Synthetic and electrochemical studies on electroactive ionophores based on the di-η-cyclopentadienyl-molybendum and -tungsten fragments

Abstract

The compound [W(η-C 5H 5) 2Cl 2] reacts with HSCH 2(CH 2OCH 2) 3CH 2SH in the presence of base giving the metalla-crown ether complex [W(η-C 5H 5) 2SCH 2-(CH 2OCH 2) 3CH 2S] which can undergo a reversible one-electron oxidation. Treatment of [M(η-C 5H 5) 2Cl 2] (M  Mo or W) with 4′-carboxybenzo-15-crown-5 and base gives the complexes [M(η-C 5H 5) 2&[;(benzo-15-crown-5)-4′-carboxylato&]; 2], which also undergo reversible oxidation. Small changes in the E 1 2 (< 20 mV) were observed upon changing the electrolyte from (C 2H 5) 4NPF 6 to NaPF 6. The new compounds, [M(η-C 5H 5) 2&[;(benzo-15-crown-5)-4′-thiolato&]; 2] (M  Mo or W) prepared from the sodium salt of (benzo-15-crown-5)-4′-thiol and [M(η-C 5H 5) 2Cl 2], undergo a reversible one-electron oxidation and the E 1 2 is shifted anodically upon addition of alkali metal cations.