ChemInform Abstract The title reactions give complexes of the type (III), (V), and (VI) or (X) in a sequential manner. In the case of the tungsten complexes (X) it was not possible to isolate any member of the series in a pure state. In the case of Mo the compounds analogous to (III) and (VI), containing the reduced form of (IV) as ligand are also obtained. (IIIa) (P1, Z=1), (IIIb) (P21/c, Z=2), (Va) (P1, Z=2) and (VIII) (P21/c, Z = 8) are characterized by crystallographic studies. 1H NMR spectra are generally supportive of the structures found in the solid state, though for type (V) compounds temp.-dependent behavior indicative of stereochemical lability is observed (some yields not given).