Carbonyl ligands from alkynes: oxidative decarbonation of acetylide bridged complexes

Article abstract of DOI:10.1016/0022-328X(90)85142-L

The organometal acetylides Cp(CO)2MC<*>CR (1,M = Fe, R = Ph and 2, M = Ru, R = Ph, t-Bu, Me) react with Co2(CO)8 to form the acetylide bridged trinuclear complexes Co2(CO)6-μ-CR> (3, M = Fe, and 4, M = Ru).Of these, the phenyl acetylide compounds undergo a non-destructive reaction with oxygen which results in the net loss of one carbon atom together with a CO ligand and the formation of the alkylidyne bridged clusters Co2MCp(CO)7(μ₃-CPh) (5, M = Fe, and 6, M = Ru).The molecular structure of 6 has been determined by an X-ray analysis.The mechanism ofthe oxidation reaction has been elucidated by 13C labelling of the acetylide α-C atom and EI mass spectrometry.It has been found that this C atom is converted to CO which, with a probability of 7/9, ends up as a CO ligand in the product cluster.This means that the oxidation converts the α-C to CO before elimination of the CO ligands.