| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Bis (crown-ether) derivatives are able to bind alkali metal cation, which has a little larger size than the cavity of a crown ether, more selectively by cooperative action of their two adjacent crown ether rings on complexation. These derivativers which might be stereoisomeric mixtures, however, so far were investigated as an ISE neutral carrier. The effect of stereochemistry due to the presence of a chiral center on the encapsulation of Na^+ into the cavity between two crown ether rings seems to be considerable. Therefore, at the first, optically active bis (12-crown-4)s, (R,R)-type 2-decyl-2-methylmalonate derivative, (R,R)-type dibenzylmalonate derivative, and (S,S)-type 2-decyl-2-methylmalonate derivative, were synthesized and Na^+-selectivity of resulting bis (12-crown-4)s were evaluated by electrochemical measurement. The Na^+-selectivity coefficient with respect to alkali and alkaline earth metal cation for these new optically active bis (12-crown-4) based electrodes were determ
… More
ined by fixed interference method. The best selectivity (logk^<pot>_=-2.3) was obtained when the sensons containing optically active bis (12-crown-4) as newtral carrier in 2.8 % were used in association with o-nitorophenyl octyl ether (NPOE) as a plasticizing solvent mediator and sodium tetrakis [3,5-bis (trifluorophenyl] borate (NaHFPB) as an anion excluder in PVC matrices. Na^+ selectivity against K^+ was augmented by a factor of nearly two using (R,R)- or (S,S)-bis (12-crown-4) compared with that of optically inactive bis (12-crown-4)s reported previously. FAB-MASS method revealed that superior Na^+ selectivity was depend on difference in the complexation crown with Na^+ and K^+.
At the second, four kinds of bis (15-crown-5) derivatives were also synthesized and K^+-selectivity were similarly estimated. In the (R,R)-type bis (15-crown-5)s based electrodes, NPOE gave good results, allowing high K^+-selectivity (logk^<pot>_=-3.4) compared with that of optically inactive bis (15-crown-5) derivatives. Less
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