Synthesis, Structure, Photoluminescence and Thermal Properties of Sodium Ethene-Bis-Nitrobenzenesulfonate

Abstract. Sodium ethene-bis-nitrobenzenesulfonate, [Na2(ENS)·6H2O]n(1) was synthesized through coupling reaction of o-nitrotoluenesulfonic acid in NaOH solution and characterized by single crystal X-ray diffraction, elemental analysis, IR and 1H NMR spectroscopy, XRPD, DSC and TGA (where ENS2– = ethene-bis-nitrobenzenesulfonate). The asymmetrical unit of (1) consists of two octahedral NaI ions, and the neighboring metal centers are bridged by μ2 water molecules resulting in the formation of an inorganic tetranuclear unit. The tetranuclear units were connected through the ENS2– ligands into a 2D topology net. The weak π–π stacking and H-bonding interactions further stabilized the structure. The crystals of (C7H6NO5S)–·(H5O2)+ (2) were obtained by post-processing the unreacted raw material to recycle. Furthermore, the rigidity and the conjugation effect of the aromatic system in compound 1 were increased through the coordination interactions of metal atoms to ligands, resulting in the emission coming from ligand enhanced with red-shifting about 9 nm of the maximal wavelength. The conjugation effects and the steric arrangement of the substituent groups play the main role to the luminescence intensity and red-shift effect.