Synthesis, reactions, and crystal structures of cyclo-η5-[1-(disubstituted methyl)cyclopentadienyl](η-arene)-molybdenum and -tungsten compounds

The arene rings of W(η-C6H5Me)2 and Mo(η-C6H6)2 are readily displaced by the fulvenes C5H4CR2(R = Me or Ph) giving M(η5:η1-C5H4-µ-CR2)(η-arene), M = Mo or W; when M = Mo and R = Me then treatment with HCl gives the binuclear [Mo(η-PriC5H4)(µ-Cl2)]2 whose crystal structure has been determined and which is a convenient precursor to mono-cyclopentadienylmolybdenum derivatives.