Journal of the Iranian Chemical Society最新文献

Thiamine detection has been developed using Copper-Metal Organic Frameworks (CuMOF) and Rhodamine B-complexed Graphene Oxide (RhGO), facilitating both direct and indirect fluorescence-based sensing of thiamine. Both these methods are less cumbersome and sensitive fluorometric methods which are developed from less expensive materials. CuMOF offered the oxidation route of thiamine to thiochrome, which is a fluorescence compound; through which thiamine was detected conveniently by measuring thiochrome. On the other hand, rhodamine B bound graphene oxide–RhGO, released rhodamine B upon interaction with the thiamine through the competitive binding against the rhodamine B located on the graphene oxide, which allowed us to develop a facile sensor for thiamine in DMF. Moreover, the sensitivity of the sensor was improved through the encapsulation effect with cucurbit[7]uril (CB[7]). The limits of detection (LOD) for CuMOF and RhGO with CB[7] were determined to be 48.39 × 10^–8 M and 68.33 × 10^–8 M, respectively. The sensing ability of RhGO was effectively utilized in commercially available thiamine drugs, and its performance was evaluated against other hydrochloride drugs such as metformin, ciprofloxacin, and cetirizine demonstrating its suitability for real-time sample analysis. This approach provides a practical solution for both analytical and pharmaceutical laboratories. Overall, two different detection methods for thiamine have been developed with good selectivity and sensitivity.

Graphical Abstract

A method for the analysis of trace nitrogen trifluoride impurities in high-purity carbon tetrafluoride (≥ 99.999%) by gas chromatography equipped with a flame ionization detector is described. A 10-port valve and three columns have been used in this instrument system, which can completely separate nitrogen trifluoride and carbon tetrafluoride. In the best analytical conditions, the quantification limit was estimated at 16.62 ppb for an injected sample volume of 1 mL. Furthermore, this method can be completed by one sample injection without the need to vent some of the main component-high-purity carbon tetrafluoride through the valve switch, which is more accurate and simple.

In this study, the catalytic activity of an oxovanadium(IV) unsymmetrical salophen complex immobilized on chloro-functionalized silica-coated CoFe₂O₄ magnetic nanoparticles CoFe₂O₄@SiO₂@CPTMS@VO(salophen-OH), in which salophen-OH = 4-[(E)-{(2-[(E)-2-hydroxybenzylidene)amino]phenyl}imino)methyl]benzene-1,3-diol was explored in the oxidation of alcohols and hydrocarbons. This heterogeneous nanocatalyst showed high activity and selectivity in oxidizing various primary and secondary alcohols to the equivalent aldehydes and ketones with 30% H₂O₂ as a green oxidant in polyethylene glycol (PEG) as an eco-friendly solvent at 80 °C. Furthermore, the above catalyst demonstrated significant catalytic efficiency in the alkene epoxidation and alkane hydroxylation using tert-butyl hydroperoxide (tert-BuOOH), and the corresponding products were achieved in good to excellent yields in acetonitrile at ambient temperature. This magnetic nanocatalyst can be easily separated from the reaction mixture utilizing an external magnet and reused up to five times without significant activity loss. Moreover, the recovered catalyst’s structure was scrutinized using Fourier transform infrared (FT-IR), vibrating sample magnetometry (VSM), and X-ray diffraction (XRD) techniques, which confirmed that the structure of the catalyst remained unaltered post-recovery.

Two new complexes of europium (III) and erbium (III) were synthesized from diaminodiphenylether bridged spacer in 1:1 molar ratio of ligand and metal salt, whereas the ligand was synthesized in 1:2 molar ratio of diaminodiphenylether and aldehyde. The synthesized complexes were structurally analyzed through nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), energy-dispersive X-ray diffraction (EDX), UV–visible and photoluminescence spectroscopy. In both synthesized complexes, the metals were found in coordination to nitrogen and oxygen atoms of the azomethine (HC = N) and hydroxyl (–OH) groups as evident by FTIR and NMR spectral results in both synthesized complexes. Molar conductivity data for Eu(III) and Er(III) observed in the range of 129–135.5 Ω⁻¹cm² mol⁻¹ determined that both complexes were 1:2 electrolytes. The presence of characteristic peaks for Eu, C, O and N was clearly identified in energy-dispersive X-ray diffraction, which confirmed its successful synthesis. Furthermore, the luminescence behavior of the complexes was investigated in the solution state with dichloromethane (DCM). Upon excitation at 274 nm, both complexes exhibited two emission bands centered at 379 nm to 399 nm and 519 nm for Eu(III) and Er(III). Consequently, the good emission properties illustrated that the synthesized complexes featured their potential as promising cost-effective luminescent materials.

