2001 年 69 巻 3 号 p. 187-192
The facilitated transfer of chloride/bromide ion encapsulated into macrotricyclic quaternary ammonium ion NtMQA4+ (Nt= –CH2C10H7) through the water (aq)/nitrobenzene (nb) interface was revealed using cyclic voltammetry. The observed anodic-peak current ip,a between 100 and 400 mV vs. Hg/Hg2SO4/SO42- resulted from the transfer of NtMQA4+ as well as Cl- ⊂NtMQA4+ from (aq) to (nb) : the cathodic-peak current ip,a was also observed as a result of their transfer from (nb) to (aq). However, benzyl (=Bn) derivative BnMQA4+ showed no clear anodic peak because of its own less hydrophobicity, compared with NtMQA4+ . The order of I- ≧ Cl- > Br in the magnitude of the observed ip,a resulted from the order, Cl- > Br- > I- , for ip,a controlled by the order, Cl- ~ Br- < I-, for stability constants of the ion-pair of halide ion with NtMQA4+ as well as from the order, Cl- ~ Br- < I-, for ip,a controlled by the inclusion of each halide ion into NtMQA4+ . The plots of ip,a and −ip,a as a function of log [X-] became linear for Cl- and hyperbola for Br between 10-6 M and 10-3 M X-. The chloride-ion transfer across (aq)/(nb) interface may be more selectively facilitated using an advanced NtMQA4+, the electrolytic cell may be developed for its own application to efficient chloride-ion prove.
