Density functional theory studies of Tetrathiafulvalene compounds and their redox isomers

Abstract

We performed density functional theory (DFT) calculations to analyze the geometrical and electronic properties of eight differently substituted tetrathiafulvalene (TTF) units (some with two Se heteroatoms) with 0, +1 and +2 charges. We demonstrate that, by minor deformations from planarity in the uncharged units disappear with electron removal. The release of the electrons as well as the stacking between units may be related to the delocalized π character of the HOMO, which is prevailing antibonding between C and S (Se) atoms. Energy considerations suggest the TTF precursor is less susceptible to oxidation compared to its different derivatives. Additionally, a noteworthy correlation is observed between the organic molecules under study and established square planar bis-dithiolene d8 metal complexes, which also exhibit a tendency towards redox isomerism.