Diyne-bridged metal clusters: Synthesis and spectroscopic characterization of [(CO) 6Fe 2Se 2{μ-HCC(CCR)}M](R  Me and nBu; M  Cp 2 Mo 2(CO) 4, Co 2(CO) 6, Ru 3(CO) 10 and Os 3(CO) 10). Structural characterization of [(CO) 6Fe 2Se 2{μ-HCC(CC nBu)}Cp 2Mo 2(CO) 4] and [(CO) 6Fe 2Se 2{μ-HCC(CCMe)}Ru 3(CO) 10

Abstract

Room temperature reaction of [(CO) 6Fe 2{μ-SeC(H)C(CCR)Se}], with the dimetallic species, Cp 2Mo 2(CO) 4 and Co 2(CO) 8, afforded the adducts [(CO) 6Fe 2Se 2(μ-HCC(CCR))Cp 2Mo 2(CO) 4] (R  Me, 1; R  nBu, 2) and [(CO) 6Fe 2Se 2(μ-HCC(CCR))Co 2(CO) 6] (R  Me, 3; R  nBu, 4) respectively. On reaction of Ru 3(CO) 10 (NCMe) 2 with [(CO) 6Fe 2(μ-SeC(H)C(CCR)Se)], the new diyne-bridged mixed-metal clusters [(CO) 6Fe 2Se 2(μ-HCC(CCR))Ru 3(CO) 10] (R  Me, 5; R  nBu, 6) were obtained. Similarly, [(CO) 6Fe 2Se 2(μ-HCC(CC nBu))Os 3(CO) 10], 7, was isolated from the reaction of [(CO) 6Fe 2(μ-SeC(H)C(CC nBu)Se)] with Os 3(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 Fe 2Se 2 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 μ 3-// η 2 bridge to an Ru 3 triangular core.