The triethylamine-based nanomagnetic ionic liquid, [(Et)3 N-H]FeCl4, was synthesized, and its structural and chemical characteristics were detected. The thermogravimetric analysis indicated its high thermal stability with a decomposition temperature higher than 300 °C. Additionally, [(Et)3 N-H]FeCl4 was used to efficiently catalyze the synthesis of xanthene derivatives under solvent-free conditions at 120 °C. [(Et)3 N-H]FeCl4 was recycled and reused at least five times.
Graphical abstractHerein, a green and efficient heterogeneous and photocatalytic system for the oxidation of bisnaphthols in acetonitrile under light-emitting diode will be presented. In this reaction, aerial oxygen and H2O2 have been used as oxidant in the presence of copper ferrite nanoparticles and N-hydroxyphthalimide as an organic co-catalyst. Copper ferrite nanoparticles were magnetically separated, the efficiency of which remained nearly unchanged up to five cycles. Magnetic copper ferrite nanoparticles were synthesized by sol–gel method and characterized by XRD, FT-IR, SEM, TEM, VSM and DRS analysis. In this project, both sets of diastereomers were formed.
Graphical abstractCatalytic system for the oxidation of bisnaphthols.
Here, iron, sulfur and poly(ethylene glycol) doping to TiO2 nanoparticles toward the effect on photodegradation of the methylene blue (MB) and Evans blue (EB) was investigated. The present nanostructured photocatalysts displayed notable catalytic activity for the decomposition of colorants in water under visible light irradiation. The photocatalytic reaction constants of different samples were determined for EB and MB to be 0.007, 0.008, 0.009 and 0.01, 0.026, 0.021 1/min, respectively. The values of optical band gap for pure TiO2, Fe–S/TiO2, and Fe–S/TiO2@PEG were estimated to be 3.21, 2.75, and 2.81, respectively. X-ray analysis was performed and correlated with BET, Fe–SEM, and TEM results. The lattice structure was studied by W–H (Williamson–Hall) and H–W (Halder–Wagner) methods with a different assumption in the isotropic and homogenous nature. The results revealed that the SSP model shows the most accuracy and adaption to determine the lattice structure.
Graphic abstractAn eco-friendly method for diversity-oriented synthesis of substituted dihydropyrano[2,3-c]pyrazole and benzylpyrazolyl coumarin derivatives has been achieved via one-pot and multicomponent reaction in the presence of PdO/Al-SBA-15 as an efficient and recyclable catalyst in H2O/EtOH under reflux conditions. The significant merits of this method are wide scope, high yields of the desired products, short reaction times and simple workup procedure. In addition, this nanocatalyst was simply recovered and reused five times without significant loss in catalytic activity and also performance.
Graphical abstractHeterocyclic chemistry has fascinated the researchers owing to its wide range of applications in various chemical fields. With this perspective, herein we present an environmentally benign procedure for the synthesis of pyrazole and its derivatives through multicomponent reaction by using SPVA as a heterogeneous acid catalyst. The synthesis protocol of SPVA catalyst includes functionalization of polyvinyl alcohol by sulfonic acid groups. The synthesized SPVA catalyst was then subjected to several characterization techniques to confirm its formation and study its physicochemical properties. The SPVA catalyst was then tested for its activity toward a multicomponent reaction of aromatic aldehyde, malononitrile and phenyl hydrazine. The SPVA catalyst with sufficient acidic sites displayed appreciable catalytic performance yielding 89% of the desired pyrazole product under ambient reaction conditions. The SPVA catalyst showed recyclability up to the sixth cycle without considerable loss in its activity. Furthermore, we made an effort to demonstrate the plausible mechanistic pathway for the SPVA-catalyzed pyrazole synthesis reaction. Interestingly, the present synthetic approach could effectively produce pyrazole products with high yields in the absence of base and solvent and in short reaction time making it a green and sustainable process.
Graphic abstractA simple and efficient method for the synthesis of pyrazolopyranopyrimidines under solvent-free has been developed. The one-pot multicomponent condensation of arylaldehydes with hydrazine hydrate, ethyl acetoacetate and barbituric acid in the vicinity of a mesoporous basic nanomagnetic catalyst, namely DBU immobilized on Fe3O4@nSiO2@mSiO2 was synthesized in remarkably high yields and in short reaction times. Significantly, this catalyst can be easily separated from the reaction media by applying an external magnet, and can be reused for several cycles.
