Cottrell Scholar Awards - 2017
Conjugated Ladder Molecules and Polymers Containing Antiaromaticity Enabled by Efficient Catalytic Annulation
In chemistry, the word “aromaticity” has very little to do with odor, although in 1855, when the term was coined, a pioneering chemist used it to describe petroleum-based benzene compounds, many of which have distinct aromas. These days, however, aromaticity describes a large class of ring-shaped molecules with the electrons moving about in the molecule’s pi system, an orbital realm of very specific energy levels. Because of this form of electron delocalization, aromatic molecules tend to be very stable, slow to react with other compounds, and importantly have interesting optical and electronic properties.
Yan Xia, chemistry, Stanford University, has received a Cottrell Scholar Award from Research Corporation for Science Advancement to counter the stability inherent in aromaticity by introducing “antiaromatic” motifs into the mix. As the term might imply, antiaromatic compounds are very unstable and highly reactive.
While aromatic molecules and polymers are extremely important and well explored for the development of organic optical and electronic materials, antiaromatic non-benzenoid structures are still much less understood in terms of their electronic structures, chemical reactivity and solid-state properties, largely due to their challenging synthesis and limited stability.
Why would Xia want to combine molecules with opposite qualities?
“Juxtaposition of the two motifs is intellectually stimulating and creates an intriguing family of molecular ladder structures,” he says, noting the end products might lead to new carbon-rich (and therefore relatively inexpensive) materials for electronics and many other applications. Besides, he adds, “This project manifests how the development of new chemistry drives the discovery of novel materials.” Fundamental scientific research, when all is said and done, is about pushing the limits of human knowledge.
There is also an education component to the Cottrell Scholar Award. Xia will use some of the funding to promote a curiosity- and self-driven, research-like atmosphere for students to excel in organic chemistry and acquire skills to solve complex problems beyond organic chemistry in their future careers. His educational plan will focus on 1) constructing organic concepts inventory in an interactive format and under a research-mimicking context; 2) encouraging peer-led team learning to stimulate talking and collaboration between students; 3) actively involving TAs (graduate students) in active learning―training TAs to implement effective pedagogical strategies and cultivate future science educators who promote active learning.