The Development of Pi-Extension Strategies for the Conversion of Strained Benzenoid Macrocycles to Curved, PAH Segments of Carbon Nanotubes
Type of DegreePhD Dissertation
Chemistry and Biochemistry
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Chapter 1: The synthesis of smallest carbon nanoring, CPP and its potential precursor has been an area of interest for last decade. The challenge associated with synthesis of this highly strained nanoring is macrocyclization as well as aromatization. Two viable macrocyclization protocols have been delineated for the strained macrocycle synthesis and several intermediates as the potential precursor for CPP have been synthesized. Chapter 2: A series of bent p-terphenyl-containing macrocycles have been synthesized, then regioselectively brominated, arylated, and subsequently subjected to a Scholl-based cyclodehydrogenation reaction. Shortening the alkyloxy bridging unit of these macrocycles increases the bend in the p-terphenyl unit, as well as the strain energy (SE) of the central para-phenylene ring system. For the first time, incremental increases in SE of the macrocyclic structure of this class of benzenoid compounds has been investigated in the context of pi-extension to strained PAH systems using the Scholl reaction. The mechanistic pathway of these Scholl reaction has been investigated on the basis of both experimental and computational results. Chapter 3: A series of substituted (central arene unit), bent p-terphenyl containing macrocycles with different homologs have been synthesized from macrocyclic a-ketol and the alkynylated functionalized p-terphenyl containing macrocycle is amenable to IClmediated annulation reaction. The formation of chiral, twisted and highly strained phenanthrene unit containing macrocycles incorporate with Iodine as a functional group handle by alkyne benzannulation shows high prospective in terms of pi-extension on benzenoid macrocycles.