Diareno Fusion To Modify Antiaromaticity And Diradical Character in s-Indacenes and Dicyclopenta[b,g]naphthalenes

Abstract

Antiaromatic and diradical molecules are emerging both as novel synthetic targets for fundamental studies and as promising materials for next generation organic electronics. In order to properly apply these types of molecules it is important to understand how their properties may be tuned in order to optimize them for device applications. The diradical literature especially suffers from a lack of thorough structure-activity relationship studies. In this dissertation I discuss strategies to tune diradical character and the associated singlet triplet energy gap as well as heteroatom effects in heterocycle-fused s-indacenes.Chapter I is an account of the research the Haley lab has reported in the last five years on tuning strong antiaromaticity and diradical character in a class of indenofluorene-derived molecules. Chapter II describes the synthesis of fluoreno[3,2-b]fluorene, a novel quinoidal molecule. Chapter III uses synthetic strategies from Chapter II to fuse benzothiophenes to the Fluorenofluorene structure described in Chapter II which unlocks diradical character in this structure. Chapter IV is an exploration of late-stage modification of benzothiophene-fused indenofluorene and fluorenofluorene derivatives to control their electronics properties. Chapter V revisits the Fluorenofluorene structure from Chapter II and explores how dibenzofusion to this structure changes the diradical character of the core naphthoquinoidal unit. Finally, Chapter VI explores the heteroatom effects of changing the sulfur atom in the above described benzothiophene fused systems to an oxygen atom through benzofuran fusion. This dissertation contains previously published and unpublished co-authored material.