A 'passe-partout' for the stabilization of highly polar unsupported M-M' bonds (M=Ti,Zr,Hf; M'=Fe,Ru) and alpha-addition of the metal nucleophile electrophile pairs to an isocyanide

The coordination of a novel type of tripodal amido ligand provides the key to the synthesis of stable M-M' (M = Ti, Zr, Hf; M' = Fe, Ru) heterobimetallic complexes, [MeSi(SiMe(2)N(C(6)H(4)Me-4)}(3)M-M'(eta(5)-C5H5)(CO)(2)] 4-9, with unsupported metal-metal bonds and thus enables systematic studies of these complexes; the crystal structures of the Ti-Fe (4) and Zr-Fe (6) complexes are reported, the latter being the first X-ray structure of a compound containing a Zr-Fe bond; reaction of the M-M' complexes with methyl isocyanide leads to the immediate insertion into the metal-metal bond, a reaction which is analogous to alpha-additions to isocyanides.