| Supramolecular chemistry provides a means by which synthetic systems can be designed to mimic and possibly surpass biological ones in complexity and scope. One particularly interesting catalytic regulatory method ubiquitously employed in natural systems, but all but unexplored in synthetic ones, is allosteric control.; This dissertation discusses the design, synthesis and implementation of a series of allosteric catalysts. These are the first structures of their kind and they demonstrate the utility of combining structure control and catalytically active sites within supramolecular architectures to achieve exquisite catalytic control.; In Chapter 2, a synthetic allosteric catalyst is presented. The catalyst contains structural Rh(I) centers in hemilabile pockets, and functional Cr(III) centers bound within salen-based moieties. Allosteric control is afforded via reactions that occur at the Rh(I) structure control domains which convert a closed, rigid structure with a small cavity into an open, dilated macrocycle. This shape change facilitates a catalytic reaction occurring at the Cr(III) sites located within the cavity.; In Chapter 3, a mimic for the reversible nature of biological allosteric regulation is presented. A molecular tweeter containing a structural Rh(I) metal and two functional catalytic Cr(III) metals was developed as the first reversible abiotic allosteric catalyst. The catalyst can be switched between two states in situ, and is a rare example of a molecular tweezer containing a working, adjustable hinge. This combination of catalysis and reversible molecular motion amounts to a catalytic molecular machine.; The benefit from an ELISA or PCR-like assay capable of detecting a broad range of analytes motivated the development of the small molecule signal amplification and detection system presented in Chapter 4. The catalyst is switched "on" by an analyte behaving as an allosteric activator. In this manner, nanomolar concentrations of Cl- ions were catalytically amplified and detected. The three-part detection scheme involving analyte binding, allosteric activation, and signal transduction, represents a new and general approach to small molecule detection.; Investigations into the generality of this approach to allosteric catalysts are presented in Chapter 5. A Rh(I)/Zn(II) heterobimetallic square is among several new architectures synthesized towards developing future signal amplification systems and catalysts exhibiting unprecedented reactivity. |
