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Bright, NIR‐Emitting Au 23 from Au 25 : Characterization and Applications Including Biolabeling
Author(s) -
Muhammed Madathumpady Abubaker Habeeb,
Verma Pramod Kumar,
Pal Samir Kumar,
Kumar R. C. Arun,
Paul Soumya,
Omkumar Ramakrishnapillai Vyomakesannair,
Pradeep Thalappil
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901425
Subject(s) - quantum yield , fluorescence , chemistry , solvent , quenching (fluorescence) , yield (engineering) , metal , phase (matter) , photochemistry , metal ions in aqueous solution , ion , analytical chemistry (journal) , materials science , chromatography , organic chemistry , physics , quantum mechanics , metallurgy
A novel interfacial route has been developed for the synthesis of a bright‐red‐emitting new subnanocluster, Au 23 , by the core etching of a widely explored and more stable cluster, Au 25 SG 18 (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au 22 and Au 33 . Whereas Au 22 and Au 23 are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au 33 is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au 23 exhibits quenching of fluorescence selectively in the presence of Cu 2+ ions and it can therefore be used as a metal‐ion sensor. Aqueous‐ to organic‐phase transfer of Au 23 has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au 23 before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au 23 emission has been demonstrated. The inherent fluorescence of Au 23 was used for imaging human hepatoma cells by employing the avidin–biotin interaction.