Long, multicenter bonding in π-[terthiophene] 2 2+ dimers

摘要

The repulsive nature of the interaction between the cation radicals of the π-[terthiophene] 2 2+ dimers, 1 2 2+ , found in crystals has been concluded from B3LYP/6-31+G(d) calculations. Hence, the bonding component is weaker than the Coulombic repulsion, consistent to recent findings for [TTF]·+–[TTF]·+ interactions (TTF = tetrathiafulvalene). The existence of 1 2 2+ dimers originates from the cation+–anion? electrostatic interactions, which exceeds the combined effect of the 1 .+–1 .+ plus (SbF6)?–(SbF6)? repulsions in 1 2(SbF6)2, similar to what is found for [TTF]·+–[TTF]·+ interactions in [TTF]2(ClO4)2 aggregates and in crystals. The long, multicenter bond in 1 2 2+ is characterized as a 2e?/10c bond from an Atoms-in-molecules analysis.