LOWER RIM 2-METHYLTHIOETHOXY SUBSTITUTED CALIX[4]ARENES AS SHAPE-SELECTIVE COMPLEXANTS FOR MERCURY AND SILVER

The compounds 5, 11, 17, 23-tert-butyl-25, 26, 27, 28-(2-methylthioeth oxy)calix[4] arene 1 and 25, 26, 27, 28-(2-m ethylthioethoxy)cal ix[4] arene 2 have been synthesized from their corresponding 2-bromoethoxy derivatives. The crystal structure of 2 shows that the molecule has a flattened cone conformation. For the extraction of heavy metals from w ater into chloroform 1 and 2 show similar effectiveness for SnCl3-, Pd CI42-, PtCI42- and AuCl4-, but for Hg2+ and Ag+, 2 is a better extract ant than 1. This difference is discussed in terms of the relative hydr ophobicities and structures of the two compounds.