Dipyrrinato-Iridium(III) Complexes for Application in Photodynamic Therapy and Antimicrobial Photodynamic Inactivation.

Benjamin F Hohlfeld, Burkhard Gitter, Christopher J Kingsbury, Keith J Flanagan, Dorika Steen, Gerhard D Wieland, Nora Kulak, Mathias O Senge, Arno Wiehe

Chemistry (Weinheim an der Bergstrasse, Germany) 2021 Apr 12

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The generation of bio-targetable photosensitizers is of utmost importance to the emerging field of photodynamic therapy and antimicrobial (photo-)therapy. A synthetic strategy is presented in which chelating dipyrrin moieties are used to enhance the known photoactivity of iridium(III) metal complexes. Formed complexes can thus be functionalized in a facile manner with a range of targeting groups at their chemically active reaction sites. Dipyrrins with N- and O-substituents afforded (dipy)iridium(III) complexes via complexation with the respective Cp*-iridium(III) and ppy-iridium(III) precursors (dipy=dipyrrinato, Cp*=pentamethyl-η5 -cyclopentadienyl, ppy=2-phenylpyridyl). Similarly, electron-deficient [IrIII (dipy)(ppy)2 ] complexes could be used for post-functionalization, forming alkenyl, alkynyl and glyco-appended iridium(III) complexes. The phototoxic activity of these complexes has been assessed in cellular and bacterial assays with and without light; the [IrIII (Cl)(Cp*)(dipy)] complexes and the glyco-substituted iridium(III) complexes showing particular promise as photomedicine candidates. Representative crystal structures of the complexes are also presented. © 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.

Citation

Benjamin F Hohlfeld, Burkhard Gitter, Christopher J Kingsbury, Keith J Flanagan, Dorika Steen, Gerhard D Wieland, Nora Kulak, Mathias O Senge, Arno Wiehe. Dipyrrinato-Iridium(III) Complexes for Application in Photodynamic Therapy and Antimicrobial Photodynamic Inactivation. Chemistry (Weinheim an der Bergstrasse, Germany). 2021 Apr 12;27(21):6440-6459