Syntheses and Structures of Functionalized [n]Cycloparaphenylenes and Related Carbon Nanohoops

West Virginia University Research Corporation, Morgantown WV

Investigators

Abstract

With this award, the Chemical Synthesis program is supporting fundamental research of Professor Kung K. Wang at West Virginia University. Professor Wang will use organic reactions for the construction of a group of organic molecules called cycloparaphenylenes (CPPs) and related carbon nanohoops. The structures of CPPs represent the shortest segments of the repeating hoop-like structures of armchair carbon nanotubes. The intense current interest in CPPs is due in part to the possibility of using these hoop-like molecules as templates for growing armchair single-walled carbon nanotubes. This synthetic approach offers a potential advantage over existing empirical methods in its potential to produce carbon nanotubes of a uniform diameter and structural arrangement, two factors of critical importance for applications in a variety of nanotechnology fields, including electronics, energy, and nanophotonic devices. Professor Wang will integrate the research and educational components of this project by training graduate students in the design of new synthetic strategies and by providing them with the opportunities to acquire high-level laboratory skills. The development of well-trained synthetic organic chemists during the course of their involvements in this research project will add to the human resources for chemical and pharmaceutical industries. In addition, undergraduate students who are selected to participate in the West Virginia University NSF-Research Experiences for Undergraduates program and in the WVU Summer Undergraduate Research Experience program will be invited to participate in this research project. Many of these undergraduate students are from populations that are underrepresented in higher education or are first generation college students. Providing the opportunity to involve these students in a research environment during their college years will encourage them pursue careers in STEM. In this research, new methods will be developed for the synthesis of CPPs. Specifically, the use of the Diels-Alder reactions between 1,4-bis(haloaryl)-1,3-dienes and dienophiles are expected to produce precursors of functionalized CPPs and related carbon nanohoops with diverse structural features. The high stereoselectivity of the Diels-Alder reaction will place the two haloaryl substituents on the same side of the resulting cyclohexenyl structure, which is essential for the success of the subsequent homo- or cross-coupling step to form macrocyclic CPP precursors. Oxidative aromatization of the CPP precursors, either with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or other oxidizing agents, is expected to lead to the corresponding CPPs.