Three-dimensional bpe-pillared layer architectures of metal 2-sulfoterephthalate complexes with a unique 2,3,4-connected topological network: Isomorphism, polymorphism and characterization

Three new coordination polymers, [M1.5(stp)(bpe)(H2O)] (M = Mn(1), Cd(2), Zn(3)) have been prepared by hydro-/solvo-thermal reactions of 2-sulfoterephthalate (stp) and 1,2-bis(4-pyridyl)ethane (bpe) ligands with d-block Mn(II), Cd(II) and Zn(II) salts. Complexes 1 and 2 are isomorphic except for the difference of the metal ions, while complexes 1–3 are polymorphic because of the different coordination modes that stp ligand adopts. The left- and right-handed helixes construct 2D layer from metal ions and stp ligands for 1–3, and the anti-bpe ligands as the pillars complete 3D structure. All the three complexes exhibit a new (2,3,4)-connected network with the Schläfli symbol {8;122}4{82; 12; 142; 16}{8}2 based on the different structural motifs. The magnetic properties of 1 reveal that there exists weak antiferromagnetic coupling between the Mn(II) ions. And the solid-state photoluminescence of 2 and 3 can be attributed to the intraligand π–π* transition.