CO-free, aqueous mediated, instant and selective reduction of nitrobenzene via robustly stable chalcogen stabilised iron carbonyl clusters (Fe3E2(CO)9, E = S, Se, Te)

Iron-Catalyzed Chemoselective Transfer Hydrogenation of α,β-Unsaturated Ketones Using H2O as a Surrogate of Hydrogen

Sustainable and highly economical iron-catalyzed chemoselective reduction of C═C of α,β-unsaturated ketones has been established under mild reaction protocols. Water is used as a green and abundant surrogate of hydrogen and is scarcely used in organic synthetic transformations as a source of hydrogen. The developed protocol offers a broad spectrum for chemoselective transfer hydrogenation of α,β-unsaturated ketones. Moreover, the method was found to be highly effective for aryl and ferrocenyl α,β-unsaturated ketones consisting of one or two double bonds and with multiple functionalities. Moreover, the present method avoids prolonged reaction time, provides a wide range of substrates with excellent yield, and circumvents the tedious chromatographic workup.

A new strategy for immobilization of copper on the Fe3O4@EDTA nanocomposite and its efficient catalytic applications in reduction and one-pot reductive acetylation of nitroarenes and also N-acetylation of arylamines

A new and efficient Cu(II)-containing mesoporous nanocatalytic system was synthesized by direct immobilization of copper metal powder on the Fe3O4@EDTA nanocomposite. The as-prepared Fe3O4@EDTA@Cu(II) nanocomposite was then characterized by FT-IR, XRD, SEM, TEM, SEM-based EDX and elemental mapping, XPS, TGA, VSM, and also BET and BJH analyses. The resulting Fe3O4@EDTA@Cu(II) mesoporous nanocomposite exhibited satisfactory catalytic activity towards the reduction and one-pot reductive acetylation of nitroarenes and also N-acetylation of arylamines in water at 60 °C. Notably, the applied Cu(II)-containing nanocatalyst was efficiently recovered from the reaction mixture using an external magnetic field and could be reused successfully for five cycles. The protocol developed in this study offers several advantages in terms of mild reaction conditions, simple workflows, using water as a green solvent, and easy recovery and catalyst reuse, making it more ecologically and economically attractive.

NiII-containing l-glutamic acid cross-linked chitosan anchored on Fe3O4/f-MWCNT: a sustainable catalyst for the green reduction and one-pot two-step reductive Schotten-Baumann-type acetylation of nitroarenes

In this research, new and eye-catching catalytic applications of the nickelII (NiII) nanoparticles (NPs)-containing l-glutamic acid cross-linked chitosan anchored on magnetic carboxylic acid-functionalized multi-walled carbon nanotube (Fe3O4/f-MWCNT-CS-Glu/NiII) system, which was characterized by Fourier transform infrared (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), SEM-based energy-dispersive X-ray (EDX) and elemental mapping, inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and vibrating sample magnetometry (VSM), have been introduced for the environmentally benign and efficient reduction and one-pot two-step reductive Schotten-Baumann-type acetylation of nitroarenes in water at 60 °C under an air atmosphere. It is worth noting that the NiII-containing hybrid nanocatalyst, in the mentioned organic reactions, showed short reaction times, high yields of the desired products, acceptable turnover numbers (TONs) and turnover frequencies (TOFs), and also satisfactory magnetic recycling and reusability performance even after ten times of reuse. As another significant point, all the titled organic transformations have been carried out in water as an entirely favorable and green solvent for chemical reactions.

A Reusable FeCl3∙6H2O/Cationic 2,2′-Bipyridyl Catalytic System for Reduction of Nitroarenes in Water

The association of a commercially-available iron (III) chloride hexahydrate (FeCl3∙6H2O) with cationic 2,2′-bipyridyl in water was proven to be an operationally simple and reusable catalytic system for the highly-selective reduction of nitroarenes to anilines. This procedure was conducted under air using 1–2 mol% of catalyst in the presence of nitroarenes and 4 equiv of hydrazine monohydrate (H2NNH2∙H2O) in neat water at 100 °C for 12 h, and provided high to excellent yields of aniline derivatives. After separation of the aqueous catalytic system from the organic product, the residual aqueous solution could be applied for subsequent reuse, without any catalyst retreatment or regeneration, for several runs with only a slight decrease in activity, proving this process eco-friendly.

Diverse and efficient catalytic applications of new cockscomb flower-like Fe3O4@SiO2@KCC-1@MPTMS@CuII mesoporous nanocomposite in the environmentally benign reduction and reductive acetylation of nitroarenes and one-pot synthesis of some coumarin compounds

In this research, Fe3O4@SiO2@KCC-1@MPTMS@CuII as a new cockscomb flower-like mesoporous nanocomposite was prepared and characterized by various techniques including Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), SEM-based energy-dispersive X-ray (EDX) spectroscopy, inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis/differential thermal analysis (TGA/DTA), vibrating sample magnetometry (VSM), UV-Vis spectroscopy, and Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses. The as-prepared Fe3O4@SiO2@KCC-1@MPTMS@CuII mesoporous nanocomposite exhibited satisfactory catalytic activity in the reduction and reductive acetylation of nitroarenes in a water medium and solvent-free one-pot synthesis of some coumarin compounds including 3,3'-(arylmethylene)bis(4-hydroxy-2H-chromen-2-ones) (namely, bis-coumarins) (3a-n) and 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles (6a-n) along with acceptable turnover numbers (TONs) and turnover frequencies (TOFs). Furthermore, the mentioned CuII-containing mesoporous nanocatalyst was conveniently recovered by a magnet from reaction environments and reused for at least seven cycles without any significant loss in activity, which confirms its good stability.

Iron- and copper-based bifunctional catalysts for the base- and solvent-free C–N coupling of amines and aryl/benzyl chlorides under aerobic conditions

The chalcogenised ironcarbonyl clusters Fe3Se2(CO)9 and Cu(OAc)2 were found to be outstanding bimetallic catalyst for the Buchwald type C–N cross coupling reaction of amine and aryl chloride.

PdII on Guanidine-Functionalized Fe3O4 Nanoparticles as an Efficient Heterogeneous Catalyst for Suzuki-Miyaura Cross-Coupling and Reduction of Nitroarenes in Aqueous Media

This paper presents guanidine-functionalized Fe3O4 magnetic nanoparticle-supported palladium (II) (Fe3O4@Guanidine-Pd) as an effective catalyst for Suzuki-Miyaura cross-coupling of aryl halides using phenylboronic acids and also for selective reduction of nitroarenes to their corresponding amines. Fe3O4@Guanidine-Pd synthesized is well characterized using FT-IR spectroscopy, XRD, SEM, TEM, EDX, thermal gravimetric analysis, XPS, inductively coupled plasma-optical emission spectroscopy, and vibrating sample magnetometry analysis. The prepared Fe3O4@Guanidine-Pd showed effective catalytic performance in the Suzuki-Miyaura coupling reactions by converting aryl halides to their corresponding biaryl derivatives in an aqueous environment in a shorter reaction time and with a meagerly small amount of catalyst (0.22 mol %). Also, the prepared Fe3O4@Guanidine-Pd effectively reduced nitroarenes to their corresponding amino derivatives in aqueous media at room temperature with a high turnover number and turnover frequency with the least amount of catalyst (0.13 mol %). The most prominent feature of Fe3O4@Guanidine-Pd as a catalyst is the ease of separation of the catalyst from the reaction mixture after the reaction with the help of an external magnet with good recovery yield and also reuse of the recovered catalyst for a few cycles without significant loss in its catalytic activity.