Metal-stabilised diynyl radicals: structure and reactivity of [Mo(C[triple bond]C-C[triple bond]CSiMe3)L2(eta-C7H7)]*+ (L2 = 2,2'-bipyridine or dppe)

The unprecedented spectroscopic and structural characterisation of a series of 17-electron, monometallic diynyl radicals, [Mo(C[triple bond]C-C[triple bond]CR)L(2)(eta-C(7)H(7))]*(+) (L(2) = bipy, R = SiMe(3); L(2) = dppe, R = SiMe(3) or H), are reported; the (L(2) = dppe, R = SiMe(3)) derivative is reactive to chain-centred C(beta)-C(beta') dimerisation.