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

Abstract

Three new polynuclear copper(II) complexes with aminoalcoholate and acetate as ligands, [Cu2(O2CMe)2(OCH2CH2NMe2)2]1, [Cu2(O2CMe)2(OCH2CH2NMe2)2(H2O)2]2 and [Cu4(µ4-O)-(bdmmp)2Br4]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 1H 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.