The reactions of Cp(CO) 2 MCH 2 CtCPh with Pt(PPh 3 ) 4 or Pt(PPh 3 ) 2 C 2 H 4 in THF at reflux and of Cp(CO) 2 MCHdCdCH 2 with Pt(PPh 3 ) 2 C 2 H 4 in THF or hexane at -78 °C to ambient temperature afforded the heterobinuclear metal µ-allenyl complexes (PPh 3 ) 2 Pt(µ-η 1 :η 2b)). The products reacted with Ru 3 (CO) 12 or Fe 2 (CO) 9 (Ru, Fe ) M′) in THF at room temperature to yield open heterotrinuclear metal µ-allenyl complexes (PPh 3 )-(CO)Pt(µ 3 -η 1 :η 7)), as well as M′(CO) 4 PPh 3 . The reaction of 1a with Fe 2 (CO) 9 also afforded the COfor-PPh 3 substitution product ( PPhin THF at 0 °C with warming to ambient temperature gave three heterometallic products: 6a, the PPh 3 -for-CO substituted (PPh 3 )(CO) 2 Fe(µ-η 3 :η 2 -C(O)C(Ph)dCdCH 2 )Ru(CO)Cp, and (PPh 3 ) 2 Pt(µ 3 -η 1 :η 1 :η 3 -C(Ph)CCH 2 )Ru(CO)Cp(µ 2 -CO)Fe(CO) 2 (8). All new products were characterized by a combination of IR and NMR ( 1 H, 13 C{ 1 H}, and 31 P{ 1 H}) spectroscopy, FAB mass spectrometry, and elemental analysis; the structures of 1b, 3, 6a, and 8 were elucidated by X-ray diffraction analysis. Complexes 1b and 3 each contain a Pt-Ru bond and a µ-allenyl group that is η 1 ligated to Pt and η 2 ligated, through the internal CdC bond, to Ru. 6a contains an open Pt-Fe-Ru metal framework, with the µ-C(Ph)dCdCH 2 ligand being attached η 1 to Pt, η 2 through the C(Ph)dC to Fe, and η 2 through the CdCH 2 to Ru. 8 is also an open, Pt-Fe-Ru bonded cluster; however, it contains an η 3 -allyl group ligated to Fe and metalated at CPh (Ru) and C β (Pt). Possible mechanisms of formation of the new µ-allenylmetal complexes are presented. Complexes 1 and 2 underwent fragmentation of the binuclear framework to yield Cp(CO) 2 MCHdCdCH 2 (M ) Ru, Fe), Cp(CO) 2 RuC(Ph)dCdCH 2 , or Cp-(CO) 2 FeCH 2 CtCPh, as appropriate, in addition to Pt(PPh 3 ) 2 (CO) 2 , upon treatment with CO at room temperature. The reverse of these processes can be effected by sweeping the product solutions with Ar for the three η 1 -allenyl complexes, but not for Cp(CO) 2 FeCH 2 CtCPh. † To whom inquiries concerning the X-ray crystallographic work should be addressed.(1) Reviews: (a) Wojcicki, A.; Shuchart, C. E.