A rare three-coordinated zinc cluster–organic framework with two types of secondary building units

A rare chiral 3D cluster–organic framework {[Zn₁₇O₅(NTB)₆(NDB)₃]·41H₂O}_n (1) (H₃NTB = 4,4′,4′′-nitrilotrisbenzoic acid and H₂NDB = 4,4′-nitrilodibenzoic acid) was prepared and structurally characterized. Complex 1 contains two types of [Zn₄(μ₄-O)(COO)₆] and unreported [Zn₉(μ₃-O)₃(COO)₁₂] SBUs, which link bi- and tri-carboxylic acids and extend to an unprecedented (3,6,12)-connected framework. In addition, electronic structure calculations were performed to scrutinize the features of embedded clusters.