Rotation of the acetylide ligand on the triangular face of tungsten-diruthenium clusters. Crystal structure and solution dynamics of LWM2(CO)8(CCPh), L = C5H5, C5Me5 and M = Os, Ru

Reaction of CpW(CO)3CCPh with OS3(CO)10(CH3CN)2 or Ru3(CO)12 in refluxing toluene gives trinuclear mixed-metal acetylide clusters, CpWOs2(CO)8(CPh) (1) and CpWRu2(CO)8(CCPh) (3); the acetylide ligands of these two complexes are related to each other by a 120° rotation as indicated by X-ray diffraction studies. In solution, the variable temperature 1H and 13C NMR spectra suggest that the acetylide ligand of 3 undergoes a 360° rotation on the face of the WRu2 triangle.