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Rawson, Jeff

Chemistry

2009

MS

Highly conjugated and crystalline organic compounds are relative newcomers to the field of semiconducting materials. Their properties are best understood through molecular orbital theory, considering both the energy levels of the single molecules and the spatial relationships of the molecules within the lattice. The functional effectiveness of these materials therefore depends upon their solid-state packing, in addition to more traditionally considered properties such as HOMO-LUMO gap, presenting a new challenge in organic synthesis. Pentacene and its relatives have emerged as useful compounds for these applications, and so the synthesis of substituted linear acenes is of great current interest. Prominent strategies for this include Friedel-Crafts acylations, Knoevenagel condensations, and Diels-Alder cycloadditions. The latter of these, in the form of the trapping of an o-quinodimethane by benzoquinone, has been applied to the synthesis of a highly arene-substituted derivative of pentacene.