Graphical abstractIn this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30 nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity.
Graphic abstractIn this research, a new heterogeneous catalyst is fabricated through covalent modification of iron-based metal–organic framework with ionic liquid. In more detail, using 2-aminoterephthalic acid and iron (III) chloride hexahydrate, amino-functionalized metal–organic framework has been synthesized and then reacted with 2,4,6-trichloro-1,3,5-triazine and 1,4-diazabicyclo[2.2.2]octane successively to furnish ionic liquid on metal–organic framework. The as-prepared catalyst was characterized by FTIR, TGA, BET, SEM/EDS, XRD and elemental mapping analysis and then employed for catalyzing synthesis of pyrano [2,3‐d]pyrimidines (with yields of 80–100%) from one-pot three-component reaction of aldehydes, barbituric acid and malononitrile in aqueous media. The catalytic test inferred high catalytic activity of the catalyst, superior to that of IL and metal–organic framework. Furthermore, the catalyst could be recovered and recycled for five reaction runs with preserving its morphology.
Graphic abstractThe AHA coupling of amines, haloalkane and alkynes under UV visible light was achieved with a higher yield in the presence of Au/Fe2O3. The catalyst was prepared by two methods using different gold content and then characterized by XRD, UV–vis, BET, TEM, ICP-OES and TPR spectroscopies. A comparative study of the ordinary and photocatalytic conditions, showed that the UV visible light could activate the gold nanoparticles and lead to the formation of CH2Cl? and Cl? radicals through CH2Cl2 fragmentation. The propargylamine was afforded at low temperature and a short time using 2% Au/Fe2O3. The catalyst was stable for five cycles with good photoactivity.
Graphical abstractAn efficient and convenient procedure for the synthesis of novel 6-hydroxy-14-aryl-8H-dibenzo[a,i]xanthene-8,13(14H)-dione derivatives has been developed by one-pot, three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes and 2,3-naphthalenediol in glacial acetic acid under reflux conditions. This domino reaction implies Knoevenagel condensation, Michael addition, intramolecular cyclization and dehydration. The reaction avoids tedious workup procedure due to the direct precipitation of products from the reaction medium. The notable features of this domino transformation are operational simplicity, clean reaction, easy handling, easy purification process and high yields of the products.
Graphical abstractSeveral new derivatives of thiazolidine-2,4-dione and 1-H-imidazole were prepared using imidazole aldehydes 6a–6f in ethanol as a solvent. Products 7a–7f were obtained in reasonable yields and great purity. The antioxidant activity for finish products was evaluated by DPPH radical scavenging activity and showed relatively good activity against ascorbic acid. Compounds 7d, 7e, and 7f had the highest antioxidant activity. Compound 7c showed the lowest amount of IC50 versus ascorbic acid. The antimicrobial activity of these compounds against gram-positive bacteria including Bacillus anthracis (B. anthracis) and Staphylococcus aureus (S. aureus) and gram-negative bacteria including Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) bacteria was evaluated by the inhibition zone diameter assay method, and the compounds showed moderate to low antibacterial activity. The toxicity properties of all synthesized compounds against cisplatin were investigated. Most of the compounds showed good activity against the positive control group, and the toxicity of compound 7b was higher than that of other compounds.
Graphic abstractd-Sorbitol-cored PAMAM dendrimer (SOR-G1) was effectively synthesized by the ring opening polymerization of epichlorohydrin. The dendrimer was characterized using different spectroscopic and analytical techniques including IR and NMR spectroscopy, TG–DTA, and GPC. Dihydropyrano[3,2-c]chromene derivatives were synthesized using SOR-G1 as a catalyst, and it was synthesized within 30 min in ethanol/water medium and excellent yield was obtained. SOR-G1 acted as a good base catalyst on the basis of amine capacity and good thermal stability. The prepared dihydropyrano[3,2-c]chromene derivatives were characterized using GCMS, LCMS, IR, 1H NMR, and 13C NMR spectra. The catalyst could be reused up to three reaction cycles without losing its catalytic activity.
