Nanoring · Pi-Conjugated Porphyrin Nanorings
FP7 — People (Marie Curie Actions)
- Duration
- 2011-03-01 → 2012-02-29
- EU contribution
- €200,050
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
Pi-Conjugated Porphyrin Nanorings
Aim of this project was to get a deeper understanding of the p-delocalisation in a six-porphyrin nanoring. An informative method for the investigation of the p-delocalisation in extended p-system is to oxidise the molecule and to explor the resulting radical cation. The optical properties of radical cations can provide information about relative energy and symmetry of p-orbitals. Even more information can be aquired by electron paramagnetic resonance (EPR) measurements on radical species. The bandshape of continuous wave (CW)-EPR signals can provide information on the p-delocalisation by means of the hyperfine coupling of the unpaired electron with nuclei having a nuclear spin. In general, the bandwith of the EPR signal is decreasing by increasing p-system because the individual hyperfine couplings become smaller. Theories for the quantification of the p-delocalisation haven been developed for conjugated polymers and have already been used for the investigation of conjugated porphyrin systems. The work carried out in this project shows that the cyclic conjugated systems show an even more delocalised p-system than the linear oligomers. This could be observed in absorption as well as in CW-EPR measurements. For a more detailed and quantitative understanding of the CW-EPR results obtained so far, pulsed-EPR measurements on this samples and quantum chemical calculations were performed and the evaluation is in progress.
Data: CORDIS, © European Union
Project objective
This project will explore the synthesis and properties of fully pi-conjugated molecular nanorings with diameters of 3-5 nm. These covalent rings of molecular wire will be constructed from porphyrin and alkyne units, via non-covalent supramolecular assembly on wheel-shaped templates. Their highly delocalized electronic structures are expected to result in unusual optical and magnetic behavior. The photophysical and light-harvesting behavior of the nanorings are expected to mimic natural light-harvesting photosynthetic chlorophyll arrays. Physicists have long been fascinated by the persistent ring-currents and quantized magnetization observed in small loops of wire; it is important to discover whether similar effects can be observed in molecular nanorings. The synthesis of these wire rings could herald the development of molecular solenoids and induction coils with unusual optical and magnetic characteristics, leading to applications in nanoelectronics and nonlinear optics. This project will extend the researcher's experience of organic synthesis, large delocalized chromophores and near-infrared dyes, while introducing him to the latest developments in template-directed synthesis, ESR spectroscopy and ultra-fast photophysics through established collaborations involving the host research group.
Original text from CORDIS.
Participants
- THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD · OxfordCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union