organic compounds
Tetramethylammonium hydrogen terephthalate
aDepartment of Chemistry, Zanjan Branch, Islamic Azad University, PO Box 49195-467, Zanjan, Iran, bDepartment of Chemistry, Faculty of Sciences, Azarbaijan University of Shahid Madani, 35 Km Tabriz-Maragheh Road, PO Box 53714-161, Tabriz, Iran, cDepartment of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779, Iran, dDepartment of Chemistry, Faculty of Sciences, Tarbiat Modares University, PO Box 14155-4838, Tehran, Iran, eDepartment of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran, and fDipartimento di Chimica Inorganica, Vill. S. Agata, Salita Sperone 31, Università di Messina, 98166 Messina, Italy
*Correspondence e-mail: liladolatyari1351@yahoo.com
The 4H12N+·C8H5O4−, contains one half of a tetramethylammonium cation and one half of a hydrogen terephthalate monoanion. The N atom of the ammonium cation lies on a twofold rotation axis and the centre of mass of the terephthalate anion is on a centre of inversion. In the crystal, the centrosymmetric terephthalate ions are linked by a very short symmetric O—H⋯O hydrogen bond [O⋯O = 2.4610 (19) Å] into a one-dimensional polymeric chain along [1-12]. The tetramethylammonium cations and terephthalate anions are then connected through a pair of bifurcated acceptor C—H⋯O hydrogen bonds, generating a three-dimensional supramolecular network. The carboxylate groups at both ends of the terephthalate anion are charge-shared with an equal probability of 0.5.
of the title salt, CRelated literature
For a review of very short O—H⋯O hydrogen bonds, see: Speakman (1972). For recent reports of acidic salts of dicarboxylic acids with short intra- and intermolecular O—H⋯O hydrogen bonds, see: Starosta & Leciejewicz (2010); Hemamalini & Fun (2010); Sun et al. (2002); Sharma et al. (2006); Wang et al. (2004); Taka et al. (1998). For examples of diphosphonates with strong O—H⋯O hydrogen bonds, see: Tsaryk et al. (2011); Courtney et al. (2006); Cheng & Lin (2006). For background to symmetric and asymmetric O—H⋯O hydrogen bonds, see: Misaki et al. (1986); Catti & Ferraris (1976). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For the synthesis of the 5,5′-(o-phenylene)di-1H-tetrazole ligand, see: Demko & Sharpless (2001).
Experimental
Crystal data
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Refinement
|
Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XPW (Siemens, 1996) and ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and enCIFer (Allen et al., 2004).
Supporting information
https://doi.org/10.1107/S1600536812039487/bg2478sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812039487/bg2478Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536812039487/bg2478Isup3.cml
In an attempt to synthesize metal–organic framework materials, we obtained the title compound as a side-product.
The ligand H2L [5,5'-(o-Phenylene)di-1H-tetrazole] used in this work was synthesized according to literature procedures (Demko & Sharpless, 2001).
A mixture of Zn(NO3)2.6H2O (0.357 g, 1.2 mmol), H2L (0.086 g, 0.4 mmol), terephthalic acid (0.066 g, 0.4 mmol), 1,4-diazabicyclo[2.2.2]octane (0.045 g, 0.4 mmol) and CH3OH/DMF (1/2, 15 ml) were sealed in a 25 ml Teflon-lined stainless steel autoclave, heated at 433 K for 40 h, and then cooled to room temperature over a period of 90 h. The resulting solution was filtered and the filtrate was allowed to stand in air at room temperature. After several days, colorless single crystals of the title compound were isolated.
C-H atoms were located on a ΔF map, further idealized and finally refined in the riding model aproximation d(C—H) = 0.93Å; U(H) = 1.2U(C)eq; d(C—H3) = 0.96Å; U(H) = 1.5U(C)eq. Atom H2 is fixed by symmetry, and its isotropic displacement factor was freely refined.