Graphic abstractA simple, efficient and green approach to the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones has been developed via one-pot three-component reaction of aromatic aldehyde, malononitrile and phthalhydrazide catalyzed by zinc–proline complex (Zn[L-proline]2) using H2O: PEG400?=?6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method.
Graphical abstractThe one-pot catalytic conversion of cellulose into ethylene glycol (EG) is an attractive way of biomass utilization. However, low-cost, efficient, and stable catalysts are the premise and research challenges of industrial application. Herein, the magnetic recyclable W–Ni@C catalyst was synthesized by in-situ pyrolysis of Ni-MOFs impregnated with ammonium metatungstate. Compared with the Ni-W bimetallic catalysts prepared by the impregnation method and the sol–gel method, the W–Ni@C catalyst for cellulose hydrogenolysis reaction can achieve a higher ethylene glycol yield (67.1% vs 43.3% and 42.6%) and 100% of cellulose conversion rate. The uniformly dispersed Ni nanoparticles and abundant defective WOx were formed in a reductive atmosphere generated in pyrolysis of Ni-MOFs, which was indispensable for the hydrogenolysis of cellulose into EG. Besides, the hierarchical porous carbon derived from organic ligands in Ni-MOFs reduces the mass transfer resistance while confining Ni nanoparticles and WOx to prevent their leaching, effectively enhancing the stability of the W–Ni@C catalyst. Therefore, the remarkable catalytic performance, the simple and effective recovery method as well as satisfying stability would make W–Ni@C become a promising catalyst for the conversion of cellulose to EG.
Graphical abstractIn this work, the electrochemical performance of Na-doped layered cathode material LiCoO2 for Li-ion batteries is studied using first-principles calculations. The results show that the doped Na ion acts as a pillar, which can greatly increase the diffusion rate of Li ions, but it is not conducive to improving cycle performance and delithiation potential. These research results provide a theoretical reference for the study of Li-ion batteries with high-rate performance. Due to the conflicting role of single element doping, the multi-element co-doping strategy will be the best way to develop high-performance Li-ion batteries.
Graphical abstractToday, plant extracts based on synthetic procedures have drawn consideration over conventional methods like physical and chemical procedures to synthesize nanomaterials. Green synthesis of nanomaterials has become an area of interest because of numerous advantages such as non-hazardous, economical, and feasible methods with a variety of applications in biomedicine, nanotechnology and nano-optoelectronics and as catalysts for various organic transformations. In this research, silver nanoparticles were deposited on the surface of nano-silica spheres by an in-situ reduction of Ag+ ions using an aqueous extract of Thymus kotschyanus aerial parts as a natural reducing and a capping agent. The result recorded from ultraviolet–visible (UV–Vis) spectrometer, Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS) and X-ray powder diffraction supports the biosynthesis and characterization of Ag/SiO2 nanoparticles. The results indicated that the average size of Ag/SiO2 nanoparticles is 25–60 nm. The Ag/SiO2 nanoparticles act as an environmentally friendly heterogeneous catalyst in the synthesis of spirooxindoles via the three-component condensation reaction of isatins, activated methylene reagents, and 1,3-dicarbonyl compounds in aqueous media, and the desired products were obtained with yields ranging from 90 to 98%. The catalyst can be recovered easily and used repetitively without significant loss of catalytic activity.
Graphical abstractTiO2 nanorods (NRs) have been successfully synthesized via simple hydrothermal technique utilizing TiCl4 as precursor at varied temperature of 160 °C, 200 °C and 250 °C, respectively. Further, thermal treatment was done in the close system at calcinations temperature thrice of the synthesis temperature. The prepared NRs were well characterized for the various physio-chemical natures of the materials. Crystallographic and morphological investigations showed that the samples exhibited high crystallinity with diameter ranges from 300 to 400 nm and length in several micrometers. XPS analysis proved the existence of oxygen defects that were created during the synthesis. The solar photocatalysis showed 81.27%, 92.20% and 58.79% removal of color by NR1, NR2 and NR3, respectively, within 300 min of direct sun irradiation time. The first-order kinetic model fits the better curve with the correlation coefficients of 0.97509, 0.97608 and 0.98417, respectively. Trapping experiments shows the dominant of holes and superoxide as the primary reactive oxygen species.
