Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities.

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Unique and outstanding catalytic behavior of a novel MOF@COF composite as an emerging and powerful catalyst in the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives.

The creation of an emerging porous structure using the hybridization of UiO-66-NH2-MOF, a zirconium-based metal-organic framework (MOF), with a covalent organic framework (COF) based on terephthaldehyde and melamine (UiO-66-NH2-MOF@COF), was assessed using SEM, XRD, EDX/mapping, FT-IR, BET, and TGA analyses. Using the obtained composite as a potential recoverable heterogeneous nanocatalyst, different aldehydes were condensed with isatoic anhydride and anilines or ammonium acetate under solvent-free conditions to create derivatives of 2,3-dihydroquinazolin-4(1H)-one. Examining the catalytic capabilities of the designed UiO-66-NH2-MOF@COF to efficiently produce 2,3-dihydroquinazolin-4(1H)-ones was a standout activity. Low catalyst loading, simple set-up, outstanding yields, and catalyst recoverability are all benefits of this research.

An efficient protocol for the synthesis of pyridines and hydroquinolones using IRMOF-3/GO/CuFe2O4 composite as a magnetically separable heterogeneous catalyst.

This study reports a facile and cost-effective technique for preparing magnetic copper ferrite nanoparticles supported on IRMOF-3/GO [IRMOF-3/GO/CuFe2O4]. The synthesized IRMOF-3/GO/CuFe2O4 was characterized with IR, SEM, TGA, XRD, BET, EDX, VSM, and elemental mapping. The prepared catalyst revealed higher catalytic behavior in synthesizing heterocyclic compounds through a one-pot reaction between various aromatic aldehydes, diverse primary amines, malononitrile, and dimedone under ultrasound irradiations. Among the notable features of this technique are higher efficiency, easy recovery from the reaction mixture, removal of a heterogeneous catalyst, and uncomplicated route. In this catalytic system, the activity level was almost constant after various stages of reuse and recovery.

Exopolysaccharide-mediated silver nanoparticles synthesized from Lactobacillus paracasei with antimicrobial, antibiofilm and antioxidant activities.

Biofilm formation and resistance to antibiotics in pathogenic bacteria are important concerns in the treatment of infectious diseases. A new rapid, eco-friendly and cost-effective strategy to overcome these problems is the use of microbial exopolysaccharides (EPS) for green synthesis of various metal nanoparticles (NPs). This study used EPS from a native probiotic Lactobacillus isolate to synthesize silver nanoparticles (AgNPs) with effective antimicrobial, antibiofilm and antioxidant properties. AgNPs were synthesized by 10 mg of EPS of Lactobacillus paracasei (L. paracasei MN809528) isolated from a local yogurt. The characteristics of EPS AgNPs were confirmed using UV-VIS, FT-IR, DLS, XRD, EDX, FE-SEM, and zeta potential. Antimicrobial, antibiofilm and antioxidant activities of EPS AgNPs were evaluated by the agar well diffusion, microtiter dilution, SEM electron microscopy, and DPPH radical absorption methods, respectively. Spectroscopy data indicated the presence of a 466-nm peak as a feature of AgNPs. FT-IR confirmed the presence of biological agents in the synthesis of AgNPs. FE-SEM results showed that the synthesized AgNPs had a spherical shape with the size of 33-38 nm. Synthesized AgNPs at a concentration of 100 mg/ml demonstrated a significant inhibitory activity compared to chemically synthesized AgNPs. These NPs, exhibited the greatest effect of inhibiting the Escherichia coli and Pseudomonas aeruginosa biofilm formation at sub-MIC concentration, and the best effect of DPPH radical as antioxidant activity was determined at 50-µg/ml concentration. Our findings reveal that EPS AgNPs synthesized by the native isolate of L. paracasei (MN809528) is an inexpensive and environment-friendly candidate for application in pharmaceuticals fields.

Recent developments in hydrogels containing copper and palladium for the catalytic reduction/degradation of organic pollutants.

