General Synthetic Route to Double-Butterfly Fe/S Cluster Complexes via Reactions of the Dianions {[(μ-CO)Fe₂(CO)₆]₂(μ-SZS-μ)}^2- with Electrophiles^†

A simple and convenient route for the synthesis of linear and macrocyclic double-butterfly Fe/S cluster complexes has been developed, which involves a sequential reaction of Fe3(CO)12 with the dithiol HSZSH in the presence of Et3N, followed by treatment of the intermediate [Et3NH]+ salts of dianions {[(μ-CO)Fe2(CO)6]2(μ-SZS-μ)}2- (4) with electrophiles. For example, treatment of the [Et3NH]+ salts of dianions 4 with allyl bromide and PhSBr produces the linear complexes [(μ-CH2CHCH2)Fe2(CO)6]2(μ-SZS-μ) (5a, Z = (CH2)4; 5b, Z = CH2(CH2OCH2)2CH2; 5c, Z = CH2(CH2OCH2)3CH2) and [(μ-PhS)Fe2(CO)6]2(μ-SZS-μ) (6a, Z = CH2(CH2OCH2)2CH2; 6b, Z = CH2(CH2OCH2)3CH2), whereas treatment with S2Cl2 and ClSZSCl yields the macrocyclic complexes [Fe2(CO)6]2(μ-S−S-μ)(μ-SZS-μ) (7a, Z = CH2(CH2OCH2)2CH2; 7b, Z = CH2(CH2OCH2)3CH2) and [Fe2(CO)6]2(μ-SZS-μ)2 (8a, Z = CH2(CH2OCH2)2CH2; 8b, Z = CH2(CH2OCH2)3CH2), respectively. In addition, while the [Et3NH]+ salts of dianions 4 react in situ with PhNCS and SCN(CH2)4NCS to give the linear complexes [(μ-PhNHCS)Fe2(CO)6]2(μ-SZS-μ) (9a, Z = CH2CH2OCH2CH2; 9b, Z = CH2(CH2OCH2)2CH2; 9c, Z = CH2(CH2OCH2)3CH2) and macrocyclic complexes [Fe2(CO)6]2[μ-SCNH(CH2)4NHCS-μ](μ-SZS-μ) (10a, Z = (CH2)4; 10b, Z = CH2(CH2OCH2)2CH2), the in situ reactions with PhC⋮CPh and PhC⋮CH afford the linear complexes [(μ-σ,π-PhCHCPh)Fe2(CO)6]2(μ-SZS-μ) (11a, Z = CH2(CH2OCH2)2CH2; 11b, Z = CH2(CH2OCH2)3CH2) and [(μ-σ,π-PhCHCH)Fe2(CO)6]2(μ-SZS-μ) (12a, Z = (CH2)4; 12b, Z = CH2(CH2OCH2)2CH2; 12c, Z = CH2(CH2OCH2)3CH2). The possible pathways for production of these linear and macrocyclic cluster complexes are suggested, and their structures have been characterized by elemental analysis and IR and 1H NMR spectroscopy, as well as for 5a, 7a, 8a, and 12a by X-ray diffraction analysis.本研究开发了一条简便高效的线性及大环双蝶状Fe/S簇合物合成路线：以十二羰基三铁（Fe₃(CO)₁₂）与二硫醇HSZSH在三乙胺（Et₃N）存在下发生分步反应，随后将二阴离子{[(μ-CO)Fe₂(CO)₆]₂(μ-SZS-μ)}²⁻的三乙胺正离子盐中间体（4）与亲电试剂反应。 例如，将二阴离子4的三乙胺正离子盐分别与烯丙基溴、苯硫基溴（PhSBr）反应，可得到线性簇合物[(μ-CH₂=CHCH₂)Fe₂(CO)₆]₂(μ-SZS-μ)（5a：Z=(CH₂)₄；5b：Z=CH₂(CH₂OCH₂)₂CH₂；5c：Z=CH₂(CH₂OCH₂)₃CH₂）以及[(μ-PhS)Fe₂(CO)₆]₂(μ-SZS-μ)（6a：Z=CH₂(CH₂OCH₂)₂CH₂；6b：Z=CH₂(CH₂OCH₂)₃CH₂）；而与二氯化二硫（S₂Cl₂）、二氯化物ClSZSCl反应时，则分别得到大环簇合物[Fe₂(CO)₆]₂(μ-S−S-μ)(μ-SZS-μ)（7a：Z=CH₂(CH₂OCH₂)₂CH₂；7b：Z=CH₂(CH₂OCH₂)₃CH₂）与[Fe₂(CO)₆]₂(μ-SZS-μ)₂（8a：Z=CH₂(CH₂OCH₂)₂CH₂；8b：Z=CH₂(CH₂OCH₂)₃CH₂）。 此外，二阴离子4的三乙胺正离子盐可分别与异硫氰酸苯酯（PhNCS）、1,4-丁二异硫氰酸酯（SCN(CH₂)₄NCS）原位反应，得到线性簇合物[(μ-PhNHC=S)Fe₂(CO)₆]₂(μ-SZS-μ)（9a：Z=CH₂CH₂OCH₂CH₂；9b：Z=CH₂(CH₂OCH₂)₂CH₂；9c：Z=CH₂(CH₂OCH₂)₃CH₂）以及大环簇合物[Fe₂(CO)₆]₂[μ-S=C(NH)(CH₂)₄C(NH)=S-μ](μ-SZS-μ)（10a：Z=(CH₂)₄；10b：Z=CH₂(CH₂OCH₂)₂CH₂）；而与二苯基乙炔（PhC≡CPh）、苯乙炔（PhC≡CH）的原位反应则生成线性簇合物[(μ-σ,π-PhCH=CPh)Fe₂(CO)₆]₂(μ-SZS-μ)（11a：Z=CH₂(CH₂OCH₂)₂CH₂；11b：Z=CH₂(CH₂OCH₂)₃CH₂）与[(μ-σ,π-PhCH=CH)Fe₂(CO)₆]₂(μ-SZS-μ)（12a：Z=(CH₂)₄；12b：Z=CH₂(CH₂OCH₂)₂CH₂；12c：Z=CH₂(CH₂OCH₂)₃CH₂）。 本研究提出了上述线性及大环簇合物的可能生成路径，并通过元素分析、红外光谱（IR）与氢核磁共振（¹H NMR）波谱对所有产物的结构进行了表征；其中产物5a、7a、8a及12a的结构还通过X射线衍射分析得到了进一步确证。