Tunable Aromaticity and Biradical Character in Tetrathiafulvalene and Tetraselenafulvalene Derivatives

Tetrathiafulvalene (TTF), Tetraselenafulvalene (TSF), and their derivatives have become well-known for their desirable electronic, photochemical, and redox properties, with applications in organic conductors, molecular machines, and charge-transfer materials. Furthermore, the TTF derivative TTF-2,3,6,7-tetrathiolate has recently been demonstrated to exhibit tunable biradical character in dimetallic complexes, expanding its utility to areas including molecular qubits and spintronics. To complement these recent experimental advances, we elucidate the electronic structures of a series of TTF and TSF derivatives, investigating the interplay between biradical character, aromaticity, and redox chemistry, and elucidating how they may be modulated.