A ferrocene∩europium assembly showing phototriggered anticancer activity and fluorescent modality imaging

Dalton Trans. 2018 Jan 30;47(5):1479-1487. doi: 10.1039/c7dt04492e.

Abstract

Two macrocyclic ferrocenophanes containing a coumarin fluorophore, Se2N[7]ferrocenophane (fc1), and Se4N2[7,7]ferrocenophane (fc2), construct an assembly of fc1-H+ClO4[Eu(C10H21COO)2(H2O)2(ClO4)] (fc1∩Eu) and fc2-2H+{ClO4[Eu(C10H21COO)2(H2O)2(ClO4)]}2 (fc2∩Eu) via a N-HO hydrogen bond and a coordinate bond between EuIII and ClO4-. In fc1∩Eu, UV light irradiation triggers non-covalent bond cleavage to release a ferrocenium and EuII complex, accompanying chromism and luminescence signals. Investigations through the steady-state UV-vis absorption, fluorescence, time-resolved fluorescence, femtosecond transient absorption spectra and electrochemical characterization elucidate a stepwise mechanism: firstly, an effective electron transfer occurs from a ferrocene unit to the singlet state of a coumarin unit; the following proton-coupled electron transfer (PCET) reduces EuIII and results in a non-covalent interaction cleavage. Further in vitro exploration of fc1∩Eu in HepG2 cells demonstrated phototriggered integrated cell cytotoxicity and fluorescent modality imaging.

MeSH terms

  • Drug Design
  • Europium / chemistry*
  • Ferrous Compounds / chemistry*
  • Hep G2 Cells
  • Humans
  • Hydrogen Bonding
  • Metallocenes / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Optical Imaging*
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry*
  • Organometallic Compounds / pharmacology*
  • Photosensitizing Agents / chemical synthesis
  • Photosensitizing Agents / chemistry*
  • Photosensitizing Agents / pharmacology*

Substances

  • Ferrous Compounds
  • Metallocenes
  • Organometallic Compounds
  • Photosensitizing Agents
  • Europium
  • ferrocene