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By considering the importance of heterogeneous catalysts with separation and recycling ability from the reaction environment and ring opening of epoxide as a regularly essential conversion in organic synthesis, tetraaza macrocyclic complexes of Cu(П), Fe(IП) and Cr(Ш) were grafted on the acylated multiwalled carbon nanotubes (MWCNTs) to produce new nanocomposites as heterogeneous catalysts. Then the nanocomposites were applied in the regioselective ring-opening reaction of epoxystyrene with different alcohols to obtain β-alkoxy compounds. For the characterization of tetraazamacrocycle and nanocomposites, FT-IR, TGA, XRD, FE-SEM and Raman were employed. Results showed that the complexes were successfully grafted on the functionalized MWCNTs. Ring-opening reactions took place at high yield and favorite time, especially for the shorter chain alcohols. In the best case, nanocomposite containing Fe(Ш) (MWCNTs-C (=O)–TAM·Fe^III) accomplished the ring opening of epoxystyrene by methanol (100%) within 15 min at 50 °C, and after 3 recycling test, there are negligible changes in its catalytic performance.

Until now, there have been many reports on the regulation of inorganic metal ions on the catalytic activity of nanozymes, but few reports on the regulation of anions (such as NO₂⁻) on enzyme activity. In this work, a copper-molybdenum doped carbon dots (Cu, Mo-CDs) with peroxidase-like (POD) activity was synthesized by simple one-step microwave digestion method. The Cu, Mo-CDs + NO₂⁻ system can promote 3,3′,5,5′-tetramethylbenzidine (TMB) oxidizing to blue oxidative product (oxTMB) due to the formation of ∙NO₂ free radical. While Hg²⁺ was introduced into the system, the POD-like activity of Cu, Mo-CDs + NO₂⁻ system was inhibited due to the strong interaction and the electron transfer between Cu, Mo-CDs and Hg²⁺. The formation of ∙NO₂ and the electron transfer capability of Cu, Mo-CDs + Hg²⁺ were confirmed through ESR spectra and FMN experiments. The bioenzyme-free colorimetric assay based on Cu, Mo-CDs nanozyme is used for detection of NO₂⁻ and Hg²⁺, showing lower detection limit (LOD) of 1.63 µg/L for NO₂⁻, 0.13 µg/L for Hg²⁺, respectively and good recovery from 90.79 to 108.90%. The work paves a new way to design a nanozyme-based colorimetric protocol for traces NO₂⁻ and Hg²⁺ residues in food analysis.

A novel 2-(2,3,4-trimethoxyphenyl)-1H-phenanthro[9,10-d]imidazole crystal has been reported and characterized by FT-IR, ¹H NMR, and ¹³C NMR spectral techniques. Single-crystal XRD studies reveal that the compound crystallizes into orthorhombic crystal system with Pbcn space group, and crystallographic data have been deposited in the Cambridge crystallographic data centre with CCDC number: 2244532. Various computational analyses such as hydrogen bond analysis, molecular electrostatic potential analysis, natural population analysis, Hirshfeld surface, and Frontier molecular orbital analysis were performed to elucidate the structure of the crystal. The calculation of reorganization energy and coupling constant using DFT methods reveals that the compound could be investigated as a hole transport material.

In recent years, “sulfate-free” products have become increasingly common for most cosmetics and personal care products. With a boom in the number of sulfate-free claims, an analytical method for determining sulfate is certainly needed. Analysis of sulfate in cosmetic products can be difficult due to matrix interference and the complex nature of the ingredients used in the formulation. A simple and novel modified method for the determination of sulfate was developed by using UV–Vis spectroscopy. The procedure involved the precipitation of sulfate as barium sulfate and the removal of interference under controlled conditions, using different reagents such as acid, glycerol and ethanol. The method was optimized for the best conditions using response surface methodology. According to the experimental design, nitric acid and glycerol at 2% concentration yielded the maximum absorbance and the optimized method was validated in terms of linearity, accuracy, precision, limit of detection and limit of quantification. Fifteen market samples belonging to the shampoo and conditioner product types were analyzed to evaluate the performance of the optimized method. The results obtained were found to be satisfactory, and the proposed method is linear (R²—0.9971), accurate (89 to 92%), precise (%RSD < 4) and robust (% deviation < 5) with limit of detection (4.2 mg/l), limit of quantification (12.59 mg/l) and can be employed for the analysis of sulfate in cosmetics and personal care products.

Vitamins are not only essential for normal cell function but also important in organic transformations, specifically in the field of organocatalysis. Due to the increasing importance of sustainable and ecofriendly organic reaction protocols, there has been growing attention in organocatalysis owing to easy access, biocompatibility, and excellent reactivity. As vitamins are environmentally benign, nontoxic, and economic organocatalyst, VB₁, VB₂, and VB₁₂ have been employed successfully in variety of organic transformations. The catalysts exhibited very high efficacy in various C–C bond-forming reactions from multicomponent reaction to cross-coupling reactions. This review concisely demonstrates catalytic performance of natural organocatalyst VB₁, VB₂, and VB₁₂ and also provides basic knowledge about this important synthetic tool for the preparation of organic compounds in a greener manner. The review explores the versatile application of vitamins where vitamins acted as the principal catalyst (Lewis acidic catalyst, photocatalyst), co-catalyst, organometallic catalyst, and ligand of metal ion catalysts. Utilization of vitamin-functionalized nanocatalysts in cross-coupling, A³-coupling, oxidation reaction, etc. has been demonstrated thoroughly. Additionally, the mechanistic details illuminating the roles of vitamins in important organic transformations are meticulously explained, providing insights into reaction pathways and empowering the described organcatalysis approaches.