Highly flexible O,O′,N ligands and their Fe, Ni, Cu and Zn complexes

Three new chiral ligands bearing an O,O′,N donor set (OmethoxyOhydroxyNpyridine) were synthesised and coordinated to FeIII, FeII, NiII, CuII and ZnII to yield complexes with the general formula [M(OON)Clx]y. While the pyridine N and the hydroxy O atoms coordinate strongly to all applied metal ions, the methoxy donor seems not to be involved in coordination, although some evidence for a weak interaction between OMe and the ZnII were found in NMR spectra. In the bidentate O′,N coordination mode the new ligands exhibit several coordination geometries as analysed in the solid compounds by XRD, EXAFS and EPR and in solution by UV–Vis absorption, cyclic voltammetry, EXAFS, EPR or NMR spectroscopy.