The hydrocarbon perylene (C20H12) has been crystallized, and several of 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 negative charge
perturbation based on geometry-optimized density functional calculations at the B3LYP level
with 6-31G* basis sets. All perylene radical anion salts [C20H12
•-][M+
solv] and [C20H12
•-···C20H12][M+
solv]
crystallize as solvent-separated ion pairs, whereas the structures of the perylene dianion
salts [C20H12
2 -(M+
solv)2] or [C20H12
2 -][M+
solv]2 strongly depend on the optimum solvation of
the alkali metal countercations. The experimental results allow the rationalization of
essential facets of the network of redox equilibria in solution.