Preparation and electrochemical behavior of water-soluble inclusion complex of ferrocene with β-cyclodextrin polymer

Abstract

A new water-soluble inclusion complex of ferrocene (Fc) with β-cyclodextrin polymer (β-CDP) was prepared by a facile strategy and characterized by 1H NMR spectroscopy, elemental analysis, powder X-ray diffractometry, thermogravimetry, UV–vis spectroscopy and cyclic voltammetry. Compared with Fc and the inclusion complex of Fc with β-cyclodextrin (Fc-β-CD), the solubility of ferrocene-β-cyclodextrin polymer (Fc-β-CDP) was greatly enhanced due to the water-soluble β-CDP host. The ratio of β-cyclodextrin (β-CD) unit in β-CDP to Fc was determined as 1:1. At 25°C, the dissociated constant of Fc-β-CDP was measured as 3.65mM by UV–vis spectroscopy and cyclic voltammetry. The electrochemical properties of Fc-β-CDP in water were studied. The diffusion coefficients of oxidation state and reduction state were calculated as 3.52×10−7cm2s−1 and 3.93×10−7cm2s−1. The resulting value of standard rate constant was measured as 1.95×10−3cms−1. The diffusion activation energy was calculated as 21.8kJmol−1.