The elimination of toxic and hazardous contaminants from different environmental media has become a global challenge, causing researchers to focus on the treatment of pollutants. Accordingly, the elimination of inorganic and organic pollutants using sustainable, effective, and low-cost heterogeneous catalysts is considered as one of the most essential routes for this aim. Thus, many efforts have been devoted to the synthesis of novel compounds and improving their catalytic performance. Recently, palladium- and copper-based hydrogels have been used as catalysts for reduction, degradation, and decomposition reactions because they have significant features such as high mechanical strength, thermal stability, and high surface area. Herein, we summarize the progress achieved in this field, including the various methods for the synthesis of copper- and palladium-based hydrogel catalysts and their applications for environmental remediation. Moreover, palladium- and copper-based hydrogel catalysts, which have certain advantages, including high catalytic ability, reusability, easy work-up, and simple synthesis, are proposed as a new group of effective catalysts.

Poly(acrylic acid)/Fe3O4 supported on MIL-100(Cr) MOF as a novel and magnetic nanocatalyst for the synthesis of Pyrido[2,3-d]Pyrimidines.

In the current work, a convenient and simple approach for preparing poly (acrylic acid)/Fe3O4 supported on MIL-100(Cr) for the synthesis of pyrido [2,3-d]pyrimidine derivatives via the three-component one-pot reaction of 1,3-indandione, 6-amino uracil, and aromatic aldehydes is reported. The effectiveness of this new magnetic nanocatalyst was proved. The results showed this nanocatalyst's moderate to high yield under reflux conditions. SEM, TEM, IR, EDX, XRD, BET, and TGA were used to characterize the structure of the synthesized nanocatalyst. This synthetic protocol offers various advantages, including cost-saving, excellent yields in short reaction times (67-98%), low catalyst loading, and catalyst reusability.

Preparation of NiFe2O4@MIL-101(Fe)/GO as a novel nanocarrier and investigation of its antimicrobial properties.

In this research, we have investigated a novel magnetic nanocomposite including NiFe2O4@MIL-101(Fe)/GO for the delivery of the antibiotic tetracycline (TC). Moreover, the antibacterial activity of NiFe2O4@MIL-101(Fe)/GO, NiFe2O4@MIL-101(Fe)/GO/TC and pure TC was evaluated by agar well diffusion and minimum inhibitory concentration (MIC) methods on both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. In addition, the cytotoxicity of NiFe2O4@MIL-101(Fe)/GO/TC on HeLa cells was determined by an MTT assay which showed good results. The structure of the prepared nanocarrier was investigated by various spectroscopic techniques such as Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), and thermal gravimetric analysis (TGA). The results of this study showed that 98% of the TC was loaded on the synthesized nanocomposite. Drug release occurred at pH: 7.4 (phosphate buffer saline) and pH: 5.0 (acetate buffer) within 3 days, resulting in 77% and 85% release of the drug, respectively.

Enhanced Removal of Methyl Violet Dye from Aqueous Solution by a Novel Co3O4@SiO2@TiO2-Ag Heterogeneous Semiconductor.

BACKGROUND: This research proposes the application of a novel photocatalyst including Co3O4@SiO2@TiO2-Ag nanocomposite with highly photocatalytic stability and core-shell structure for the removal of toxic methyl violet from aqueous solution. OBJECTIVE: The removal of toxic dyes and organic contaminants from water is an outstanding research area among the scientists. Methyl violet is a toxic cationic pollutant that has a disruptive influence on humans. In this research, with an aim to remove methyl violet from the wastewater, we developed a new photocatalyst including Co3O4@SiO2@TiO2-Ag nanocomposite as an ecofriendly and low-cost nanostructure with high photocatalytic activity in order to reduce the risks of this pollutant from aqueous media. METHODS: The Co3O4@SiO2@TiO2-Ag nanostructure was prepared via hydrothermal and sol-gel methods and the structure elucidation of the prepared photocatalyst was analyzed by different spectroscopy techniques, including XRD, FT-IR, FE-SEM, TEM, VSM and EDX. RESULTS: Photodegradation of methyl violet in the presence of different structures showed that Co3O4@SiO2@TiO2-Ag possesses superior photocatalytic activity (about 98% decomposed after 40 min) compared to the previous shells and pure Co3O4 NPs. Loadings of SiO2@TiO2-Ag nanocomposite over the Co3O4 surface led to the reduction in the bandgap energy of visible light and improvement in the photocatalytic activity of Methyl Violet dye f o r the aqueous phase decomposition. CONCLUSION: The remarkable benefits of this nanocomposite are high photocatalytic efficiency in the degradation of methyl violet (almost 100 % within 1 h), easy magnetic separation, low cost, and high chemical stability. The collected results demonstrated that the rate of degradation increased by increasing the irradiation time, while the rate of degradation decreased with increasing dye concentration.

