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

In the centrosymmetric title compound, 2C₄H₁₂NO⁺·C₈H₄O₄²⁻, 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 R₂²(7). The crystal structure is further stabilized by C—H...O hydrogen bonds, leading to the fomation of a ribbon-like network.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.087
• wR factor = 0.220
• Data-to-parameter ratio = 14.8

checkCIF/PLATON results

No syntax errors found



Alert level C
DIFMX01_ALERT_2_C  The maximum difference density is > 0.1*ZMAX*0.75
            _refine_diff_density_max given =      0.661
            Test value =      0.600
DIFMX02_ALERT_1_C  The maximum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.46
PLAT097_ALERT_2_C Large Reported Max.  (Positive) Residual Density       0.66 eA-3
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          6

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        273 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        273 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

Supramolecular aggregate design is an active field of research and in a series of papers various supramolecular structures comprising benzene-dicarboxylic acids have been elucidated (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.

As shown in Fig. 1 two N,N-diethylhydroxylammonium (DTHA) cations are linked to the benzene-1,4-dicarboxylate anion (BDL), which is situated about an inversion center, by a special combination of O—H···O and N—H···O hydrogen bonds (Table 1), N1—H1···O1 and O3—H3···O2, which can be described by graph-set R²₂(7) [Bernstein, et al., 1995].

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 and Table 1), is fomed via C7—H7···O2ⁱ interactions [symmetry code (i) = 1 + x, y, z] .

Related literature

For similar supamolecular structures involving benzenedicarboxylic acids, see: Chatterjee et al. (2000); Herbstein & Kapon (1978); Karpova et al. (2004); Mak & Xue (2000); Yuge et al. (2006); Zhao et al. (2007). For graph-set theory, see: Bernstein et al. (1995).

S2. 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.

S3. Refinement

The H-atoms were included in calculated positions and treated as riding atoms: O-H = 0.82 Å, N-H = 0.91 Å, C-H = 0.93, 0.96, and 0.97 Å for aromatic, methyl and methylene H-atoms, respectively, with U_iso(H) = k × U_eq(parent O, N or C atom), where k = 1.5 for hydroxyl and methyl H-atoms and = 1.2 for all others.

Computing details

Data collection: SMART (Bruker, 2007); cell refinement: 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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A view of the molecular structure of the title compound [The O—H···O and N—H···O hydrogen bonds are illustrated by dotted lines].
	Fig. 2. A perspective view, along the c-axis, of the crystal packing of the title compound [The O—H···O and N—H···O hydrogen bonds nd the C-H···O interactions are illustrated by dotted lines; the symmetry code for the atom labeled O2^' is = x+1, y, z].

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

Crystal data

2C4H12NO^+·C8H4O4^2^−	F(000) = 372.0
Mr = 344.40	Dx = 1.221 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2185 reflections
a = 6.507 (2) Å	θ = 2.1–25.0°
b = 11.478 (4) Å	µ = 0.09 mm^−1
c = 12.649 (5) Å	T = 273 K
β = 97.380 (7)°	Block, colorless
V = 936.9 (6) Å^3	0.37 × 0.31 × 0.27 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer	1653 independent reflections
Radiation source: fine-focus sealed tube	1460 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
phi and ω scans	θmax = 25.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −7→7
Tmin = 0.954, Tmax = 0.969	k = −10→13
4737 measured reflections	l = −14→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.087	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.220	H-atom parameters constrained
S = 1.13	w = 1/[σ^2(Fo^2) + (0.0871P)^2 + 0.9891P] where P = (Fo^2 + 2Fc^2)/3
1653 reflections	(Δ/σ)max < 0.001
112 parameters	Δρmax = 0.66 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

