The Electronic Nature and Reactivity of the Larger Acenes

The astounding electronic performance of acenes such as tetracene and pentacene (and their heteroaromatic counterparts) stands to revolutionize the field of organic electronics, promising novel consumer electronics for power generation and information display in lightweight, flexible form factors. These results have rekindled interest in acenes larger than pentacene, to determine how electronic properties are further altered by extending conjugation. This research has had to encompass many fundamental studies, as even the simple nature of aromaticity in larger acenes is still a controversial topic. Further, the reactivity of acenes toward oligomerization or oxidation becomes significant in larger acenes, while the diminishing solubility complicates isolation and characterization. This article surveys recent works describing the nature of aromaticity and reactivity in larger acenes, methods used to prepare parent acenes larger than pentacene, and functionalization approaches to soluble, reasonably stable large acenes.