Date of Award

2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Graduate Group

Chemistry

First Advisor

David W. Christianson

Abstract

ABSTRACT

ADVANCES IN SUPRAMOLECULAR ORIENTATIONAL MEMORY MEDIATED BY FRANK-KASPER PHASES OF SELF-ASSEMBLING DENDRONSNing Huang Virgil Percec Synthetic methodologies to develop and program complex self-assembling soft matter have pushed the forefront of bioinspired materials, nanoscale architecture design, and the development of drug delivery systems. Self-assembling dendrons and dendrimers have emerged as one of the most promising candidates that allow monodisperse molecular weights, programmable primary structures, sequence-defined peripheral groups, and versatile functional group modifications. To control the functions of supramolecular assemblies in complex biological and non-biological systems, it is necessary to define and program their structures via the molecular design of self-assembling dendrons. In this work, three novel synthetic strategies are introduced to the field of soft matter design. These include: an accelerated, nickel-catalyzed cross-coupling methodology to synthesize symmetric and nonsymmetric self-assembling dendrons; a sequence-defined synthetic method to facilitate highly ordered self-organization in the solid state; and a new class of drug delivery vesicles self-assembled from ionizable amphiphilic Janus dendrimers. Structural and retrostructural analyses are conducted by a robust methodology that includes: initial investigation of thermal behavior of supramolecular assemblies by differential scanning calorimetry; structural determination of supramolecular assemblies by oriented fiber X-ray diffraction (XRD); mechanistic studies supported by molecular modeling; and XRD simulation of the constructed models of supramolecular assemblies. The scientific findings reported in this work consist of: (1) an accelerated synthetic route to obtain self-assembling dendrons with rigid solid angle; (2) statistical and mechanistic studies of supramolecular orientational memory (SOM); (3) the development of SOM-competent noncovalent crown conformations via the tuning of intermolecular interactions at the apex of a self-assembling dendron; (4) the discovery of two unprecedented arrangements of columnar hexagonal lattices; (5) a sequence-defined modification on the peripheral groups of a self-assembling dendron that drastically enhances the self-organization of its supramolecular assemblies; and (6) a sequence-defined ionizable amphiphilic Janus dendrimer employed in mRNA delivery systems. In conclusion, the principles of supramolecular self-assembly and the newly developed synthetic methodologies elaborated in this work are expected to facilitate advances in the design and synthesis of functional supramolecular materials.

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