Phosphonate-Functionalized Polyfluorene as a Highly Water-Soluble Iron(III) Chemosensor

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• 作者：Chuanjiang Qin ; Yanxiang Cheng ; Lixiang Wang ; Xiabin Jing ; Fosong Wang
• 刊名：Macromolecules
• 出版年：2008
• 出版时间：November 11, 2008
• 年：2008
• 卷：41
• 期：21
• 页码：7798-7804
• 全文大小：278K
• 年卷期：v.41,no.21(November 11, 2008)
• ISSN：1520-5835

文摘

An anionic, phosphonate-functionalized polyfluorene, i.e., poly(9,9-bis(3′-phosphatepropyl)fluorene-alt-1,4-phenylene) sodium salt (PFPNa), has been synthesized by copolymerization of phosphonic acid-substituted 2,7-dibromofluorene and phenyldiboronic ester via direct Suzuki polycondensation reaction in DMF/water. Polymer PFPNa is highly soluble and emissive in water with a solubility of 60 mg/mL and a photoluminescence quantum yield of 75%. The absorption and fluorescence spectra of PFPNa are strongly dependent on pH value owing to the partial protonation of phosphate groups and the aggregation of the polymer chains. In aqueous media polymer PFPNa shows high sensitivity and selectivity for Fe³⁺. A 400-fold fluorescence quenching was achieved upon adding Fe³⁺ into its aqueous solution. Most importantly, ultrathin multilayer films constructed by alternatively depositing polyanionic PFPNa and polycationic poly(diallyldimethylamine) via the layer-by-layer (LbL) self-assembling method are stable and highly sensitive to Fe³⁺ with a sensitivity up to 10⁻⁷ M.