Fluorinated diaminobicyclooxacalixarene and diaminotetraoxacalixarenes: Synthesis and conformational behaviour

Polyfluorinated diaminotetraoxacalixarenes and diaminobicyclooxacalixarene were obtained in good yield by reduction of the corresponding dinitrooxacalixarenes with sodium dithionite. Fluorinated tetraoxacalix[4]arenes with nitro and amino groups located in the inner rim of the macrocycle exists in the solution as an equilibrium mixture of two conformers. For diaminotetraoxacalixarenes the conformational equilibrium is shifted towards conformers having a 1,3-alternate structure. The ESI-MS method shows the possibility of complexing fluorinated diaminotetraoxacalixarenes and diaminobicyclooxacalixarenes with metal cations.