Homologs and Substructures of

Princeton University, Princeton NJ

Investigators

Abstract

The focus of this research is the synthesis of a number of substructures or fragment of an expanded version of "cubic graphite." These fragments, with formulae ranging from C168H116 to C672H432, contain large cavities and channels. The fundamental repeating units are hexaphenylbenzene molecules, linked together at the para positions of the phenyl groups. Palladium catalyzed coupling reactions (Suzuki couplings) will be carried out using simple derivatives of hexaphenylbenzene. Approximately ten halogenated or organoboron-containing derivatives of hexaphenylbenzene will be prepared as building blocks, and from this library, a variety of substructures will be made. The cyclodehydrogenation of these substructures will be attempted, perhaps to yield yield homologs of cubic graphite where benzene rings have been replaced by hexabenzocoronenes. As many of the target molecules as possible will be characterized by single crystal X-ray diffraction methods. With this renewal award, the Organic and Macromolecular Chemistry Program is supporting the research of Dr. Robert A. Pascal of the Department of Chemistry at Princeton University. Professor Pascal will focus his work on the synthesis of large polyphenyl aromatic compounds. The compounds are based on the structure of so-called "cubic graphite," a hypothetical allotrope of carbon composed of benzene rings interconnected in three dimensions in a cubic space group. The compounds could have host-guest applications or use in separation technology. In terms of broader impacts, the Pascal group has proven to be an excellent venue for the training of both undergraduate and graduate students.