Synthesis of a novel ternary ZIF-8/GO/MgFe2O4 nanocomposite and its application in drug delivery.

In recent year, metal-organic frameworks (MOFs) have been displayed to be a category of promising drug delivery systems because of their crystalline structure, the potential of further functionality, and high porosity. In this research, graphene oxide was synthesized from pure graphite via hummer method and then MgFe2O4 nanoparticles was incorporated into the synthesized ZIF-8 metal-organic frameworks which followed with loading on the surfaces of graphene oxide. In continue, tetracycline as an antibiotic drug was loaded on the surfaces and the cavities of the prepared nanocomposite. The outcomes of this research revealed that 90% of the tetracycline was loaded on the synthesized ZIF-8/GO/MgFe2O4 nanostructure. Next, drug release was done at pH: 5 and pH: 7.4 within 3 days, resulting about 88% and 92% release of the tetracycline, respectively. With using different spectroscopic methods like X-ray crystallography (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermalgravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET), the structure of synthesized materials was confirmed. Furthermore, the antibiotic activity of tetracycline trapped into the ZIF-8/GO/MgFe2O4 was evaluated by agar-well diffusion method on both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, which showed good antibacterial results.

Synthesis of tetrazolo[1,5-a]pyrimidine-6-carbonitriles using HMTA-BAIL@MIL-101(Cr) as a superior heterogeneous catalyst.

A one-pot three component reaction of benzaldehydes, 1H-tetrazole-5-amine, and 3-cyanoacetyl indole in the presence of a new hexamethylenetetramine-based ionic liquid/MIL-101(Cr) metal-organic framework as a recyclable catalyst was explored. This novel catalyst, which was fully characterized by XRD, FE-SEM, EDX, FT-IR, TGA, BET, and TEM exhibited outstanding catalytic activity for the preparation of a range of pharmaceutically important tetrazolo[1,5-a]pyrimidine-6-carbonitriles with good to excellent yields in short reaction time.

Hexamethylenetetramine-based ionic liquid/MIL-101(Cr) metal-organic framework composite: a novel and versatile tool for the preparation of pyrido[2,3-d:5,6-d']dipyrimidines.

In the current paper, a hexamethylenetetramine-based ionic liquid immobilized on the MIL-101(Cr) metal-organic framework was successfully synthesized as a novel, efficient, and recoverable catalyst for the synthesis of pyrido[2,3-d:5,6-d']dipyrimidine derivatives via the reaction of barbituric acid derivatives, 6-aminouracil/6-amino-1,3-dimethyl uracil, and aromatic aldehydes under solvent-free conditions. Characterization of the catalyst was carried out using various methods such as field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrophotometry (FT-IR), and Brunauer-Emmett-Teller (BET). Efficient transformation, short reaction times, excellent yields, easy product isolation, mild conditions, and the potential high recyclability of the organocatalyst are the main features of this protocol.

Green synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazoles] using Fe3O4@l-arginine as a robust and reusable catalyst.

The synthesized Fe3O4@l-arginine showed strong catalytic performance in the one-pot synthesis of spiropyranopyrazoles via the reactions of hydrazines, ß-keto esters, isatins, and malononitrile or ethyl cyanoacetate under solvent-free conditions. The biologically active heterocyclic compounds including spiropyranopyrazole derivatives were efficiently synthesized in short reaction times and excellent yields in the presence of Fe3O4/l-arginine at room temperature. The highlighted features of the Fe3O4@l-arginine nanocomposite are highly stable, easy to separate, low loading, cost-effective with easy preparation and reusability of the catalyst. The heterogeneous nanocomposite was fully characterized by SEM, EDX, FT-IR, XRD and TEM analysis.

Novel Brönsted Acidic Ionic Liquids Confined in UiO-66 Nanocages for the Synthesis of Dihydropyrido[2,3-d]Pyrimidine Derivatives under Solvent-Free Conditions.

