Synthesis, Structure and Inclusion Properties of<i>distal</i>-bis{[(5′-methyl-2,2′-bipyridyl)-5-yl]methoxy}tetrathiacalix[4]arene with 1,3-<i>alternate</i>Conformation
distal-Tetrathiacalix[4]arene having [(5′-methyl-2,2′-bipyridyl)-5-yl]methoxy group with 1,3-alternate conformation was prepared, which shows strong Ag+ affinity and the high Ag+ selectivity. The conformational change of 2,2′-bipyridyl moiety from the original outward orientation of the ring nitrogen to the inside orientation toward the thiacalixarene cavity was observed in the process of Ag+ complexation