Professor Mark Chen of Lehigh University

Professor Mark Chen of Lehigh University will present 

"Practical Access to Open-Shell Organic Electronic Materials: Concise Synthesis of bis(Phenalenyl) Compounds"

on March 28, 2018 at 4:10 PM in Neville Hall, Room 3.

Abstract:

Organic electronic materials are an appealing complement to silicon-based technologies since they allow for devices to be energy-efficient, lightweight, and solution-processable.  State-of-the-art organic materials are capable of achieving high charge transport efficiency, but they often require lengthy syntheses or meticulous processing techniques to do so.  A strategy that may circumvent these challenges is through the design of open-shell organic compounds that exhibit electron density in non-bonding molecular orbitals (NBMOs).  The presence of electron density in NBMOs makes these compounds fundamentally different from conventional organic materials, and has powerful implication on materials properties.  Towards obtaining such compounds, our lab has focused on the synthesis of bis(phenalenyl) compounds; however, syntheses of these molecules were complicated and disallowed simple structural diversification.  In this seminar, I will describe our novel convergent coupling strategy that we used to generate bis(phenalenyl) Ph2-s-IDPL in fewer steps (8 versus 11) than previous reports.  We now have rapid access to bis(phenalenyl) biradicaloids and the ability to develop these compounds into solution-processable materials via side-chain substitution.  Additionally, the generality of our strategy has also permitted elucidation of structure-property relationships amongst bis(phenalenyl) compounds through the synthesis of new derivatives substituted with N- and O- functional groups.  Significantly, we have discovered a new molecular radical that is not only remarkably air stable, but also displays intermolecular covalency in two dimensions in the solid-state.  Altogether these studies establish that biradicaloids and other open-shell compounds can be obtained via short and scalable syntheses, which represent our first steps toward developing functional, solution-processable organic electronic materials.