A novel 3-connected [3 + 3] topological net showing both rotaxane- and catenane-like motifs

Abstract

A novel metal–organic compound, namely [Zn₆(bib)₆L₆]·7H₂O (1) where H₂L = 4-(4-carboxybenzyloxy)benzoic acid, and bib = 4,4′-bis(imidazol-1-ylmethyl)benzene, has been synthesized under hydrothermal conditions. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and thermogravimetric (TG) analysis. In the structure of 1, two bib ligands cuddle two metal ions to form a ring, and are linked by deprotonated L²⁻ to form a 6-fold interpenetrated 3D framework. From the topological analysis, each Zn^II ion is considered as a three-connected node, and a pair of bib ligands and L²⁻ anions are linkers. The framework of compound 1 can be classified as a (6²·10)(6·10²)(10²·12) topology, which is a novel 3-connected [3 + 3] 6-fold interpenetrated net showing both polyrotaxane and polycatenane characters. In addition, the luminescent properties of the compound are discussed.