Design of discrete supramolecular architectures via self-assembly of macromolecular building blocks.

摘要

This dissertation describes the design of tapered building blocks or exo-receptors that have covalently bound endo-receptors and/or polymerizable groups that, after complexation and/or polymerization processes, self-assemble into discrete cylindrical supramolecular architectures. This approach is modeled after the self-assembly of the Tobacco Mosaic Virus (TMV). The dimension and stability of the resulting synthetic architecture is tuned by the selection of a suitable exo-receptor. This is subsequently linked to an appropriate endo-receptor or polymerizable group which acts to bind the taper shaped units together, and results in a nanoscale supramolecular architecture. The synthetic pathway to these architectures and the relationship between the building block constituents and the stability and dimensions of the resulting supramolecular structure will be presented.; The first part of this dissertation describes the synthesis and characterization of taper-shaped monodendrons with semi-fluorinated alkyloxy tails. The addition of a semi-fluorinated component to the superstructure of these microphase segregated columns dramatically enhances the thermal stability of the self-assembled supramolecular architecture. Increasing the size of the aromatic component in the taper-shaped macromolecule also leads to an enhanced thermal stability of the resulting supramolecular architecture through intracolumnar microphase segregation.; This methodology also permits the ability to tailor the diameter of the supramolecular and macromolecular columns. The design of polymerizable building blocks derived from monodendrons that self-organize into well defined supramolecular architectures is also investigated. The ability to precisely control the resulting dimension of the supramolecular architecture depends on the ability to generate living polymerization reactions in the presence of a variety of functional groups. Well defined Ru based metathesis catalysts are well suited for the living ring opening metathesis polymerization of norbornenes and 7-oxanorbornenes. This dissertation will discuss the polymerization of norbornene and 7-oxanorbornene monomers functionalized with monodendrons and demonstrate the scope of this polymerization reaction in the construction of supramolecular systems. These monodendrons are also used to generate a three dimensional rigid rod polymer. Strategic placement of the polymerizable group in close proximity to the sterically demanding taper shaped monodendron acts to limit the conformational freedom of the resulting polymer backbone.