Ruthenium cluster chemistry with Ph2PC6H4-4-C = CH

The new phosphines Ph2PC6H4-4-C=CR [R = SiMe3 (1), 1-1 (2)] have been used to prepare RU3(CO)(9)(Ph2PC6H4-4-C = CSiMe3)(3) (4) and Ru(C = CC6H4-4-PPh2 )(PPh3)(2)(eta -C5H5) (3), respectively, the latter with a pendent phosphin e. Reaction of 4 with carbonate or fluoride affords Ru-3(CO)(9)(Ph2PC6H4-4- C= CH)(3) (5) with pendent terminal alkynyl groups, the identity of which w as confirmed by a structural study. Reaction of 5 with Ru(NCMe)(PPh3)(2)(et a -C5H5 )]PF6 Or reaction of Ru-3(CO)(12) with 3 gives Ru-3(CO)(9)((Ph2PC6H 4-4-C=C)Ru(PPh3)(2)(eta -C5H5))(3) (6)Complexes 36 hav been studied by cycl ic voltammetry. Proceeding from Ru,(CO),, to 4 or 5 shifts the cluster-cent ered reduction to more negative potential and affords facile cluster-centre d oxidation. Proceeding from 4:5 and 3 to 6 results in similarly-located cl uster-centred reduction and peripheral ruthenium-centred oxidation, but res ults in a lack of observable cluster-centred oxidation. Crystal data for 5 . C6H14: space group P (I) over bar, a = 12.760(1) Angstrom, b = 17.077(1) Angstrom, c = 17.924(2) Angstrom, alpha = 108.656(5)degrees, beta = 96.344( 5)degrees gamma = 93.523(5)degrees. V = 3658.4(6) Angstrom (3), Z = 2, R = 0.078, R-w=0.105 for.5008 reflections [I > 2.00 sigma (I)].