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دانشگاه فردوسي مشهد
دانشگاه صنعتي شريف
گروه آموزشی شیمی
گروه آموزشی شیمی
A bioinspired iron(III)porphyrinic Zr-MOF, PCN-222(Fe), was modified by post-synthetic cluster metalation with iron(III) chloride, as a cheap, earth-abundant, and environmentally friendly metal precursor, towards formation a new multifunctional MOF, namely Fe@PCN-222(Fe). The MOF consists of bimetallic (Zr-oxo-Fe) nodes linked by Fe(III)porphyrin struts. The cluster metalation and pre-activation treatment of PCN-222(Fe) were performed cooperatively using the FeCl3. The respective MOF was characterized through various techniques, such as FT-IR, PXRD, ICP-AES, BET surface area, SEM, UV–Vis DRS, TGA/ DSC, PL, and XPS analyses. The solid showed catalytic activity for one-pot tandem synthesis of quinazolin-4(3H)-ones from alcohols and 2-aminobenzamide through a three-consecutive-step reaction (oxidation-cyclization-oxidation) under visible light irradiation using air or oxygen without adding any additive. In addition, its catalytic performance was superior to that of the bare PCN-222(Fe) and the corresponding homogeneous catalysts. The experiments indicate that the solid MOF acts as both a photoredox and Lewis acid catalyst. Hot-filtration and Fe-leaching tests as well as reusability experiments confirm that the nominal MOF acts as an efficient reusable heterogeneous catalyst for at least three runs without significant decrease in its activity. This work demonstrates the potential of using MOFs as supports for single-site metal species towards preparation of multifunctional MOFs for modern organic transformations combining photocatalysis and catalysis.
An amino-functionalized zirconium metal-organic framework was composed with a 3D urea-based porous organic polymer to give a hybrid material termed UiO-66-NH2/urea-POP. The material was characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller surface area measurements. It is shown to be a viable sorbent for solid-phase extraction of uranium from water samples. Parameters such as the pH value of the sample, amount of adsorbent, type and volume of eluent, adsorption and desorption time, and sample volume were optimized. Uranyl ion was quantified by using UV-vis spectrophotometry by using 1-(2- pyridyl-azo)-2-naphthol as the indicator. Figures of merits include (a) a maximum sorption capacity of 278 mg g−1; (b) a detection limit of 0.6 μg L−1; and (c) intra-day and inter-day precisions (for n = 5 at a concentration of 100 μg L−1) of 4.8 and 1.9%, respectively. The sorbent can be recycled, and no significant change was observed in the capacity and repeatability of the sorbent after seven extractions. The high surface area, metal-binding sites, and stability of the sorbent makes it a most viable tool for efficient and fast extraction and removal of uranium.
Greenhouse whitefly, Trialeurodes vaporariorum is a major pest of horticultural and ornamental plants and is usually controlled with insecticides or biological control agents. In the current study, we examined the effects of synthesized zinc oxide nanoparticles (ZnO NPs) and Beauveria bassiana TS11 on T. vaporariorum adults. ZnO NPs were synthesized by precipitation method. Field emission scanning electron microscope images indicated that ZnO NPs were noncompacted uniformly. X-ray diffraction results confirmed the hexagonal wurtzite structure of ZnO NPs. Fourier transform infrared analysis showed an intense absorption peak at a range of 434-555 cm-1 related to Zn-O bond. In bioassays, adults were exposed to different concentrations of ZnO NPs (3, 5, 10, 15, 20 mg l-1) and fungi (104, 105, 106, 107, 108 spores ml-1). LC50 values for ZnO NPs and fungi were 7.35 mg l-1and 3.28×105 spores ml-1, respectively. Mortality rates obtained with ZnO NPs and fungi at the highest concentration were 91.6 % and 88.8 %, respectively. The results indicate a positive effect of ZnO NPs and B. bassiana TS11on adults. The current study was conducted under laboratory conditions, therefore, more studies are needed in field.
Chitosan and its derivatives have received attention as alternatives to pesticides in agriculture. Insects are a good source for chitosan isolation. In the present study, chitosan was obtained from Chrotogonus trachypterus (Orthoptera, Acrididae), and its N-alkyl derivatives were synthesized. Experiments were conducted to assay their aphicidal activity against three aphid species. All derivatives had a higher aphicidal action (> 98%) than pure chitosan (> 15.2%) against aphid species. N-(3-phenyl butyl) chitosan and N-(ethyl butyl) chitosan were the most and least active derivatives. Results confirmed that the chemical modification of chitosan increased the aphicidal activity. A comparison of the aphicidal activities confirmed that N-alkyl derivatives of commercial chitosan had more toxic effects on aphid species than derivatives of grasshopper chitosan. No significant differences were observed between the two groups of commercial and C. trachypterus chitosan derivatives. This encourages us to introduce N-alkyl derivatives of grasshopper chitosan as a promising alternative source of aphicides in future.
determination of gold from water samples prior to UV-Vis spectrophotometry. An artificial neural network (ANN) combined with imperialist competitive algorithm (ICA) has been applied to optimize the EME. The effective parameters including pH of acceptor phase, extraction time (t), volume of sample solution (V), stirring rate (S), and voltage (E) were chosen as input variables and the extraction recovery of gold was considered as output variable. The mean of squared error (i.e., 0.0009) and determination coefficient (i.e., 0.9821) were applied to estimate the performance of the ANN model. The limit of detection was 4.5 μg L
New trans-A2B2-porphyrins substituted at phenyl positions were synthesized from 4-methylphthalic acid as a starting material through sequential multistep reactions. These macrocycles were characterized by 1H NMR, 13C NMR, 19F NMR, 1H–1H COSY NMR, and MALDI-TOF mass spectrometry. Computational studies were performed on the porphyrins to investigate various factors such as structural features, electronic energy, energy gaps, and aromaticity. Energy band gap values of these compounds especially N-hydroxyphthalimide-functionalized porphyrins were small that makes them as good candidates for solar cell systems and photocatalysis. Relationships between electronic energies and aromaticity of the compounds were then investigated. The data indicated that the aromaticity features at the center of two series of these compounds (fluorinated and non-fluorinated porphyrins) were in the opposite manner.
