Water-soluble luminescent cyclometalated gold(III) complexes with cis-chelating bis(N-heterocyclic carbene) ligands: Synthesis and photophysical properties

Faan Fung Hung, Wai Pong To, Jing Jing Zhang, Chensheng Ma, Wai Yeung Wong, Chi Ming Che

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45 Citations (Scopus)


A new class of cyclometalated AuIIIcomplexes containing various bidentate C-deprotonated C^N and cis-chelating bis(N-heterocyclic carbene) (bis-NHC) ligands has been synthesized and characterized. These are the first examples of AuIIIcomplexes supported by cis-chelating bis-NHC ligands. [Au(C^N)(bis-NHC)] complexes display emission in solutions under degassed condition at room temperature with emission maxima (λmax) at 498-633 nm and emission quantum yields of up to 10.1 %. The emissions are assigned to triplet intraligand (IL) π→π* transitions of C^N ligands. The AuIIIcomplex containing a C^N (C-deprotonated naphthalene-substituted quinoline) ligand with extended π-conjugation exhibits prompt fluorescence and phosphorescence of comparable intensity with λmaxat 454 and 611 nm respectively. With sulfonate-functionalized bis-NHC ligand, four water-soluble luminescent AuIIIcomplexes, including those displaying both fluorescence and phosphorescence, were prepared. They show similar photophysical properties in water when compared with their counterparts in acetonitrile. The long phosphorescence lifetime of the water-soluble AuIII complex with C-deprotonated naphthalene-substituted quinoline ligand renders it to function as ratiometric sensor for oxygen. Inhibitory activity of one of these water-soluble AuIIIcomplexes towards deubiquitinase (DUB) UCHL3 has been investigated; this complex also displayed a significant inhibitory activity with IC50value of 0.15 μM. KGaA, Weinheim.
Original languageEnglish
Pages (from-to)8604-8614
Number of pages11
JournalChemistry - A European Journal
Issue number28
Publication statusPublished - 7 Jul 2014
Externally publishedYes


  • cyclometalation
  • gold
  • luminescence
  • N-heterocyclic carbenes
  • water chemistry

ASJC Scopus subject areas

  • Chemistry(all)

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