Selective Additions of Group 11 and 12 Metal Fragments to the Fe4C and Fe5C Units

A selective site of interaction has been observed in reacting HgM+ or M‘PPh3 + (M = Mo(CO)3Cp, W(CO)3Cp; 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 Mössbauer 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)3Cp}{AuPPh3}] has been carried out.