HOMOCALIXPYRIDINES - LIGANDS EXHIBITING HIGH SELECTIVITY IN EXTRACTION AND SENSOR PROCESSES

A series of differently functionalised all-homocalixpyridines I and th eir open-chain analogues II were synthesised by use of the Muller-Rosc heisen reaction. Their complexation properties were then investigated, by extraction and liquid membrane experiments. This new class of macr ocycles con;posed of pyridine units shows a pronounced selectivity tow ards soft metal ions, such as Ag-I, Pd-II, Hg-II and Au-III. The compl exation behaviour can be easily modified by variation of the ring size and substitution pattern, Molecular modelling studies of the ligands, as well as their silver(I) and mercury(II) complexes, were performed in order to understand the principles of complex formation. Furthermor e, the use of the new ligands as ionophores in PVC-based membrane elec trodes was studied.