Calix arene-pyridinium cation

Other calix[4]arenes combine both a host and a guest unit, such as the pyridinium-conjugated derivative 11-17 (Scheme 12.12) which forms oligomers by cation- r interaction both in solution, in the solid state, and also in the gas phase, as revealed by H NMR spectroscopy, crystal structure determination, and crystallographic studies. °... 

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