Synthesis and properties of interspersed structure complexes prepared from 4,4'-(phenylazanediyl)- dibenzoic acid with rigid and semi-rigid nitrogen-containing ligands

Three novel coordination polymers (CPs), namely, [CdL (bif)]·H₂O (1), [Cd₂L₂ (tipa)₂]·3H₂O (2) and [Co₂L₂ (bif)₂]·4DMF (3), (H₂L = 4,4'-(phenylazanediyl)dibenzoic acid, tipa = Tris [4-(imidazol-1yl)- phenyl] amine, bif = 2,7-bis(1-imidazoly) fluorene), have been synthesized under hydrothermal conditions withdifferent solvents. Compounds 1-3 were also characterized by FT-IR spectroscopy, elemental analyses, thermal analysis, power X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Compound 1 displays a 3-fold interpenetrating 3D framework and contains two kinds 1D helical chains, one is the intertwined one-dimensional double helix chain and another is a 5-fold interpenetrating helical chains. Compound 2 shows a 2-fold interpenetrating 3D framework. Compound 3 exhibits a 3-fold interpenetrating 2D layer. Furthermore, complex 2 can be used as a fluorescent probe for detecting Fe³⁺ ions, and complex 3 shows a good electrochemical reversibility.