Four novel alkaline-earth metal coordination polymers with networks controlled by the diverse coordination modes of amino-sulfonate ligand: Synthesis, crystal structures and luminescent properties

摘要

Four novel alkaline-earth metal coordination polymers based on 4,4′-diamino-2,2′-stilbenedisulfonic acid ligand (H 2dsd), namely, [Mg(dsd)(H _2O) _4] _n (1), {[Ca(dsd)(H _2O) _2]·H _2O} _n (2), {[Sr(dsd)(H _2O) _6]·H _2O} _n (3), [Ba(dsd)(H _2O) _2] _n (4), were synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR, single-crystal X-ray diffraction and thermogravimetric analysis. These complexes exhibit various polymeric networks due to the diverse coordination modes of dsd ~(2-). Complexes 1 and 3 display a 1D zigzag chain structure with dsd ~(2-) group as a μ-bis(monodentate) ligand (denoted as μ _2-η ~1η ~1 ligand). Complex 2 is a 1D ribbon chain coordination polymer in which dsd ~(2-) shows the μ _3-η ~1η ~2η ~1 coordination mode, and complex 4 is a 2D coordination polymer in which dsd ~(2-) presents the unusual μ _4- η ~1η ~2η ~1η ~1 coordination mode. The present four complexes exhibit different fluorescent emissions in the solid state at room temperature.