Syntheses, Characterizations, and Applications of Heli-viologens and Heli-twisted-acenes

点击翻译按钮获取中文摘要

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professors Edward L. Clennan and Caleb Hill of the Department of Chemistry at the University of Wyoming are developing hybrid polyaromatic hydrocarbons consisting of helical and linear domains of aromatic rings. These compounds have non-superimposable mirror images and are anticipated to emit circularly polarized light. The goal is to take advantage of these and other novel optoelectronic features of these molecules to construct circularly polarized light emitting diodes and other optoelectronic devices. These devices have significant potential in liquid-crystal display, stereoscopic three-dimensional displays, and information storage. This project also provides training to scientists at all educational levels in organic synthesis, photophysical characterization, computational chemistry, and optoelectronic device construction. The results will be widely disseminated and will be a critical feature of outreach efforts to all the community colleges in the State of Wyoming. More technically, the helicene backbone of these molecules provides a torque that simultaneously twists and locks the acene into either a right- or left-handed twist. Synthetic modifications are being made to extend the acene domain from one to five aromatic rings and phenyl- and cyano-substituents are being appended to the acene domain to propagate the twist down the full length of the acene. In addition, nitrogen atoms are being embedded in both the acene and helical domains to generate diaza-acene and heli-viologen analogues. Measurements of racemization barriers and photophysical and electrochemical studies of the resolved enantiomers are being used to determine how the structures and chiroptical properties change as a function of acene length and the composition of the helical and acene domains. Circularly polarized light emitting diode devices are being constructed with suitable heli-twisted-acene substrates to determine their current density-voltage-luminescence characteristics and their circularly polarized electroluminescence spectra.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.