The synthesis of tetracarbonyl derivatives of thiacalix[4]arene in different conformations and their complexation properties towards alkali metal ions
The three conformations of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis[(benzoyl)methoxy]-2,8,14,20-tetrathiacalix[4]arene 1: cone, partial cone and 1,3-alternate, were prepared by the treatment of 5,11,17,23-tetra-tert-butyl-2,8,14,20-tetrathiacalix[4]arene25,26,27,28-tetraol (TCA) with a-bromo acetophenone in the presence of appropriate alkali carbonate M2CO3 (M¼Na, K, Cs) as base catalyst in acetonitrile. Structure of the conformers were established by 1H NMR, 1H–1H COSY, 1D NOE, 2D ROESY and X-ray experiments. The alkali cation binding ... إقراء المزيد