Synthesis and properties of tetracyanoquinodimethane derivatives

Two new aza-acenequinone derivatives 4 and 5 were prepared by cyclocondensation of diamines 2 and 3 with bis(triisopropylsilyl)-dialkynyl-l,2-dione 1. Further reactions of compounds 4 and 5 with malononitrile using the Lehnert reagent afforded corresponding tetracyanoquinodimethane (TCNQ) derivatives 6 and 7. Compounds 4, 6 and 7 were characterized by single crystal X-ray diffraction techniques. Compounds 6 and 7 were studied electrochemically and photochemically. Density functional theory (DFT) calculations on compounds 6 and 7 indicate that both compounds have the potential to be candidates for organic semiconductor materials.