Synthesis and Crystal Structure of 1-(2,5-Dimethylphenyl)piperazinium Dihydrogenmonophosphate Monohydrate: (C12H19N2)H2PO4 H2O

The synthesis and crystal structure of a new monophosphate, (C12H19N2)H2PO4·H2O, are discussed, based on an X-ray crystal structure investigation. This compound crystallizes in the monoclinic system, with the space group P21/c and the following parameters: a = 15.226(2), b = 6.984(3), c = 15.359(5)Å, β = 95.44(2)°, Z = 4 and V = 1625.8(9)Å3. The crystal structure was determined and refined to R = 0.0483 using 2208 independent reflections. The atomic arrangement of this compound is built up by (H4P2O8)2- dimers. Each dimer aggregates with water molecules to form inorganic layers, in the x = 1/2 planes, through hydrogen-bond interactions. Between those layers, the organic cations (C12H19N2)+ are oriented in a similar direction, so that they form intermolecular van der Waals interactions and, particularly, strong hydrogen bonds with oxygen atoms of the anionic layers.