Alkynes As High-Energy Carbon-Rich Functionality For Synthesis Of Polyaromatics

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The Chemical Synthesis Program of the Chemistry Division supports the project by Professor Igor Alabugin. Professor Alabugin is a faculty member in the Department of Chemistry and Biochemistry at the Florida State University. He is developing new ways to prepare precisely shaped and functionalized structures of graphene (a flat sheet containing only carbon atom). The goal of the project is to provide the missing synthetic tools needed to construct new molecules with interesting optoelectronic properties. To do this, the high energy and unique, tunable reactivity of carbon-rich precursors for will be used to develop strategies that build the shaped graphene structures from smaller pieces. Key to this effort are cascade reactions that form multiple bonds and unite multiple cyclic unites in a single operation. By splicing together the smaller structure in a controlled fashion, the shape of the larger object can be controlled more precisely. The results will be disseminated in the PI's publications and outreach activities, including participation in public lectures, scientific symposia, giving talks at industrial, undergraduate, and graduate institutions, as well as recording educational videos at the GEOSET studio at Florida State University.The intellectual merit of this research is in leveraging electronic factors that control alkyne cyclizations for the development of efficient routes to conjugated carbon nanostructures with predesigned shape and functionality. In this approach, oilgoalkyne chains of varying sizes, equipped with different substituents, are built in a modular fashion and then "zipped" up via a cascade of fast and efficient radical cyclizations. Selectivity of initial radical attack on the multifunctional substrates is controlled by the presence of a "traceless directing group" that is removed in the course of the one-pot process. By the choice of the relay functional groups and the terminal pi-system, the final step of the cascade can be controlled, so that either a five- or a six-membered rings is formed. In particular, this work is developing a suite of peri-cyclizations based on a combination of traceless directing groups, cyclization at the "zigzag edge" of acene subunits, and fragmentations. This approach opens access to unusual aromatics and conjugated persistent radicals. The broader impact include the applications of the new carbon-rich conjugated molecules as components in the design of optoelectronic materials, energy storage devices, sensors, transistors, solar cells, polymer composites etc. The educational plan includes providing advanced research training to students of different backgrounds, including students from the Florida historically black universities. The scholarly findings will be presented in scientific journals, conferences and incorporated in the mini-courses on stereoelectronic effects.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.