REACTIONS OF COORDINATED LIGANDS .51. THE REACTIONS OF SIGMA,ETA-3(5E)-BUTADIENYLRUTHENIUM COMPLEXES [RU[=C(PH)-ETA-3-C(PH)C(PH)CR(PH)](ETA-C5H5)](R = H OR CHO) WITH P(OME)3, PHC=CPH, H+ AND ARYLDIAZONIUM CATIONS - CRYSTAL-STRUCTURE OF [RU[C(O)C(PH)=C(PH)-ETA-2-(Z)-C(PH)=CH(PH)][P(OME)3](ETA-C5H5)]

Treatment of the sigma,eta-3(5e)-butadienyl complex [Ru{ = C(Ph)-eta-3-C(Ph)C(Ph)C(Ph)CHO}(eta-C5H5)] 1 with P(OMe)3 affords the acyl complex [Ru{C(O)C(Ph) = C(Ph)-eta-2-(Z)-C(Ph) = CH(Ph)}{P(OMe)3}(eta-C5H5)], structurally identified by single-crystal X-ray diffraction. This reaction involves an apparent 1,5-hydrogen shift from the aldehydic carbon to the former alkylidene carbon. Reaction of the related complex [Ru{ = C(Ph)-eta-3-C(Ph)C(Ph)CH(Ph)}(eta-C5H5)] 2 with diphenylacetylene gives [Ru(eta-5-endo-C6Ph6H)(eta-C5H5)], whereas reaction of 2 with the electrophilic reagent HBF4.Et2O affords the 1,3-diene cationic complex [Ru{eta-4-(E,Z)-CH(Ph) = C(Ph)C(Ph) = CH(Ph)}{P(OMe)3}(eta-C5H5)][BF4]. In contrast, protonation of the adduct formed between 2 and P(OMe)3, the complex [Ru{C(Ph) = C(Ph)-eta-2-C(Ph) = CH(Ph)}{P(OMe)3}(eta-C2H5)], gives the isomeric cation [Ru{eta-4-(Z,Z)-CH(Ph) = C(Ph)-C(Ph) = CH(Ph)}{P(OMe)3}(eta-C5H5)][BF4]. An attempt to convert 2 into a 17e cation by oxidation with p-nitrobenzenediazonium tetrafluoroborate leads instead to formation of the aryldiazenido complex [Ru{C(Ph) = C(Ph)-eta-2-C(Ph) = CH(Ph)}(p-NO2C6AH4N2) (eta-C5H5)]. The mechanisms of these reactions are discussed.