Solvent extraction of perrhenate with 25,26,27,28-tetrakis[(ethoxycarbonyl)methoxy]-p-tert-butylcalix[4]arene and crystal structure of the extracted complex

The extraction of perrhenate with 25,26,27,28-tetrakis[(ethoxycarbonyl)meth oxy]-p-tert-butylcalix[4]arene (L) into 1,2-dichloroethane was investigated . The presence of Na+ in the aqueous phase is necessary for the extraction. The extraction equilibrium has been established and the thermodynamic quan tities Delta H degrees, T Delta S degrees and log K-ex are -61.3 kJ/mol, -4 1.4 kJ/mol and 3.69, respectively. The effect of diverse ions on the extrac tion of ReO4- was studied. The corresponding extracted complex [NaL]ReO4. H 2O was prepared and characterized by EA, IR and X-ray structure analysis. T he complex crystallizes in the tetragonal space group P4/ncc with a = b = 1 4.735(3), c = 29.094(3) Angstrom, V = 6316(2) Angstrom(3), Z = 4.