Synthesis of pyrene, phenanthrene and pyrimidine device candidates for use in molecular electronics

Abstract

Several fully conjugated organic molecules incorporating 2,7-difunctionalized pyrenes, 2,7-difunctionalized phenanthrenes, 2,5-difunctionalized pyrimidines and 5-functionalized pyrimidines have been synthesized. These molecules all feature a protected thiophenol terminus which under suitable deprotection conditions liberates the free thiol permitting for their self-assembly in the presence of a clean gold surface. This thesis features an improved synthesis of 2,7-dibromopyrene via an optimized hydrogenation/nitration/separation procedure. In addition, a novel route to 2,7-dibromophenanthrene is presented which begins with an easy bromination of diphenic acid and culminates in a hydrazine-induced cyclization of the corresponding 2,2'-dicarbaldehyde to give the desired product dibromophenanthrene in high yield. The completed device syntheses feature various palladium-catalyzed coupling methods to afford the appropriate arylene-ethynlene systems and these will be presented