Bistable Charge-Transfer Complex Formation in the TCNE-Biphenylene System Based on the Intermolecular HOMO-LUMO Interaction in the Neutral and Dianionic Redox States of TCNE

It has been demonstrated that the tetracyanoethylene dianion (TCNE2-) forms the charge-transfer complex with biphenylene (BP), caused by the favorable intermolecular HOMO–LUMO interaction. The TCNE–BP system involving the bistable chargetransfer (CT) complex formation modulated by redox reactions of TCNE is characterized by the geometrical properties and the trichromic change.