In 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 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.
A 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 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 abstractIn this paper, we developed a microbial route to fabricate wood-inspired biomimetic composites comparable to natural wood. Focusing on the chemical composition of woody biomass, we performed in situ bioprocessing of bacterial cellulose (BC) imbibed in modified cationic lignin (Catlig), which exhibited significant bioactivity in improving the microbial growth dynamics. The structural and morphological characteristics were enhanced by the formation of hydrophobic and electrostatic interactions between BC and Catlig during biosynthesis. Microbially derived BC/Catlig composites exhibited enhanced thermal stability and crystallinity, with oriented cellulose fibers. The tensile properties, toughness, and specific strength of BC/Catlig composites were comparable to those of a heavy wood species (Zelkova serrata) under hydrated conditions and synthetic soft materials.
Graphic abstractThe 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 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 abstractHere, 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 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 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 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 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 abstractThe effect of Ce doping and pretreatment of Pt/Al2O3 on its catalysis of propane oxidation was investigated after aging the catalysts. The Ce amount and pretreatment conditions were varied, and the propane oxidation activity was measured. The properties of the catalysts were investigated by means of XRD, STEM-EDX, FT-IR, and H2-TPR. The size of the Pt nanoparticles (PtNPs) decreased for water-treated catalysts doped with a small amount of Ce, suggesting that water treatment of Ce-doped catalysts inhibits Pt sintering. The minimum PtNP size was obtained with ca. 3.6 wt% of Ce. The Ce species with less than 3.6 wt% existed in a dispersed state, whereas above this value, CeO2 particulates co-existed. The propane oxidation temperature of the water-treated catalysts was lowered to an extent that depended on the Ce content. This tendency is consistent with the PtNP size in the catalysts. It is considered that highly dispersed Ce species take a primary role in promoting propane oxidation on PtNPs. The reduction temperature of Ce species on water-treated catalysts was lower than that of untreated catalysts, probably owing to a stronger interaction between Pt and Ce, demonstrated by FT-IR measurements. The increased reducibility of Ce species may be the reason for the improved oxidation activity of the catalysts.
Graphic 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 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 abstractA green, highly efficient, and eco-friendly protocol for Knoevenagel–Michael addition reaction is reported in Chickpea leaf exudates (CLE) as a naturally sourced biosurfactant. The reactions between dimedone/4-hydroxycoumarins and a variety of aryl aldehydes were carried out in presence of CLE to afford diketodiols/biscoumarins. The synthetic pathway complies with several key requirements of green chemistry principles such as the employment of natural feedstock as green reaction media, ambient temperature, atom economy along with natural biosurfactant type Bronsted acids, and recyclable and biodegradable catalyst which led to a 28-fold increase in molar efficiency versus industrial standard protocols. Its dynamic phase is confirmed by the optical microscopy technique and critical micelle concentration measurement. The notable advantages of the present protocol were simple work-up procedure, high yield within short reaction time, easy separation of products, avoiding tedious column chromatography thus making the protocol environmentally friendly, sustainable, and economical.
Graphical abstractA series of new mix aza- and thia-macrocyclic glycolipids (9, 10, 16 and 17) have been synthesized and their enantiomeric selectivity was studied. The synthesis of the macrocycles involved a simple protection of two hydroxyl groups of the glycolipids followed by building up the mix-heteroatom macrocyclic in simple sequences. The macrocycles and previously investigated analogues (18, 19, 20 and 21) have been applied as phase transfer catalysts in the enantioselective Michael addition of 2-nitropropane to chalcone and showed good-to-excellent enantiomer excess (ee). Among the catalysts, the galactose aza-crown ether-based glycolipid 21 proved to be the most effective with 90% ee.
Graphic abstractCellulose nanocrystals (CNCs) with high crystallinity exhibit high mechanical stiffness and strength. However, the high dispersibility of CNCs results in limited spinnability and orientation. In this study, oxidized nanocellulose was selected to obtain regionally oxidized CNCs (RO-CNC) with carboxyl groups appended. For the formation of orientable and extensible RO-CNC filaments, chitosan was introduced as the sheath solution to induce orientation by electrostatic action. The chemical structures were analyzed by Fourier transform infrared spectroscopy. The morphology of the oriented CNCs filaments was characterized by scanning electron microscopy and wide-angle X-ray scattering. Analysis of the relationship between the mechanical strength and the CNCs directional arrangement revealed that the mechanical strength of the composite fibers increased with the injection speed ratio as a result of the orientation of the RO-CNC. The mechanical strength of the oriented reinforced composite filaments reached as high as 104 MPa with an orientation index of 0.73. The tensile strength and elastic modulus of the filaments increased by 33% and 20%, respectively, compared to the unmodified CNCs spun fiber.
Graphic abstractThe development of a simple surface barrier discharge plasma device is presented to enable more widespread access to and utilization of plasma technology. The application of the plasma device was demonstrated for pretreatment of wood prior to application of protective coatings for outdoor usage. The coatings' overall performance was increased, showing a reduction or absence of cracking due to weathering on plasma-pretreated specimens. Moreover, after ten months of outdoor weathering, the plasma-pretreated specimens showed fewer infections with biotic factors and improved adhesion performance in cross-cut tests, while the surface gloss performed independently from plasma pretreatment. In contrast to that, plasma-pretreated specimens were slightly more prone to discoloration due to outdoor weathering, whereas the plasma pretreatment did not impact the initial color after coating application.
Graphic 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 abstract