Enhanced Fluorescence Detection of Metal Ions Using Light-Harvesting Mesoporous Organosilica

Authors

  • Dr. Minoru Waki,

    1. Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    2. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    Search for more papers by this author
  • Dr. Norihiro Mizoshita,

    1. Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    2. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    Search for more papers by this author
  • Yoshifumi Maegawa,

    1. Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    2. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    Search for more papers by this author
  • Takeru Hasegawa,

    1. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    2. Department of Chemical Engineering, Nara National College of Technology, Yamatokoriyama, Nara 639-1080 (Japan)
    Search for more papers by this author
  • Dr. Takao Tani,

    1. Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    2. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    Search for more papers by this author
  • Dr. Toyoshi Shimada,

    1. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    2. Department of Chemical Engineering, Nara National College of Technology, Yamatokoriyama, Nara 639-1080 (Japan)
    Search for more papers by this author
  • Dr. Shinji Inagaki

    Corresponding author
    1. Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    2. Core Research for Evolutional Science and Technology (CREST), Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 (Japan)
    • Toyota Central R&D Laboratories, Inc. Nagakute, Aich 480-1192 (Japan), Fax: (+81) 561-63-6507
    Search for more papers by this author

Abstract

Enhanced fluorescence detection of metal ions was realized in a system consisting of a fluorescent 2,2′-bipyridine (BPy) receptor and light-harvesting periodic mesoporous organosilica (PMO). The fluorescent BPy receptor with two silyl groups was synthesized and covalently attached to the pore walls of biphenyl (Bp)-bridged PMO powder. The fluorescence intensity from the BPy receptor was significantly enhanced by the light-harvesting property of Bp-PMO, that is, the energy funneling into the BPy receptor from a large number of Bp groups in the PMO framework which absorbed UV light effectively. The enhanced emission of the BPy receptor was quenched upon the addition of a low concentration of Cu2+ (0.15–1.2×10−6M), resulting in the sensitive detection of Cu2+. Upon titration of Zn2+ (0.3–6.0×10−6M), the fluorescence excitation spectrum was systematically changed with an isosbestic point at 375 nm through 1:1 complexation of BPy and Zn2+ similar to that observed in BPy-based solutions, indicating almost complete preservation of the binding property of the BPy receptor despite covalent fixing on the solid surface. These results demonstrate that light-harvesting PMOs have great potential as supporting materials for enhanced fluorescence chemosensors.

Ancillary