| Zirconium bis(monohydrogen orthophosphate) monohydrate (Zr(HPO4 )2˙H2O, &agr;-ZrP) is the best characterized zirconium phosphate (ZrP). The highly hydrated phase of the layered ZrP, known as the 10.3 A phase, is an acidic ion exchanger that has been used for the immobilization of several photo-, bio- and redox-active compounds. Among these compounds are those consisting of two cyclopentadienyl anions bonded to a metal center in the oxidation state II which are called metallocenes. Ferrocene (Cp2Fe) is an example of a metallocene compound that has been used as an electron mediator in amperometric sensors. We have performed the synthesis of various derivatives of ferrocene and chemically and electrochemically characterized them. In addition, we have worked with a metallocene derivative known as titanocene dichloride (Cp2TiCl2) which has been proposed and investigated as a potential anticancer drug and it has been reported to undergo a 1e- reduction process which is chemically and electrochemically reversible. Furthermore, we incorporated to the investigation molybdocene dichloride (Cp2MoCl2) and one of its derivatives: Cp2Mo(2-amino-6-mercaptopurine)Cl. Using the 10.3 A phase of ZrP as a host to intercalate by direct ion exchange these metallocene derivatives we chemical and electrochemically characterized them for possible applications in biotechnology. The direct intercalation reaction of the metallocene derivatives into 10.3 A ZrP was performed. The compounds and their intercalated materials were characterized using IR spectroscopy, X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. The XRPD data indicate that new intercalated phases with expanded interlayer distances were obtained for Fc-R derivatives, titanocene dichloride, molybdocene dichloride and its derivative of 9.1--9.9 A, 9.7--10.0 A, 10.8 A and 13.8 A, respectively. Some of the metallocenes remained electrochemically active upon intercalation. It is concluded that ZrP is a suitable material to produce robust intercalated materials with these metallocene compared to the non-layered materials. |
