Bis[diethyl(hydroxy)ammonium] benzene-1,4-dicarboxylate

In the centrosymmetric title compound, 2C4H12NO+·C8H4O4 2−, two N,N-diethyl(hydroxy)ammonium cations are linked to a benzene-1,4-dicarboxylate dianion by a combination of O—H⋯O and N—H⋯O hydrogen bonds, which can be described in graph-set terminology as R 2 2(7). The crystal structure is further stabilized by C—H⋯O hydrogen bonds, leading to the fomation of a ribbon-like network.

In the centrosymmetric title compound, 2C 4 H 12 NO + Á-C 8 H 4 O 4 2À , two N,N-diethyl(hydroxy)ammonium cations are linked to a benzene-1,4-dicarboxylate dianion by a combination of O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds, which can be described in graph-set terminology as R 2 2 (7). The crystal structure is further stabilized by C-HÁ Á ÁO hydrogen bonds, leading to the fomation of a ribbon-like network.

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2169).  (Herbstein et al., 1978;Chatterjee et al., 2000;Karpova et al., 2004;Zhao et al., 2007). Some cases have been reported where the use of terephthalic acid has lead to the fomation of supramolecular architectures through hydrogen bonding (Mak et al., 2000;Yuge et al., 2006). The title compound was synthesized by the reaction of terephthalic acid with N,N-diethylhydroxylammine.
In the BDL anion the dihedral angle between phenyl ring and carboxylate group is 11.3 (3)/%. In general the BDLanion is almost coplanar with the mean plane through the C and N-atoms in the DTHA cations. The carboxylate groups are nearly perpendicular with the mean plane through the C and N-atoms of DTHA [dihedral angle of 81.0 (3)/%].
In the crystal structure a ribbon-like structure ( Fig. 2  Experimental N,N-diethylhydroxylammine and terephthalic acid, in a molar ratio of 2:1, were mixed and dissolved in sufficient ethanol that by heating to 353 K a clear solution was obtained. The reaction system was then cooled slowly to RT, and crystals of the title compound were formed. They were collected and washed with ethanol.

Refinement
The

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.