Synthesis and Characterization of a new Cyclohexaphosphate, (C9H14N)4(H3O)2(P6O18)

Abstract

The physicochemical properties of a new cyclohexaphosphate, (C9H14N)4(H3O)2(P6O18), prepared by an acid-base reaction between cyclohexaphosphoric acid H6P6O18 and 2,4,6-trimethylaniline, are discussed on the basis of X-ray crystal structure investigation. The crystal structure determination reveals that the complete cyclohexaphosphate anion, with chair conformation, is generated by crystallographic inversion symmetry. The asymmetric unit consists of two organic cations, one half-anion and one hydronium cation. The atomic arrangement can be described by thick layers built by P6O18 anions and H3O+ cations parallel to the (a, b) plane. Each cyclohexaphosphate group is connected to its adjacent neighbors by six hydronium ions through strong O-H...O hydrogen bonds. The protonated amines are located between these successive inorganic layers, in order to balance the negative charge of the inorganic framework by establishing N–H...O hydrogen bonds with the O atoms of the P6O18 anions. The three-dimensional cohesion is assured by different interactions (electrostatic, H-bonds, van der Waals) established between the various molecular components. This compound is also characterized by infrared spectroscopy and solid state MAS-NMR. Structure and physicochemical properties of a new cyclohexaphosphate, (C9H14N)4(H3O)2(P6O18), are discussed on the basis IR spectrum, solid state MAS-NMR and X-ray crystal structure. The cyclohexaphosphate anion, with chair conformation, is generated by crystallographic inversion symmetry. The atomic arrangement can be described by thick layers built by P6O18 anions and H3O+ cations parallel to the (a, b) plane. Each cyclohexaphosphate group is connected to its adjacent neighbors by six hydronium ions through strong O-H…O hydrogen bonds.