Piperazine-1,4-diium bis­(3-carb­oxy-4-hydroxy­benzene­sulfonate) dihydrate

The asymmetric unit of the title compound, C₄H₁₂N₂²⁺·2C₇H₅O₆S⁻·2H₂O, comprises one-half of the piperazine-1,4-diium cation, which lies across an inversion centre, a 3-carb­oxy-4-hydroxy­benzene­sulfonate anion and a water mol­ecule. An extensive network of inter­molecular O—H...O and N—H...O hydrogen bonds links the cations and anions in alternating rows down the b axis.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.035
• wR factor = 0.104
• Data-to-parameter ratio = 11.1

checkCIF/PLATON results

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Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       2.00 Ratio
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        300 Deg.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3
PLAT480_ALERT_4_C Long H...A H-Bond Reported H4     ..  S1      ..       2.96 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H7A    ..  S1      ..       3.00 Ang.

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6

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

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
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S1. Comment

3-carboxy-4-hydroxy benzene sulfonate also known as 5-sulfosalicylic acid (SSA) has six potential donor sites in the three substituent groups (the sulfonic acid, the carboxylic acid and the phenolic groups), and it can form mono-, di- and trianionic ligand species through deprotonation. The presence of the numerous oxygen atoms in three substituent groups usually results in hydrogen-bonding associations, and the self-assembly process of crystallization often requires the incorporation of water molecules in the structures (Smith et al. 2007).

We report here the synthesis and structure of piperazine-1,4-diium 3-carboxyl-4-hydroxyl benzene sulfonate monohydrate, (I), Fig. 1 which was obtained from a solution of 2-hydroxy-5-sulfobenzoic acid and piperazine. Bond distances and angles in (I) are normal (Allen et al., 1987). The asymmetric unit of the title compound comprises one half of the piperazine-1,4-diium cation, which lies about an inversion centre, a 3-carboxy-4-hydroxybenzenesulfonate anion and a water solvate. In the crystal structure molecules were interlinked by hydrogen bonds, Table 1, involving oxygen atoms from the sulfonate and carboxylate groups of the 5-sulfosalicylate, and the nitrogen atoms of the piperazinediium cation. The water molecules function as a bridge between two anions and a cation producing a three-dimensional hydrogen-bonded framework structure. The hydroxyl group of the 5-sulfosalicylate forms an intramolecular O6—H6···O5 hydrogen bond but is not involved in the crystal packing.

Related literature

For information on the role of water in self-assembly processes, see: Smith et al. (2007). For reference structural data, see: Allen et al. (1987).

S2. Experimental

2-hydroxy-5-sulfobenzoic acid (2.18 g, 10 mmol) and piperazine (0.86 g, 10 mmol) were dissolved in warm H₂O (20 ml). Crystals of the title compound were obtained by slow evaporation of this solution.

S3. Refinement

The H atoms of the water molecule and those on the N atoms were located in difference Fourier maps; their the parameters were freely refined. All other H atoms were positioned geometrically and refined using a riding model, with O—H = 0.82 Å for hydroxy H atoms, C—H = 0.93 Å for aromatic H atoms, and 0.97 Å for methylene H atoms, respectively, and with U_iso(H) = 1.5Ueq(O) for hydroxy and U_iso(H) = 1.2Ueq(C) for aromatic and methylene H atoms.

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 2001); software used to prepare material for publication: SHELXTL (Sheldrick, 2001).

