Alkyl chain length influence of the functionalized diethanolamine ligand on the slow relaxation of the magnetization in {CoIII3DyIII3} complexes

Abstract

We are reporting the synthesis, structural characterization and magnetic properties of a series of Co(III)/Dy(III) complexes built up from N-alkyl derivatized amino-alcohol ligand diethanolamine, functionalized with CnH2n+1 alkyl chains (n = 3, 4, 6, 8 and 10). While n = 3 afforded a butterfly {CoIII2DyIII2} core, the other alkyl chains (n = 4, 6, 8) afforded hexanuclear triangle-in-triangle {CoIII3DyIII3} complexes as shown by single crystal X-ray determinations. Infrared spectroscopy allows to characterize the C10 derivative complex, which was not crystallizing. Magnetic ac susceptibility data collected below 10 K at driving frequencies up to 10 kHz under zero dc field and up to 1 T provide insight into the SMM behaviour of the studied complexes. The characteristic time of the magnetization dynamics can be understood in terms of competing Raman, Direct and Orbach-like mechanisms. A relationship between the magnetization dynamics along the family of complexes and the increasing alkyl chain length is discussed.