Acid salts of dicarboxylic acids usually form very short O—H···O hydrogen bonds (with O···O distances between 2.4 and 2.5 Å) in their crystal structures (Speakman, 1972). This type of hydrogen bond is formed between the carboxyl and carboxylate groups by intramolecular (Starosta & Leciejewicz, 2010; Hemamalini & Fun, 2010; Sun et al., 2002) or intermolecular (Sharma et al., 2006; Wang et al., 2004; Taka et al., 1998) interactions. However, diphosphonates can also display such short and strong hydrogen bonds between neighbouring phosphonate groups (Tsaryk et al., 2011; Courtney et al., 2006; Cheng & Lin, 2006). There are two types of short O—H···O hydrogen bonds: symmetric, in which two O atoms are related by
and asymmetric, in which crystal symmetry does not impose the O—H···O hydrogen bond to be symmetric. Furthermore, symmetric hydrogen bonds typically display a shorter (2.43–2.51 Å) O···O distance than asymmetric ones (2.44–2.57 Å) (Misaki et al., 1986). In this work, we report the of the title compound, whose structure contains a strong symmetric O—H···O hydrogen bond (Catti & Ferraris, 1976): atom H2 lies on a center of symmetry, located between two crystallographic equivalent carboxyl O2 atoms. The H atom, clearly visible on the Fourier map, is involved in a symmetric O2—H2···O2i [symmetry code: (i) -x + 1/2, -y + 3/2, -z] hydrogen bond with an O—H bond distance of 1.23 Å (Table 1).The title compound (Fig. 1), [N(CH3)4]+[4-COOH-C6H4COO]-, consists of one half tetramethylammonium cation and one half terephthalate anion in the
The cation lies on a twofold rotation axis and the anion on an inversion center. In the terephthalate anions, the two carboxyl groups are twisted from the mean plane of the benzene ring by a dihedral angle of 6.57 (2)°. Carboxyl atom O2 lies slightly farther [0.083 Å] from this plane than atom O1 [0.065 Å], owing to the strong O—H···O hydrogen bond between the terephthalate anions.In the crystal, the terephthalate anions are linked end-to-end to form a one-dimensional polymeric chain in which adjacent ions are interconnected by a strong symmetric O—H···O (O···O distance of 2.4610 (19) Å) hydrogen bond (Table 1). Then the weak C—H···O hydrogen bonds link the ammonium cations and terephthalate anions together in a three-dimensional
The C8—H8A···O1 and C9—H9A···O1 interactions form a pair of bifurcated acceptor bonds (Fig. 2), involving two C—H donor from an ammonium ion and an acceptor O atom from the terephthalate ion, generating an R21(6) ring motif (Etter et al., 1990; Bernstein et al., 1995).For a review of very short O—H···O hydrogen bonds, see: Speakman (1972). For recent reports of acid salts of dicarboxylic acids with short intra- and intermolecular O—H···O hydrogen bonds, see: Starosta & Leciejewicz (2010); Hemamalini & Fun (2010); Sun et al. (2002); Sharma et al. (2006); Wang et al. (2004); Taka et al. (1998). For examples of diphosphonates with strong O—H···O hydrogen bonds, see: Tsaryk et al. (2011); Courtney et al. (2006); Cheng & Lin (2006). For background to symmetric and asymmetric O—H···O hydrogen bonds, see: Misaki et al. (1986); Catti & Ferraris (1976). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For the synthesis of the 5,5'-(o-phenylene)di-1H-tetrazole (H2L) ligand, see: Demko & Sharpless (2001).
