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RESEARCH PRODUCT

Impact of O → S Exchange in Ferrocenyl Amides on the Structure and Redox Chemistry

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The conformations and redox chemistry of ferrocenyl amides have been investigated in considerable depth in the last few years, while ferrocenyl thioamides have attracted less interest so far, although distinctly different conformations and reactivity patterns are expected. Monoferrocenyl amides Fc-NHC(O)CH3 (1) and 1,1′-CH3O(O)C-Fn-NHC(O)CH3 (2) and diferrocenyl amides Fc-NHC(O)-Fc (5) and Fc-NHC(O)-Fn-NHC(O)CH3 (6) are easily transformed into the corresponding thioamides (3, 4, 7, 8) by treatment with Lawesson’s reagent (2,4-bis(p-methoxyphenyl)-1,3-dithiaphosphetane-2,4-disulfide) (Fc = Fe(C5H4)(C5H5), Fn = Fe(C5H4)2). The thioamide conformations (cis/trans) in 3, 4, 7, and 8 and the hydrogen bond determined secondary structure of dithioamide 8 have been elucidated by IR and NMR spectroscopy as well as by DFT calculations (B3LYP, LANL2DZ, PCM CH2Cl2) and contrasted with the corresponding amides 1, 2, 5, and 6. The electronic communication via the thioamide bridge in 7+ and 8+ in comparison to the intera...