Synthesis of a Heptanuclear Rhenium−Iridium Carbido Carbonyl Cluster and of (Triphenylphosphine)gold(I) Derivatives

The octanuclear cluster
[Re5Ir(μ6-C)(CO)17(μ3-Re(CO)3)2]2-
loses a [Re(CO)3]+ capping unit in
refluxing acetonitrile
to give the heptanuclear cluster
[Re5Ir(μ6-C)(CO)17(μ3-Re(CO)3)]3-.
The latter compound can be capped with
[AuPPh3]+ groups to form the monogold and
digold derivatives
[Re6IrC(CO)20(AuPPh3)]2-
and [Re6IrC(CO)20(AuPPh3)2]-.
These three new anionic clusters have been isolated as
PPN+ and/or PPh4+ salts and
are
formulated on the basis of microanalytical and FAB mass spectrometric
data. The solid-state structure of
[PPh4][Re6Ir(μ6-C)(CO)20(μ3-AuPPh3)2]·CH2Cl2
has been determined by X-ray diffraction. Crystal data: 
triclinic, space
group P1̄, a = 13.1182(1) Å,
b = 15.1806(1) Å, c = 23.4061(3)
Å, α = 74.251(1)°, β = 82.058(1)°, γ
=
70.306(1)°, Z = 2. Further information on the
structures of the compounds in solution has been derived from
13C
and 31P NMR studies.