Synthesis and characterization of a new p-phenylenediammonium dihydrogenmonophosphate [p-NH3C6H4NH3][H2PO4]2

Chemical preparation, crystal structure and NMR spectroscopy of a new organic cation p-phenylenediammonium monophosphate [p-NH3C6H4NH3][H2PO4]2 are presented. This new compound crystallizes in the orthorhombic system, with the space group Pnma and the following parameters: a = 7.970 (2) Å; b = 22.770 (7) Å; c = 7.000 (7) Å, V = 1270.3 (11) Å3, Z = 4 and Dx = 1.590 g cm−3. The crystal structure has been determined and refined to R = 0.043 and R(w) = 0.057 using 2623 independent reflections. The structural arrangement can be described as inorganic layers of (H8P4O16)4− units, parallel to (a, c) planes. The organic groups (p-H3NC6H4NH3)2+are anchored between the phosphoric layers to form a three-dimensional infinite network. This compound is also investigated by IR and solid-state 1H, 13C and 31P MAS NMR spectroscopies. The ab initio method is used in the calculation of chemical shifts.