Unusual Zn5(μ3-OH)2(COO−)8 secondary building units for the construction of a metal–organic framework

A new three-dimensional (3D) metal–organic framework (MOF) {Zn5(μ3-OH)2(obb)4[(CH3)2NH]2}·2DMF (1; H2obb = 4,4′-oxybisbenzoic acid; DMF = N,N′-dimethyl formamide) with unusual Zn5(μ3-OH)2(COO−)8 secondary building units (SBUs) has been solvothermally synthesized and structurally characterized by the aid of single crystal X-ray diffraction, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Elemental analysis (EA) and Infrared Spectroscopy (IR). The unprecedented pentanuclear Zn5(μ3-OH)2(COO−)8 SBU was formed by two trimeric Zn3(μ3-OH)(COO−)6 SBUs, which can be simplified as 4-connected node. Correspondingly, compound 1 exhibits dia structural topology.