Chemical and Magnetic Tuneability in Structurally Defined Hetero-Trimetallic Dendrimers

Abstract

The inaccessibility of magnetic dendrimers stems not only from the complexity of their synthesis, but more critically from the challenge of crystallising dendritic structures. Magnetic architectures are difficult to decipher without X-ray data considering magneto-structural correlations for the rational design of molecular magnets and better understanding of the physical and magnetic properties. Here, we report the synthesis and characterisation of a tuneable magnetic hetero-trimetallic dendrimer family, MLn₃Co₆, with Ln³⁺ = La, Gd, Tb, Dy and M³⁺ = Cr or Co. We present, for the first time, a hetero-trimetallic dendrimer with a fully resolved X-ray structure and direct mass spectrometry evidence, providing unprecedented insight into the structural and magnetic properties of metallo-dendrimers. Furthermore, the chemical flexibility enables the synthesis of species with distinct magnetic behaviours depending on the incorporated metal ions. The choice of spin carriers determines whether the system exhibits a high-spin molecule behaviour or slow relaxation of magnetization.