Diyne-bridged metal clusters: synthesis and spectroscopic characterization of [(CO)₆Fe₂Se₂{μ-HC=C(CCR)}M](R = Me and ⁿBu; M = Cp₂ Mo₂(CO)₄, Co₂(CO)₆, Ru₃(CO)₁₀ and Os₃(CO)₁₀). Structural characterization of [(CO)₆Fe₂Se₂{μ-HC=C(CCⁿBu)}Cp₂Mo₂(CO)₄] and [(CO)₆Fe₂Se₂{μ-HC=C(CCMe)}Ru₃(CO)₁₀]

Abstract

Room temperature reaction of [(CO)₆Fe₂{μ-SeC(H)=C(C≡CR)Se}], with the dimetallic species, Cp₂Mo₂(CO)₄ and Co₂(CO)₈, afforded the adducts [(CO)₆Fe₂Se₂(μ-HC=C(CCR))Cp₂Mo₂(CO)₄] (R = Me, 1; R = ⁿBu, 2) and [(CO)₆Fe₂Se₂(μ-HC=C(CCR))Co₂(CO)₆] (R = Me, 3; R = ⁿBu, 4) respectively. On reaction of Ru₃(CO)₁₀ (NCMe)₂ with [(CO)₆Fe₂(μ-SeC(H)=C(C≡CR)Se)], the new diyne-bridged mixed-metal clusters [(CO)₆Fe₂Se₂(μ-HC=C(CCR))Ru₃(CO)₁₀] (R = Me, 5; R = ⁿBu, 6) were obtained. Similarly, [(CO)₆Fe₂Se₂(μ-HC=C(CCⁿBu))Os₃(CO)₁₀], 7, was isolated from the reaction of [(CO)₆Fe₂(μ-SeC(H)=C(C≡CⁿBu)Se)] with Os₃(CO)₁₀(NCMe)₂. Compounds 1-7 were characterized by IR and ¹H, ¹³C and ⁷⁷Se NMR spectroscopy. The structures of 2 and 5 were established by single crystal X-ray diffraction study. Both contain an Fe₂Se₂ butterfly core bridged by an HCC unit of the diyne HC≡CC≡CR across the two Se atoms. In 2, the substituted acetylenic moiety is transversely bridged to the Mo---Mo bond and in 5, it forms a μ₃-//η² bridge to an Ru₃ triangular core.