Structures, Multicenter π-Bonding, and Spin Equilibria in the Mixed-Valence Trimers of Tetramethyltetrathiafulvalene Cation-Radicals

Pancake bonding between partially oxidized tetramethyltetrathiafulvalene (TMTTF) moieties was examined via X-ray structural, spectral, and magnetic susceptibility measurements of the salts comprising mono- and dicationic trimers, together with the computational analysis of their trimeric and dimeric associations. The salt with hexabromocarborane anions contained isolated dicationic (TMTTF)32+ trimers, in which charge was residing mainly on the...