Abstract: The complex constants K_tfor 1 :1 complexes of KC1O₄with cholesteryloxy-carbonyl mesomorphic crown ether compounds derived from DB-18-C-6 and B-15-C-5, i. e. cis(trains)-4, 4'-bis-[(N-cholesteryloxy-carbonyl) amino]-dibenzo-18-crown-6-(C-l and C-2), 4'-[(N-cholesteryloxy-carbonyl) amino]-benzo-15-crown-5(C-3), were determined at 25℃ in CH₃CN+CHCl₃conducto-metrically. The results show that the complex behaviour of K⁺ toward crown ether compounds depends on the solvability and ring hole size of macrocyclic polyethers. The lgK_tof K⁺toward C-l, C-2 and C-3 in CH₃CN+CHCl₃are 5. 56±0. 03, 5. 77±0. 02 and 4. 85±0. 02, respectively.

Key words: Mesomorphic crown ether, Complex constant, Conductance