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 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.4427 (3)	0.3065 (2)	0.0657 (2)	0.0636 (8)
O2	0.1752 (4)	0.2241 (2)	0.1261 (2)	0.0682 (8)
C1	0.2564 (5)	0.3044 (3)	0.0788 (3)	0.0482 (8)
C2	0.1228 (4)	0.4052 (3)	0.0370 (2)	0.0423 (8)
C3	−0.0744 (5)	0.4198 (3)	0.0657 (3)	0.0476 (8)
H3A	−0.1258	0.3653	0.1100	0.057*
C4	0.1945 (5)	0.4869 (3)	−0.0298 (3)	0.0469 (8)
H4	0.3257	0.4784	−0.0505	0.056*
O3	0.4471 (5)	0.0641 (2)	0.1778 (3)	0.0851 (10)
H3	0.3444	0.1052	0.1629	0.128*
N1	0.6262 (5)	0.1284 (3)	0.1645 (2)	0.0573 (8)
H1	0.5847	0.1967	0.1320	0.069*
C5	0.6600 (11)	0.2447 (5)	0.3266 (4)	0.110 (2)
H5A	0.6382	0.3143	0.2846	0.164*
H5B	0.7486	0.2617	0.3914	0.164*
H5C	0.5292	0.2162	0.3433	0.164*
C6	0.7561 (8)	0.1574 (4)	0.2672 (3)	0.0784 (13)
H6A	0.7786	0.0874	0.3101	0.094*
H6B	0.8901	0.1855	0.2525	0.094*
C7	0.7465 (6)	0.0633 (4)	0.0917 (3)	0.0660 (11)
H7A	0.6599	0.0520	0.0241	0.079*
H7B	0.8644	0.1102	0.0783	0.079*
C8	0.8225 (8)	−0.0519 (4)	0.1328 (4)	0.0938 (16)
H8A	0.9352	−0.0411	0.1888	0.141*
H8B	0.8694	−0.0961	0.0761	0.141*
H8C	0.7121	−0.0930	0.1601	0.141*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0377 (13)	0.0655 (17)	0.0879 (19)	0.0015 (11)	0.0087 (12)	0.0270 (14)
O2	0.0510 (15)	0.0536 (15)	0.103 (2)	−0.0012 (12)	0.0227 (14)	0.0214 (15)
C1	0.0434 (19)	0.0489 (19)	0.0519 (19)	−0.0079 (15)	0.0049 (14)	−0.0012 (15)
C2	0.0377 (16)	0.0466 (18)	0.0418 (16)	−0.0111 (13)	0.0013 (13)	−0.0047 (14)
C3	0.0415 (17)	0.053 (2)	0.0490 (18)	−0.0096 (15)	0.0093 (14)	0.0067 (15)
C4	0.0342 (16)	0.058 (2)	0.0500 (18)	−0.0045 (14)	0.0094 (13)	0.0012 (16)
O3	0.0704 (18)	0.0558 (17)	0.137 (3)	0.0022 (14)	0.0415 (19)	0.0251 (18)
N1	0.0621 (18)	0.0444 (16)	0.0636 (19)	−0.0028 (14)	0.0010 (15)	0.0095 (14)
C5	0.167 (6)	0.094 (4)	0.070 (3)	0.034 (4)	0.024 (3)	−0.002 (3)
C6	0.100 (3)	0.071 (3)	0.062 (2)	0.019 (2)	0.004 (2)	0.010 (2)
C7	0.058 (2)	0.072 (3)	0.066 (2)	−0.0090 (19)	0.0050 (18)	0.002 (2)
C8	0.100 (4)	0.073 (3)	0.111 (4)	0.015 (3)	0.020 (3)	−0.006 (3)

Geometric parameters (Å, º)

O1—C1	1.245 (4)	N1—H1	0.9100
O2—C1	1.252 (4)	C5—C6	1.442 (6)
C1—C2	1.502 (5)	C5—H5A	0.9600
C2—C4	1.384 (4)	C5—H5B	0.9600
C2—C3	1.388 (4)	C5—H5C	0.9600
C3—C4^i	1.368 (5)	C6—H6A	0.9700
C3—H3A	0.9300	C6—H6B	0.9700
C4—C3^i	1.368 (5)	C7—C8	1.481 (6)
C4—H4	0.9300	C7—H7A	0.9700
O3—N1	1.408 (4)	C7—H7B	0.9700
O3—H3	0.8200	C8—H8A	0.9600
N1—C7	1.484 (5)	C8—H8B	0.9600
N1—C6	1.494 (5)	C8—H8C	0.9600
O1—C1—O2	123.8 (3)	C6—C5—H5C	109.5
O1—C1—C2	117.9 (3)	H5A—C5—H5C	109.5
O2—C1—C2	118.3 (3)	H5B—C5—H5C	109.5
C4—C2—C3	118.3 (3)	C5—C6—N1	111.9 (4)
C4—C2—C1	120.8 (3)	C5—C6—H6A	109.2
C3—C2—C1	120.9 (3)	N1—C6—H6A	109.2
C4^i—C3—C2	121.0 (3)	C5—C6—H6B	109.2
C4^i—C3—H3A	119.5	N1—C6—H6B	109.2
C2—C3—H3A	119.5	H6A—C6—H6B	107.9
C3^i—C4—C2	120.7 (3)	C8—C7—N1	114.3 (4)
C3^i—C4—H4	119.7	C8—C7—H7A	108.7
C2—C4—H4	119.7	N1—C7—H7A	108.7
N1—O3—H3	109.5	C8—C7—H7B	108.7
O3—N1—C7	108.7 (3)	N1—C7—H7B	108.7
O3—N1—C6	113.4 (3)	H7A—C7—H7B	107.6
C7—N1—C6	111.6 (3)	C7—C8—H8A	109.5
O3—N1—H1	107.7	C7—C8—H8B	109.5
C7—N1—H1	107.7	H8A—C8—H8B	109.5
C6—N1—H1	107.7	C7—C8—H8C	109.5
C6—C5—H5A	109.5	H8A—C8—H8C	109.5
C6—C5—H5B	109.5	H8B—C8—H8C	109.5
H5A—C5—H5B	109.5
O1—C1—C2—C4	11.2 (5)	C3—C2—C4—C3^i	0.6 (5)
O2—C1—C2—C4	−169.9 (3)	C1—C2—C4—C3^i	−178.4 (3)
O1—C1—C2—C3	−167.8 (3)	O3—N1—C6—C5	−71.7 (5)
O2—C1—C2—C3	11.1 (5)	C7—N1—C6—C5	165.2 (4)
C4—C2—C3—C4^i	−0.6 (5)	O3—N1—C7—C8	−62.6 (4)
C1—C2—C3—C4^i	178.4 (3)	C6—N1—C7—C8	63.1 (5)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2	0.82	1.78	2.576 (5)	164
N1—H1···O1	0.91	1.72	2.605 (5)	164
C7—H7b···O2^ii	0.97	2.42	3.327 (5)	156

Symmetry code: (ii) x+1, y, z.