Figures

	Fig. 1. The molecular structure of (I) with 30% probability displacement ellipsoids. H atoms are shown as small spheres of arbitary radii. [Symmetry code; (i) 1 - x, -y, 1 - z.]
	Fig. 2. The crystal packing of (I) showing the O—H···O and N—H···O hydrogen bonds (dashed lines). [Symmetry codes: (i) 1 - x, 1 - y, 1 - z; (ii) 1 - x, 2 - y, 2 - z; (iii) 1 + x, y, z; (iv) 1 + x, 1 + y, z; (v) 1 - x, 2 - y, 1 - z; (vi) x, 1 + y, z; (vii) 1 - x, - y, 1 - z]

Piperazine-1,4-diium bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate

Crystal data

C4H12N2^2+·2C7H5O6S^−·2H2O	Z = 1
Mr = 558.52	F(000) = 292
Triclinic, P1	Dx = 1.607 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8980 (13) Å	Cell parameters from 2045 reflections
b = 7.2012 (14) Å	θ = 3.1–26.3°
c = 12.800 (2) Å	µ = 0.31 mm^−1
α = 100.280 (3)°	T = 294 K
β = 93.084 (3)°	Block, colourless
γ = 111.459 (3)°	0.24 × 0.20 × 0.18 mm
V = 577.31 (19) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	2016 independent reflections
Radiation source: fine-focus sealed tube	1786 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ϕ and ω scans	θmax = 25.0°, θmin = 1.6°
Absorption correction: multi-scan (SADABS;Bruker, 2000)	h = −8→8
Tmin = 0.930, Tmax = 0.947	k = −8→5
2992 measured reflections	l = −13→15

