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A selective and efficient olefin epoxidation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs as a heterogeneous magnetically recyclable nanocatalyst. The nanocatalyst was synthesized through several steps including chlorophyll b de-metallation, imine functionalization with ally amine, co-polymerization with acrylated TEMPO, re-metalation with cobalt, and immobilization on magnetite NPs. Selective catalytic epoxidation of olefins was accomplished under mild conditions and in an O2 atmosphere. High selectivity and conversion were achieved for a variety of substrates. The results indicated a synergistic effect between TEMPO moieties and the coordinated Co(III) centers as two active sites. The epoxide products could be separated by the heterogeneous poly(benzoic acid) with the highest possible isolated yields. Also, the heterogeneous nanocatalyst could be recycled for at least 7 consecutive cycles with a negligible reactivity loss. A selective and efficient olefin epoxidation with smart isolation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs under mild conditions. [ABSTRACT FROM AUTHOR]

An asymmetric Mn/TEMPO-Salen complex was utilized as a reducing agent and template for the synthesis of Mn/TEMPO-doped Fe3O4 NPs in situ. The subsequent thermal decomposition of Mn/TEMPO-doped Fe3O4 NPs, as a precursor, provides the highly porous (641 m2 g–1) Mn2O3-doped Fe3O4 NPs. The highly porous NPs was characterized by FTIR, BET, TGA, VSM, ICP, TEM, XRD, UV–Vis, and XPS analyses. High stability and catalytic activity was found for the NPs in the synthesis of α-aminonitriles via the Strecker synthesis from primary and secondary alcohols under mild conditions. TAIm[CN] ionic liquid (IL) was used as an efficient solvent and nitrile-required reagent to synthesis of α-aminonitriles. TAIm[CN] IL could be recycled for several times by a simple recovery and subsequent treatment. Also, the catalytic activity of the NPs was evaluated toward the selective alcohol oxidation to carbonyl compounds and the direct transformation of imines from alcohols and aryl amines. Mn2O3-doped Fe3O4 NPs could be recovered and reused for several consecutive cycles without any considerable reactivity loss. Highly porous MnO-doped Fe3O4 NPs were synthesized via thermal decomposition of Mn/TEMPO-doped Fe3O4 NPs as a precursor, and used as an efficient recyclable catalyst for the Strecker synthesis from alcohols in TAIm[CN] ionic liquid [ABSTRACT FROM AUTHOR]

In this paper, a novel unsymmetric Mn(III)/TEMPO-salen complex bearing three hydroxyl groups was served as a reducing agent for the efficient preparation of Mn/TEMPO-doped Fe3O4 NPs in situ. This protocol suggests an in situ Mn(III)/TEMPO-salen complex doping via a co-precipitation method for the preparation of magnetic NPs that was studied and confirmed by FTIR, TGA, VSM, ICP, TEM, XRD, UV–Vis, BET, DLS, zeta potentials, EDX, and XPS analyses. The resulting Mn/TEMPO-doped Fe3O4 NPs was found as an efficient nanocatalyst for the selective oxidation of benzyl alcohol to the corresponding carbonyl and carboxylic acid by the change of oxidant type. In the presence of oxone as an oxidant, the alcohol oxidation proceeds to carboxylic acid, while underwent O2 bubbling, carbonyl product was obtained selectively. Mn/TEMPO-doped Fe3O4 could be recycled for at least 8 consecutive recycles without any considerable reactivity loss. Unsymmetric Mn(III)/TEMPO-salen complex was used as a reducing agent for the synthesis of Mn/TEMPO-doped Fe3O4 NPs in situ as an efficient catalyst for alcohols oxidation selectively [ABSTRACT FROM AUTHOR]

An efficient and mild protocol was developed for the reduction of 4-nitrophenol to the 4-aminophenol in the presence of recyclable silver (Ag@BH4− NPs) and magnetite nanoparticles (Fe3O4@BH4− MNPs). The NPs were characterized by TEM, HRTEM, UV–Vis, TGA, VSM, XRD, EDX, XPS, and DLS analyses. The reduction was conducted in the absence of any external reducing agent like NaBH4 underwent ultrasound irradiation at 60 °C for 2 h. Also, in the presence of TAIm[BH4] ionic liquid, the reduction was performed under normal conditions (no need to ultrasound irradiation) and gave quantitative yield for 4-aminophenol at room temperature. TAIm[BH4] ionic liquid (density = 1.42 g/cm−3, viscosity = 1165 cP), as a new reducing agent was applied for the efficient preparation of Ag@BH4− NPs and Fe3O4@BH4− MNPs, with a mean diameter and zeta potential of 26 nm, 16 nm, and – 40 mV and – 55 mV, respectively. It was suggested that TAIm[BH4] ionic liquid plays the role of a capping agent in addition to reducing capability in order to metal NPs preparation, which improves the dispersion stability of the NPs with a negatively charged zeta potential resulted in the decreased agglomeration of NPs. The NPs as well as TAIm[BH4] ionic liquid showed high antioxidant activity evaluated by DPPH assay, which the total DPPH quenching was observed at 180 μg/mL. Also, TAIm[BH4] IL showed a 70% inhibitory effect at a concentration of 200 μg/mL. The Ag@BH4− and Fe3O4@BH4− NPs follows first-order kinetics for the reduction of 4-NP with the reaction rate of (6.75 × 10–3 s−1) and (5.6 × 10–3 s−1), respectively. A reasonable mechanism was suggested based on the observation and literature review. A new approach to synthesis of reductive Ag and Fe3O4 NPs with high antioxidant activity was introduced by TAIm[BH4] reductive ionic liquid for the efficient reduction of 4-NP to 4-AP. [ABSTRACT FROM AUTHOR]