Electrically conductive nanowires are of interest for applications that range from energy production & storage to nanoscale electronics that can interface with living cells. This project focuses on developing nanowires that are prepared by connecting together metal ions, such as iron and cobalt, with specially designed organic linkers (ligands). The Lipke group focuses specifically on preparing ligands that have electron-accepting properties that are well-matched to those of the metal ions, thereby allowing electrons to flow readily across the metal and organic components. Additionally, we are working on tuning the ligands to solubilize the resulting nanowires and control their interactions with other molecules, which is important for incorporating these conductive structures into hybrid materials for applications such as wearable electronics.
This project builds on our recent discovery of interesting electronic properties in an assembly of cobalt with ligands derived from organic compounds known as viologens.1 Viologens are well-known organic molecules that can readily accept multiple electrons, facilitating their use in many electronic applications. For example, they are studied as organic semiconductors and as color-changing materials that utilize the rich blue/purple colors they display in response to the addition of electrons (hence the name viologen). Previous combinations of metals and viologens have not shown synergistic properties, while our system shows unique and useful features, such as an expanded range of color changes, that result from electrons being shared evenly by the metal and organic components. We are now working to connect such molecules together to make conductive nanowires that will have potential applications in electronics as well as for the interconversion of electrical and chemical energy.
This project rests at the junction of theory and experimentation. We use concepts in inorganic and physical chemistry to design systems that can then be studied in the lab. Students involved in this project will gain hands-on lab experience while also learning about the theory underpinning these experiments. This project will involve the synthesis of organic, inorganic, and solid-state materials, with students learning general synthetic methods and more specialized air- and moisture-free experimental techniques. Students will also learn to acquire and analyze data for characterizing molecules and materials by a variety of methods, including nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HRMS), UV-vis-NIR absorbance spectroscopy (UV-Vis-NIR), electrochemistry, and molecular structural analysis by single crystal X-ray diffraction. Computational techniques will be used to supplement experimental results. If possible, this work will be included in future publications in peer-reviewed journals (note that our previous accomplishments1 on this project were led by an undergraduate).
(1) Mansoor, I. F.; Wozniak, D. I.; Wu, Y.; Lipke, M. C. "A Delocalized Cobaltoviologen with Seven Reversibly Accessible Redox States and Highly Tunable Electrochromic Behaviour" Chem. Commun. 2020, 56, 13864–13867
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