Synthesis of calix[4]arenequinone dimers for alkali metal ion sensor

Abstract

25,27-Di(ethyleneglycol)-bis-p-tert-butylcalix[4]arene, 5, and 25,27-di(methoxy)-26,28-di(ethyleneglycol)-bis-p-tert-butylcalix[4]arene, 11, have been synthesized by a one-pot method and a stepwise approach, respectively. The one pot reaction in a pressurized vessel resulted in the symmetrical biscalixarene 5 with high yield (69%). The quinone derivatives 25,27-di(ethylene glycol)-bis-p-tert-butylcalix[4]tetraquinone, 12, and 25,27-di(methoxy)-26,28-di(ethylene glycol)-bis-p-tert-butylcalix[4]diquinone, 13, were obtained from reactions of 5 and 11, respectively with Tl(CO[subscript 2]CF[subscript 3])[subscript 3] in CF[subscript 3]COOH. Molecular dynamic simulations were performed for compounds 12 and 13 both before and after addition of Na+ in acetonitrile solution. The MD calculation at 300 K showed the change of conformations among cone, partial cone and 1,3-alternate conformations of the calixarene unit. The lowest energy of each possible morphology has been determined. The preliminary investigation on electrochemical properties of 12 and 13 by cyclic voltammetry showed significant changes of the quinone reduction signals upon addition of Na+ ion. Voltammograms of 12 and 13 exhibited complicated electrons transfer reduction processes following by chemical reactions.