Conformational transition effects of anion recognition by calix[4]arene derivatives

A calix[4]arene derivative (3) possessing naphthalene sulfonyl amide groups has been synthesised in satisfactory yield. Furthermore, its conformation and anion-binding behaviours are systemically investigated by the methods of fluorescence spectrometry, (1)H NMR spectrometry and X-ray crystallography. The results indicate that compound 3 assumes two different configurations in polar/apolar solutions, and therefore presents the interestingly solvent-dependent binding properties for anions. It is demonstrated that hydrogen-bonding interactions do play a great role in the conformation of 3 and its anion recognition.