Catalytic Oxidation of Benzyl Alcohol Using Nanosized Cu/Ni Schiff-Base Complexes and Their Metal Oxide Nanoparticles

Abstract

In this work, nanosized Cu and Ni Schiff-base complexes, namely ahpvCu, ahpnbCu, and ahpvNi, incorporating imine ligands derived from the condensation of 2-amino-3-hydroxypyridine, with either 3-methoxysalicylaldehyde (ahpv) or 4-nitrobenzaldehyde (ahpnb), were synthesized using sonochemical approach. The structure and properties of the new ligands and their complexes with Ni(II) and Cu(II) were determined via infrared (IR), nuclear magnetic resonance (NMR), electronic spectra (UV-Vis), elemental analysis (CHN), thermal gravimetric analysis (TGA), molar conductivity (Λm), and magnetic moment (μeff). The combined results revealed the formation of 1:1 (metal: ligand) complexes for ahpvCu and ahpvNi and 1:2 for ahpnbCu. Additionally, CuO and NiO nanoparticles were prepared by calcination of the respective nanosized Cu/Ni complexes at 500 °C, and characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Significantly, the as-prepared nanosized Schiff-base Cu/Ni complexes and their oxides showed remarkable catalytic activity towards the selective oxidation of benzyl alcohol (BzOH) in aqueous H2O2/ dimethylsulfoxide (DMSO) solution. Thus, catalytic oxidation of BzOH to benzaldehyde (BzH) using both ahpvCu complex and CuO nanoparticles in H2O2/DMSO media at 70 °C for 2 h yielded 94% and 98% BzH, respectively, with 100% selectivity.

Fabrication, spectroscopic characterization, calf thymus DNA binding investigation, antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

“…Job's method (continuous variation method) was used to determine the stoichiometry of the investigated complexes. A mixture of metal salt and ligand solution was mixed, stirred and left to equilibrate, and the absorbance measured at λ max up to 2 h. The absorbance of each solution was then plotted against the mole fraction of metal ion or mole fraction of ligand.…”

Synthesis, Spectroscopic Studies and X-Ray Diffraction of Heptacoordinated Mn(II) and Co(II) Complexes with Ligands Derived from Carbonohydrazide

“…Transition metal coordination compounds with Schiff bases continue to attract the attention of researchers because of the easier synthesis, the stability of the molecular structures and the large diverse properties observed [1]- [11]. Indeed catalytic [12] [13] [14], optical [15], magnetic [16] [17], fluorescent [18] [19] and biological activities [8] [20] [21] [22] are reported. The complexes derived from the first row of transition metals can give several models of metalloenzymes [23] [24] and metalloproteins [25] [26].…”

Green Synthesis of AgNPs() Ultilizing Delonix Regia Extract as Anticancer and Antimicrobial Agents**

“…04–0783 [47] . The average crystallite size in the nanometer has been evaluated using Debye Scherrer formula [48–52] form crystallization parameters (cf. Table 1 ) and found to be 12 nm.…”