Some new results on the Fischer–Hafner synthesis of vanadium arenes

The biphasic liquid system formed in the Fisher–Hafner reduction of VCl3 in toluene contains the [V(η6-MeC6H5)2]+ cation which has been isolated in the solid state as the tetraphenylborato- (from aqueous solution) or as the [Al2Cl7]−, [Al4O2Cl10]2− and [catena-Al4O2Cl9]− salt (directly from the biphasic liquid system). The crystal structures of [V(η6-MeC6H5)2]2[Al4O2Cl10] (2), and [V(η6-MeC6H5)2][catena-Al4O2Cl9] (3), have been solved representing the first structural report of the [V(η6-MeC6H5)2]+ cation (compounds 2 and 3) and of the polymeric nonachlorodioxoaluminate anion [Al4O2Cl9]− (compound 3).

Graphical abstractThe biphasic liquid system formed in the Fisher–Hafner reduction of VCl3 in toluene contains the [V(η6-MeC6H5)2]+ cation, which has been isolated in the solid state as the tetraphenylborato-, [Al2Cl7]−, [Al4O2Cl10]2− and [catena-Al4O2Cl9]− salts. The [V(η6-MeC6H5)2]+ cation shows two different conformations of the toluene rings: a trans-eclipsed conformation in [V(η6-MeC6H5)2]2[Al4O2Cl10] (2), and an almost cis-eclipsed one in [V(η6-MeC6H5)2][catena-Al4O2Cl9] (3).Figure optionsDownload full-size imageDownload as PowerPoint slide