The synthesis of N, N-diethyi-2,11-diaza-5,8-dithia(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 PdCl2, PdCl2. 2HCl, Pd(CA). 2H2O and 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 Pd(CA) prefers ligation through both N and S donor atoms, leaving one thioether S to interact with the FeII center.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry