Magnet-responsive choline carbomer ionogels as a versatile and recyclable catalyst for one-pot synthesis of benzopyran in water

Ionogels are gaining popularity as a potential replacement for volatile organic solvents in various processes, such as catalysts, electrochemistry, spectroscopy, and medicinal chemistry, due to their low toxicity, high thermal stability, and good solubility. Magnet-responsive ion gels with high magnetic susceptibility are promising and can be used as catalysts, sensors, and MRI contrast agents. Herein, we fabricated simple and novel magnet choline carbomer ionogels using a precipitation-deposition method with carbomers and choline hydroxide. The morphology and structure of the resulting ionogels were analyzed using various characterization techniques, including FTIR, EDX, TGA, and SEM spectroscopy. These magnet ionogels were effective catalysts for a one-pot, three-component synthesis of benzopyran derivatives, providing mild reaction conditions, environmental friendliness, and good to excellent (78-96%) yields within a short reaction time (1-2 h). Additionally, the magnet ionogels were easily recyclable, and they could be reused up to five times without catalytic deactivation.

Magnetic UiO-66 functionalized with 4,4'-diamino-2,2'-stilbenedisulfonic as a highly recoverable acid catalyst for the synthesis of 4H-chromenes in green solvent

According to 4H-chromenes importance, we synthesized a novel magnetic UiO-66 functionalized with 4,4′-diamino-2,2′-stilbenedisulfonic as an efficient and reusable solid acid catalyst for synthesizing 4H-chromene skeletons via a one-pot three components reaction in a green solvent. The structure of the synthesized catalyst was confirmed by various techniques including FT-IR, XRD, BET, TGA, TEM, EDX, and SEM, and also the product yields were obtained in 83–96% of yields for all the reactions and under mild conditions. The reported procedure presents an environmentally friendly approach for synthesizing a significant number of 4H-chromene derivatives. Correspondingly, MOF-based catalyst makes it easy to separate from reaction media and reuse in the next runs.

Large-scale synthesis of mixed valence K3[Fe2S4] with high dielectric and ferrimagnetic characteristics

Large scale, high purity synthesis of K3[Fe2S4] which indicates soft ferrimagnetic, high dielectric and semiconductive characteristics.

Metformin functionalized dendritic fibrous nanosilica (KCC-1-nPr-Met) as an innovative and green nanocatalyst for the efficient synthesis of tetrahydro-4H-chromene derivatives

An innovative nanocatalyst (KCC-1-nPr-Met) has been prepared from the covalent attachment of metformin on the channels and the pores of n-propyl amine functionalized dendritic fibrous nanosilica (DFNS) and used towards efficient, green, and high yield synthesis of tetrahydro-4H-chromenes derivatives by one-pot three-component reaction of aromatic aldehydes, malononitrile, and dimedone in H₂ O-EtOH at room temperature. The designed nanocatalyst has been characterized by energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and adsorption/desorption analysis (BET) techniques. Also, field emission scanning electron microscopy (FE-SEM) was used to study the morphology of prepared nanocatalyst. The engineered nanocatalyst with uniform fibrous spheres has dendritic structure, high pore volume (0.35 cm³ /g), and great surface area (178 m² /g). Hence, the specific dendritic structure of the prepared nanocatalyst not only improve the diffusion ability of the reactants and products, but also, increase the availability of dynamic sites in the pores and channels of the catalyst. According to the obtained results, a unique strategy was proposed towards the synthesis of important biologically active scaffolds in the presence of nontoxic and environmental friendly nanocatalyst and media. Milder reaction conditions (room temperature), shorter reaction times (5-30 minutes), excellent yields (92%-98%) of the products with higher purity, very simple workup procedure, and using of EtOH: H₂ O as a green solvent are the advantages of the presented work.

Cysteic acid grafted to magnetic graphene oxide as a promising recoverable solid acid catalyst for the synthesis of diverse 4H-chromene

4H-chromenes play a significant role in natural and pharmacological products. Despite continuous advances in the synthesis methodology of these compounds, there is still a lack of a green and efficient method. In this study, we have designed cysteic acid chemically attached to magnetic graphene oxide (MNPs·GO-CysA) as an efficient and reusable solid acid catalyst to synthesize 4H-chromene skeletons via a one-pot three components reaction of an enolizable compound, malononitrile, an aldehyde or isatin, and a mixture of water-ethanol as a green solvent. This new heterogeneous catalyst provides desired products with a good to excellent yield, short time, and mild condition. This procedure presents an environmentally friendly approach for the synthesis of a great number of 4H-chromene derivatives.

One-pot synthesis of benzopyrano[2,3-d]pyrimidine derivatives catalyzed by LDHs@Propyl-ANDSA

A general, effective, and operationally simple approach to highly substituted benzopyrano[2,3-d]pyrimidine through the annulation of salicylaldehydes, malononitrile, and secondary amines is explained. The reaction is promoted by the Brønsted–Lowry acid, furnishing a variety of benzopyrano[2,3-d]pyrimidine derivatives in synthetically useful yields.

One-pot synthesis of 2-amino-4H-chromene derivatives by MNPs@Cu as an effective and reusable magnetic nanocatalyst

MNPs@Cu as an effective, recyclable nanocatalyst was prepared and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis vibrating sample magnetometry, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction.

Synthesis, structure and magnetic properties of multipod-shaped cobalt ferrite nanocrystals

A non-aqueous sol–gel route followed by oriented attachment to make multi-pod CoFe₂O₄ nanocrystals showing large room temperature saturation magnetization.

