Heteronuclear bonding between heavier Group 14 elements and transition-metals: novel halogermylene- and stannylene transition-metal complexes L2(X)MM′L′n [L2=PhNC(Me)CHC(Me)NPh; X=Cl, I; M=Ge, Sn; M′L′n=W(CO)5, Fe(CO)4]

Reactions of the stable heteroleptic halodivalent species L2(X)M [L2=PhNC(Me)CHC(Me)NPh; M=Ge, X=Cl (1); X=I (2); M=Sn, X=Cl (5)] with the intermediate metal complexes W(CO)5 THF and Fe(CO)4 have provided the new halogermylene- or stannylenetungsten- and iron-complexes L2(X)MM′L′n [M′L′n=W(CO)5, M=Ge, X=Cl (3), X=I (4); M′L′n=Fe(CO)4, X=Cl, M=Ge (6), M=Sn (7)] respectively; complexes 3, 4 and 6, 7 have been characterized via X-ray crystallography and a detailed discussion of their structures is presented. All the MM′ bonds are very short but calculations are consistent with the L2MX ligands being good σ-donors and very poor π-acceptors in complexes 3, 4 and 6, 7. Selective metathesis reaction between 3 and MeLi resulted in the formation of the stable monomeric complex L2(Me)GeW(CO)5 (8).