volcano had the highest activity with a 80% yield of n‐butyl acetate. Moreover, the significant catalytic performances were well correlated with the acidity of the samples and to the reaction rate constants. 相似文献
44.
Katritzky AR Abo-Dya NE Abdelmajeid A Tala SR Amine MS El-Feky SA 《Organic & biomolecular chemistry》2011,9(2):596-599
The transprotection of N-Fmoc-cysteine containing di- and tripeptides possessing a free SH group to produce the corresponding S-Fm-cysteine di- and tripeptides bearing a free amino group is accomplished efficiently with DBU in dry THF. The N-Fmoc to S-Fm transformation mechanism is discussed. S-Fm-Cysteine di- and tripeptides readily form amide bonds on coupling with N-(Pg-α-aminoacyl)benzotriazoles and N-(Pg-α-dipeptidoyl)benzotriazoles to give larger peptides. 相似文献
45.
Jacob J. Habeeb Farouq F. Said Dennis G. Tuck 《Journal of organometallic chemistry》1980,190(4):325-334
The electrochemical oxidation of indium metal in cells of the type
leads to the formation of RInX2 compounds; if 2,2′-bipyridine is also present, the products are the adducts RInX2·bipy (R = CH3, C2H5, C6H5, C6H5CH2, C6F5; X = Cl, Br, I (not all combinations)). When R′4NX is present instead of bipy, the products are the salts R′4N[RInX3]. The electrochemical oxidation apparently proceeds via the general mechanism discussed previously. Anomalous results with CH3I or C2H5I are discussed in the light of the known solution chemistry of organoindium(III) compounds. 相似文献
46.
Nathaniel L SegravesSuzette Lopez Tyler A JohnsonSadri A Said Xiong FuFrancis J Schmitz Halina PietraszkiewiczFrederick A Valeriote Phillip Crews 《Tetrahedron letters》2003,44(17):3471-3475
The structural variations and bioactivity properties of the alkaloids in the fascaplysin (1) and the reticulatine (3) families were examined. Four organisms were analyzed consisting of two collections of the sponge Fascaplysinopsis reticulata and two collections of the tunicate Didemnum sp. Reported are the isolation of three new compounds: 3-bromofascaplysin (2), 14-bromoreticulatine (4), and 14-bromoreticulatate (6) along with reticulatate (5) previously known as a semi-synthetic product of 1. Compounds 1 and 5 showed selectivity in a cell based cytotoxicity assay. 相似文献
47.
Bouchonnet S Kinani S Sablier M 《European journal of mass spectrometry (Chichester, England)》2007,13(3):223-226
Users of ion trap mass spectrometers frequently develop methods that associate chemical ionization with tandem mass spectrometry detection. With apparatus using internal ionization, the chemical reagent is present in the trap during the collision induced dissociation (CID) step and one may wonder if the reagent influences the fragmentation ratios in MS/MS. We report a comparison of the fragmentation ratios of protonated molecules when using the most common reagents (methane, ammonia, methanol, acetonitrile, isobutane) for performing in situ chemical ionization. Four molecules were chosen in the medical field to serve as models: alprazolam, diazepam, flunitrazepam and acetaminophen. In the non-resonant CID mode, the influence of the reagent mass is clearly seen in spite of its low partial pressure in the ion trap; the reagent acts as a "heavy target": the degree of fragmentation increases with the molecular weight of the reagent. In the resonant CID mode, there is no evident correlation between the fragmentation ratio of MH(+) ions and the nature of the CI reagent; a slight shift of the secular frequency of the precursor ion, which tends to reduce the CID efficiency, could compensate for the "heavy target" effect underscored in the non-resonant mode. 相似文献
48.
Said A. S. Ghozlan Fathy M. Abdelrazek Mona H. Mohammed Khaled E. Azmy 《Journal of heterocyclic chemistry》2014,51(4):1179-1184
The newly synthesized ethyl 3‐amino‐5‐phenylpyrazole‐4‐carboxylate 1 was diazotized and coupled with β‐naphthol, active methylene reagents 6 , 9 , 12 , 15 , and the active methine 19 to afford the pyrazolo[5,1‐c]triazines 5 , 8 , 11 , 14 , 17 , 18 , and the pyrazolo[5,1‐ c ]‐1,2,4‐triazoles 21 , 22 , and 23 , respectively. Structures are elucidated and mechanisms are discussed. 相似文献
49.
50.