Synthetic Strategies Toward Boracycles Featuring Uncommon Bonds

Professor Robert J. Gilliard of the Massachusetts Institute of Technology will develop a new generation of boron-containing molecules that may serve as the foundation for future advanced materials and technologies. Boron is a unique element that can dramatically alter how molecules absorb, store, transfer, and emit energy, making it especially valuable for designing materials with customized electronic, optical, and magnetic properties. Professor Gilliard and his team will create and study previously unexplored classes of boron-based ring-shaped molecules, including compounds with unusual electronic structures that challenge traditional ideas about chemical bonding and reactivity. By uncovering how the arrangement of atoms within these molecules influences their behavior, they will establish fundamental design rules that scientists can use to create improved materials for applications such as energy-efficient lighting and displays, solar energy conversion, microelectronics, sensors, semiconductors, and quantum information storage technologies. In addition to expanding fundamental scientific knowledge, this research strengthens U.S. competitiveness in a rapidly growing area of chemistry and provides valuable educational training opportunities for undergraduate and graduate students who will contribute to the nation's future scientific and technological workforce. A key focus of this project is the synthesis and characterization of boracycles, ring-shaped molecules that incorporate boron atoms into conjugated π-electron systems. Professor Gilliard’s team will investigate compounds containing boron in unusual redox states and electronic configurations, including radical, biradical, and polyradical species, as well as boron–nitrogen and boron–phosphorus functionalized heterocycles. Two complementary research thrusts will be pursued: (1) the development of π-extended, multiply boron-doped polycyclic aromatic hydrocarbons and related borole-containing frameworks to probe magnetic, optical, and redox properties, and (2) the creation of new boron-containing heterocycles through the use of advanced main-group element synthons, frustrated Lewis pairs, and diazoborane-type precursors. Detailed structural characterization, mechanistic studies, electrochemical measurements, spectroscopic investigations, and computational analyses will be used to establish fundamental structure–property relationships. These studies will provide a molecular-level understanding of how ring size, boron content, heteroatom incorporation, and electronic state influence chemical reactivity, spin distribution, and photophysical behavior, thereby enabling the rational design of next-generation functional materials while providing advanced training environments for students in synthetic inorganic and organic chemistry. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.