Interaction of β‐cyclodextrin‐capped CdSe quantum dots with inorganic anions and cations

• Published in: Luminescence
• Main Authors: Shang, Zhuo Bin, Hu, Shuang, Wang, Yu, Jin, Wei Jun
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2011
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/bio.1274; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fbio.1274; http://onlinelibrary.wiley.com/wol1/doi/10.1002/bio.1274/fullpdf

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, H 2 PO 4 – exhibited the largest quenching effect. For the polyprotic acids (HO) 3 AO, the effect of acidic anions on the fluorescence of β ‐CD‐QDs was in the order: monoanion (HO) 2 AO 2 – > dianion (HO)AO 3 2– >> trianion AO 4 3– . 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 + , Hg 2+ and Co 2+ have significant quenching effect on the fluorescence of the β ‐CD‐QDs. The Stern–Volmer quenching constants increased in the order: Hg 2+ < Co 2+ <Ag + . The adsorption model of metal ions on β ‐CD‐QDs was explored. Copyright © 2011 John Wiley & Sons, Ltd.