Alkyl chain length influence of the functionalized diethanolamine ligand on the slow relaxation of the magnetization in {Co III3Dy III3} complexes

Abstract

We report the synthesis, structural characterization and magnetic properties of a series of Co(III)/Dy(III) complexes built up from an N-alkyl derivatized amino-alcohol ligand diethanolamine, functionalized with C_nH_2n+1 alkyl chains (n = 3, 4, 6, 8 and 10). While n = 3 afforded a butterfly {Co^III₂Dy^III₂} core, the other alkyl chains (n = 4, 6, 8) afforded hexanuclear triangle-in-triangle {Co^III₃Dy^III₃} complexes as shown by single-crystal X-ray determinations. Infrared spectroscopy allows us to characterize the C₁₀ derivative complex, which did not crystallize. 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 the competing Raman, Direct and Orbach-like mechanisms. A relationship between the magnetization dynamics within the family of complexes and the increasing alkyl chain length is discussed.