Size-independent energy transfer in biomimetic nanoring complexes

Journal article

Supramolecular antenna-ring complexes are of great interest due to their presence in natural light-harvesting complexes. While such systems are known to provide benefits through robust and efficient energy funneling, the relation-ship between molecular structure, strain (governed by nuclear co-ordinates and motion) and energy dynamics (arising from electronic behavior) is highly complex. We present a synthetic antenna-nanoring system based on a series of conjugated porphyrin chromophores ideally suited to explore such effects. By systematically varying the size of the acceptor nanoring, we reveal the interplay between antenna-nanoring binding, local strain and energy dynamics on the picosecond timescale. Binding of the antenna unit creates a local strain in the nanoring, and this strain was measured as a function of the size of the nanoring, by UV-vis-NIR titration, providing information on the conformational flexibility of the system. Strikingly, the energy transfer rate is independent of nanoring size, indicating the existence of strain-localized acceptor states, spread over about six porphyrin units, arising from the non-covalent antenna-nanoring association.

Authors: Parkinson, P; Kamonsutthipaijit, N; Anderson, H; Herz, L

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: ACS Nano
• Volume: 10
• Issue: 6
• Pages: 5933–5940
• Publication date: 2016-05-13
• Acceptance date: 2016-05-13
• DOI: 10.1021/acsnano.6b01265
• EISSN: 1936-086X
• ISSN: 1936-0851
• Language: English
• Keywords: biomimetics; ultrafast spectroscopy; energy transfer; porphyrin nanoring