1,3-Phenyl­enediammonium dinitrate

In the title compound, C6H10N2 2+·2NO3 −, the dication lies on a crystallographic twofold rotation axis. The nitrate ions are linked to the dications though N—H⋯O hydrogen bonds, forming a three-dimensional network

An Ideal <i>C</i>₃‑Symmetric Sulfate Complex: Molecular Recognition of Oxoanions by <i>m</i>‑Nitrophenyl- and Pentafluorophenyl-Functionalized Hexaurea Receptors

The anion-binding properties of two tripodal-based hexaureas appended with the <i>m</i>-nitrophenyl (<b>1</b>) and pentafluorophenyl (<b>2</b>) groups have been studied both experimentally and theoretically, showing strong affinities for sulfate over other inorganic oxoanions such as hydrogen sulfate, dihydrogen phosphate, bicarbonate, nitrate, and perchlorate. The structural analysis of the sulfate complex with <b>1</b> reveals that the receptor organizes all urea-binding sites toward the cavity at precise orientations around a tetrahedral sulfate anion to form an ideal <i>C</i>₃-symmetric sulfate complex that is stabilized by 12 hydrogen-bonding interactions. The receptor and the encapsulated sulfate are located on the threefold axis passing through the bridgehead nitrogen of <b>1</b> and the sulfur atom of the anionic guest. The high-level density functional theory calculations support the crystallographic results, demonstrating that the <i>C</i>₃-symmetric conformation of the sulfate complex is achieved due to the complementary NH···O between the receptor and sulfate

An Ideal <i>C</i>₃‑Symmetric Sulfate Complex: Molecular Recognition of Oxoanions by <i>m</i>‑Nitrophenyl- and Pentafluorophenyl-Functionalized Hexaurea Receptors

The anion-binding properties of two tripodal-based hexaureas appended with the <i>m</i>-nitrophenyl (<b>1</b>) and pentafluorophenyl (<b>2</b>) groups have been studied both experimentally and theoretically, showing strong affinities for sulfate over other inorganic oxoanions such as hydrogen sulfate, dihydrogen phosphate, bicarbonate, nitrate, and perchlorate. The structural analysis of the sulfate complex with <b>1</b> reveals that the receptor organizes all urea-binding sites toward the cavity at precise orientations around a tetrahedral sulfate anion to form an ideal <i>C</i>₃-symmetric sulfate complex that is stabilized by 12 hydrogen-bonding interactions. The receptor and the encapsulated sulfate are located on the threefold axis passing through the bridgehead nitrogen of <b>1</b> and the sulfur atom of the anionic guest. The high-level density functional theory calculations support the crystallographic results, demonstrating that the <i>C</i>₃-symmetric conformation of the sulfate complex is achieved due to the complementary NH···O between the receptor and sulfate