| An azobenzene functionalized monomolecularly imprinted dendrimer (MID) was synthesized from a template structurally related to dopamine. This MID was designed to bind amine guests through a covalent linkage to a reporter group, which signals binding by a color change from red to yellow, and by two noncovalent amino-carboxylic acid contacts. Control dendrimers were synthesized, and binding studies with guests having 1, 2, or 3 primary amino groups showed that the key functional groups of the MID were situated in complimentary positions with respect to the template.; For potential encapsulation applications, a star polymer with a porphyrin core and eight alkene-functionalized arms was synthesized. Intramolecular cross-linking and removal of the porphyrin core produced a nanosized cored star copolymer with a size exclusion chromatography (SEC) estimated molecular weight of approximately 20 kDa and a polydispersity index (PDI) of 1.5. Molecular modeling and subsequent binding studies collectively indicated that the cross-linked star polymer scaffold probably contained a majority of intra-arm cross-links resulting in a flexible structure that is not ideal for template-mediated imprinting.; Dendrimers having 16, 24, 32, or 64 alkene groups were synthesized and intramolecularly cross-linked. The combined use of MALDI-TOF MS and SEC analysis of the resulting structures indicated that in each case, as the degree of dendrimer cross-linking increased, its radius of gyration (Rg) decreased linearly. Upon cross-linking of the dendrimer having 64 alkene groups, atomic force microscopy (AFM) data indicated that as the degree of cross-linking increased, the height of the resulting structure deposited on a mica surface increased linearly. These results were interpreted in terms of an increase in rigidity with cross-linking. In addition, smaller dendrons and a dendrimer having 16 alkene groups were cross-linked, and the resulting structures were analyzed by 1H NMR, x-ray crystallography, MALDI-TOF MS, and SEC to provide insight into the types of the cross-links that are preferred in the cross-linking process. |
