Binding of calixarene-based Langmuir monolayers to mercury chloride is dependent on the amphiphile structure

Abstract

Two amphiphilic calix[4]​arenes bearing four dodecyl chains at the lower rim and two amino functions (vicinal and distal) at the para-​phenolic positions have been synthesized. Surface-​pressure vs. mol.-​area isotherms reveal that Langmuir monolayers of the two regioisomers show considerably distinct self-​assembly behaviors at the air-​water interface. Compression isotherms, Brewster angle microscopy and synchrotron-​based X-​ray near-​total-​reflection fluorescence, X-​ray reflectivity and grazing incidence X-​ray diffraction reveal that the monolayers of the two diamino calix[4]​arene derivs. and those of their structural analogs bearing four amino moieties in para positions exhibit significant differences in their binding properties towards HgCl2 despite the structural and functional similarity among the macrocycles.