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XPW (Siemens, 1996) and ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and enCIFer (Allen et al., 2004).C4H12N+·C8H5O4− | F(000) = 512 |
Mr = 239.27 | Dx = 1.274 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 9931 reflections |
a = 16.0585 (4) Å | θ = 2.8–30.3° |
b = 9.1527 (2) Å | µ = 0.10 mm−1 |
c = 11.5866 (3) Å | T = 298 K |
β = 132.915 (2)° | Irregular, colourless |
V = 1247.21 (7) Å3 | 0.42 × 0.37 × 0.32 mm |
Z = 4 |
Bruker APEXII CCD diffractometer | 1360 independent reflections |
Radiation source: fine-focus sealed tube | 1269 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.022 |
φ and ω scans | θmax = 27.0°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −20→20 |
Tmin = 0.708, Tmax = 0.746 | k = −11→11 |
20680 measured reflections | l = −14→14 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.147 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0714P)2 + 1.1167P] where P = (Fo2 + 2Fc2)/3 |
1360 reflections | (Δ/σ)max < 0.001 |
80 parameters | Δρmax = 0.57 e Å−3 |
0 restraints | Δρmin = −0.43 e Å−3 |
C4H12N+·C8H5O4− | V = 1247.21 (7) Å3 |
Mr = 239.27 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 16.0585 (4) Å | µ = 0.10 mm−1 |
b = 9.1527 (2) Å | T = 298 K |
c = 11.5866 (3) Å | 0.42 × 0.37 × 0.32 mm |
β = 132.915 (2)° |
Bruker APEXII CCD diffractometer | 1360 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 1269 reflections with I > 2σ(I) |
Tmin = 0.708, Tmax = 0.746 | Rint = 0.022 |
20680 measured reflections |
R[F2 > 2σ(F2)] = 0.054 | 0 restraints |
wR(F2) = 0.147 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.57 e Å−3 |
1360 reflections | Δρmin = −0.43 e Å−3 |
80 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
O2 | 0.32784 (9) | 0.78319 (13) | 0.13940 (12) | 0.0451 (4) | |
C5 | 0.51647 (12) | 0.89007 (16) | 0.43479 (16) | 0.0341 (4) | |
H5 | 0.5278 | 0.8165 | 0.3914 | 0.041* | |
C4 | 0.40806 (11) | 0.94633 (15) | 0.34990 (15) | 0.0312 (3) | |
C6 | 0.30731 (12) | 0.89045 (17) | 0.18691 (16) | 0.0363 (4) | |
O1 | 0.21412 (12) | 0.94615 (19) | 0.11216 (16) | 0.0789 (6) | |
N | 0.5000 | 0.3608 (2) | 0.2500 | 0.0416 (5) | |
C9 | 0.4511 (2) | 0.4550 (3) | 0.2947 (3) | 0.0794 (8) | |
H9A | 0.5097 | 0.5155 | 0.3823 | 0.119* | |
H9B | 0.4188 | 0.3951 | 0.3239 | 0.119* | |
H9C | 0.3928 | 0.5157 | 0.2070 | 0.119* | |
C3 | 0.39205 (12) | 1.05665 (16) | 0.41571 (16) | 0.0353 (4) | |
H3 | 0.3198 | 1.0950 | 0.3594 | 0.042* | |
C8 | 0.58943 (19) | 0.2666 (3) | 0.3849 (3) | 0.0695 (6) | |
H8A | 0.6473 | 0.3266 | 0.4737 | 0.104* | |
H8B | 0.6224 | 0.2071 | 0.3565 | 0.104* | |
H8C | 0.5565 | 0.2049 | 0.4120 | 0.104* | |
H2 | 0.2500 | 0.7500 | 0.0000 | 0.098 (13)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O2 | 0.0364 (6) | 0.0526 (7) | 0.0300 (6) | −0.0050 (5) | 0.0162 (5) | −0.0175 (5) |
C5 | 0.0348 (7) | 0.0345 (7) | 0.0276 (7) | −0.0003 (5) | 0.0191 (6) | −0.0076 (5) |
C4 | 0.0315 (7) | 0.0324 (7) | 0.0218 (6) | −0.0030 (5) | 0.0150 (6) | −0.0043 (5) |
C6 | 0.0319 (7) | 0.0405 (8) | 0.0235 (6) | −0.0026 (6) | 0.0138 (6) | −0.0054 (5) |
O1 | 0.0420 (7) | 0.0938 (12) | 0.0411 (7) | 0.0188 (7) | 0.0048 (6) | −0.0263 (7) |
