Tetranuclear zinc complexes of ligands containing the 2-pyridyl oxime chelating site

Three tetranuclear zinc(II) complexes of the general formula [ Zn 4 ( μ 3 -OH ) 2 ( LR N,N, O 1 – 3 ) 4 ( LR N,N 1 – 3 ) 2 ] (1–3) were formed from the reaction of ZnCl2 with 2 equiv. of the respective 2-pyridyl ketone oximes, HLR1−3 (R1–3 = H, Ph and Py). The synthesis and the characterization (elemental analysis, IR, 1H NMR and UV–Vis) are described. Complexes 2 and 3 were structurally characterized by single-crystal X-ray crystallography, revealing new examples of anti 12-metallocrown-4 complexes where anions such as hydroxyl groups are encapsulated into the cavity of the tetranuclear cluster.