Synthesis of 1,6/7-(NO2)2-Perylenediimide and 1,6/7-(NH2)2-Perylenediimide as Regioisomerically Pure Materials

The use of perylenediimide (PDI) building blocks in materials for organic electronic is of considerable interest. This popular n-type organic semiconductor is tuned by introducing peripheral groups in their ortho and bay positions. Such modifications radically alter their optoelectronic properties. In this article, we describe an efficient method to afford regioisomerically pure 1,6/7-(NO2)(2)- and (NH2)(2)-PDIs employing two key steps: the selective crystallization of 1,6-(NO2)(2)-perylene-3,4,9,10-tetracarboxy tetrabutylester and the nitration of regiopure 1,7-Br-2-PDI with silver nitrite. The optoelectronic properties of the resulting regioisomerically pure dinitro, diamino-PDIs and bisazacoronenediimides (BACDs) are reported and demonstrate the need to separate both regioisomers of such n-type organic semiconductors for their inclusion in advanced optoelectronic devices. For the first time, the two regioisomers of the same PDI starting material are available on the multigram scale, which will stimulate the exploration of regioisomerism/properties relationship for this family of dyes.