N | 0.0410 (10) | 0.0367 (9) | 0.0405 (10) | 0.000 | 0.0252 (9) | 0.000 |
C9 | 0.0718 (15) | 0.0875 (17) | 0.0706 (14) | 0.0197 (12) | 0.0452 (13) | −0.0130 (12) |
C3 | 0.0292 (7) | 0.0373 (8) | 0.0278 (7) | 0.0024 (5) | 0.0149 (6) | −0.0043 (5) |
C8 | 0.0627 (13) | 0.0587 (12) | 0.0605 (13) | 0.0133 (10) | 0.0315 (11) | 0.0174 (10) |
O2—C6 | 1.2739 (19) | N—C8 | 1.481 (2) |
C5—C4 | 1.390 (2) | C9—H9A | 0.9600 |
C5—C3i | 1.3896 (19) | C9—H9B | 0.9600 |
C5—H5 | 0.9300 | C9—H9C | 0.9600 |
C4—C3 | 1.391 (2) | C3—C5i | 1.3896 (19) |
C4—C6 | 1.5115 (18) | C3—H3 | 0.9300 |
C6—O1 | 1.218 (2) | C8—H8A | 0.9600 |
N—C9ii | 1.478 (2) | C8—H8B | 0.9600 |
N—C9 | 1.478 (2) | C8—H8C | 0.9600 |
N—C8ii | 1.481 (2) | ||
C4—C5—C3i | 120.25 (13) | N—C9—H9A | 109.5 |
C4—C5—H5 | 119.9 | N—C9—H9B | 109.5 |
C3i—C5—H5 | 119.9 | H9A—C9—H9B | 109.5 |
C5—C4—C3 | 119.41 (12) | N—C9—H9C | 109.5 |
C5—C4—C6 | 121.22 (12) | H9A—C9—H9C | 109.5 |
C3—C4—C6 | 119.37 (13) | H9B—C9—H9C | 109.5 |
O1—C6—O2 | 124.70 (13) | C5i—C3—C4 | 120.33 (13) |
O1—C6—C4 | 119.89 (14) | C5i—C3—H3 | 119.8 |
O2—C6—C4 | 115.39 (13) | C4—C3—H3 | 119.8 |
C9ii—N—C9 | 108.6 (3) | N—C8—H8A | 109.5 |
C9ii—N—C8ii | 109.57 (15) | N—C8—H8B | 109.5 |
C9—N—C8ii | 110.17 (15) | H8A—C8—H8B | 109.5 |
C9ii—N—C8 | 110.17 (15) | N—C8—H8C | 109.5 |
C9—N—C8 | 109.57 (15) | H8A—C8—H8C | 109.5 |
C8ii—N—C8 | 108.7 (2) | H8B—C8—H8C | 109.5 |
C3i—C5—C4—C3 | 0.2 (3) | C5—C4—C6—O2 | 4.7 (2) |
C3i—C5—C4—C6 | 179.82 (13) | C3—C4—C6—O2 | −175.69 (14) |
C5—C4—C6—O1 | −176.70 (17) | C5—C4—C3—C5i | −0.2 (3) |
C3—C4—C6—O1 | 2.9 (2) | C6—C4—C3—C5i | −179.83 (13) |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+1, y, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2iii | 1.23 | 1.23 | 2.4610 (19) | 180 (1) |
C8—H8A···O1iv | 0.96 | 2.39 | 3.267 (3) | 152 |
C9—H9A···O1iv | 0.96 | 2.47 | 3.321 (3) | 148 |
Symmetry codes: (iii) −x+1/2, −y+3/2, −z; (iv) x+1/2, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C4H12N+·C8H5O4− |
Mr | 239.27 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 298 |
a, b, c (Å) | 16.0585 (4), 9.1527 (2), 11.5866 (3) |
β (°) | 132.915 (2) |
V (Å3) | 1247.21 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.42 × 0.37 × 0.32 |
Data collection | |
Diffractometer | Bruker APEXII CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.708, 0.746 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 20680, 1360, 1269 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.639 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.147, 1.07 |
No. of reflections | 1360 |
No. of parameters | 80 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.57, −0.43 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XPW (Siemens, 1996) and ORTEP-3 for Windows (Farrugia, 1997), SHELXTL (Sheldrick, 2008) and enCIFer (Allen et al., 2004).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2i | 1.23 | 1.23 | 2.4610 (19) | 180.000 (1) |
C8—H8A···O1ii | 0.96 | 2.39 | 3.267 (3) | 151.9 |
C9—H9A···O1ii | 0.96 | 2.47 | 3.321 (3) | 148.2 |
Symmetry codes: (i) −x+1/2, −y+3/2, −z; (ii) x+1/2, −y+3/2, z+1/2. |
Acknowledgements
The authors are grateful to the Islamic Azad University, Zanjan Branch, for financial support.
