Selective additions of group 11 and 12 metal fragments to the Fe4C and Fe5C units

ii selective site of interaction has been observed in reacting HgM+ or M'PPh3+ (M = Mo(CO)(3)Cp, W(CO)(3)Cp; M' = Au, Cu, Ag) with [Fe4C(CO)(12){HgM}](-) to give the mixed-transition-metal clusters [Fe4C(CO)(12){HgM}(2)] and [Fe4C(CO)(12){HgM}{M'PPh3}], respectively. The reaction of [Fe5C(CO)(14){HgM}](-) with M'PPh3+ permits us to obtain the very unstable neutral octanuclear [Fe5C(CO)(14){HgM}{M'PPh3}] clusters. The new compounds have been studied by VT-NMR and Mossbauer spectroscopy. The electrochemical behavior of the Fe4C derivatives has been investigated, and an X-ray crystal structure determination of the complex [Fe4C(CO)(12){HgMo(CO)(3)Cp}{AuPPh3}] has been carried out.