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Chelate-free "turn-on"-type fluorescence detection of trivalent metal ions
Shota Matsumoto1, Tomohiro Umeno1, Noriko Suzuki1
1Faculty of Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165 Higashi-tamagawagakuen, Machida 194-8543, Japan. karasawa@ac.shoyaku.ac.jp.
Abstract:
Trivalent metal ions are essential elements in materials and life sciences. To date, fluorescence is the gold standard for the detection of trivalent metal ions, which form a complex with fluorescent chelate ligands (Lewis base type). In this study, we report pH-responsive fluorescent probes for the selective detection of trivalent metal ions that utilize a new chelate-free approach using Brønsted base-type probes. Moreover, an X-ray structure of the outer-sphere aluminum(III) aqua complex coordinated by the fluorescent probes through hydrogen bonds was discovered. The outer-sphere complex consisting of an Al(III) aqua complex and protonated cationic probe showed cation-cation coordination.
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