Through Space Interaction Mediated by a Sulfoxide
Two new bisferrocenylphenylsulfoxides were synthesized and studied to determine the effect of the polar sulfoxide bond on through space interaction between the ferrocene moieties. The electronic and redox properties of these compounds were studied by ultra-violet photoelectron spectroscopy, cyclic voltammetry, differential pulse voltammetry, and DFT computations. Electrochemical results for 2,6-bis(ferrocenyl) thioanisole S-oxide 5b show two, fully reversible one electron redox processes. The initial oxidation shows a 62 mV negative shift compared to the sulfide analog 2,6-bis(ferrocenyl)thioanisole, and an increased peak separation for the oxidations of 160 vs 145 mV. No peak separation is observed in 6b. No intervalence charge transfer band was observed in the complex 5b+1by UV-Vis/NIR spectroscopy, ruling out electronic communication. Thus, the through space electrostatic interactions of the sulfoxide renders the non-equivalent ferrocenes in 5b to have different oxidation potentials.
