Stabilization of ruthenium on biochar-nickel magnetic nanoparticles as a heterogeneous, practical, selective, and reusable nanocatalyst for the Suzuki C-C coupling reaction in water

A novel magnetic FSM-16 supported ionic liquid/Pd complex as a high performance and recyclable catalyst for the synthesis of pyrano[3,2-c]chromenes

In this work, Fe3O4@FSM-16/IL-Pd was successfully designed and synthesized via a new procedure of palladium(ii) complex immobilization onto magnetic FSM-16 using an ionic liquid, as a novel heterogeneous nanocatalyst. Multiple techniques were employed to characterize this magnetic nanocatalyst such as Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscopy (FE-SEM), thermogravimetric analysis (TGA), Transmission electron microscopy (TEM), and Vibrating Sample Magnetometry (VSM). After complete characterization of the catalyst, its catalytic activity was used for the synthesis of pyrano[3,2-c]chromene-3-carbonitriles via the reaction of 4-hydroxycoumarin, aldehyde, and malononitrile under solvent-free conditions. Also, it can be recovered and reused several times without a significant decrease in its catalytic activity or palladium leaching.

Greener design and characterization of biochar/Fe3O4@SiO2-Ag magnetic nanocomposite as efficient catalyst for synthesis of bioactive benzylpyrazolyl coumarin derivatives

The study aimed to develop an efficient catalyst, biochar/Fe₃O₄@SiO₂-Ag magnetic nanocomposite, to synthesize bioactive benzylpyrazolyl coumarin derivatives through a one-pot multicomponent reaction. The catalyst was prepared using Ag nanoparticles synthesized with Lawsonia inermis leaf extract and carbon-based biochar obtained through pyrolysis of Eucalyptus globulus bark. The nanocomposite contained a silica-based interlayer, highly dispersed Ag nanoparticles, and a central magnetite core, which responded well to external fields. The biochar/Fe₃O₄@SiO₂-Ag nanocomposite showed excellent catalytic activity and could be easily recovered using an external magnet and reused five times without significant loss of performance. The resulting products were tested for antimicrobial activity and showed significant activity against various microorganisms.

Immobilization of Ni(ii) complex on the surface of mesoporous modified-KIT-6 as a new, reusable and highly efficient nanocatalyst for the synthesis of tetrazole and pyranopyrazole derivatives

In this paper, KIT-6@SMTU@Ni was successfully synthesized via a new method of Ni(ii) complex stabilization on modified mesoporous KIT-6, as a novel and green heterogeneous catalyst. The obtained catalyst (KIT-6@SMTU@Ni) was characterized using Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) calculation, X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), energy-dispersive X-ray spectroscopy (EDS), X-ray mapping, thermogravimetric analysis (TGA) techniques and scanning electron microscopy (SEM). After complete characterization of the catalyst, it was successfully used for the synthesis of 5-substituted 1H-tetrazoles and pyranopyrazoles. Moreover, tetrazoles were synthesized from benzonitrile derivatives and sodium azide (NaN₃). All tetrazole products were synthesized with high TON, TOF and excellent yields (88-98%) in a reasonable time (0.13-8 h), demonstrating the efficiency and practicality of the KIT-6@SMTU@Ni catalyst. Furthermore, pyranopyrazoles were prepared through the condensation reaction of benzaldehyde derivatives with malononitrile, hydrazine hydrate and ethyl acetoacetate with high TON, TOF and excellent yields (87-98%) at appropriate times (2-10.5 h). KIT-6@SMTU@Ni could be reused for five runs without any re-activation. Significantly, this plotted protocol has prominent benefits, such as applying green solvents, the use of commercially available and low-cost materials, excellent separation and reusability of the catalyst, short reaction time, high yield of products and a facile work-up.

A new samarium complex of 1,3-bis(pyridin-3-ylmethyl)thiourea on boehmite nanoparticles as a practical and recyclable nanocatalyst for the selective synthesis of tetrazoles

Boehmite is a natural and environmentally friendly compound. Herein boehmite nanoparticles were primarily synthesized and, then, their surface were modified via 3-choloropropyltrimtoxysilane (CPTMS). Afterwards, a new samarium complex was stabilized on the surface of the modified boehmite nanoparticles (Sm-bis(PYT)@boehmite). The obtained nanoparticles were characterized using thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), wavelength dispersive X-ray spectroscopy (WDX), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), Inductively coupled plasma mass spectrometry (ICP-MS), dynamic light scattering (DLS), and X-ray diffraction (XRD) pattern. Sm-bis(PYT)@boehmite was used as an environmentally friendly, efficient, and organic-inorganic hybrid nanocatalyst in the homoselective synthesis of tetrazoles in polyethylene glycol 400 (PEG-400) as a green solvent. Notably, Sm-bis(PYT)@boehmite is stable and has a heterogeneous nature. Thus, it can be reused for several runs without any re-activation.

