Electrophilic additions of metal fragments containing 11-and 12-group elements to the anion carbide cluster [Fe5MoC(CO)(17)](2-). X-ray crystal structures of (NEt4) [Fe5MoAuC(CO)(17)(PMe3)] and [Fe5MoAu2C(CO)(17)(dppm)]

The reaction of (NEt4)(2)[FesMoC(CO)(17)] With cationic metal fragments giv es a series of clusters whose most striking structural feature is the selec tive addition of the incoming metal units on the triangular Fe2Mo face of t he starting anion. The use of Au-2(dppm)(2+) (dppm = diphenylphosphinometha ne)gives the cluster [Fe5MoAu2C(CO)(17)( dppm)] in which the di-gold fragme nt adopts an unprecedented bonding mode.