Structural studies and anticancer activity of a novel (N6O4) macrocyclic ligand and its Cu(II) complexes

Spectrochim Acta A Mol Biomol Spectrosc. 2011 Jan;78(1):360-70. doi: 10.1016/j.saa.2010.10.021. Epub 2010 Oct 26.


A novel (N6O4) macrocyclic ligand (L) and its Cu(II) complexes have been prepared and characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and conductivity measurements. Quantum chemical calculations have also been carried out at B3LYP/6-31+G(d,p) to study the structure of the ligand and one of its complexes. The results show a novel macrocyclic ligand with potential amide oxygen atom, amide and amine nitrogen atoms available for coordination. Distorted square pyramidal ([Cu(L)Cl]Cl·2.5H2O (1), [Cu(L)NO3]NO(3)·3.5H2O (2), and [Cu(L)Br]Br·3H2O (4) and octahedral ([Cu(L)(OAc)2]·5H2O (3)) geometries were proposed. The EPR data of 1, 2, and 4 indicate d1x2(-y)2 ground state of Cu(II) ion with a considerable exchange interaction. The measured cytotoxicity for L and its complexes (1, 2) against three tumor cell lines showed that coordination improves the antitumor activity of the ligand; IC50 for breast cancer cells are ≈8.5, 3, and 4 μg/mL for L and complexes (1) and (2), respectively.

MeSH terms

  • Antineoplastic Agents / chemistry*
  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Copper / chemistry*
  • Electron Spin Resonance Spectroscopy
  • Electrons
  • Humans
  • Ligands
  • Macrocyclic Compounds / chemistry*
  • Macrocyclic Compounds / pharmacology*
  • Magnetic Resonance Spectroscopy
  • Magnetics
  • Mass Spectrometry
  • Models, Chemical
  • Spectrophotometry, Infrared
  • Temperature
  • Thermogravimetry
  • Vibration


  • Antineoplastic Agents
  • Ligands
  • Macrocyclic Compounds
  • Copper