Fluxionality in polynuclear copper(II) complexes containing aminoalcoholate ligands: Syntheses, crystal structures, and H-1 nuclear magnetic resonance studies

Three new polynuclear copper(II) complexes with aminoalcoholate and acetate as ligands, [Cu-2(O(2)CMe)(2)(OCH(2)CH(2)NMe(2))(2)] 1, [Cu-2(O(2)CMe)(2)(OCH(2)CH(2)NMe(2))(2)(H2O)(2)] 2 and [Cu-4(mu(4)-O)-(bdmmp)(2)Br-4] 3 [Hbdmmp = 2,6-bis(dimethylaminomethyl)-4-methylphenol], have been synthesised and their structures were determined by X-ray diffraction analysis. In the solid state 1 has a one-dimensional structure linked by covalent bonds while 2 has an extended structure linked by both covalent and hydrogen bonds: The solution behaviour of compounds 1 and 3 has been examined by H-1 NMR spectroscopy. Compound 1 exists as a mixture of oligomers and undergoes a dynamic process in solution, which can be attributed to the formation of weak intermolecular Cu ... O bonds through the acetate ligands. In contrast, no dynamic behaviour of 3 was observed. The magnetic properties of 1 and 3 were examined via magnetic susceptibility measurements which showed that both compounds are dominated by antiferromagnetism.