I. Synthesis and anion recognition of preorganized colorimetric urea/thiourea compounds and their reference receptors, and II. The selective reactions of chlorosilanes: Applications for dendritic and degradable materials

I. Four new thiourea/urea preorganized colorimetric tripodal anion receptors were synthesized in high yield utilizing the thiol-Michael reaction as a key synthetic step. The binding affinity and selectivity of the various receptors towards chloride, fluoride, acetate, and dihydrogen phosphate were evaluated through UV-vis and 1H NMR spectroscopic titrations. In addition, four new thiourea/urea reference receptors were synthesized and analyzed in a similar fashion in order to evaluate the cooperative binding effects often observed with preorganized tripodal receptors. The binding constants for the various preorganized tripodal receptors and their reference receptors were determined using HypSpec and HypNMR2008.;II. A library of multi-functional silyl-thiols was synthesized through the selective reaction of various chlorosilanes and mercaptoalcohols. Utilizing the selective reactions of chlorosilanes and mercaptoalcohols, as well as the selective thiol-ene reaction of chlorovinylsilanes, a number of dendritic precursors were synthesized. The dendritic precursors were analyzed using multi-nuclear NMR spectroscopic techniques. The potential use of the precursors for the synthesis of dendrimers was evaluated. Furthermore, degradable crosslinked networks were prepared via thiol-ene reactions between the multi-functional thiols and various -ene containing compounds. The resulting materials were thermomechanically characterized. Dynamic mechanical analysis, mass loss, and tensile testing were used to study the samples' thermomechanical properties as they were degraded under physiological conditions. Additionally, the degradation products were analyzed and identified using 1H NMR spectroscopy and GC-MS.