Pentakis(Methoxycarbonyl)-Cyclopentadiene Chemistry .X. Crystal-Structure of the Charge-Transfer Complex Tropylium Pentakis(Methoxycarbonyl)Cyclopentadienide

Abstract

The compound [C₇H₇][C₅(CO₂Me)₅] forms very long but thin orange-red needles, which, in contrast to a previous report, form orange-red to deep red solutions in polar solvents. Decolorization of an acetone solution occurs on standing, but the white compound so obtained has not been identified. Single-crystal X-ray structure determination at 295 K (R = 0.078 for 1030 'observed' reflections) shows the presence of an infinite sandwich structure comprising columns of interleaved anion and cation planes normal to b. Crystals are rthorhombic, Pbcn , a 18.206(6), b 13.954(12), c 17.243(5)Ǻ, Z 8.