Synthesis, self-assembled monolayers and alkaline earth metal ion recognition of p-tert-butylcalix[4]arene derivatives

The synthesis and self-assembled monolayer (SAM) formation of three conformational isomers of p-tert-butylcalix[4]crown-6 derivatives 3a-3c and one p-tert-butylcalix[4]arene derivative (3d) are reported. The SAMs of these compounds were prepared and characterized by electrochemistry, reflection-absorption infrared spectroscopy (RAMS) and contact-angle measurements. The recognition properties of these SAMs with metal cations were systematically investigated using electrochemical techniques and impedance spectroscopy. The monolayers exhibit selective binding and sensing abilities with alkaline earth metal cations such as Ca2+ and Ba2+ over alkali metal ions. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.