Reactions of bis(diphenylphosphine)acetylene with metal carbonyl complexes

The reaction of [Co-2(CO)(8)] with DPPA at room temperature yields a diphosphine bridged product [Co-4(CO)(12)(mu-Ph-2-P-C=C-P-Ph-2)(2)] 1. Heating of 1 at 45degreesC promoted cleavage of the P-C-sp bond with the formation of binuclear, phosphido-bridged sigma-pi-acetylide isomer complexes [Co-2(CO)(5)(mu-PPh2) (mu-sigma-pi-C=C-PPh2)] 2a, 2b. Heating (60degreesC) of the complex [CpFe(CO)(2)CH3] and DPPA affords mono and binuclear acetyl, P-coordinated diphenylphosphinoalkyne metal complexes [CpFe(Ph2P-C=C-PPh2)CO(COCH3)] 3, [CpFeCO(COCH3)](2)-mu-(Ph2P-C=C-PPh2) 4.