Synthesis, Structure, and Extraction Properties of paco-Calix[4]arene Crown-6 Ethers

anti-25,27-Bis-n-octyloxycalix[4]arene, the paco-isomer of25,27-bis-n-octyloxycalix[4]arene crown-6 ether, and the paco- and1,3-alt isomers of 25,27-bis-n-octyloxycalix[4]arene t-butylbenzocrown-6 ether were prepared. The crystal structures of anti-25,27-bis-n-octyloxycalix[4]arene, paco-25,27-bis-n-octyloxycalix[4]arene crown-6, and 1,3-alt-25,27-bis-n-octyloxycalix[4]arene crown-6 were determined and thesolution structure of anti-25,27-bis-n-octyloxycalix[4]arene was studied by 2D- and VT-NMR. The extraction of alkali metal nitrates by thepaco-25,27-bis-n-octyloxycalix[4]arene crown-6 and t-butylbenzocrown-6 ethers in 1,2-dichloroethane was compared to that of the corresponding 1,3-alt isomers.