Graphical abstractA novel multiple-target chemoprobe (E)-N′-((9-pentyl-9H-carbazole-3-yl)methylene)thiophene-2-carbohydrazide (CTH) was designed, successfully synthesized and employed for the detection of Hg2+ and Fe3+ ions as off–on fluorometric and colorimetric responses, respectively, in H2O/DMF (10/90, v/v, Britton–Robinson buffer, pH 7) medium. The chemoprobe CTH demonstrated high sensitivity towards Hg2+ and Fe3+, among wide range of competitive cations with low recognition limits of 5.1 nM and 5.89 µM, respectively. The complexes of the chemoprobe CTH were synthesized and characterized by 1H-NMR titration, FT-IR and MALDI-TOF MS techniques, which confirmed the binding stoichiometries and the possible sensing mechanisms, were suggested based on the hydrolysis reaction of C=N group. The practical utility of the chemoprobe CTH was revealed in quantification of the trace amounts of Hg2+ and Fe3+ in water samples. Also, a silica-coated test paper was used for the fluorescent monitoring of Hg2+, providing a novel approach for the quantitative and on-site detection in real samples. More excitingly, a smartphone application was employed for the visual detection of Fe3+ by recognizing the RGB (red/green/blue) of the chemoprobe CTH solution.
Graphical abstractA facile green synthesis of platinum nanoparticles (PtNPs) using chlorogenic acid (CGA) as a reducing agent and stabilizing agent has been reported here for the first time to the knowledge of the authors. Well-dispersed PtNPs are synthesized in spherical shapes and are tuned in size by simply changing the molar ratio of H2PtCl6 to CGA, with the same salt, temperature and solvent. The average sizes of the particles were 16.9 ± 4.7, 13.3 ± 4.0, 10.8 ± 3.4, and 7.5 ± 2.3 nm, respectively, corresponding to molar ratios of the initial H2PtCl6/CGA of 1:1, 1:2, 1:3 and 1:4 and decreased with an increase in CGA concentration. Transmission electron microscope; energy-dispersive spectrometer; UV–visible absorption spectra (UV–Vis); and Fourier transmission infrared spectra were used to characterize the PtNPs. Additionally, the advantage of CGA for possible synergistic biological activity was studied through the in vitro antioxidant activity of PtNPs by CGA for capture of free radicals. Our results indicate that CGA is an excellent reducing and stabilizing agent in green synthesis of PtNPs, and these size-tunable PtNPs can provide potential applications in the field of biomedicines.
Graphic abstractIn CO2 transformation catalysis, the synthesis of cyclic carbonates using two classes of MOF catalysts viz., zeolitic imidazolate frameworks (ZIF) and MOFs with carboxylate-capped SBUs have gained large attention. Herein we propose the strategy of employing a unified multifunctional framework formed in the metal-centered assembly of imidazole and amino-carboxylates for CO2 transformation, such as propylene carbonate (PC) by the cycloaddition of CO2 with propylene oxide. The framework {[Cu(L-asp)(1,4-bix)0.5]·3H2O}n (CuAspBix) comprises of the amino acid building units, L-aspartic acid (L-Asp) and the flexible ligand, 1,4-bis(imidazole-1-yl methyl)benzene [1,4-Bix]. The 1,4-Bix ligand with imidazole terminals renders elongated M-M distances and flexibility in comparison with pristine ZIF materials. The cumbersome synthesis procedure poor phase purity of the bulk catalyst in solvothermal conditions were improved by a microwave-assisted synthesis, preserving the structural and physicochemical properties. Minimal energy input or room temperatures for the catalysis occurred via the synergistic participation of CuAspBix and quaternary ammonium bromide salt, demonstrated by density-functional theory computational studies to propose mechanistic pathway of the reaction. Reaction conditions were optimized by altering the parameters. The heterogeneous catalyst was reused four times without a significant change in activity.
Graphic abstract