A preparative study of some coronands and their complexation of silver(I), zinc(II), cadmium(II) and lead(II)

Abstract

A study of the complexation of heavy metal ions by the coronands 3,12,20,29-tetraoxa-35,36-diazapentacyclo[29.3.1.1.14,18.0 5,10.022,27]-hexatriaconta-1(35),5(10),6,8,14,16,18(36), 22(27),23,25,31,33-dodecaene (1); 2,3,11,12-bis (4′-methylbenzo)-1,4,10, 13-tetrathia-7,16-dioxacyclo-octadeca-2,11-diene (2); 7,16-diaza-1,4,10,13- tetraoxa-2,3,11,12-dibenzocyclooctadeca-2,11-diene (3); 2-[19-(2-hydroxy-2- phenylethyl)-7,8,9,10, 18,19,20,21-octahydro-6H,17H-dibenzo[b,k][1,4,10,13,7,16] tetraoxadiazacyclooctadecin-8-yl]-1-phenyl-1-ethanol (4); 1,4,10,13-tetraoxa-7, 16-diazacyclo-octadecane (5); and 2-[16-(2-hydroxy-2-phenylethyl)-1,4,10,13- tetraoxa-7,16-diazacyclo-octadecanyl]-1-phenyl-1-ethanol (6) is described. Coronands 1 and 3 were prepared by literature methods, improved methods were used to prepare 2, and 4 and 6 were prepared from 3 and 5 (obtained commercially), respectively. Potentiometric studies in N,N-dimethylformamide yielded (logK/dm3 mol-1)=5.50, 6.49, 9.42 and 7.52 for [Ag·1]+, [Ag·2]+, [Ag·5]+ and [Ag·6]+, respectively; <2, <2, 4.30 and <2 for [Zn·1]2+, [Zn·2]2+, [Zn·5] 2+ and [Zn·6]2+, respectively, <2, <2, 5.92 and 7.52 for [Cd·1]2+, [Cd·2]2+, [Cd·5]2+, and [Cd·6]2+, respectively, and 2.62, 2.38, 6.71 and 7.52 for [Pb·1]2+, [Pb·2] 2+, [Pb·5]2+, and [Pb·6]2+, respectively. ESI-MS studies of the interactions of 1-6 with Ag+, Zn2+, Cd2+ and Pb2+ are also reported. © 2003 Elsevier B.V. All rights reserved.