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In this study, preparation of novel pH-sensitive N-doped carbon dots (NCDs) using glucose and urea is reported. The prepared NCDs present strong excitation-dependent fluorescence changes towards the pH that is a new behavior from these nanomaterials. By taking advantage of this unique behavior, two separated ratiometric pH sensors using emission spectra of the NCDs for both acidic (pH 2.0 to 8.0) and basic (pH 7.0 to 14.0) ranges of pH are constructed. Additionally, by considering the entire Excitation–Emission Matrix (EEM) of NCDs as analytical signal and using a suitable multivariate calibration method, a broad range of pH from 2.0 to 14.0 was well calibrated. The multivariate calibration method was independent from the concentration of NCDs and resulted in a very low average prediction error of 0.067 pH units. No changes in the predicted pH under UV irradiation (for 3 h) and at high ionic strength (up to 2 M NaCl) indicated the high stability of this pH nanosensor. The practicality of this pH nanosensor for pH determination in real water samples was validated with good accuracy and repeatability. 相似文献
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In this article, the effect of the space dimensions on the generalized hydrogen-atom specific heat in the generalized Boltzmann-Gibbs
statistics is studied. The temperature dependence of the specific heat for a few different values of q and for different low space dimensions using Tsallis statistics is numerically calculated. The results indicate that for
a fixed value of q, as the space dimension increases the temperature range where the specific heat has a nonzero value, decreases, while the
general behavior of the specific heat does not show any change. Also, there exits a q-independent quantity related to two specific temperatures of the system which is almost linearly dependent on the space dimensions. 相似文献
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Let G be a group. By using a family 𝒜 of subsets of automorphisms of G, we introduced a simple graph Γ𝒜(G), which is a generalization of the non-commuting graph. In this paper, we study the combinatorial properties of Γ𝒜(G). 相似文献
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Synthesis of a novel tetracationic acidic organic salt based on DABCO containing two sulfonic acid groups in the skeleton and four hydrogensulfate groups as counterion is described. Its catalytic efficiency in the Knoevenagel condensation of aldehydes with active cyclic methylene compounds in water is investigated. While 2,2'-(phenylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) derivatives were obtained in 40–98% isolated yields in the reaction of aldehydes with dimedone, the corresponding Knoevenagel adducts were provided in 85–95% yields using 1,3-dimethylbarbituric acid. In addition, a DABCO-based polycationic organic salt polymer was prepared and characterized for the first time. 相似文献
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Kazem Barati William Clegg Mohammad Hossein Habibi Ross W. Harrington Arash Lalegani Morteza Montazerozohori 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(3):239-242
Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N′‐bis(trans‐2‐nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ‐chlorido‐μ‐hydroxido‐bis(chlorido{(1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]‐κ2N,N′}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four‐membered ring in an unsymmetrical Cu2OCl3 core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two CuII atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five‐coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring‐stacking interactions supported by C—H…Cl interactions with solvent molecules; a further ring‐stacking interaction exists between the two Schiff base ligands of each molecule. 相似文献