RESUMO
Five novel 1,3-alternate calix[4]azacrown ethers having 2-picolyl, 3-picolyl, and benzyl unit on the nitrogen atom were synthesized and used as ionophores for transition metal-selective polymeric membrane electrodes. The electrode based on 2-picolyl armed 1,3-alternate calix [4] azacrown ether exhibited Nernstian response toward copper (II) ion over a concentration range (10(-4.5) M-10(-2.5) M). The detection limit was determined as 10(-5) M in pH 7 and the selectivity coefficients for possible interfering cations were evaluated. Anions in the sample solution strongly affected the electrode response.
RESUMO
A new calix[4]-crowned azacrown ether, C(51)H(59)NO(11)S, consisting of four phenyl rings in a 1,3-alternate conformation was synthesized from the reaction of 25, 27-bis(5-chloro-3-oxapentyloxy)calix[4]crown-5 and p-toluenesulfonamide in the presence of Cs(2)CO(3). A crown-5 loop was attached on the two facing lower rims of the calix[4]arene and the N-tosyl azacrown group was attached on the other set of lower rims of the calix[4]arene backbone. This molecule seems to offer an inside cavity for the formation of a host-guest complex.