Magnetic nanoparticle‐tethered Schiff base–palladium(II): Highly active and reusable heterogeneous catalyst for Suzuki–Miyaura cross‐coupling and reduction of nitroarenes in aqueous medium at room temperature

Abstract

As a continuation of our efforts to develop new heterogeneous nanomagnetic catalysts for greener reactions, we identified a Schiff base-palladium(II) complex anchored on magnetic nanoparticles (SB-Pd@MNPs) as a highly active nanomagnetic catalyst for Suzuki-Miyaura cross-coupling reactions between phenylboronic acid and aryl halides and for the reduction of nitroarenes using sodium borohydride in an aqueous medium at room temperature. The SB-Pd@MNPs nanomagnetic catalyst shows notable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easy magnetic work up and recyclability. Characterization of the synthesized SB-Pd@MNPs nanomagnetic catalyst was performed with various physicochemical methods such as attenuated total reflectance infrared spectroscopy, UV-visible spectroscopy, inductively coupled plasma atomic emission spectroscopy, energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, powder X-ray powder diffraction, thermogravimetric analysis and Brunauer-Emmett-Teller surface area analysis.

Magnetite tethered mesoionic carbene‐palladium (II): An efficient and reusable nanomagnetic catalyst for Suzuki‐Miyaura and Mizoroki‐Heck cross‐coupling reactions in aqueous medium

“…In the second stage, up to 11% weight loss of the MNPs‐MIC‐Pd nanomagnetic catalyst can be observed from the range of 150 °C to 730 °C and this is because of the decomposition of organic moiety immobilized on surface of MNPs. Moreover, TGA result confirms the successful immobilization of organic moiety on the surface of MNPs and also reveals that MNPs‐MIC‐Pd nanomagnetic catalyst is stable up to 230 °C which helps to carry out the cross‐coupling reactions even at higher temperature …”

“…Figure shows the FT‐IR spectra of MNPs‐MIC‐Pd nanomagnetic catalyst and recycled MNPs‐MIC‐Pd nanomagnetic catalyst. FT‐IR spectra of ten times recycled MNPs‐MIC‐Pd nanomagnetic catalyst from Suzuki‐Miyaura cross‐coupling (Figure b) and five times recycled MNPs‐MIC‐Pd nanomagnetic catalyst from Mizoroki‐Heck cross‐coupling reactions (Figure c) confirmed that MNPs‐MIC‐Pd nanomagnetic catalyst was unaltered and remained almost same even after ten cycles in Suzuki‐Miyaura and five cycles in Mizoroki‐Heck cross‐coupling reactions …”

“…Continuing our work on functionalizing magnetic nanoparticles with variety of derivatives for catalytic applications, in the research accounted here we determined to demonstrate the synthesis of magnetic nanoparticles by attaching mesoionic carbene‐palladium (II) complex on the surface of hydroxyl substituted magnetic nanoparticles for the first time. The MNPs‐MIC‐Pd nanomagnetic catalyst was prepared following the procedure shown in Scheme .…”

“…Extensive literature survey reveals that no reports are available on the synthesis and characterization of 1,3,4‐trisubstituted 1,2,3‐triazol‐5‐ylidene metal complexes on the surface of magnetic nanoparticles with high catalytic activity in Suzuki–Miyaura and Mizoroki‐Heck cross‐coupling reactions. Thus in continuation of our investigations on magnetically recyclable nanomagnetic catalysts in various organic transformations, we report here a new magnetic nanoparticle supported 1,3,4‐trisubstituted 1,2,3‐triazol‐5‐ylidene‐palladium (II) nanomagnetic catalyst whose ligand system is based on mesoionic carbenes which is entirely different from NHCs and Schiff‐base ligand system which were reported in our earlier work . The MNPs‐MIC‐Pd nanomagnetic catalyst was structurally characterized from spectroscopic and microscopic techniques.…”

Olefins oxidation with molecular O2 in the presence of chiral Mn (III) salen complex supported on magnetic CoFe2O4@SiO2@CPTMS

“…To resolve these drawbacks, homogeneous metal salen complexes are converted to heterogeneous counterpart. Several insoluble solid supports such as zeolites, polymer supports, mesoporous materials, clays, organic polymer‐inorganic hybrid materials, SBA‐15, MCM‐41 and activated silica were employed for immobilizing of homogeneous metal‐salen complexes …”