Interaction of β‐cyclodextrin‐capped CdSe quantum dots with inorganic anions and cations |
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Authors: | Zhuo Bin Shang Shuang Hu Yu Wang Wei Jun Jin |
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Institution: | 1. School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, People's Republic of China;2. College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China |
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Abstract: | A facile method was developed for the preparation of water soluble β‐Cyclodextrin (β‐CD)‐modified CdSe quantum dots (QDs) (β‐CD‐QDs) by directly replacing the oleic acid ligands on the QDs surface with β‐CD in an alkaline aqueous solution. The as‐prepared QDs show good stability in aqueous solution for several months. Oxoanions, including phosphoric acid ion, sulphite acid ion and carbonic acid ion, affect the fluorescence of β‐CD‐QDs. Among them, H2PO4– exhibited the largest quenching effect. For the polyprotic acids (HO)3AO, the effect of acidic anions on the fluorescence of β‐CD‐QDs was in the order: monoanion (HO)2AO2– > dianion (HO)AO32– >> trianion AO43–. After photoactivation for several days in the presence of anions at alkaline pH, the β‐CD‐QDs exhibited strong fluorescence emission. The effect of various heavy and transition metal ions on the fluorescence properties of the β‐CD‐QDs was investigated further. It was found that Ag+, Hg2+ and Co2+ have significant quenching effect on the fluorescence of the β‐CD‐QDs. The Stern–Volmer quenching constants increased in the order: Hg2+ < Co2+ <Ag+. The adsorption model of metal ions on β‐CD‐QDs was explored. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | CdSe quantum dots β ‐cyclodextrin fluorescence acidic anions metal ions |
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