Formation of novel conjugated polycarbon–metal systems via metal migration on a M–CC–CC–M linkage

Abstract

Reactions of butadiynediyldimetal complexes, Fp*–CC–CC–M(η⁵-C₅ R₅)(CO)₂ 1 [M = Fe, Ru; R = Me, H; Fp* = FeCp*(CO)₂], with group 8 metal carbonyls result in migration of a σ-bonded metal fragment along the C₄ rod to form novel highly conjugated polycarbon–metal systems; the zwitterionic μ-but-2-yn-1-ylidene-4-ylidyne complex Ru₃(CO)₁₀(μ₃-C–CC– μ-C)Fe₂Cp*₂(CO)₃ 2, and the dimerized product with a cumulenic μ-C₈ ligand (Cp*Fe)₄- Ru₂(CO)₁₃[μ₆-C₈–C( O)] 3, via 1,4-migration and the zwitterionic acetylide cluster-type product Fp*⁺[Cp(CO)₂Ru-(η²-CC)– (μ₃-CC)Fe₃(CO)₉]⁻ 4, via 1,3-migration.