SOLVENT-SHARED AND SOLVENT-SEPARATED ION MULTIPLES OF PERYLENE RADICAL-ANIONS AND DIANIONS - AN EXEMPLARY CASE OF ALKALI-METAL CATION SOLVATION

The hydrocarbon perylene (C20H12) has been crystallized, and several o f its radical anions and dianion salts have been prepared by reduction with various alkali metal mirrors under argon and aprotic conditions in different ether solvents. The single-crystal structures determined at low temperature are discussed in terms of single and double negativ e charge perturbation based on geometry-optimized density functional c alculations at the B3LYP level with 6-31G basis sets. All perylene ra dical anion salts [C20H12.-][M-solv(+)] and [C20H12.-... C20H12][M-sol v(+)] crystallize as solvent-separated ion pairs, whereas the structur es of the perylene dianion salts [C20H122-(M-solv(+))(2)] or [C20H122- ][M-solv(+)](2) strongly depend on the optimum solvation of the alkali metal countercations. The experimental results allow the rationalizat ion of essential facets of the network of redox equilibria in solution .