Three azido-, alk/phenoxido- and acetato-bridged tetranuclear nickel complexes featuring defective double-cubane

Three new tetranuclear nickel(II) complexes of general formula [Ni4(L)2(N3)2(CH3COO)2(CH3O)2]2·xCH3OH·yH2O (HL = HL1, HL2 and HL3; x = 0, y = 1 for 1; x = 2, y = 0 for 2 and x = 2, y = 4 for 3) were synthesized and characterized by single crystal X-ray diffraction and magnetic measurements. Single crystal X-ray studies reveal that all three complexes exhibit similar tetranuclear face-shared defective double-cubane structure, having azido-, alk/phenoxido- and acetato-bridges. Magnetic susceptibility measurements on the complexes in the range of 300–2 K indicate ferromagnetic coupling between the metal ions. The slightly different magnetic behaviors observed are probably caused by subtle structural differences between the respective [Ni4O4N2] cores induced by ligand variation.

Graphical abstractThe self-assembly between Schiff-base ligand, NiII ions and NaN3 led to NiII4 complexes featuring defective double-cubane. The obtained bridging moieties cause dominant intramolecular ferromagnetic interactions. The slightly different magnetic behaviors observed are probably caused by subtle structural differences between the respective [Ni4O4N2] cores induced by ligand variation.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Three NiII4 complexes feature defective double-cubane structure. ► Four dissimilar bridges are present in these NiII4 complexes. ► Magnetic analysis indicates ferromagnetic coupling between the metal ions.