Periodic Reporting for period 1 - NanoRad (Phenylene-Bridged Grossly Warped Radical Nanographenes)
Période du rapport: 2020-09-01 au 2022-08-31
Carbon-based materials play a significant role in the fields of photonics, spintronics, electronics, quantum information technology, etc. In particular, polyaromatic hydrocarbons (PAHs) with open-shell characteristics are very attractive due to their unique physicochemical properties, although the inherent instability rising from their incompletely satised valency delays further development. In the recent years, there have been successes in designing open-shell materials, showing that stable radicals are accessible through rational design and appropriate chemical construction. Accordingly, the incorporation of odd-numbered rings in PAHs tunes molecular strain and topology. Seven-membered ring such as cycloheptatriene (CHT) molecular nanocarbons are particularly promising, but functional examples remain relatively limited. In this project, we report a hexacationic (HC) PAH incorporated with six dibenzosuberenyl (DBS) moiety in hexaphenylbenzene (HPB) and its redox behaviours. This proposal fills this gap in our knowledge by synthesising odd-numbered ring polyaromatic hydrocarbons and characterising their properties throughout several electronic states, including states with potential radical, diradical and polyradical character. The project was based in Durham to make use of the extensive hands-on experience in making and investigating of similar compounds with in Prof. Paul McGonigal (PRM) group.
At the beginning of the project a critical overview of existing subject literature and unpublished results was made with cooperation of the PRM research group. This lead to slight modification of the proposed structures in light of recent progress by other group members. The target molecules were then chosen and synthetic routes were theoretically established and modified with project progress to overreach any difficulties discovered along the way. Some initial theoretical calculations was also done to visualize the geometry of targets and their feasibility in terms of practical considerations. Then highly charged polyaromatic molecules were made, separated and purified and their structure characterized by means of state-of-the-art methods (Nuclear Magnetic Resonance and Ultraviolet-visible spectroscopy, mass spectrometry). While initial experiments showed that the designed highly charged PAH systems highly unstable degrade to starting materials in substantial amount time, although with aid of moisture or oxygen free conditions (thanks to Durham and York University for providing me to use the Glovebox) there are some publishable data were collected. The project is, however, continued by current group members and results are expected to be published in the coming months in reputed chemistry journal. Initial results were shown on Durham university departmental seminars for undergraduate and postgraduate student’s part of presentations aimed to visualize and highlight the importance of scientific research. These talks showcased not only the created data, but promoted scientific and academic careers in chemistry and natural sciences in general.
During the course of work two major and one minor research projects related to open-shell PAH and shape shifting molecules were planned and executed. This implied initial synthesis optimization, up-scaling and characterization of 30+ non-literature compounds. Obtained results give new insight into the structure-property relationships in such molecular architectures and the established synthetic methodologies can be used for the development of similar compounds in the future. This research contributes toward creating and understanding the phenomena observed in functional materials in the field of molecular electronics. On the other hand, multiple outreach activities focused on showcasing not only the results, but the scientific process and career development can not only communicate the importance of chemical research, but also inspire future generations to pursue interest in natural sciences in general. Showing the MSCA fellows path, from early interests to the current position and achievements, hopefully will encourage some to take on science studies and become a scholar and/or a scientist in the future.