In the light-driven membrane (o-dichlorobenzene) transport with azobis(benzo-15-crown-5)(Cr(5,5)), we have found that by alternate irradiation with u.v. light and visible light the rate of K+ is considerably accelerated while the rates of Na+ and Rb+ transport are accelerated only a little. This result indicates that efficient light-driven ion-transport is achieved with moderately stable complexes (e.g. K[cis-Cr(5,5)] rather than with unstable (Na[cis-Cr(5,5)]) or very stable (Rb[cis-Cr(5,5)]) complexes. The rate ratio of K+ versus Na+ independent transport in the dark ([M+] in the aqueous phase/[Cr(5,5)] in the membrane phase = 80) was only 2.7-fold, whereas that in competitive ion transport ([M+] in the aqueous phase/ [Cr(5,5)] in the membrane phase = 1 000) was enhanced up to 27-fold. In competitive ion transport, the rates of Na+ and K+ transport were both suppressed by u.v. light irradiation and significantly enhanced under alternate irradiation with u.v. and visible light. Since the photoirradiation effect is similar to that of K + transport, it is proposed that the rate of competitive ion transport is primarily governed by the affinity of K+ for the carrier molecule.
|Number of pages||5|
|Journal||Journal of the Chemical Society, Perkin Transactions 1|
|Publication status||Published - Dec 1 1982|
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