The one-electron oxidations of [Fe2(μ,κ2-3,6-R2-bdt)(μ-PPh2)(CO)5]– (R = H, 1–; OSitBuMe2, 4–) lead to the formation of mixed-valent [Fe8(μ,μ,κ2-bdt)4(μ-PPh2)4(CO)18] (2), [Fe4(μ,κ2-3,6-R2-bdt)2(μ-PPh2)2(CO)8] (R = H, 3; OSitBuMe2, 5) complexes and a persistent metal-stabilized thiyl radical species (4). The calculation results are in line with the spectroscopic evidences that the unpaired spin in 4 delocalizes over the Fe2 center and the 1,2-dithiolate unit, mostly on the terminal sulfur site. The subsequent dimerization of the singly oxidized Fe2 species to the Fe4 product retains the partial thiyl radical character. For the analog with less steric hindrance, the π–π stacking interaction between the dithiolato aromatic rings induces the generation of the octanuclear species 2 prior to 3, in which Fe2 → Fe8 process the electronic structures of the species are modulated via reducing the thiyl radical to the thiolate. The electronic reorganization process repeats when 2 is converted to 3. The results demonstrate that electronic versatility of the benzenedithiolate exerts pronounced influences on electronic and coordination structure of the metal complexes.

Electronically versatile benzenedithiolates on electronic and coordination structures of metal complexes: Mimicking the electronic interplay in [FeFe]hydrogenase active site

253rd National Meeting (2017)

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