Chiral Radical‐Cation Salts of BEDT‐TTF Containing a Single Enantiomer of Tris(oxalato)aluminate(III) and ‐chromate(III)

Abstract

AbstractRadical‐cation salts of BEDT‐TTF with chiral anions provide the opportunity to combine chirality with conductivity in the same molecular material. We report here two salts, (BEDT‐TTF)3NaAl(C2O4)3·nitromethane and (BEDT‐TTF)3(NH4)0.83Cr1.17(C2O4)3·nitromethane. The former crystallises in space group P21 and the latter in P212121. The use of nitromethane alone as the electrolyte for electrocrystallisation produces no crystals, but the addition of chiral (R)‐(–)‐carvone yields crystals of these two new chiral radical‐cation salts of BEDT‐TTF through chiral induction from racemic tris(oxalato)aluminate(III) and tris(oxalato)chromate starting materials. The honeycomb anion layers in these salts contain a single enantiomer of tris(oxalato)metallate and creates hexagonal cavities that are smaller than those found in the superconducting β″ salts in this tris(oxalate)metallate family, which gives preference for smaller solvents to be included, such as nitromethane. The chromium salt has a non‐stoichiometric composition of the anion layer, which provides an electron doping effect to the donor layer.