Synthesis and Crystal Structure of One Porous Trinuclear Co(II) Coordination Complex with Helical Character

One three-dimensional trinuclear coordination complex {[H2bbi][Co3(MDIP)2]}n (H4MDIP = 5,5′-methylenediisophthalic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)), has been prepared under hydrothermal conditions and structurally characterized by X-ray diffraction analyses. The complex is a 3D (4,8)-connected porous framework, in which trinuclear units [Co3(CO2)8]2– are surrounded by eight MDIP4– ligands. And protonated trans-bbi isolated in the lattice. Detailed investigation shows that two kinds of helical chains [Co2(IP)]∞ (IP = isophthalic) and [Co2(MDIP)]∞ around middle atom Co(2) of linear unit [Co3(CO2)8]2– coexist to form 2D [Co3(MDIP)2]∞ layer. Magnetic measurements are carried out as well.