Two new coordination polymers, [Ni(Hpdc)(bib)(H₂O)]_n (1) and {[Ni(bib)₃](ClO₄)₂}_n (2), were prepared by mixing Ni²⁺, 3, 5-pyrazoledicarboxylic acid (H₃pdc)/p-nitrobenzoic acid and 1, 4-bis(imidazol-1-ylmethyl) butane (bib) by a hydrothermal method, respectively. X-ray crystallography reveals a 2D network constructed by six-coordinated Ni (Ⅱ) centers, bib, and Hpdc^2- ligands in complex 1, while a 2D network is built by Ni (Ⅱ) and bib ligands in 2. Furthermore, the quantum-chemical calculations have been performed on'molecular fragments'extracted from the crystal structure of 1 using the PBE0/LANL2DZ method in Gaussian 16 and the VASP program.

Two new transition-metal coordination polymers, {[Cd(oba)(L)₂]·H₂O}_n (1) and [Cd(4-nph)(L)₂]_n (2) (H₂oba=4, 4′-oxydibenzoic acid, 4-H₂nph=4-nitrophthalic acid, L=2, 2′-biimidazole), were successfully synthesized under hydrothermal conditions and characterized structurally by IR spectroscopy, elemental analyses, single-crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric analysis. The results of single-crystal X-ray diffraction show that complex 1 presents a 1D zigzag chain structure and further extends to a 2D network through N—H…O hydrogen bonds and π-π stacking interactions. Meanwhile, complex 2 has a zero-dimensional structure and also extends to form a 2D network through N—H…O hydrogen bonds and π-π stacking interactions. In addition, both 1 and 2 exhibited luminescent properties in the solid state. Furthermore, quantum chemical calculations were carried out on the "molecular fragments" extracted from the crystal structures of 1 and 2 using the PBE0/LANL2DZ method constructed by the Gaussian16 program. The calculated values signify a significant covalent interaction between the coordination atoms and the Cd(Ⅱ) ions.