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71.
POSS nanocrosslinked poly (ethylene glycol) hydrogel as hybrid material support for silver nanocatalyst
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Silver nanoparticles supported on polyhedral oligomeric silsesquioxane (OA‐POSS) nanocrosslinked poly (ethylene glycol)‐based hydrogels (PEG600‐POSS/Ag NPs) as novel nanohybrid catalysts were synthesized for the first time. The as‐prepared nanohybrid hydrogels were fully characterized by FT‐IR, SEM, EDX, XRD, TEM and TGA. PEG600‐POSS/Ag NPs exhibited excellent catalytic performance for the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in water at room temperature in the presence of borohydride. 相似文献
72.
Mehdi Salehi Fatemeh Faghani Maciej Kubicki Mehdi Bayat 《Journal of the Iranian Chemical Society》2018,15(10):2229-2240
In this research, we prepared a new series of the Cu(II) (1) and Ni(II) (2) metal complexes of a tridentate Schiff base ligand, (E)-2-(5-bromo-2-hydroxybenzylideneamino) phenol (H2L). These complexes were characterized by elemental analysis, FT-IR, UV–Vis, and 1H-NMR spectroscopy. The crystal structures of (1) and (2) were determined by X-ray diffraction studies. The single crystal X-ray diffraction analyses revealed that copper(II) cation is five-coordinated and the coordination polyhedron is a slightly distorted square pyramid. Nickel(II), on the other hand, is four-coordinated, and has a regular, square planar geometry. Further discussed were the electrochemical reduction of these complexes. We also analyzed the nature of the metal–ligand bond in the complexes through NBO and EDA analysis. Besides, vibrational sample magnetometer (VSM) revealed complex (1) was ferromagnetic. 相似文献
73.
Masoomeh Bayat Avat Arman Taherpour Seyed Mohammad Elahi Thomas Fellowes 《Journal of the Iranian Chemical Society》2018,15(6):1223-1234
Much progress has been made in the treatment of cancer. However, it remains a significant challenge to treat as toxic chemotherapeutic drugs are often poorly tolerated when administered together, limiting the patient’s treatment options. A possible solution to this problem is anchoring drugs on the surface of nanoparticles. These systems have a variety of structures with sizes, shapes and materials which determine loading capacity, cellular targeting and stability. Dendrimers are a class of nanoparticles which have been investigated in this context. In this study, we investigated the functionalization of polyamidoamine (PAMAM) dendrimers with some anticancer medications that suppresses the growth of cancer cells (carmustine, lomustine, semustine and melphalan; 1–4). The possibility of drug release, drug delivery and drug separation by PAMAM was theoretically investigated and discussed. The predicted theoretical method will be interesting to remove the pollutants from the medical solutions by PAMAM dendrimer nanoclusters. The results of the modeling were obtained by MMFF94 and RHF/PM6 methods for all form of the PAMAM–medicines complexes. The obtained results by these two methods were shown same trend of the relative energy surfaces of the complexes of PAMAM–medicines 1–4. 相似文献
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75.
Kinetics of the substitution reaction of solvent molecule in uranyl(VI) Schiff base complexes by tri‐n‐butylposphine as the entering nucleophile in acetonitrile at 10–40°C was studied spectrophotometrically. The second‐order rate constants for the substitution reaction of the solvent molecule were found to be (8.8 ± 0.5) × 10?3, (5.3 ± 0.2) × 10?3, (7.5 ± 0.3) × 10?3, (6.1 ± 0.3) × 10?3, (13.5 ± 1.6) × 10?3, (13.2 ± 0.9) × 10?3, (52.9 ± 0.2) × 10?3, and (88.1 ± 0.6) × 10?3 M?1 s?1 at 40°C for [UO2(Schiff base)(CH3CN)], where Schiff base = L1–L8, respectively. In a temperature dependence study, the activation parameters ΔH# and ΔS# for the reaction of uranyl complexes with PBu3 were determined. From the linear rate dependence on the concentration of PBu3, the span of k2 values and the large negative values of the activation entropy, an associative (A) mechanism is deduced for the solvent substitution. By comparing the second‐order rate constants k2, it was concluded that the steric and the electronic properties of the complexes were important for the rate of the reactions. 相似文献
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78.
The one-pot four-component synthesis of highly functionalized fused hydroxyl dihydropyrroles and dihydropyrazines from readily available diamines, 1,1-bis (methylsulfanyl)-2-nitroethene, phenylglyoxal monohydrates, and C-H acids have been developed. This strategy provides an efficient, catalyst-free approach for easy access to various new hydroxyl-dihydropyrrole and dihydropyrazine rings in good to high yields. The products were confirmed by 1H and 13C NMR, IR, mass, and X-ray crystal structure analyses. 相似文献
79.
During the life period of Small and Medium Enterprises (SMEs) in incubators they need some training programs to acquire the required knowledge in order to survive and succeed in the business environment. This paper presents a heuristic method based on an optimization model to schedule these programs at the most suitable times. Based on the proposed heuristic, each training program is implemented in a suitable time by considering the SMEs’ requirements and some other logical constraints. The proposed heuristic is described in detail, and its implementation is demonstrated via a real-life numerical example. The numerical results of the heuristic are compared with other methods. 相似文献
80.
phosphonate‐based bimetallic metal‐ organic frameworks, namely STA‐12(M1, M2) (M1, M2 = Mn, Fe, Co), show photocatalytic activity for the degradation of Rhodamine B (RhB) and Methylene blue (MB) from aqueous solution under natural sunlight irradiation. The degradation of the dyes, appears to be faster with STA‐12(Fe, Mn) than other synthesized MOFs. Thus, photo‐Fenton oxidative discoloration of dyes has been studied by H2O2 catalyzed with the STA‐12(Fe, Mn). The process is first order with respect to dyes and the synergistic index in the STA‐12(Fe, Mn)/sunlight/H2O2system reached as high as 472%. Mineralization of dyes was discussed by spectroscopic and TOC measurement. Besides, the efficiency of STA‐12(Fe, Mn) used in photocatalytic process was attentively investigated through the characterization of reactive radicals, the stability and reusability of the photocatalyst, also the effect of operational parameters such as H2O2 dosage, solution pH and initial dye concentration. This work demonstrates the first example of facilitating photo‐Fenton‐like excitation of H2O2 via phosphonate based mixed metal organic frameworks as photocatalysts and explained a new opportunity for solar‐induced AOP environmental remediation and protection. 相似文献