Nanocomposite‐based inorganic‐organocatalyst Cu(II) complex and SiO2‐ and Fe3O4 nanoparticles as low‐cost and efficient catalysts for aniline and 2‐aminopyridine oxidation. (7th September 2020)

• Record Type: Journal Article
• Authors: Adam, Mohamed Shaker S.; Al‐Omair, Mohammed A.
• Is Part Of: Applied organometallic chemistry. Volume 34:Number 12(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-07
• Subjects: catalysis -- copper(II) -- Fe3O4 -- imine ligand -- SiO2; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.5999
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract : Bis ‐imino Cu(II) complex (CuLAn2 ), in which the imine ligand (HLAn) acts as a bidentate chelating ligand, was synthesized. The catalytic potential of the inorganic‐organocatalyst was studied homogeneously and heterogeneously in the oxidation of aniline and 2‐aminopyridine by H2 O2 or t BuOOH. Two heterogeneous inorganic‐organocatalysts, CuLAn2 @Fe3 O4 and CuLAn2 @SiO2 @Fe3 O4, were synthesized by the successful immobilization of CuLAn2 on the Fe3 O4 surface and the composited Fe3 O4 with SiO2, respectively. The heterogeneous structure of those inorganic‐organocatalysts was confirmed using Fourier‐transform infrared, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, transmission electron microscopy, and magnetic properties. The adsorption–desorption isotherms revealed respectable adsorption parameters ( S BET, V p, and r p ). All catalysts exhibited high potential in the oxidation of aniline (with phenylhydroxylamine as the main product) and good potential in the oxidation of 2‐aminopyridine, in the first attempt (with 2‐nitropyridine‐ N ‐oxide and 2‐nitrosopyridine‐ N ‐oxide as main products), at room temperature. Acetonitrile was found to be the best solvent compared to ethanol, dimethyl sulfoxide, chloroform, and water. The homogeneous catalyst exhibited reusability for three times. The heterogeneous catalysts, CuLAn2 @Fe3 O4 and CuLAn2 @SiO2 @Fe3 O4, were active for five and seven times, respectively. A mechanism was proposed within electron and oxygen transfer processes. Abstract : Bis ‐imino copper(II) complex (CuLAn2 ) was synthesized from bidentate imino ligand. The catalytic potential of CuLAn2 was studied in homogeneous and heterogeneous phases in the oxidation processes of aniline and 2‐aminopyridine by H2 O2 or t BuOOH. Two heterogeneous catalysts, CuLAn2 @Fe3 O4 and CuLAn2 @SiO2 @Fe3 O4, were prepared by the immobilization of CuLAn2 on the surface of Fe3 O4 species and the composited Fe3 O4 with SiO2, respectively. All catalysts exhibited excellent catalytic potential in the oxidation processes at room temperature.