<strong>Synthesis and Platinum (II) Complexes of Different Polyazacyclophane Receptors</strong>

Abstract

Abstract:The interaction of PtCI4 2-with different polyazacyclophanes containing a pyridine unit as aromatic spacer has been studied by 1 H and 195 Pt NMR spectroscopy, Analysis of the recorded spectra of D2O solutions containing L and PtCl4 2-in a 1:1 molar ratio at acidic pH shows the evolution with time of the 1 H and 195 Pt signals. Different crystal structures have been solved by X-ray diffraction analysis. At acidic pHs, the metal ion is coordinated by the central amino group of the macrocyclic cavity and three chloride or bromide atoms, in a square planar geometry. Formation of [Pt(H2L1)Br3]Br (1) and [Pt(H2L2)Br3]Br (2) reveals the rapid substitution of chloride ligands in PtCl4 2-by bromide ligands. However, as reveals the crystal structure obtained for [Pt IV L3Br2](PtBr4)(H2O) (4), at slightly higher pH values, the metal ion is coordinated through all nitrogen atoms of the macrocyclic cavity and an oxidation to Pt(IV) occurs. .