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 [NiΙΙ8REΙΙΙ4(L)8(CO3)6(H2O)14]·mCH3OH·12H2O [RE = Gd (1), m = 2; Dy (2), m = 0] and [NiΙΙ8REΙΙΙ4(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 DyΙΙΙ ions. These complexes represent limited examples of high-nuclearity NiΙΙ-REΙΙΙ family trapping μ5-bridged carbonates through atmospheric carbon dioxide fixation.