Abstract
Cobalticinium (1), Methylcobalticinium (2) and 1,1 '-Dimethyl-cobalticinium (3) salts may be prepared in 30–50% yields by reaction of mixtures of cyclopentadienylthallium and methylcyclopentadienyl-thallium with aqueous cobalt (II) chloride in the presence of DMSO. This procedure avoids the necessity for inert atmospheres and anhydrous reagents and is suitable for rapid preparation of 50–100 g of mixed cobalticinium salts.