REACTIVITY OF DERIVATIVES OF PHOSPHORUS YLIDES ON RU3 CLUSTERS - INTERCONVERSIONS DUE TO ALKYNE INSERTION

The Ru3 clusters with triply bridging organic ligands derived from phosphorus ylides undergo interconversions by insertion of alkynes. The phosphoniomethylidyne-bridged cluster H2Ru3(CO)9(mu3-C-PPh3) (1) inserts alkynes either into one Ru-H bond (HC = CSiMe3, EtC = CEt) forming mu2-vinyl-Ru3 complexes or into the Ru3-mu3-C unit (HC = CSiMe3, PhC = CPh) converting it into a mu3-allyl ligand, e.g. in Ru3(CO)8(PPh3)(mu3-Ph3P-C-CH-CSiMe3) (6). HC = CPh induces fragmentation of 1. The phosphonio enolate-bridged clusters HRU3(CO)9-(mu3-Ph3P-CH-CO) (2a) and HRu3(CO)8(PPh3)(mu3-Ph3P-CH-CO) (2b) insert alkynes (HC = CPh, PhC = CPh, HC = CSiMe3, EtC = CEt) into the Ru-H bond to form mu2-vinyl-bridged derivatives, e.g. Ru3(CO)8(113-Ph3P-CH-CO)(mu2-RC = CHR') (9). In addition, the alkyne reactions of 2a induce cluster opening with concomitant CO and alkyne incorporation into the organic ligand and formation of an oxaruthenol-derived trinuclear complex 11, as proved by an X-ray structure determination of the PhC = CPh product 11b. For the cluster H2Ru3(CO)7(PPh3)(mu3-C6H4Ph2P-C(O)Me) (3) containing an ortho-metalated phosphonio ketone ligand, only alkyne insertion into one or two Ru - H units is observed.