In this project, funded by the Chemical Synthesis Program of the NSF Chemistry Division, Professor Shih-Yuan Liu and his students in the Department of Chemistry at Boston College synthesize boron-nitrogen(BN)-containing polycyclic aromatic hydrocarbons (PAHs). These molecules exhibit BN/CC (carbon-carbon) isosterism, that is, they replace two carbon atoms in an aromatic organic molecule with one boron and one nitrogen atom. While both the carbon-carbon and boron-nitrogen containing molecules have the same number of overall electrons, their properties are very different. BN-substituted PAHs may be useful in a number of applications including medicinal chemistry and devices that convert light to electricity. The Liu group is developing new synthetic methods to make BN-doped PAHs. Once prepared, the molecules are examined to see how they react differently than the related carbon-containing molecules. The broader impacts of this program include industrial internships for graduate students at local companies, science outreach to local high schools, collaboration with international researchers, hosting of an international conference, and continued involvement of undergraduates in chemical research via programs which promote participation of underrepresented groups.
Boron-Nitrogen/Carbon-Carbon (BN/CC) isosterism, i.e., the replacement of two carbon atoms with a boron and a nitrogen atom, has emerged as a novel strategy to expand the structural diversity of compounds relevant to materials science. Despite the recent advances in BN heterocycle chemistry, the systematic exploration of BN/CC isosteres of polycyclic aromatic hydrocarbons that have relevance to the development of organic materials has remained underexplored. This research seeks to develop a comprehensive structure/reactivity relationship in BN isosteres of simple acenes. Research plans include: 1) synthesis of the unreported parental BN isosteres of naphthalene and anthracene, 2) characterization of the optoelectronic properties and chemical reactivity of the synthesized materials, and 3) development of a predictive energetic model for BN/CC isosterism of polycyclic aromatic hydrocarbons. Moreover, this research serves as excellent training for graduate and undergraduate researchers in fundamental and applied chemical synthesis. Student participants in this project are exposed to a variety of experimental methods and techniques commonly applied in synthetic organic, inorganic, physical organic, and organometallic chemistry. The interdisciplinary and collaborative nature of the research in conjunction with the outreach activities seamlessly integrates with the education and career development of participating students.