Abdelwaheb Hamdi

Synthesis and cation complexation studies of a new tetra(2-pyridylmethyl)amide calix[4]arene

Abstract The synthesis of a new tetra(2-pyridylmethyl)amide calix[4]arene is reported. Its binding properties towards alkali and alkaline earth metals, transition metals and lanthanides have been determined along with the complexes stoichiometries. 1 H NMR investigations allowed the location of cations in the receptor to be determined. The synthesis and crystal structure of the related tetra(benzyl) derivative are also reported.

Synthesis and Complexing Properties of Four New Tetraamido-type p-tert-Butyl Calix[4]arenes Presenting Two Proximal Binding Subunits

The synthesis of four new tetraamido-type p-tert-butylcalix[4]arenes presenting two proximal binding subunits is reported. Complexation of alkalimetals and zinc picrates with these ligands have been carried out and monitored by 1H-NMR inCDCl3. It is shown that hard cations are included in the tetraamido cavity while thezinc cation is chelated to the pyridine rings of one of the ligands. The formation of a 1:1:1heterobinuclear complex is also described

Complex Formation of Some Tetraamido-type Calix[4]arene Derivatives Detected by Vibrational Spectroscopy

Complex formation of five teraamido-type calix [4] arene derivatives—containing a heteroaromatic ring on the carboxamide moieties forming the coordination sphere—with alkali/alkali earth ions were the subject of FT–IR studies. The selectivity of these ligands toward different cations were found in acetonitrile solution, with the best detection in the case of the thiophene derivative, ligand 3, that exhibited selectivity to thallium(I) and thallium(III) ions over alkali/alkaline earth ions. Calixarenes 2 and 4 exhibit selectivity to potassium and ligand 5 to lithium ions among alkali/alkaline earth ions, however, thallium(I) ions show interference with these measurements. Moreover, selectivity was observed in solid state when surface complexes were prepared on sodium chloride, potassium chloride, bromide and iodide, calcium chloride and fluoride. The solid samples were examined by FT–Raman and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) method. Calixarenes 2 and 4 are of potential analytical application for the recognition of cations among alkali/alkaline earth metal ions in solid state by FT–IR spectroscopic detection. The number of methylene units in the substituents of calixarenes influences the efficiency of the complexation process significantly, as it can be seen from the comparison of ligands 1 and 2 both in solution and in the solid state. FT–Raman measurements on calcium chloride show that the attachment of the ligand molecules to the salt surface is accompanied by the squeezing of water molecules from some special positions of the hydrated salt lattice.