Chemoselective Oxidation of 6,13-Bis(decylthio) Pentacene

Organic semiconductors present much potential for industrial use because of their possible low cost production, Pentacene and pentacene derivatives are promising candidates for organic semiconductor research since their ^-conjugated electronic structures possess small HOMO- LUMO gaps and high field effect mobility. Whereas there is much potential in devices made from pentacenes they do however undergo short lifetimes and poor processability due to photodegradation and poor solubility of pentacene. Previous research has shown that the pentacene lifetime and solubility can be enhanced by arylthio and alkylthio substituents placed on the pentacene backbone. For example 6,13-i?/s(decylthio)pentacene was one of the longest lived pentacene derivative known and it has been shown to exhibit excellent solubility in a variety of organic solvents. This research was performed to chemically control the chemoselective oxidation of the compound 6,13-5/s(decylthio)pentacene to produce a new pentacene derivative bearing either sulfoxide or sulfone functional groups thus forming a new pentacene derivative which may show greater photoxidative resistance. The products of this experiment were as follows: 6-(decylsulfinyl)-13-decylthio)pentacene and 6,13- £/5(decylsulfmyI)pentacene as characterized by NMR, UV, mass spectra, and electrochemical techniques. The half-life of 6-(decylsulfinyl)-13-decylthio)pentacene was longer (2900 min) compared to the starting material and 6,13-5/.v(decylsulfinyl)pentacene. However, both products had similar HOMO-LUMO gaps as determined by cyclic voltammetry. Using 0.5 equivalent of mCPBA gave the maximum yield (76%) of 6-(decylsulfmyl)-13-decylthio)pentacene. This product was a better semiconductor due to higher stability