Synthesis, Characterization, and Cu(2+) Coordination Studies of a 3-Hydroxy-4-pyridinone Aza Scorpiand Derivative

Inorg Chem. 2016 Aug 1;55(15):7564-75. doi: 10.1021/acs.inorgchem.6b01006. Epub 2016 Jul 19.

Abstract

The synthesis, acid-base behavior, and Cu(2+) coordination chemistry of a new ligand (L1) consisting of an azamacrocyclic core appended with a lateral chain containing a 3-hydroxy-2-methyl-4(1H)-pyridinone group have been studied by potentiometry, cyclic voltammetry, and NMR and UV-vis spectroscopy. UV-vis and NMR studies showed that phenolate group was protonated at the highest pH values [log K = 9.72(1)]. Potentiometric studies point out the formation of Cu(2+) complexes of 1:2, 2:2, 4:3, 1:1, and 2:1 Cu(2+)/L1 stoichiometries. UV-vis analysis and electrochemical studies evidence the implication of the pyridinone moieties in the metal coordination of the 1:2 Cu(2+)/L1 complexes. L1 shows a stronger chelating ability than the reference chelating ligand deferiprone. While L1 shows no cytotoxicity in HeLa and ARPE-19 human cell lines (3.1-25.0 μg/mL), it has significant antioxidant activity, as denoted by TEAC assays at physiological pH. The addition of Cu(2+) diminishes the antioxidant activity because of its coordination to the pyridinone moiety phenolic group.

MeSH terms

  • Antioxidants / chemistry
  • Antioxidants / pharmacology*
  • Cell Proliferation / drug effects
  • Chelating Agents / chemistry*
  • Chelating Agents / pharmacology
  • Chemistry Techniques, Synthetic
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Coordination Complexes / pharmacology*
  • Copper / chemistry*
  • Crystallography, X-Ray
  • HeLa Cells
  • Humans
  • Hydrogen-Ion Concentration
  • Magnetic Resonance Spectroscopy
  • Potentiometry
  • Pyridines / chemistry*
  • Pyridones / chemistry
  • Spectrophotometry, Ultraviolet
  • Structure-Activity Relationship

Substances

  • Antioxidants
  • Chelating Agents
  • Coordination Complexes
  • Pyridines
  • Pyridones
  • Copper