Tetradentate amido azo Schiff base Cu(II), Ni(II) and Pd(II) complexes: Synthesis, characterization, spectral properties, and applications to catalysis in C–C coupling and oxidation reaction

Jahar Lal Pratihar, Paritosh Mandal, Chung Kung Lai, Surajit Chattopadhyay

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

New Schiff base ligands (H2L1 & H2L2) were synthesized by the reaction of salicylaldehyde with (2-((2-aminophenyl)diazenyl)-N-alkylaniline), and were used for the preparation of complexes with Cu(II), Ni(II) and Pd(II) metal ions. The structural features of the synthesized compounds were examined by UV–Vis, IR and 1H NMR spectroscopy. The crystal structures of Schiff base (H2L1) and two metal complexes Cu(L1) and Ni(L2) were determined by single crystal X-ray diffraction. The studies revealed that the synthesized Schiff bases existed as tetradentate (N,N,N,O) ligands and bonded to the metal ions through the donor atoms of the amido nitrogen, azo nitrogen, azomethine nitrogen and phenolic oxygen atoms. The redox property of Cu(L1) and Ni(L1) and emission behavior of ligand H2L1 and complexes Cu(L1) and Ni(L1) were examined. The complex Cu(L1) shows excellent catalytic activity towards oxidation of benzyl alcohol to benzyldehyde (under solvent-free condition) using H2O2 as the oxidant. Complex Pd(L1) acts as highly efficient catalyst in the Suzuki–Miyaura cross-coupling reaction of various aryl halides with phenyl boronic acid to produce the corresponding biaryls with high yields under mild reaction conditions. Both the catalysts Cu(L1) and Pd(L1) were easily recovered by simple chromatographic separation and reused for next catalytic cycle.

Original languageEnglish
Pages (from-to)317-324
Number of pages8
JournalPolyhedron
Volume161
DOIs
StatePublished - 15 Mar 2019

Keywords

  • Copper(II), nickel(II) and palladium(II)
  • Crystal structures
  • Emission
  • Oxidation and C–C coupling reactions
  • Redox

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