σ Bond Metathesis Reactivity of Allyl Scandium Metallocenes with Diphenyldichalcogenides, PhEEPh (E = S, Se, Te)

The σ bond metathesis reactivity of (C5Me4H)3Sc, which has a (η5-C5Me4H)2Sc(η1-C5Me4H) structure in the solid state, has been investigated and compared with that of a conventional (C5Me4H)− metallocene complex, (C5Me4H)2Sc(η3-C3H5), 1. Complex 1 reacts with PhEEPh (E = S, Se, Te) in toluene to form the σ bond metathesis products (C3H5)EPh and [(C5Me4H)2Sc(SPh)]2, (C5Me4H)2Sc(SePh), and (C5Me4H)2Sc(TePh), respectively. Analogous reactions in toluene/THF generate the THF solvates (C5Me4H)2Sc(EPh)(THF). The monometallic sulfur derivative (C5Me4H)2Sc(Spy-κ2-S,N) forms from the reaction of 1 with 2,2′-dipyridyl disulfide, pySSpy. (C5Me4H)3Sc reacts similarly, showing that the (η1-C5Me4H)− solid-state structure yields Sc–C bond reactivity in solution.