Development of chemosensors for iron(III) and zinc(II)

This thesis describes the development, synthesis and evaluation of chemosensors for the fluorometric detection of Fe(III) and Zn(II). A Chemosensor is a molecule which can translate the presence of a sample component into a measurable signal, here fluorescence. Part A describes the synthesis of a chemosensor assembly for the fluorescence detection of Fe(III). This sensor represents the first example of a chemosensor responding to the presence of Fe(III) with a fluorescence increase. It is shown that the mechanism of operation of this sensor is the Fe(III)-specific release of a fluorescent molecule from the non-fluorescent sensor. In due course of this work, the synthetic methodology toward hydroxamate squarate esters and amides and related compounds was developed. ^ Part B of this thesis describes the synthesis of a coumarin-based chemosensor suitable for the imaging of Zn(II) in live cells. The building block-type sensor design allowed for the synthesis of a family of chemosensors varying optical, coordination and bio-distribution properties. The sensors operate according to a chelation-enhanced fluorescence enhancement mechanism. The realization of a ratiometric sensor for zinc is also presented. This sensor allows the fluorometric determination of zinc concentration in complex biological media.