Zinc(II) and cadmium(II) complexes of long flexible bis(imidazole) and phenylenediacetate ligands, synthesis, structure, and luminescent property

Four new Zn(II) and Cd(II) coordination complexes, [Zn(p-pda)(m-bib)]·H2O (1), [Zn(m-pda)(o-bib)]·H2O (2), [Cd(o-pda)(o-bib)] (3), [Cd(m-pda)(o-bib)]·H2O (4), (H2pda = phenylenediacetic acid, bib = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized, and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography. Complex 1 exhibits a 3D porous network based on 2D loop-containing layer. Complex 2–4 possesses a 3D network extended by 2D net. Differently, in complex 3, the 2D network stack in an ABAB mode, while equivalent wave-like 2D networks mutually interpenetrated with each other to generate a 2D → 3D entangled system in 2 and 4. Furthermore, the relationship between molecular conformation, packing modes and fluorescence properties have also been investigated.