Ferrocene derivatives have found a number of application in organic synthesis, as well as in material science. In the last 10 years the system ferrocene/ferricenium cation found an interesting field of applications as mediator in biosensors. A biosensor is a system of two transducer, one of which (biochemical) provides selectivity and the other (physical) provides the signal . A good mediator must fulfill a number of requisites, since it should be absorbed on the surface of the electrode, be retained on it, react rapidly with the reduced enzyme, be stable in the reduced and oxidized form, be non reactive with oxygen, and, finally, be non toxic. Moreover, the regeneration of the oxidized form should occur at low voltage and be pH independent. The first successful enzyme electrode used 1,1'-dimethylferrocene absorbed on a graphite electrode, where glucose oxidase was chemically immobilized. Several papers followed, among which we can mention an amperometric enzyme electrode for the determination of hypoxantine in fish meat, that was based on an hydoxymethylferrocene-modified carbon paste electrode [5] or the study of the kinetics of the reaction between ferrocenecarboxylic acid and glucose oxidase. Although the ferrocene system represents a good choice for applications in vivo due to its relatively low toxicity, ferrocenes-mediated enzyme electrodes suffer of some drawbacks, such as relatively short lifetimes and loss of ferrocene, beside enzyme loss or denaturation. Thus, in the attempt to improve the carachteristics of biosensors, ferrocene modified enzymes and ferrocene-containing polymers were used. Co-immobilization with various techniques of both the enzyme and the ferrocene was also used. Electropolymerization is a technique particularly suitable in order to prevent interferences and electrode fouling in biosensors. Ferrocenes were used in biosensors of this type either electropolymerizating a suitably substituted ferrocene, or by absorbing them on the electropolymerizated film. We wish to report here the synthesis and characterization of a new family of arylferrocenylphenylmethanols, prepared to be absorbed on electropolymerised materials, since their bulky and hydrophobic groups might ensure a good absorption of both the oxidized and reduced form, their oxidation potentials might be finely tuned by changing the aryl substituent, and the tertiary alcoholic function does not interfere with oxidation of FeII.
ARYLFERROCENYLMETHANOLS: A NEW FAMILY OF FERROCENES TO BE USED AS MEDIATORS IN BIOSENSORS
A Curulli;
2003
Abstract
Ferrocene derivatives have found a number of application in organic synthesis, as well as in material science. In the last 10 years the system ferrocene/ferricenium cation found an interesting field of applications as mediator in biosensors. A biosensor is a system of two transducer, one of which (biochemical) provides selectivity and the other (physical) provides the signal . A good mediator must fulfill a number of requisites, since it should be absorbed on the surface of the electrode, be retained on it, react rapidly with the reduced enzyme, be stable in the reduced and oxidized form, be non reactive with oxygen, and, finally, be non toxic. Moreover, the regeneration of the oxidized form should occur at low voltage and be pH independent. The first successful enzyme electrode used 1,1'-dimethylferrocene absorbed on a graphite electrode, where glucose oxidase was chemically immobilized. Several papers followed, among which we can mention an amperometric enzyme electrode for the determination of hypoxantine in fish meat, that was based on an hydoxymethylferrocene-modified carbon paste electrode [5] or the study of the kinetics of the reaction between ferrocenecarboxylic acid and glucose oxidase. Although the ferrocene system represents a good choice for applications in vivo due to its relatively low toxicity, ferrocenes-mediated enzyme electrodes suffer of some drawbacks, such as relatively short lifetimes and loss of ferrocene, beside enzyme loss or denaturation. Thus, in the attempt to improve the carachteristics of biosensors, ferrocene modified enzymes and ferrocene-containing polymers were used. Co-immobilization with various techniques of both the enzyme and the ferrocene was also used. Electropolymerization is a technique particularly suitable in order to prevent interferences and electrode fouling in biosensors. Ferrocenes were used in biosensors of this type either electropolymerizating a suitably substituted ferrocene, or by absorbing them on the electropolymerizated film. We wish to report here the synthesis and characterization of a new family of arylferrocenylphenylmethanols, prepared to be absorbed on electropolymerised materials, since their bulky and hydrophobic groups might ensure a good absorption of both the oxidized and reduced form, their oxidation potentials might be finely tuned by changing the aryl substituent, and the tertiary alcoholic function does not interfere with oxidation of FeII.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
