Fused-Ring Heterocyclic Aromatic Compounds
Abstract
Fused-ring heterocyclic aromatic compounds represent an intriguing family of organic π-systems for fundamental chemistry and practical properties. The term “hetero-” indicates the presence of heteroatoms in the aromatic backbone. In the past two decades, the requirement for precisely functionalized nanographenes sparked interest in nanographenes with heteroatoms. Various heteroatoms, including nitrogen, boron, oxygen, sulfur, etc., were incorporated into polycyclic aromatic compounds to manipulate the chemical and electronic properties of nanographene-like compounds.
This dissertation describes my work on the synthesis and investigation of fused-ring heterocyclic aromatic compounds containing nitrogen and/or boron atoms.
This dissertation starts with a brief introduction to the field of aromatic compounds with heteroatoms. First, the background of this topic and underlying motivations are summarized. Then selected literature examples of π-systems containing B—N bonds and azahelicenes are presented. The unexplored areas and challenges related to this field are identified. Finally, the choice of topics as the main focuses of this dissertation is discussed.
Chapter II describes the design and synthesis of a B←N coordination-containing molecule with an extended conjugation composed of 23 fused rings. The synthesis towards this novel molecule and the impact of incorporating B←N bonds are the focuses of this chapter. Chapter III presents my work on the manipulation of molecular bandgaps based on the installation of various aryl groups on the B←N bond-containing compounds, and the impact on structure and optical properties.
In Chapter IV, motivations and efforts towards the synthesis of centripetal azahelicenes are discussed. A combination of synthetic strategies and theoretical simulations is illustrated along with iterative modification on the reaction conditions to complete the synthetic route. The preliminary observations of metal binding are discussed as well.
Chapter V describes the development of undergraduate teaching labs for the broader impact of the research described above. Well-known “Nobel prize-winning reactions”, including Suzuki coupling and ring closing metathesis, are optimized, and implemented in undergraduate organic laboratory course.
Finally, Chapter VI concludes the entire dissertation by giving an overview of the results presented in the previous chapters, followed by perspectives of research that would strengthen the insight into this field.
Citation
Cao, Yirui (2022). Fused-Ring Heterocyclic Aromatic Compounds. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /197217.