Heterometallic Molybdenum−Gold and Tungsten−Gold Clusters, M3(CO)9(AuPPh3)3(μ-OEt)(μ3-OEt)2 (M = Mo, W)

Treatment of [NMe 4 ] 3 [M 3 (CO) 9 (μ-OEt)(μ 3 -OEt) 2 ] ( 1, M = Mo; 2, M = W) with 3 equiv of (Ph 3 P)AuCl/TlPF 6 affords M 3 (CO) 9 (AuPPh 3 ) 3 (μ-OEt)(μ 3 -OEt) 2 ( 3, M = Mo; 4, M = W) in 80% and 89% yields, respectively. The molecular structures of 3 and 4 have been determined by X-ray diffraction methods. Complexes 3 and 4 are isomorphous. Variable-temperature 31 P{H} and 1 H NMR spectra for 3, 4, and related complex [NMe 4 ][W 3 (CO) 9 (Au 2 (μ-dppm))(μ-OEt)(μ 3 -OEt) 2 ] ( 6 ) verify valence isomerization in these complexes at ambient conditions.