Organic Chemistry Seminar: Planar and Twisted π-Conjugated Materials

Abstract:

Planarity plays a crucial role in determining the electronic and optical properties of π-conjugated backbones. Here I will discuss two examples of non-planar and planar systems: twisted acenes and planar furan-based macrocycles.

In the first part, I will demonstrate how twisting affects the electronic, optical and chiroptical properties of acenes. We have introduced a series of twisted acenes, having an anthracene backbone diagonally tethered by an n-alkyl bridge, which induces different degrees of twisting.  This helically-locked system allows us to systematically monitor the effect of twisting on electronic and optical properties of anthracene. The effect of twisting on chiroptical properties, charge delocalization and π-conjugation will also be demonstrated.  

In the second part, I will discuss bifuranimide as a stable furan containing analog, which resulted in the introduction of the first stable polyfurans and macrocyclic furans. These π-conjugated macrocycles were found to be completely planar, in contrast with thiophene macrocycles which are highly-twisted.  The prospects of macrocyclic oligofurans as π-conjugated analogs of crown-ethers and synthons for cycloarenes by multiple Diels–Alder cycloadditions will be discussed.

Event Organizer: Dr. Roman Dobrovetsky