Structural evolution and zero-field SMM behaviour in ferromagnetically-coupled disk-type Co7 clusters bearing exclusively end-on azido bridges

Concise chemistry leads to a family of heptanuclear CoII-clusters, [Co7(N3)12(CH3CN)12] [Y2(NO3)4(piv)4]∙2CH3CN (DC1) (pivH = pivalic acid), [Co7(N3)12(CH3CN)10(NO3)0.4 (Cl)1.6]∙4CH3CN (DC2) and [Co7(N3)12(CH3CN)10(NO3)2]∙4CH3CN (DC3), in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology. The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calculations. Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear CoII complexes.