Synthesis of tetrazoles catalyzed by a new and recoverable nanocatalyst of cobalt on modified boehmite NPs with 1,3-bis(pyridin-3-ylmethyl)thiourea

In the first part of this work, boehmite nanoparticles (BNPs) were synthesized from aqueous solutions of NaOH and Al(NO₃)₃·9H₂O. Then, the BNPs surface was modified using 3-choloropropyltrimtoxysilane (CPTMS) and then 1,3-bis(pyridin-3-ylmethyl)thiourea ((PYT)₂) was anchored on the surface of the modified BNPs (CPTMS@BNPs). In the final step, a complex of cobalt was stabilized on its surface (Co-(PYT)₂@BNPs). The final obtained nanoparticles were characterized by FT-IR spectra, TGA analysis, SEM imaging, WDX analysis, EDS analysis, and XRD patterns. In the second part, Co-(PYT)₂@BNPs were used as a highly efficient, retrievable, stable, and organic-inorganic hybrid nanocatalyst for the formation of organic heterocyclic compounds such as tetrazole derivatives. Co-(PYT)₂@BNPs as a novel nanocatalyst are stable and have a heterogeneous nature; therefore, they can be recovered and reused again for several consecutive runs without any re-activation.

A Schiff base complex of lanthanum on modified MCM-41 as a reusable nanocatalyst in the homoselective synthesis of 5-substituted 1H-tetrazoles

In this work, mesoporous MCM-41 was modified by a new Schiff-base formed from the condensation of triethylenetatramine and 5-bromosalicylaldehyde. Then, it was used for the stabilization of lanthanum metal (La-Schiff base@MCM-41) as a homoselective, reusable, efficient and biocompatible catalyst in the synthesis of 5-substituted 1H-tetrazole derivatives. The synthesized tetrazoles were characterized using ¹H NMR and FT-IR spectroscopy and methods to measure their physical properties. La-Schiff base@MCM-41 was characterized by using various techniques such as ICP, CHN, XRD, TGA, BET, FT-IR spectroscopy, SEM, EDS and WDX. This catalyst has good stability and a heterogeneous nature, enabling it to be easily recovered and reused several times without significant loss in catalytic activity. This present strategy has important advantages such as utilizing PEG as a green solvent, short reaction times, excellent yields, easy recycling of the catalyst and pure separation of the products. The recovered La-Schiff base@MCM-41 catalyst was characterized by using FT-IR spectroscopy, SEM and AAS.

Investigation of Fe3O4@boehmite NPs as efficient and magnetically recoverable nanocatalyst in the homoselective synthesis of tetrazoles

Magnetic boehmite nanoparticles (Fe3O4@boehmite NPs) were synthesized from a hybrid of boehmite and Fe3O4 nanoparticles. At first, boehmite nanoparticles (aluminum oxide hydroxide) were prepared via a simple procedure in water using commercially available materials such as sodium hydroxide and aluminum nitrate. Then, these nanoparticles were magnetized using Fe3O4 NPs in a basic solution of FeCl2·4H2O and FeCl3·6H2O. Fe3O4@boehmite NPs have advantages of both boehmite nanoparticles and Fe3O4 magnetic materials. Magnetic boehmite nanoparticles have been characterized by various techniques such as TEM, SEM, EDS, WDX, ICP, FT-IR, Raman, XRD and VSM. SEM and TEM images confirmed that particles size are less than 50 nm in diameter with a cubic orthorhombic structure. Then, Fe3O4@boehmite NPs were applied as a homoselective, highly efficient, cheap, biocompatibility, heterogeneous and magnetically recoverable nanocatalyst in the synthesis of 5-substituted 1H-tetrazole derivatives. Fe3O4@boehmite NPs can be recycled for several runs in the synthesis of tetrazoles. Also, all tetrazoles were isolated in high yields, which reveals high activity of Fe3O4@boehmite NPs in the synthesis of tetrazole derivatives. Fe3O4@boehmite NPs shows a good homoselectivity in synthesis of 5-substituted 1H-tetrazole derivatives.