A key issue for constructing optical and redox-active receptors is how to conjugate a specific sensing kernel with a multi-signal-responsive system to carry out multi-feature analysis. Mercury is considered to be highly toxic to human health and ecological security. In this work, we present a novel near-infrared optical and redox-active receptor that can sense Hg2+ at ppb level in aqueous media via multi-model monitors with a low detection limit of 8.4 × 10-9 M (1.68 ppb). This receptor features a visible detection, 'off-on' fluorescence response, and efficient electrochemistry assessment, as well as pH-insensitivity to Hg2+ with high sensitivity. In view of its marked near-infrared emission and fluorescence enhancement, we successfully applied this receptor to visualize Hg2+ in live cells. Furthermore, a possible sensing model was established and rationalized with theoretical studies.
Keywords: Ferrocene; Hg(2+); NIR imaging; Near-infrared probe; Optical and redox-active receptor; Si-rhodamine.
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