Seminar
Tuesday, November 26, 2019 - 10:45am
Dr. Weley Chalifoux of the University of Nevada, Reno will present:
"Alkyne annulations for a facile synthesis of soluble polycyclic aromatics and graphene nanoribbons"
The development of new methodologies to afford novel polycyclic aromatic hydrocarbons (PAHs) is in high demand. This is because PAHs often possess interesting physical properties that can be harnessed in a variety of electronic and optical applications. Previously, the toolbox for PAH synthesis has been limited, along with the scope of compounds that could be made. This is in part due to the harsh oxidative methods often used to fuse benzene or other aromatic components together to arrive at larger conjugated p-systems. This chemistry often limits the functionality that can be incorporated into the PAH precursors and thus, often leading to insoluble materials that are difficult to characterize and utilize in various applications. Our group has sought to alleviate this problem but developing new methods that rely on high-energy alkyne-containing starting materials that can lead to highly soluble PAH products in a relatively mild and non-oxidative way. For example, we have recently developed a mild and efficient acid-catalyzed benzannulation of alkyne-containing synthetic precursors to afford soluble PAHs – including pyrenes, peropyrenes, and teropyrenes – as well as graphene nanoribbons.1-3 Using this methodology, we have also been able to expand the scope of PAHs that can be accessed to include very large compounds that are contorted, and even persistently chiral. Some of these new structures and their interesting physical properties will be presented.
References
- Yang, W.; Monteiro, J. H. S. K.; de Bettencourt-Dias, A.; Catalano, V. J.; Chalifoux, W. A. Angew. Chem. Int. Ed. 2016, 55, 10427.
- Yang, W.; Monteiro, J. H. S. K.; de Bettencourt-Dias, A.; Chalifoux, W. A. Can. J. Chem. 2017, 95, 341.
- Yang, W.; Lucotti, A.; Tommasini, M.; Chalifoux, W. A. J. Am. Chem. Soc. 2016, 138, 9137.