Synthesis and molecular structure of potassium 3,5- dinitrophloroglucinolsulfonate monohydrate

A novel coordination polymer, potassium 3,5-dinitrophloroglucinolsulfonate monohydrate ([K(DNPGS) (H₂O)] _n ), was synthesized by the reaction of 3,5-dinitrophloroglucinolsulfonic acid (DNPGS) with potassium hydroxide in aqueous solution and the structure was determined by elemental analysis, IR and x-ray single-crystal diffraction analysis. The crystal belongs to orthorhombic system with space group Pca2(1). Its unit cell parameters are as follows: a=1.0819(14) nm, b=0.56563(11) nm, c=1.8979(4) nm; V=1.1615(4) nm ³, Z=4, D _c =2.015 g/cm³, F(000)=712, chemical formula C₆H₅KN₂O₁₁S and M _r =352.28. The bridging potassium ion coordinates with nine oxygen atoms originating from the sulfonic groups, phenolic hydroxyl groups, nitro-groups of five DNPGS^- anions and two water molecules simultaneously, and a stable cross-linked three-dimensional network is formed. The thermal analysis of the complex show that it dehydrates at about 100°C, and only has an intense exothermic process at 204.2-245.2°C with exothermic enthalpy 1383.4 kJ mol^-1.