Tetraphenylantimony(V)-assisted transfer of hydroxide and fluoride anions across the 1,6-dichlorohexane | water...

The ion-transfer reaction at the 1,6-dichlorohexane (DCH) | water (W) interface in the presence of an organometallic cation, tetraphenylantimony (TPhSb⁺), in DCH was studied voltammetrically. When TPhSb⁺ salt with [(C₄F₉SO₂)₂N]^- ion was added to the DCH-phase and the W-phase was buffered at pH < 6, a reversible cyclic voltammogram due to the simple transfer of TPhSb⁺ ion across the DCH | W interface was observed within the polarizable potential window. When the W-phase was buffered at pH > 7, the midpoint potential shifted to more positive potentials with increasing pH. The voltammogram could be attributed to the transfer of the OH^- ion assisted by the formation of TPhSbOH, which is stable in DCH. Also, a 7reversible voltammogram due to the TPhSb⁺-assisted transfer of F^- ion was observed at the TPhSb⁺ (DCH) | F^- (W, unbuffered) interfacial system. The same results were achieved when TPhSb[(C₄F₉SO₂)₂N] in DCH was replaced by TPhSbOH or TPhSbF, indicating the applicability of the TPhSb⁺ and TPhSbOH (DCH) | OH^- (W) interfacial system to a pH sensor for alkaline solution and that of the TPhSb⁺ and TPhSbF (DCH) | F^- (W) interface to a F^- ion sensor.