Structural characterization of the trinuclear cluster compound [Fe(CO) 4(AuPPh 3) 2] and isolation of its parent anion [Fe(CO) 4(AuPPh 3)] −

Abstract

A re-investigation of the reaction of Au(PPh 3)Cl with [Fe(CO) 4] 2− has shown that the [Fe(CO) 4(AuPPh 3)] − monoanion and [Fe(CO) 4(AuPPh 3) 2] are obtained in sequence by using a 1:1 and 2:1 molar ratio, respectively. The complex [Fe(CO) 4(AuPPh 3) 2] crystallizes in the monoclinic space group P2 1,/ a, a=20.309(5), b=18.379(3), c=40.737(6) Å, β=96.26(2)°, Z=16, R=0.0526. There are four crystallographically independent but chemically equivalent molecules in the asymmetric unit. Each molecule consists of an Au 2Fe triangle with the two Au atoms bearing a PPh 3 ligand and the iron atom bound to four carbonyl groups. The feature of greatest interest in this molecule is the AuAu interaction whose length is found in the range 2.897–2.941(1) Å, quite different from that quoted from a previous study (3.028(1) Å).