Dyes and indicators in molecular sensing ensembles : progress toward novel uses of dendrimers and reactands in optical sensing methods

Over the past two decades, the field of molecular sensing has developed into a mature offshoot of molecular recognition, and sensing protocols based on optical signal modulations have enjoyed particularly great success. Such sensing methods are the focus of this dissertation, in which efforts toward the integration of dendrimers and reactands into separate, optically-based sensing platforms are described. To this end, Chapter 1 provides a brief introduction to molecular sensing and its supramolecular underpinnings. The remainder of Chapter 1 is dedicated to dendrimers and their application to molecular recognition and sensing. A discussion of the physicochemical properties of dendrimers is also included to lend perspective on the structure, size, and shape of these macromolecules. The role of dyes and indicators in the elucidation of dendritic structure and function is given special consideration. Finally, selected reports of dendrimers in molecular recognition and optical sensing are summarized. Chapter 2 details original research directed toward the incorporation of dendrimers into molecular sensing ensembles. This use of dendrimers in molecular recognition and sensing is distinguished from those examples described in Chapter 1 by its modular nature. This modularity is achieved through the use of a non-covalent sensing motif based on indicator displacement. The identification and optimization of the appropriate components for use in such dendrimer-based sensing ensembles represents a contribution of the research described herein. An evaluation of indicator dyes for their incorporation into an enantioselective indicator displacement assay (eIDA) for common organic molecules is the subject of the research discussed in Chapter 3. The selected indicator dyes were assessed for use in a novel eIDA that relies on covalent bond formation for the enantioselective signaling of monofunctional organic analytes. A survey of colorimetric methods for the identification and discrimination of amines is included because these compounds served as an initial target in the proposed assay. Optical enantiosensing strategies are also reviewed in light of their relevance to the present work.