References
Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Catti, M. & Ferraris, G. (1976). Acta Cryst. B32, 2754–2756. CrossRef CAS IUCr Journals Web of Science Google Scholar
Cheng, C.-Y. & Lin, K.-J. (2006). Acta Cryst. C62, m363–m365. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Courtney, B. H., Juma, B. W. O., Watkins, S. F., Fronczek, F. R. & Stanley, G. G. (2006). Acta Cryst. C62, o268–o270. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Demko, Z. P. & Sharpless, K. B. (2001). J. Org. Chem. 66, 7945–7950. Web of Science CrossRef PubMed CAS Google Scholar
Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262. CrossRef CAS Web of Science IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Hemamalini, M. & Fun, H.-K. (2010). Acta Cryst. E66, o2192–o2193. Web of Science CSD CrossRef IUCr Journals Google Scholar
Misaki, S., Kashino, S. & Haisa, M. (1986). Bull. Chem. Soc. Jpn, 59, 1059–1065. CrossRef CAS Web of Science Google Scholar
Sharma, A., Thamotharan, S., Roy, S. & Vijayan, M. (2006). Acta Cryst. C62, o148–o152. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). XPW. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Speakman, J. C. (1972). Struct. Bond. 12, 141–199. CAS Google Scholar
Starosta, W. & Leciejewicz, J. (2010). Acta Cryst. E66, m1561–m1562. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sun, Y.-Q., Zhang, J. & Yang, G.-Y. (2002). Acta Cryst. E58, o904–o906. Web of Science CSD CrossRef IUCr Journals Google Scholar
Taka, J.-I., Ogino, S. & Kashino, S. (1998). Acta Cryst. C54, 384–386. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Tsaryk, N. V., Dudko, A. V., Kozachkova, A. N. & Pekhnyo, V. I. (2011). Acta Cryst. E67, o1651–o1652. Web of Science CSD CrossRef IUCr Journals Google Scholar
Wang, Y., Odoko, M. & Okabe, N. (2004). Acta Cryst. E60, m1178–m1180. Web of Science CSD CrossRef IUCr Journals Google Scholar
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Acid salts of dicarboxylic acids usually form very short O—H···O hydrogen bonds (with O···O distances between 2.4 and 2.5 Å) in their crystal structures (Speakman, 1972). This type of hydrogen bond is formed between the carboxyl and carboxylate groups by intramolecular (Starosta & Leciejewicz, 2010; Hemamalini & Fun, 2010; Sun et al., 2002) or intermolecular (Sharma et al., 2006; Wang et al., 2004; Taka et al., 1998) interactions. However, diphosphonates can also display such short and strong hydrogen bonds between neighbouring phosphonate groups (Tsaryk et al., 2011; Courtney et al., 2006; Cheng & Lin, 2006). There are two types of short O—H···O hydrogen bonds: symmetric, in which two O atoms are related by crystallographic symmetry and asymmetric, in which crystal symmetry does not impose the O—H···O hydrogen bond to be symmetric. Furthermore, symmetric hydrogen bonds typically display a shorter (2.43–2.51 Å) O···O distance than asymmetric ones (2.44–2.57 Å) (Misaki et al., 1986). In this work, we report the crystal structure of the title compound, whose structure contains a strong symmetric O—H···O hydrogen bond (Catti & Ferraris, 1976): atom H2 lies on a center of symmetry, located between two crystallographic equivalent carboxyl O2 atoms. The H atom, clearly visible on the Fourier map, is involved in a symmetric O2—H2···O2i [symmetry code: (i) -x + 1/2, -y + 3/2, -z] hydrogen bond with an O—H bond distance of 1.23 Å (Table 1).
The title compound (Fig. 1), [N(CH3)4]+[4-COOH-C6H4COO]-, consists of one half tetramethylammonium cation and one half terephthalate anion in the asymmetric unit. The cation lies on a twofold rotation axis and the anion on an inversion center. In the terephthalate anions, the two carboxyl groups are twisted from the mean plane of the benzene ring by a dihedral angle of 6.57 (2)°. Carboxyl atom O2 lies slightly farther [0.083 Å] from this plane than atom O1 [0.065 Å], owing to the strong O—H···O hydrogen bond between the terephthalate anions.
In the crystal, the terephthalate anions are linked end-to-end to form a one-dimensional polymeric chain in which adjacent ions are interconnected by a strong symmetric O—H···O (O···O distance of 2.4610 (19) Å) hydrogen bond (Table 1). Then the weak C—H···O hydrogen bonds link the ammonium cations and terephthalate anions together in a three-dimensional crystal structure. The C8—H8A···O1 and C9—H9A···O1 interactions form a pair of bifurcated acceptor bonds (Fig. 2), involving two C—H donor from an ammonium ion and an acceptor O atom from the terephthalate ion, generating an R21(6) ring motif (Etter et al., 1990; Bernstein et al., 1995).