Synthesis and characterization of a new Schiff base ligand derived from benzo-15- crown-5 and its complexes with cobalt(II), nickel(II) and copper(II)

Abstract

A new Schiff base ligand, N-quino[8 ,7-b]azin-5-yl-2 ,3,5,6,8, 9,11,12-octahydrobenzo [b][ 1,4,7,10,13]pentaoxacyclopentadecin- 15-ylmethanimine (<b>1</b>) has been synthesized from the reaction of 5-amino-1, 10-phenanthroline with 4'- formylbenzo- 15-crown-5. The ligand reacts with Co(II), Ni(II) and Cu(II) salts to form complexes. The ligand and the complexes have been characterized by FTIR, ¹H NMR (DMSO-<i>d₆</i>), UV-vis, elemental analysis, mass spectra (LC-MS) and magnetic measurements. The metal to the ligand ratio of the Co(II), Ni(II) and Cu(II) complexes have been found to be 1:2. Protonation constants of the ligand and overall formation constants of the complexes have been calculated from potentiometric data using the computer program TITFIT.