Fluorescent Molecular Sensors
Fluorescent molecular sensor design is an active field of supramolecular chemistry, not only because of potential practical benefits in cell physiology, analytical, and environmental chemistry, but also as a proving ground for manipulation and/or engineering of various photophysical processes toward an ultimate goal of selective and sensitive signaling of targeted molecular or ionic species.
Our group is primarily involved in introducing novel red emitting fluorophores to the chemosensor scene and in finding new ways of manipulating photophysical processes to obtain useful signals for effective sensing of various analytes. In 2005, we reported [1] a novel dimeric boradiazaindacene dye which can be converted in one step to an efficient resonance energy transfer (RET) dyad. In addition, when this modification was done with appropriate ligands, RET could be coupled to ion sensing. The utility of this approach was demonstrated in a highly selective, emission-ratiometric chemosensor for Ag(I).
Boradiazaindacene dyads designed as energy transfer casettes were modified to signal cation concentrations ratiometrically. If the energy transfer efficiency is increased via changing spectral overlap on cation binding, an enhancement of emission signal ratios can be obtained. Larger range of ratios result in highly improved sensitivity to analyte concentrations. We demonstrated [2] this approach in a de novo design of a novel and highly selective ratiometric chemosensor for Hg(II) ions.
Aryl substituted boratriaza-indacenes (Aza-Bodipy’s) are a new class of dyes with long wavelength absorption and emissions. Recently, we reported [3] the first application of these dyes in metal ion sensing. 2-Pyridyl substituents at the positions 1 and 7 create a well-defined pocket for metal ion binding. The chemosensor described in this study is remarkably selective for Hg(II) ions and both absorption and emission spectra display large changes that would allow ratiometric sensing.
Relevant Publications: [