Mercury(II) coordination polymers based on aniline-substituted tetra pyridyloxy cyclotriphosphazene: Syntheses, characterizations and UV-Vis absorption properties

Abstract

Dianiline-tetrapyridyloxy-cyclotriphosphazene (AnPyCp), as a novel flexible molecular building block, and its mercury(II) coordination polymers were successfully synthesized. The isolated crystalline coordination polymers, formulated as {[Hg(AnPyCp)(Cl)(2)]center dot CH3CN}(n) (1) and {[Hg-2(AnPyCp)(I)(4)]center dot CH3CN)(n) (2), were structurally characterized by elemental analysis, FT-IR spectroscopy and single crystal X-ray crystallography. Furthermore, the X-ray crystal structure analysis revealed that complexes 1 and 2 crystallize in the triclinic crystal system with the P1 space group. In complexes 1 and 2, AnPyCp exhibited kappa N-2 and kappa N-3 coordination binding modes with the divalent Hg ions to form 1D chain structures. The central Hg2+ ion in complexes 1 and 2 has a distorted tetrahedral geometry. The UV-Vis properties and thermal stability of AnPyCp and its complexes (1 and 2) were also investigated. UV-Vis experiments, including titration and continuous variation (Job's plot analysis), showed that all of the spectrophotometric properties in the solution state support the crystal structures of the complexes. According to TGA analysis, the coordination polymers exhibited thermal stability up to similar to 230 degrees C, however AnPyCp showed a greater thermal stability than 1 and 2. (C) 2019 Elsevier Ltd. All rights reserved.