A copper(II)-Schiff base complex: Synthesis, structural characterization and catalytic oxidative coupling of 2-aminophenol

Department of Chemistry, University of North Bengal, Darjeeling-734 013, West Bengal, India

E-mail: icbbiswas@gmail.com, bhaskarbiswas@nbu.ac.in

Manuscript received online 30 January 2020, revised and accepted 28 May 2020

This present study reports the synthesis, X-ray structural analysis, supramolecular architectures and oxidative coupling of 2- aminophenol of a copper(II)-Schiff base complex, [Cu(L)](H₂O) (1) containing a previously reported Schiff base, H₂L = 2,2'- ((1,2-phenylenebis(azanylylidene))bis(methanylylidene))diphenol. Crystal structure analysis reveals that Cu(II) centre adopts a square planar coordination geometry with R-3 space group. Investigation on self-assembled crystalline architecture displays that the aqua molecule in crystal lattice involves in significant intermolecular H-bonding to lead the formation of water mediated dimeric unit of Cu(II) complex. Noteworthy π…π interactions are operative strongly among the centroids of ligands to assemble Cu(II) complex in a zigzag 1D chain. The red highlighted spots in Hirshfeld surface suggests the active involvement of C-H…O, O-H…O types H-bonding and π…π interactions. The catalytic aspects of Cu(II) complex has been evaluated towards oxidative dimerization of 2-aminophenol (2-AP) in methanol and found high catalytic efficiency, k_cat/K_M (h^–1) as 2.14×10⁵ . Mass spectrometry studies of the Cu(II) complex with 2-AP ensures that the course of catalysis undergoes through enzyme-substrate adduct formation in solution phase.