CLEAVAGE OF A PHOSPHORUS CARBON TRIPLE BOND IN THE REACTION OF 2,2-DIMETHYLPROPYLIDYNEPHOSPHINE WITH [OS-3(CO)(10)(MU(3)-ETA(1)-ETA(2)-ETA(1)-C2ME)]

The reaction of 2,2-dimethylpropylidynephosphine with the cluster [Os- 3(CO)(10)(mu(3)-eta(1):eta(2):eta(1)-C2Me)] 1 results in P-C bond clea vage and an insertion of the precoordinated but-2-yne ligand into the phosphorus carbon triple bond of the incoming phosphaalkyne with forma tion of a novel bridging C3P-moiety in the structurally characterised complex s-3(CO)(8)(mu(2)-PCBut){mu(3)-PC(Me)C(Me)C(Bu-t)}] 2, together with a second mu(2)-eta(2),eta(2)-ligated phosphaalkyne.