12-MEMBERED CROWN-ETHERS - LIPOPHILIC DERIVATIVES OF BENZO-12-CROWN-4 AND NAPHTHO-12-CROWN-4 AND THEIR MEMBRANE-ELECTRODE PROPERTIES - CRYSTAL-STRUCTURES OF BENZO-12-CROWN-4 NAI AND KI COMPLEXES

Lipophilic derivatives of benzo-12-crown-4 and naphtho-12-crown-4 have been synthesized. The behavior of the parent compounds and their derivatives in membrane ion-selective electrodes have been studied. Selectivity changes have been observed with the rise in lipophilicity. Crystal structures of the NaI and KI complexes of benzo-12-crown-4 (1 and 2) have been determined by X-ray analysis. The alkali metal and iodide ions are in direct contact in 2 but not in 1. Compound 1 [Na(benzo-12-crown-4)(2)]. I is triclinic, with a = 13.368(8), b = 10.727(7), c = 10.325(4) Angstrom; alpha = 73.56(4), beta = 77.73(4), gamma = 108.70(5)degrees; Z = 2, space group is P (1) over bar. Compound 2 [K(benzo-12-crown-4)(2) . I] is monoclinic, with a = 15.807(8), b = 12.043(4), c = 15.601(6) Angstrom, beta = 117.74(3)degrees; Z = 4, space group C2/c. In both compounds the cations interact with all oxygen atoms of two crown ether molecules. Correlation of the crystal structures and behavior of the crown ethers in ion-selective membrane electrodes is discussed.