The effective and simple one-pot, three-component protocol for the synthesis of dihydropyrido[2,3-d]pyrimidine derivatives is presented using a triethylenediamine or imidazole Brönsted acidic, ionic-liquid-supported Zr metal-organic framework (TEDA/IMIZ-BAIL@UiO-66) as a green, novel, and retrievable heterogeneous catalyst under mild conditions. The multicomponent reactions of 6-amino-1,3-dimethyl uracil, various aromatic aldehydes, and acetyl acetone were conducted under solvent-free conditions so that dihydropyrido[2,3-d]pyrimidine derivatives can be obtained. It is possible to separate and purify the respective products easily using crystallization. We can recycle the catalysts six times without losing any major activity. Also, the characterization of the catalyst was done by energy-dispersive X-ray, field emission scanning electron microscopy, Fourier transform infrared, Brunauer-Emmett-Teller, X-ray diffraction, and thermogravimetric analysis analyses.

Synthesis, identification and application of the novel metal-organic framework Fe3O4@PAA@ZIF-8 for the drug delivery of ciprofloxacin and investigation of antibacterial activity.

Today, metal-organic frameworks (MOFs) for the release of drugs have been studied extensively. In this research, we have investigated the novel magnetic framework including Fe3O4@PAA@ZIF-8 for the delivery of ciprofloxacin (CIP) antibiotic. Moreover, the antibacterial activity of Fe3O4@PAA@ZIF-8 and Fe3O4@PAA@ZIF-8@CIP screened against Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli) bacteria. The structure of the nano carrier, as well as the encapsulation of the drug in the framework was confirmed by the Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-Vis), Energy-dispersive X-ray spectroscopy (EDX), X-ray crystallography (XRD), Scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET) analysis. The results of this study showed that 93% of the CIP was loaded on the synthesized framework. Drug release was done at pH: 7.4 and pH: 5 within 2 d, resulting about 73% release of the drug.

Green Fabrication of Cobalt NPs using Aqueous Extract of Antioxidant Rich Zingiber and Their Catalytic Applications for the Synthesis of Pyrano[2,3-c]pyrazoles.

AIM AND OBJECTIVE: In this study, biological synthesis of cobalt nanoparticles was developed in the presence of ginger extract as the reducing and capping agent through the simple and convenient co-precipitation method. MATERIALS AND METHODS: The as-synthesized cobalt nanoparticles were characterized by X-ray diffraction (XRD), scanning Electron Microscopy (SEM), spectra energy dispersive analysis of Xray (EDS), Fourier transform infrared (FT-IR), and vibrating sample magnetometer (VSM) techniques. According to the vibrating sample magnetometer, cobalt nanoparticles show paramagnetic behaviour at room temperature. Furthermore, the effect of ginger extract concentration on the UV-Vis absorbance of Co nanoparticles was investigated. Based on the UVVis absorbance spectra, increasing ginger extract concentration causes particle size to decrease. In addition, the catalytic performance of the synthesized cobalt nanoparticles was investigated in the preparation of pyrano[2,3-c]pyrazoles via one-pot four-component reactions of aryl aldehydes, hydrazine hydrate, malononitrile and diethyl acetylenedicarboxylate. RESULT AND CONCLUSION: The prepared pyrano[2,3-c]pyrazole derivatives were obtained in high yields within short reaction times and the nanocatalyst was easily separated using an external magnet and reused for several times with no significant loss of its activity.

Synthesis and Antibacterial Evaluation of Some New 1,4-Dihydropyridines in the Presence of Fe3O4@Silica Sulfonic Acid Nanocomposite as Catalyst.

The synthesis of heterocyclic compounds has been a topic of significant interest because of their broad applications. In this research an effective and eco-friendly approach for the synthesis 1,4-dihydropyridines has been developed via the four-component reactions of arylamines, acetylenedicarboxylates, aromatic aldehydes and ethyl acetoacetate in the presence of Fe3O4@SiO2@OSO3H nanocomposite under solvent-free conditions. The advantages of this method involve the green reaction conditions, simple workup, broad substrates, excellent yields and the reuse of the nanocatalyst. One of the indicators to measure antimicrobial activity is Minimum Inhibitory Concentrations (MIC) that this measure and heterocyclic compounds synthesis inhibition zone diameter was measured on examined bacteria using well diffusion, disc diffusion and determination of antibiotic susceptibility. The results of all three methods suggested the susceptibility of Staphylococcus aureus to synthesized heterocyclic compounds. It can be concluded from the results that these compounds have high antibiotic properties and can be useful in other research and biomedical applications.

Preparation and Catalytic Study on a Novel Amino-functionalized Silica-coated Cobalt Oxide Nanocomposite for the Synthesis of Some Indazoles.

