| The focus on the physical properties of molecules has intensified as miniaturization of materials, specifically those in the electronics field, becomes more important. Supramolecular chemistry, which relies on noncovalent interactions to function, is used ubiquitously throughout materials chemistry. Along with H-bonding, pi-pi stacking is being recognized as one of the more significant of the noncovalent interactions. This project examines meta connected aryl acetylene oligomers and uses a pi-donor/pi-acceptor motif.;In this binary system, resorcinol is employed as the donor subunit and pyridine, with quaternization to pyridinium, is employed as the acceptor subunit with acetylene bridges connecting the moieties. The synthesis involved site specific halogenation, acetylene coupling and deprotection of various acetylene protecting groups. Various side chains are under investigation to affect solubility since pi-pi stacking forces are known to vary depending on the medium.;Specific sequences of donor and acceptor components, bridged by acetylene, were synthesized ranging from two to six subunits long. The oligomers' properties were investigated using cyclic voltammetry and UV-vis spectroscopy. UV-vis spectroscopic data indicated that the HOMO-LUMO gap could be tuned in values ranging from 3.48 eV down to 2.34 eV. CV data illustrated that tuning of the HOMO-LUMO gap was best accomplished through contiguous arrangement of analogous subunits coupled to a contiguous arrangement of its complementary subunit. The benefit of assembling one subunit to two similar subunits was much greater than the energy gained by adding a third in a contiguous manner. The benefit of arranging four similar subunits in a contiguous manner is expected to be negligible.;Other possible uses for these arylene acetylene oligomers include foldamer formation and macrocycle synthesis. These seemed to be hampered by solubility issues and were therefore not investigated to the full extent. Preliminary work on varying the oligomers' side chains to improve solubility was accomplished.;Keywords. HOMO-LUMO gap, charge transfer, donor, acceptor, resorcinol, pyridine, pyridinium, Sonogashira coupling, Glaser coupling, foldamers, macrocycles. |
