Date of Award
Spring 2026
Document Type
Open Access Dissertation
Department
Chemistry and Biochemistry
First Advisor
Linda S. Shimizu
Abstract
Bis-urea macrocycles are versatile frameworks for supramolecular assembly and functional organic materials in solution and the solid state. This dissertation examines two applications of these macrocycles in supramolecular polymerizations and as conductive crystalline materials. Chapter 1 provides an introduction and overview of supramolecular polymers and their assembly mechanisms. The chapter highlights urea as a powerful supramolecular motif and reviews the structural features of bis-urea macrocycles as building blocks for supramolecular polymerization.
Chapter 2 examines a phenylethynylene bis-urea macrocycle with exterior dodecyloxy groups, which affords a rare example of an isodesmic hydrogen-bonded supramolecular polymer in polar media and provides design principles for controlling solution-phase host–guest frameworks. Temperature-dependent UV–Vis and fluorescence studies in H₂O/THF mixtures reveal an isodesmic mechanism characterized by strong enthalpic stabilization and short chain lengths. Dynamic light scattering and atomic force microscopy confirm the formation of nanoscale aggregates and short fibrillar structures. End-capping additives enable modulation of the degree of polymerization, demonstrating tunable control of chain length.
Chapter 3 reports crystalline triphenylamine-based bis-urea macrocycles as organic hosts capable of guest-induced modulation of charge-transfer properties, enabling tunable electrical conductivity. By encapsulating electron-accepting guests with distinct reduction potentials, significant changes in electrical conductivity are achieved. Notably, the complex formed with 2,5-dichloro-1,4-benzoquinone exhibits a ~10,000-fold increase relative to the pristine host. Spectroscopic and computational analyses reveal that this conductivity enhancement arises from favorable charge-transfer interactions, electronic coupling, and minimized reorganization energies within the host–guest assemblies.
Chapter 4 explores a modified derivative of the phenylethynylene bis-urea macrocycle with a dendritic-type substituent on the exterior to assess how increased steric bulk and dispersion interactions influence supramolecular assembly behavior and the potential emergence of pathway complexity. Chapter 5 summarizes the key findings of this dissertation and discusses future directions for supramolecular assemblies based on phenylethynylene bis-urea macrocycles and conductive crystalline materials derived from triphenylamine bis-urea macrocycles.
Rights
© 2026, Fahidat Adedamola Gbadamosi
Recommended Citation
Gbadamosi, F. A.(2026). Functional Assemblies of Phenylethynylene and Triphenylamine Bis-urea Macrocycles. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8932