Preparation and Bioactivity of Iridium(III) Phenanthroline Complexes with Halide Ions and Pyridine Leaving Groups

Chembiochem. 2021 Feb 2;22(3):557-564. doi: 10.1002/cbic.202000511. Epub 2020 Nov 4.

Abstract

A series of half-sandwich structural iridium(III) phenanthroline (Phen) complexes with halide ions (Cl- , Br- , I- ) and pyridine leaving groups ([(η5 -CpX )Ir(Phen)Z](PF6 )n , Cpx : electron-rich cyclopentadienyl group, Z: leaving group) have been prepared. Target complexes, especially the Cpxbiph (biphenyl-substituted cyclopentadienyl)-based one, showed favourable anticancer activity against human lung cancer (A549) cells; the best one (Ir8) was almost five times that of cisplatin under the same conditions. Compared with complexes involving halide ion leaving groups, the pyridine-based one did not display hydrolysis but effectively caused lysosomal damage, leading to accumulation in the cytosol, inducing an increase in the level of intracellular reactive oxygen species and apoptosis; this indicated an anticancer mechanism of oxidation. Additionally, these complexes could bind to serum albumin through a static quenching mechanism. The data highlight the potential value of half-sandwich iridium(III) phenanthroline complexes as anticancer drugs.

Keywords: anticancer agents; hydrolysis; iridium(III) complexes; leaving groups.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coordination Complexes / chemical synthesis*
  • Coordination Complexes / chemistry
  • Halogens / chemistry*
  • Ions / chemistry
  • Iridium / chemistry*
  • Molecular Structure
  • Phenanthrolines / chemistry*
  • Pyridines / chemistry*

Substances

  • Coordination Complexes
  • Halogens
  • Ions
  • Phenanthrolines
  • Pyridines
  • Iridium
  • pyridine