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Ferrocene‐Fused Acenequinones: Synthesis, Structure and Reaction Chemistry

2020; Wiley; Volume: 2021; Issue: 6 Linguagem: Inglês

10.1002/ejic.202000956

1099-0682

Julia Mahrholdt, Eduard Kovalski, Marcus Korb, Alexander Hildebrandt, Valerije Vrček, Heinrich Lang,

Inorganic and Organometallic Chemistry

Abstract The synthesis of anti ‐[1.1](2,17)(6,13)ferrocenophane‐1,12‐dione ( 2 ) is discussed. By addition of LiAlH 4 , NaBH 4 or Wittig's reagent only one keto group reacted to give HO‐ or c C 3 H 4 ‐functionalized [1.1](2,17)(6,13)ferrocenophan‐12‐hydroxy‐1‐one ( 3 ) and [1.1](2,17)(6,13)ferrocenophan‐12‐cyclopropane‐1‐one ( 4 ). Exchange of CO by CS groups is possible upon addition of Lawesson's reagent to 2 forming [1.1](2,17)(6,13)ferrocenophan‐1,12‐dithioketone ( 5 ). Theoretical studies confirm the different reactivities of the CO groups. Electrochemical studies on 2 – 5 showed separated reversible one‐electron events for 2 – 4 (125–925 mV) and an irreversible one for 5 . The ferrocenyls in 4 are easier to oxidize, due to their higher electron‐richness. In 2 a larger redox separation comes about suggesting a stronger intermetallic interaction between Fe II /Fe III in the mixed‐valent species. In situ UV‐vis/NIR studies confirm that 2 is a weak coupled class II system according to the classification of Robin and Day. Compounds 3 and 4 display electrostatic interactions among the ferrocenyls as oxidation progresses.