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Enhanced Fluorescence Detection of Metal Ions Using Light‐Harvesting Mesoporous Organosilica
Author(s) -
Waki Minoru,
Mizoshita Norihiro,
Maegawa Yoshifumi,
Hasegawa Takeru,
Tani Takao,
Shimada Toyoshi,
Inagaki Shinji
Publication year - 2012
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.201102492
Subject(s) - fluorescence , bipyridine , metal ions in aqueous solution , covalent bond , mesoporous material , photochemistry , titration , metal , mesoporous organosilica , chemistry , fluorescence spectroscopy , luminescence , biphenyl , materials science , inorganic chemistry , mesoporous silica , crystallography , organic chemistry , crystal structure , quantum mechanics , physics , catalysis , optoelectronics
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 Cu 2+ (0.15–1.2×10 −6 M ), resulting in the sensitive detection of Cu 2+ . Upon titration of Zn 2+ (0.3–6.0×10 −6 M ), the fluorescence excitation spectrum was systematically changed with an isosbestic point at 375 nm through 1:1 complexation of BPy and Zn 2+ 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.