Synthesis and Properties of Nanosized Stoichiometric Cobalt Ferrite Spinel

Nanoparticles with controllable sizes of ferrite spinel CoFe₂O₄ were formed by thermal treatment of cobalt-iron glycerolate. Thermal behavior during the heating was studied by differential thermal analysis combined with thermogravimetry. The precursor, as well as the prepared nanoparticles, were analyzed by a broad spectrum of analytic techniques (X-Ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), Energy dispersive spectroscopy (EDS), Atomic absorption spectroscopy (AAS), Scanning electron microscopy (SEM), and Raman spectroscopy). The particle size of nanoparticles was obtained from Transmission electron microscopy and also calculated using Scherrer formula. A vibrating sample magnetometer (VSM) in a Physical Property Measurement System was used to analyze the magnetic properties of nanoparticles.

Selective and highly efficient synthesis of xanthenedione or tetraketone derivatives catalyzed by ZnO nanorod-decorated graphene oxide

A new and efficient method for the pseudo three-component synthesis of diverse tetraketone or xanthenedione derivatives has been described in the presence of ZnO nanorods decorated graphene oxide.

Morphology-controlled synthesis and enhanced energy product (BH)max of CoFe2O4 nanoparticles

The (BH)_max value of 2.41 MGOe at room temperature confirmed the capabilities of CoFe₂O₄ NPs in permanent magnets for current technological applications.

Position Assignment and Oxidation State Recognition of Fe and Co Centers in Heterometallic Mixed-Valent Molecular Precursors for the Low-Temperature Preparation of Target Spinel Oxide Materials

A series of mixed-valent, heterometallic (mixed-transition metal) diketonates that can be utilized as prospective volatile single-source precursors for the low-temperature preparation of M_xM'_3-xO₄ spinel oxide materials is reported. Three iron-cobalt complexes with Fe/Co ratios of 1:1, 1:2, and 2:1 were synthesized by several methods using both solid-state and solution reactions. On the basis of nearly quantitative reaction yields, elemental analyses, and comparison of metal-oxygen bonds with those in homometallic analogues, heterometallic compounds were formulated as [Fe^III(acac)₃][Co^II(hfac)₂] (1), [Co^II(hfac)₂][Fe^III(acac)₃][Co^II(hfac)₂] (2), and [Fe^II(hfac)₂][Fe^III(acac)₃][Co^II(hfac)₂] (3). In the above heteroleptic complexes, the Lewis acidic, coordinatively unsaturated Co^II/Fe^II centers chelated by two hexafluoroacetylacetonate (hfac) ligands maintain bridging interactions with oxygen atoms of acetylacetonate (acac) groups that chelate the neighboring Fe^III metal ion. Preliminary assignment of Fe and Co positions/oxidation states in 1-3 drawn from X-ray structural investigation was corroborated by a number of complementary techniques. Single-crystal resonant synchrotron diffraction and neutron diffraction experiments unambiguously confirmed the location of Fe and Co sites in the molecules of dinuclear (1) and trinuclear (2) complexes, respectively. Direct analysis in real time mass spectrometry revealed the presence of Fe^III- and Co^II-based fragments in the gas phase upon evaporation of precursors 1 and 2 as well as of Fe^III, Fe^II, and Co^II species for complex 3. Theoretical investigation of two possible "valent isomers", [Fe^III(acac)₃][Co^II(hfac)₂] (1) and [Co^III(acac)₃][Fe^II(hfac)₂] (1'), provided an additional support for the metal site/oxidation state assignment giving a preference of 6.48 kcal/mol for the experimentally observed molecule 1. Magnetic susceptibility measurements data are in agreement with the presence of high-spin Fe^III and Co^II magnetic centers with weak anti-ferromagnetic coupling between those in molecules of 1 and 2. Highly volatile heterometallic complexes 1-3 were found to act as effective single-source precursors for the low-temperature preparation of iron-cobalt spinel oxides Fe_xCo_3-xO₄ known as important materials for diverse energy-related applications.

A co-operative effect of visible light photo-catalysis and CoFe2O4 nanoparticles for green synthesis of furans in water

A novel approach to poly-functionalized furan synthesis is disclosed via oxidative decarboxylative [3+2] cycloaddition using co-operative catalysis by visible light and CoFe₂O₄ nanoparticles.

Cobalt ferrite (CoFe2O4) nanoparticles (size: ∼10 nm) with high surface area for selective non-enzymatic detection of uric acid with excellent sensitivity and stability

A high surface area CoFe₂O₄ nanoparticle based non-enzymatic uric acid biosensor with excellent sensitivity, selectivity and LOD.

Ionic liquid [Dabco-H][AcO] as a highly efficient and recyclable catalyst for the synthesis of various bisenol derivatives via domino Knoevenagel–Michael reaction in aqueous media

An efficient, green and reusable catalystic system for the synthesis of various bisenol derivatives is presented.

(CTA)3[SiW12]–Li+–MMT: a novel, efficient and simple nanocatalyst for facile and one-pot access to diverse and densely functionalized 2-amino-4H-chromene derivatives via an eco-friendly multicomponent reaction in water

A simple, facile and highly efficient one-pot synthesis of a pharmaceutically interesting diverse kind of functionalized 2-amino-4H-chromene is reported.

A unique approach to magnetization of metal oxides: nano-Fe3O4@TDI@TiO2 as a highly efficient, magnetically separable and recyclable heterogeneous nanocatalyst

Nano-Fe₃O₄@TDI@TiO₂ as a novel heterogeneous nanocatalyst is synthesized by covalent linkage of n-Fe₃O₄ and n-TiO₂ through TDI.