Electron Delocalization in Linear Heterotrimetallic Compounds

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The Chemical Synthesis Program within the Chemistry Division of the National Science Foundation is funding a research project under the supervision of Professor John Berry of the University of Wisconsin-Madison. The project explores new approaches to electronics used in electrical circuits and computers. Specifically, the project evaluates the electrical conductivity of molecules containing chains of metal atoms. New metal-containing compounds are being prepared that have a linear, wire-like structure. These molecular wires are only one metal atom thick, making them the thinnest circuit connection possible. In order to test these molecular wires, three design aspects are being tested. One aim is examining new molecules to attach the metal chains to electrodes. The linker group, a sort of a chemical solder, must attach strongly to both the wire and to the electrode. A second aim focuses on modifying the chemical sheathing that surrounds the wire, which affects the energies (voltage) of the electrons within the wire. The third aim is exploring diverse metals that comprise the wire itself. Of interest is the influence of particular metals that may change the conductivity or resistance of the wire. This research provides students with hands-on experience. A number of artistic and scientific outreach efforts are underway to encourage curiosity and public awareness of this area of science. Professor Berry helps with the Wisconsin Crystal Growing Competition, a program intended to recruit young students into STEM-related activities. Similarly, Professor Berry and his students are participating in the Pre-College Enrichment Opportunity Program for Learning Excellence, which aims to diversify the chemistry workforce. The Chemical Synthesis Program within the Chemistry Division of the National Science Foundation funds the research project under the supervision of Professor John Berry of the University of Wisconsin-Madison. This project involve chemical discoveries, but the broader scientific implications reach fields beyond chemistry, including physics, electrical engineering, magnetism, and computer science. The project examines the electrical properties of compounds containing one-dimensional metal atom chains. The most synthetically versatile class of such compounds are the extended metal atom chains (EMACs) and heterometallic extended metal atom chains (HEMACs), particularly those supported by 2,2ʹ-dipyridylamide (dpa) and related ligands. The researchers probe and tune electron delocalization. The broader goal is to assess the utility of these wire-like compounds as nanoscale components in molecular circuitry. The team collaborates with physical chemistry groups to assess electron delocalization in new HEMACs. A major goal is to assess the hypothesis that electron transport through HEMACs is gated by intramolecular, low-energy metal-metal stretching vibrations. To support these collaborative efforts, specific synthetic experiments are designed to assess fundamental properties related to single-molecule conductance: anchor group effects, modulation of frontier orbital energies for electron/hole transport, and systematic tuning of the metal atoms within the chains for molecular rectification.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.