A series of octanuclear clusters of Ni(II)/Co(II) with tunable structures and magnetism supported by thiacalix[4]arenes

Five octanuclear homometallic or heterometallic clusters based on thiacalix[4]arene (TC4A): {[Ni8(TC4A)2(μ6-CO3)2(μ2-CH3CO2)3(μ2-CO3)(DMA)4]}∙(CH3CN)2 (1) (DMA = N,N-Dimethylamine), {[Ni5.81Co2.19(TC4A)2(μ6-CO3)2(μ2-HCO2)2(μ2-Cl)2(DMA)4]}∙2DMF∙2CH3CN (2) (DMF = N,N-Dimethylformamide), {[Ni4.06Co3.94(TC4A)2(μ6-CO3)2(μ2-HCO2)2(μ2-Cl)2(DMA)4]}∙2DMF∙2CH3CN (3), {[Ni2Co6(TC4A)2(μ6-CO3)2(μ2-HCO2)2(μ2-Cl)2(DMA)4]}∙2DMF∙2CH3CN (4), {[Co8(TC4A)2(μ6-CO3)2(μ2-HCO2)3(μ2-CO3)2(DMA)4]}∙6DMF (5) have been synthesized via the solvothermal method. Single crystal X-ray diffraction structural analyses indicate that all compounds consisted of two badminton-like secondary building units (SBUs) [M4(TC4A)], (M = Co, Ni, Co/Ni), which are linked by two μ6-CO32- anions in a tail-to-tail manner, forming a chair-like octanuclear metal cluster. Their structures were further evidenced by FT-IR, UV-Vis, XPS, PXRD and so on. Magnetism studies of compounds 1-5 indicate that there is an antiferromagnetic interaction between their metal ions, and the measured magnetic susceptibility χMT of compounds 1 to 5 increases as the cobalt content rises in the range of 50-300 K. The structures and magnetic properties of the Co(II)/Ni(II) cluster supported by TC4A can be conveniently tuned by varying the molar ratio of Ni(II) to Co(II), providing a straightforward approach to construct heterometallic clusters based on TC4A.