Synthesis, structures, and magnetic properties of four dodecanuclear Ni₈RE₄ (RE = Gd, Dy, Y) clusters trapping four μ₅-bridged carbonate anions

Abstract

The syntheses, structures, and magnetic properties of four heterometallic dodecanuclear aggregates with molecular formulas [Ni^ΙΙ₈RE^ΙΙΙ₄(L)₈(CO₃)₆(H₂O)₁₄]·mCH₃OH·12H₂O [RE = Gd (1), m = 2; Dy (2), m = 0] and [Ni^ΙΙ₈RE^ΙΙΙ₄(L)₈(CO₃)₄(CH₃OH)₄(H₂O)₈]·(ClO₄)₄·8H₂O [RE = Dy (3), Y (4)] are presented. These complexes were obtained from two easy synthetic procedures through atmospheric CO₂ fixation involving direct reaction of 2-(2-hydroxy-3-methoxybenzylideneamino)phenol (H₂L) with RE(NO₃)₃·nH₂O and Ni(ClO₄)₂·6H₂O in the presence of triethylamine in different solvents under ambient conditions. Single-crystal X-ray diffraction reveals that these complexes possess very similar core structures featuring an unprecedented “tetra-capped hexahedron” topology bridged by four μ₅-bridged carbonates. Static magnetic susceptibility measurements indicate dominant ferromagnetic coupling between the metal centers for 1 and 4. The dissimilar static and dynamic magnetic behaviors seen in 2 and 3 are probably ascribed to different coordination environments and ligand fields around Dy^ΙΙΙ ions. These complexes represent limited examples of high-nuclearity Ni^ΙΙ-RE^ΙΙΙ family trapping μ₅-bridged carbonates through atmospheric carbon dioxide fixation.

Graphical abstract

By varying reaction solvent, four heterometallic dodecanuclear clusters trapping four μ₅-bridged carbonates have been assembled. The Ni₈Dy₄ analogs display dissimilar static and dynamic magnetic behavior, which are ascribed to different coordination environments and ligand fields around the Dy^III ions.

Keywords:

• Carbon dioxide fixation
• Solvent effect
• Heterometallic
• Coordination perturbation
• High nuclearity

Additional information

Funding

This work was supported by Natural Science Foundation of China [grant number 21073142]; Education Committee of Shaanxi Province [grant number 11JK0812]; the start-up foundation of Northwest University [grant number PR13094]; the school fund of Northwest University [grant number NF14023].