Chromophores in Molecular Nanorings: When Is a Ring a Ring?

Parkinson, Patrick; Kondratuk, Dmitry V.; Menelaou, Christopher; Gong, Juliane Q.; Anderson, Harry L.; Herz, Laura M.

Abstract

The topology of a conjugated molecule plays a significant role in controlling both the electronic properties and the conformational manifold that the molecule may explore. Fully π-conjugated molecular nanorings are of particular interest, as their lowest electronic transition may be strongly suppressed as a result of symmetry constraints. In contrast, the simple Kasha model predicts an enhancement in the radiative rate for corresponding linear oligomers. Here we investigate such effects in linear and cyclic conjugated molecules containing between 6 and 42 butadiyne-linked porphyrin units (corresponding to 600 C–C bonds) as pure monodisperse oligomers. We demonstrate that as the diameter of the nanorings increases beyond ∼10 nm, its electronic properties tend toward those of a similarly sized linear molecule as a result of excitation localization on a subsegment of the ring. However, significant differences persist in the nature of the emitting dipole polarization even beyond this limit, arising from variations in molecular curvature and conformation.

Citation

Parkinson, P., Kondratuk, D. V., Menelaou, C., Gong, J. Q., Anderson, H. L., & Herz, L. M. (2014). Chromophores in Molecular Nanorings: When Is a Ring a Ring?. Journal of Physical Chemistry Letters, 5(24), 4356-4361. https://doi.org/10.1021/jz5022153

• Journal Article Type: Article
• Acceptance Date: Nov 20, 2014
• Online Publication Date: Nov 20, 2014
• Publication Date: Dec 18, 2014
• Deposit Date: Mar 10, 2017
• Publicly Available Date: Jun 6, 2018
• Journal: Journal of Physical Chemistry Letters
• Electronic ISSN: 1948-7185
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 5
• Issue: 24
• Pages: 4356-4361
• DOI: https://doi.org/10.1021/jz5022153
• Public URL: https://durham-repository.worktribe.com/output/1383475