The Oxyanions of Calix[4]arene:The NMR Investigation of the Structure of the Oxyanions of Calix[4]arene

The structure and conformational behavior of the oxyanions of calix[4]arene have been studied by the NMR spectrum. The structure of the oxyanions of calix[4]arene was completely dependent upon the counter cation in present. All of the anions derived from in the presence of NaH and KH appear to exist as a cone conformation, whereas those produced with lithium cation such as n-butyllithium and LiOD show a more varied conformational behavior. The mono and tetraanions with lithium cation exist as a cone conformation, the trianions appear to exist as a partial cone conformation, and the dianions appear to disproportionate to the mono and trianions. The conformational stability decreases in the order of <TEX>$Li^+$</TEX> oxyanion > <TEX>$Na^+$</TEX> oxyanion > <TEX>$K^+$</TEX> oxyanion.