A Coordination-Catalyzed Multistep Tandem Reaction Constructs Hexanuclear Dysprosium Clusters with a Misaligned Double-Layer Triangular Shape Composed of Complex Acetal Trimers

It is extremely challenging to rapidly and efficiently generate complex organic polymers from very simple industrial raw materials through coordination-driven multistep tandem reactions under “one-pot” conditions. Herein, simple industrial raw materials, o-vanillin derivatives, 2-amino-1,2-diphenylethanol, and Dy(NO₃)₃·5H₂O, were used to react under “one-pot” solvothermal conditions to form complex acetal trimers, and dislocated double-layer triangular hexanuclear clusters 1 and 2, formed by the above trimers chelating Dy(III) ions, were obtained. The complex acetal trimer chelating ligands within clusters 1 and 2 are formed by a coordination-catalyzed multistep tandem reaction of o-vanillin derivatives with 2-amino-1,2-diphenylethanol. In the abovementioned tandem reaction process, the Schiff base reaction first occurs to form an imine intermediate, followed by a multistep acetal reaction to finally form an acetal trimer chelating ligand. The abovementioned hexanuclear clusters are composed of two parallel and staggered triangular Dy₃ clusters, the o-vanillin derivative (second ligand), the terminal coordinated NO₃^–, and the in situ formed acetal trimer in the structure are all arranged in antiparallel. It is worth noting that clusters 1 and 2 both showed distinct single-molecule magnet (SMM) behavior under zero-field conditions, with their effective energy barriers and magnetic relaxation times being U_eff = 9.2 K and 92.7 K, τ₀ = 8.6 × 10^–5 s and 8.8 × 10^–8 s, respectively. Coordination-catalyzed tandem reactions enrich the synthesis strategies of complex organic compounds, avoiding multistep organic synthesis and purification steps that require complex operations and provide low yields. They have the advantages of being fast, simple, efficient, and having high atomic utilization. This work utilized a complex in situ tandem reaction assisted by Dy(III) ion coordination to obtain hexanuclear dysprosium clusters with SMM behavior, which not only promoted the progress of crystal engineering of lanthanide clusters but also opened a door to the synthesis of magnetic crystalline materials constructed by complex organic chelating ligands.