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

A new water-soluble inclusion complex of ferrocene (Fc) with beta-cyclodextrin polymer (beta-CDP) was prepared by a facile strategy and characterized by (1)H NMR spectroscopy, elemental analysis. powder X-ray diffractometry, thermogravimetry, UV-vis spectroscopy and cyclic voltammetry. Compared with Fe and the inclusion complex of Fc with beta-cyclodextrin (Fc-beta-CD), the solubility of ferrocene-beta-cyclodextrin polymer (Fe-beta-CDP) was greatly enhanced due to the water-soluble beta-CDP host. The ratio of beta-cyclodextrin (beta-CD) unit in beta-CDP to Fc was determined as 1:1. At 25 degrees C, the dissociated constant of Fc-beta-CDP was measured as 3.65 mM by UV-vis spectroscopy and cyclic voltammetry. The electrochemical properties of Fc-beta-CDP in water were studied. The diffusion coefficients of oxidation state and reduction state were calculated as 3.52 x 10(-7) cm(2) s(-1) 3.93 x 10(-7) cm(2) s(-1). The resulting value of standard rate constant was measured as 1.95 x 10(-3) cm s(-1). The diffusion activation energy was calculated as 21.8 kj mol(-1). (C) 2011 Elsevier Ltd. All rights reserved.