The Amadori product is a stable intermediate in the glycation process, and its increased formation is a marker of hyperglycemia in diabetes mellitus. Its accumulation in the body contributes to pathological complications of diabetes including diabetic nephropathy and retinopathy, and cardiovascular diseases. In this study the effect of 3-b-hydroxybutyrate on the production of Amadori products and structural changes of human serum albumin (HSA) after incubation with glucose was investigated using FT-IR, circular dichroism (CD), and UV-visible and fluorescence spectroscopy. Our results showed that the production of Amadori products in HSA incubated with glucose was decreased in the presence of 3-b-hydroxybutyrate. The glycation-mediated alterations in HSA secondary and tertiary structures were also reduced in the presence of 3-b-hydroxybutyrate. These changes were attributed to reduced formation of glucose covalent bonds with the HSA lysine residues in the presence of 3-b-hydroxybutyrate. Thus, 3-b-hydroxybutyrate reduced the production of Amadori products by reacting with lysine residues and decreasing HSA covalent modifications by glucose.
In this study, gases adsorption on a series of mesoporous zirconium-based metal-organic framework analogues [PCN-222(M) where M = Mg, Fe, Co, Ni, Cu, and Zn)] has been evaluated by quantum mechanical calculations. These bioinspired frameworks are one of the most stable MOF materials, comprising the metalloporphyrin linkers/building blocks and the Zr6 nodes. The metalloporphyrins, open-zirconium coordination sites, and terminal hydroxyl groups on the nodes have been considered for the interactions. The structural and electronic properties of the complexes were investigated via the atoms in molecules (AIM), natural bond orbital (NBO), and harmonic oscillator model of aromaticity (HOMA) index. The results showed that the ironporphyrin is an appropriate candidate for the ammonia capture. It is observed that the hydrogen bond interactions of H2O with the hydroxyl groups of node are stronger than the others, while the interactions of NH3 with the open-zirconium coordination sites are stronger than the others. The all results indicated that the PCN-222(Fe) is selective for adsorption of NH3 over the other gases.
This work reports the synthesis of pyridyltriazol-functionalized UiO-66 (UiO stands for University of Oslo), namely, UiO-66-Pyta, from UiO-66-NH2 through three postsynthetic modification (PSM) steps. The good performance of the material derives from the observation that partial formylation (∼21% of −NHCHO groups) of H2BDC-NH2 by DMF, as persistent impurity, takes place during the synthesis of the UiO- 66-NH2. Thus, to enhance material performance, first, the as-synthesized UiO-66-NH2 was deformylated to give pure UiO-66-NH2. Subsequently, the pure UiO-66-NH2 was converted to UiO-66-N3 with a nearly complete conversion (∼95%). Finally, the azide−alkyne[3+2]-cycloaddition reaction of 2-ethynylpyridine with the UiO-66-N3 gave the UiO-66-Pyta. The porous MOF was then applied for the solid-phase extraction of palladium ions from an aqueous medium. Affecting parameters on extraction efficiency of Pd(II) ions were also investigated and optimized. Interestingly, UiO-66-Pyta exhibited selective and superior adsorption capacity for Pd(II) with a maximum sorption capacity of 294.1 mg g−1 at acidic pH (4.5). The limit of detection (LOD) was found to be 1.9 μg L−1. The estimated intra- and interday precisions are 3.6 and 1.7%, respectively. Moreover, the adsorbent was regenerated and reused for five cycles without any significant change in the capacity and repeatability. The adsorption mechanism was described based on various techniques such as FT-IR, PXRD, SEM/EDS, ICPAES, and XPS analyses as well as density functional theory (DFT) calculations. Notably, as a case study, the obtained UiO-66-Pyta after palladium adsorption, UiO-66-Pyta-Pd, was used as an efficient catalyst for the Suzuki−Miyaura cross-coupling reaction.
Inorganic nanoparticles and combination of inorganic nanoparticles with organic materials to form hybrids possess unique physical, chemical, optical and electrical properties which make them different and more applicable than large size materials. These types of platforms can be synthesized by different organic , inorganic or hybrid of organic and inorganic materials but among all these inorganic platformsare of most important for diagnosis and simultaneous therapy due to their easy modification, stability and high drug loading capacity . Metal nanoparticles specifically gold nanoparticles have abundant use in the field of biotechnology and biomedicine because they have large surface bio conjugation with molecular probes. In this study, we synthesized Au- Peptide nanoparticles using microwave, Sonochemistry and organic reducing agents and their anticancer effects were investigated. The resulting Au-nanoparticles were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), particle size analyzer and fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) techniques. The interaction of calf thymus DNA with Au-nanoparticles has been investigated following UV-Vis spectroscopic studies at 300 and 310 K. [L]1/2, ΔG0, ΔS0, ΔH0 values were obtained at 300 K, respectively, 0.24352 mM, 26.729 (KJ/mol), 0.8574 (KJ/mol.k), 286.435 (KJ/mol) and at 310 K, respectively, 0.33248 mM, 19.17 (KJ/mol), 0.8587 (KJ/mol), 286.435 (KJ/mol). Kapp, n and g values were obtaind 83.24, 6.74 and 4 at 310 K, respectively.