The compound [AuMe( PPh3)] reacts under mild conditions (diethyl ether, ambient temperatures) with the compounds [M3(p-H) (p-COMe) (CO),o] and [ R u ~( ~-H ) ~( ~~-C O M ~) ( C O ) ~] to give the complexes [ A U M , ( ~-C O M ~) ( C O ) , ~( P P ~~) ~ [M = Fe ( 1 ) or Ru ( 2 ) L [ A ~R u ~( c L -H ) ~( c L ~-C O M ~) ( C O ) ~( P P ~~) ~ ( 3 ) , Spectroscopic properties of the new species are reported and discussed, and the structures of ( 2 ) , ( 3 ) , and (5) have been established by X-ray diffraction studies. The structure of [AuRu3(p-COMe) (CO),,( PPh3)] ( 2 ) can be regarded as a molecule of [ R u ~( ~-H ) ( ~-C O M ~) ( C ~) , ~]in which the bridging hydrido-ligand is replaced by a bridging AuPPh, group, thus producing a ' butterfly ' metal atom core (interplanar angle 1 17") with the gold atom occupying a ' wing-tip ' site. The COMe ligand bridges the body of the butterfly on the convex side. The Au-Ru bonds [2.760(2) and 2.762(2) A] are ca. 0.1 A shorter than the non-bridged Ru-Ru bonds [2.845(2) and 2.839(3) A] but the bridged Ru-Ru bond is significantly longer at 2.879(2) A. Crystals of ( 2 ) are triclinic, space group P i , and the asymmetric unit comprises two molecules of complex. The structure has been refined to R 0.075 for 4 868 intensities measured to 29 = 40" at 220 K. In [ A U R U , ( ~-H ) ~( ~~-C O M ~) ( C O ) ~( P P ~~) ] ( 3 ) the carbyne ligand triply bridges an equilateral triangle [Ru-Ru 2.865(2)-2.879(2) A] of ruthenium atoms, while on the opposite side of the triangle there are two edge-bridging hydrido-ligands and one edge-bridging AuPPh, group. Each ruthenium atom carries three terminal carbonyl ligands, giving octahedral co-ordination if the Ru-Ru bonds are ignored. The molecule has approximate C, symmetry, not required crystallographically. The structure is triclinic, space group P i , and has been refined to R 0.042 for 3 247 intensities measured to 28 = 45" at 293 K. The complex [ A U ~R U , ( ~~-C O M ~) ( C ~) ~( P P ~~) ~] (5) crystallises with half a molecule of CH2CI2 per molecule of (5) incorporated into the crystals. Again the carbyne ligand triply bridges a near-equilateral triangle of Ru atoms [Ru-Ru 2.895(3)-2.929(2) A], but on the opposite side of this triangle one gold atom is co-ordinated to form a tetrahedron [Au-Ru 2.818(2), 2.825(2), and 2.987(2) A]. The two faces of this tetrahedron adjacent to the long Au-Ru bond are each further