In this research an efficient synthesis of a novel nanocomposite including SiO2@(3-aminopropyl)triethoxysilane-coated cobalt oxide (Co3O4) nanocomposite has been reported by three step method. The structure and magnetic characterization of Co3O4@SiO2@NH2 have been done by using various spectroscopic analyses which include FT-IR, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry. Amino-functionalized SiO2 coated Co3O4 nanocomposite exhibited superparamagnetic behavior and strong magnetization at room temperature. The average crystallite sizes of the Co3O4 are 23.7 nm. The obtained magnetic nanocomposite showed excellent catalytic activity as a new heterogeneous magnetic catalyst for the synthesis of some indazole derivatives under mild reaction conditions along with high level of reusability.

Magnetite Nanoparticles-Supported APTES as a Powerful and Recoverable Nanocatalyst for the Preparation of 2-Amino-5,10-dihydro- 5,10-dioxo-4H-benzo[g]chromenes and Tetrahydrobenzo[g]quinoline-5,10- diones.

AIM AND OBJECTIVE: This study introduces a green and effective approach for the preparation of biologically-active heterocyclic compounds including 2-amino-5,10-dihydro-5,10-dioxo-4Hbenzo[ g]chromenes and tetrahydrobenzo[g]quinoline-5,10-diones using one-pot multi-component reactions in the presence of Fe3O4@SiO2-NH2 nanocomposite. The preparation and use of aminofunctionalized Fe3O4@SiO2 as a powerful and reusable nanocatalyst is described. The catalyst was characterized by spectral techniques including FT-IR, SEM, XRD, EDX and VSM analysis. This method offers the advantages of high yields, short reaction times, comfortable work-up and reusability of the catalyst. MATERIAL AND METHOD: The amino-functionalization silica-coated magnetite nanocomposite was prepared by three step method and the structure elucidation of the nanocatalyst has been done using various spectroscopic analyses. Then, the Fe3O4@SiO2-NH2 nanocomposite was used in the multicomponent synthesis of 2-amino-5,10-dihydro-5,10-dioxo-4H-benzo[g]chromenes and tetrahydrobenzo[g]quinoline-5,10-diones under reflux conditions. All of the products were analyzed with m.p., 1H NMR, 13C NMR and FT-IR spectroscopy techniques. The study on the recoverability of the nanocatalyst showed the recovered Fe3O4@SiO2-NH2 nanocomposite could be reused sixth consecutive times with a little-decreased activity. RESULTS: Amino-functionalized SiO2 coated Fe3O4 nanocomposite exhibited superparamagnetic behavior and strong magnetization at room temperature. The average crystallite sizes of the catalyst was about 50-60 nm. The obtained magnetic nanocomposite showed excellent catalytic activity as a new heterogeneous magnetic catalyst for the synthesis of some benzo[g]chromenes and tetrahydrobenzo[g]quinoline-5,10-diones. We propose that NH2 groups on the surfaces of nanocomposite act as the Brønsted base and cause to dehydrogenation of substrates to promote the reactions. CONCLUSION: It was found that Fe3O4@SiO2-NH2 nanocomposite act as an eco-friendly and efficient catalyst for one-pot synthesis of three/four component condensation reactions. In this research, aminofunctionalized Fe3O4@SiO2 was used as recoverable catalyst for the synthesis of 2-amino-5,10- dihydro-5,10-dioxo-4H-benzo[g]chromenes and tetrahydrobenzo[g]quinoline-5,10-diones under reflux conditions. The significant advantages of this method are the reasonably simple work-up, little catalyst loading, short reaction times, excellent yields, non-hygroscopic quality and reusability of the nanocatalyst which is in good agreement with green chemistry disciplines.

Fe3O4@SiO2-NH2 Nanocomposite as a Robust and Effective Catalyst for the One-pot Synthesis of Polysubstituted Dihydropyridines.

A practical, simple and efficient method for the synthesis of polysubstituted dihydropyridines was described via multicomponent reactions of aldehydes, arylamines, dimethyl acetylenedicarboxylate and malononitrile/ethyl acetoacetate in the presence of Fe3O4@SiO2-NH2 nanocomposites. The present methodology provides a novel and efficient method for the synthesis of dihydropyridine derivatives with some advantages, such as excellent yields, short reaction times, recoverability and low catalyst loading. The nanomagnetic catalyst could be readily recovered using an external magnet and reused several times without any significant loss in activity. The catalyst was fully characterized by FT-IR, SEM, XRD, EDX and VSM analysis.