Synthesis and characterisation of water soluble ferrocenes: Molecular tuning of redox potentials
ABSTRACT A range of novel water-soluble alkylated ferrocene sulfonate compounds are reported. Mono- and di-sulfonation on a series of alkyl ferrocenes produced 1,1′-dimethyl ferrocene sulfonate, 1,1′-dimethyl ferrocene disulfonate, 1,1′-diethyl ferrocene sulfonate, 1,1′-diethyl ferrocene disulfonate, t-butyl ferrocene sulfonate, t-butyl ferrocene disulfonate, ethyl ferrocene sulfonate, ethyl ferrocene disulfonate, n-butyl ferrocene sulfonate and n-butyl ferrocene disulfonate. All compounds were characterized by NMR spectroscopy, UV/Vis spectroscopy and electrochemical analysis. 1H and 13C NMR studies have revealed the formation of several isomers with sulfonation occurring on positions α and β to the alkyl substituent or on the unsubstituted cyclopentadienyl ring. Variation of the alkyl group allowed the isomeric pattern to be tuned such that the final products followed either electronic or steric control. Cyclic voltammetry of the resulting products showed that the redox potential of the iron centre can be easily manipulated by changing the substituents on the cyclopentadienyl rings. This result has significant implications in the future development of homogenous redox mediators for sensing applications.
Article: Capacitive Biosensors[Show abstract] [Hide abstract]
ABSTRACT: Work on a new type of biosensor, in which changes in the dielectric properties of an electrode surface are detected, started during the late 80s. The binding of an analyte to an immobilized affinity element can be detected directly without the need for a label or an indicating reaction. The changes can be determined by measuring the electrical capacitance or impedance either by using interdigitated electrodes or more commonly by potentiostatic methods. Capacitive biosensors have been used for detection of antigens, antibodies, proteins, DNA fragments and heavy metal ions. Extremely low detection limits, down below 10−15 M, have been reached with plugged, self-assembled recognition layers.Electroanalysis 03/2001; 13(3):173 - 180. · 2.82 Impact Factor