Comparison of Isomeric Aryldibenzopyrylium Salts as Highly Conjugated Planar Dyes

Abstract

Planar conjugated organic compounds can be incorporated into a variety of applications due to their unique optical properties. One such class of these compounds contains the pyryliumunit, which is capable of reversible pH-driven conformational changes. This project focuses on the synthesis of novel aryldibenzopyryliumdyes with optimized pH sensitivity and the ability to reversibly alter their conformations, thus producing variable optical properties. We set out to synthesize a new class of isomeric compounds, which incorporate a doubly benzannulated pyryliumunit in each structure, to determine how the molecular shape impacted the optical properties. These properties can be studied using UV-vis and fluorescence emission detection techniques. These analyses allow for a deeper understanding of the electronic properties of these molecules and how both the conjugation path length and structural motifs alter these properties. This work has not only yielded an entirely new class of pH-sensitive fluorescent molecules but has contributed to the constantly evolving understanding of electronic activity in conjugated pathways.