Synthesis and properties of sulfur-bridged analogs of p-tert-butylcalix[4]arene

p-tert-Butylcalix[4]arene analogs in which up to four methylene bridges were replaced by sulfur bridge(s) were synthesized. NMR studies indicated that the thiacalixarenes were conformationally much more flexible than the parent calixarene in CDCl3 solution; the flexibility was greater with increasing number of the sulfur bridge. The thiacalixarenes serve as inclusion hosts for some organic compounds, forming 2:1 (host:guest) crystalline complexes in many cases. (C) 1997 Elsevier Science Ltd.