Design of oligozulene-based organometallics for probing new paradigms in charge delocalization, transport, and storage at the nanoscopic scale

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Professor Mikhail V. Barybin of the University of Kansas is supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry to design, synthesize and characterize azulene-based molecules (combination of 5- and 7-membered carbon rings) that are capable of electric charge transport. The goal is to develop molecules with improved functionality relevant to organic electronic, computer, optoelectronic, and energy storage (battery) applications. A major emphasis is placed on targeting molecules comprised of multiple azulenic units to enable efficient molecular charge transport and rectification. Such molecules offer the potential of creating ultra-small molecular components for electronic devices that function with minimal power consumption. This project improves our understanding of charge transport through single molecules. It also affords a platform for the development of functional materials with surfaces modified by self-assembled monolayers. The award supports training of graduate and undergraduate students in an interdisciplinary research environment. A partnership with Clayton State University (a primarily undergraduate institution with a predominantly African American student base) attracts students from underrepresented minority and involves them in the project. The PI brings a first-hand perspective on challenges faced by science students and faculty affected by a chronic illness in pursuit of their educational and professional aspirations. By showcasing the scientific and human resource development outcomes of the project at professional conferences and less formal community-centered venues, the PI's advocacy highlights societal benefits of enhancing the diversity of university campuses through inclusion of persons with chronic illnesses.In this project, synthetic, computational, electrochemical, spectroscopic and surface chemistry techniques are synergistically employed to develop nonbenzenoid, aromatic azulene-based platform that exhibit redox, electronic, and optoelectronic properties, typically inaccessible through the use of benzenoid aromatics. The molecules are designed to have anchoring groups, such as mercapto and isocyano, capable of self assembly on surfaces without affecting the azulenic scaffold's aromaticity. DFT calculations are used to inform the design of the azulenic molecules. The products are characterized and tested as potential components in nanoelectronic devices. The specific aims are: (1) to design asymmetrically anchored organic linkers that feature key structural rigidity and spatial separation of the bridge's frontier molecular orbitals; (2) to evaluate the conductivity/rectification profiles and the electron transfer dynamics in azulene self-assembled monolayers; and (3) to construct molecular electron reservoirs composed of azulene-based organometallic nanocomplexes with at least 12-electron reversible organic redox capacity, and to examine their charge delocalization potential, including organic intervalence coupling.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.