Solvent, N-alkyl substituent and coordination effects on the electrochemistry of 2,11-diaza-5,8-dithia[12](1,1')ferrocenophanes

Robert A. Holwerda, Jong Seung Kim, Thomas W. Robison, Richard A. Bartsch, Bronislaw P. Czech

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Abstract

The synthesis of N, N-diethyi-2,11-diaza-5,8-dithia[12](1,1')ferrocenophane (6), cyclic voltammetric studies of diazadithiaferrocenophanes in ten organic solvents and the electrochemical characteristics of four diazadithiaferrocenophane complexes with palladium(II) are reported with the objective of better understanding the factors which govern Fe-S bonding in such compounds. As compared with the N-decyl analog 7 (E1/2(FeIII/II = 727 mV vs. SHE), the half-wave reduction potential of 6 (388 mV) in acetonitrile solution (25°C, 0.1 M N(uBu)4ClO4) is displaced by 0.34 V to more negative potential. However, the E1/2 values for 6 and 7 are essentially identical (average of 0.39 ± 0.02 V) in butyronitrile, benzonitrile, dichloromethane, N,N-dimethylformamide, acetone and methanol. On this basis it is concluded that conformations which permit FeII-S bonding in 7 are supported by hydrophobic attractions between the N-decyl substituents. The perturbation of Fe-S bonding by coordination of S and/or N atoms to PdII was examined by preparing [7]PdCl2, [6]PdCl2. 2HCl, [6]Pd(CA). 2H2O and [7]Pd(CA), where CA2- = 2,5-dioxo-3,6-dichloro-1,4-benzoquinone (chloranilate dianion). Electrochemical and 13C NMR findings suggest that both ferrocenophane sulfur atoms ligate PdII in the former three complexes, while [7]Pd(CA) prefers ligation through both N and S donor atoms, leaving one thioether S to interact with the FeII center.

Original languageEnglish
Pages (from-to)123-129
Number of pages7
JournalJournal of Organometallic Chemistry
Volume443
Issue number1
Publication statusPublished - 1993 Jan 12
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Chemical Engineering (miscellaneous)
  • Inorganic Chemistry
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Science (miscellaneous)
  • Materials Chemistry

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