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.035	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0606P)^2 + 0.226P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
2016 reflections	Δρmax = 0.29 e Å^−3
182 parameters	Δρmin = −0.33 e Å^−3
6 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.056 (7)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > 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
S1	0.18428 (7)	0.46867 (7)	0.70639 (4)	0.0325 (2)
O1	0.3025 (3)	0.4558 (3)	0.61877 (12)	0.0540 (5)
O2	0.0505 (3)	0.5810 (3)	0.69897 (13)	0.0549 (5)
O3	0.0567 (2)	0.2658 (2)	0.72449 (10)	0.0366 (4)
O4	0.1360 (2)	0.7404 (3)	1.09825 (12)	0.0498 (4)
H4	0.0971	0.7675	1.1564	0.075*
O5	0.4490 (3)	0.8749 (3)	1.19742 (12)	0.0526 (4)
O6	0.7792 (2)	0.9051 (3)	1.09761 (12)	0.0512 (4)
H6	0.7159	0.9232	1.1484	0.077*
N1	0.7087 (3)	0.0786 (3)	0.55348 (14)	0.0383 (4)
C1	0.3649 (3)	0.5961 (3)	0.82344 (15)	0.0304 (4)
C2	0.2889 (3)	0.6465 (3)	0.91627 (15)	0.0308 (4)
H2	0.1452	0.6130	0.9160	0.037*
C3	0.4238 (3)	0.7473 (3)	1.01111 (15)	0.0307 (4)
C4	0.6405 (3)	0.8012 (3)	1.00941 (16)	0.0353 (5)
C5	0.7156 (3)	0.7501 (3)	0.91494 (18)	0.0405 (5)
H5	0.8594	0.7859	0.9140	0.049*
C6	0.5800 (3)	0.6470 (3)	0.82266 (17)	0.0367 (5)
H6A	0.6315	0.6112	0.7597	0.044*
C7	0.3409 (3)	0.7940 (3)	1.11070 (16)	0.0364 (5)
C8	0.5938 (3)	0.2154 (3)	0.54583 (17)	0.0402 (5)
H8A	0.6926	0.3507	0.5437	0.048*
H8B	0.5224	0.2265	0.6085	0.048*
C9	0.5640 (3)	−0.1322 (3)	0.55349 (17)	0.0383 (5)
H9A	0.4917	−0.1324	0.6164	0.046*
H9B	0.6435	−0.2184	0.5560	0.046*
O7	0.0665 (3)	0.9051 (3)	0.61474 (14)	0.0545 (4)
H1A	0.779 (3)	0.077 (4)	0.4952 (11)	0.048 (7)*
H1B	0.802 (3)	0.129 (4)	0.6142 (10)	0.068 (8)*
H7A	0.092 (5)	1.019 (2)	0.6563 (17)	0.074 (10)*
H7B	0.063 (5)	0.808 (3)	0.6449 (19)	0.079 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0353 (3)	0.0313 (3)	0.0238 (3)	0.0054 (2)	0.00128 (19)	0.00453 (19)
O1	0.0540 (9)	0.0603 (10)	0.0288 (8)	0.0014 (8)	0.0137 (7)	0.0040 (7)
O2	0.0631 (10)	0.0487 (9)	0.0510 (10)	0.0232 (8)	−0.0133 (8)	0.0082 (8)
O3	0.0381 (7)	0.0324 (7)	0.0271 (7)	0.0018 (6)	0.0016 (6)	0.0019 (5)
O4	0.0404 (9)	0.0569 (10)	0.0330 (8)	0.0032 (7)	0.0099 (6)	−0.0059 (7)
O5	0.0569 (10)	0.0558 (10)	0.0293 (8)	0.0104 (8)	−0.0054 (7)	−0.0026 (7)
O6	0.0372 (8)	0.0585 (10)	0.0429 (9)	0.0085 (7)	−0.0128 (7)	0.0004 (8)
N1	0.0303 (8)	0.0426 (10)	0.0324 (9)	0.0065 (8)	−0.0060 (7)	0.0032 (8)
C1	0.0311 (10)	0.0249 (9)	0.0295 (10)	0.0051 (8)	0.0019 (8)	0.0042 (7)
C2	0.0265 (9)	0.0264 (9)	0.0315 (10)	0.0025 (7)	0.0021 (7)	0.0031 (7)
C3	0.0320 (10)	0.0245 (9)	0.0291 (10)	0.0041 (8)	0.0005 (8)	0.0052 (7)
C4	0.0325 (10)	0.0285 (10)	0.0379 (11)	0.0051 (8)	−0.0059 (8)	0.0070 (8)
C5	0.0254 (9)	0.0421 (12)	0.0492 (12)	0.0077 (9)	0.0033 (9)	0.0095 (9)
C6	0.0333 (10)	0.0359 (11)	0.0378 (11)	0.0096 (9)	0.0088 (8)	0.0063 (9)
C7	0.0412 (11)	0.0280 (10)	0.0296 (10)	0.0036 (8)	0.0009 (8)	0.0024 (8)
C8	0.0429 (11)	0.0323 (10)	0.0371 (11)	0.0087 (9)	−0.0028 (9)	0.0012 (8)
C9	0.0394 (11)	0.0367 (11)	0.0358 (11)	0.0121 (9)	−0.0018 (9)	0.0074 (9)
O7	0.0682 (11)	0.0440 (10)	0.0561 (10)	0.0247 (9)	0.0157 (9)	0.0133 (9)

Geometric parameters (Å, º)

S1—O1	1.4310 (16)	C2—H2	0.9300
S1—O2	1.4419 (17)	C3—C4	1.403 (3)
S1—O3	1.4713 (14)	C3—C7	1.460 (3)
S1—C1	1.7640 (19)	C4—C5	1.384 (3)
O4—C7	1.314 (3)	C5—C6	1.372 (3)
O4—H4	0.8200	C5—H5	0.9300
O5—C7	1.221 (2)	C6—H6A	0.9300
O6—C4	1.345 (2)	C8—C9^i	1.504 (3)
O6—H6	0.8200	C8—H8A	0.9700
N1—C9	1.481 (3)	C8—H8B	0.9700
N1—C8	1.485 (3)	C9—C8^i	1.504 (3)
N1—H1A	0.914 (9)	C9—H9A	0.9700
N1—H1B	0.907 (10)	C9—H9B	0.9700
C1—C2	1.368 (3)	O7—H7A	0.848 (10)
C1—C6	1.393 (3)	O7—H7B	0.849 (10)
C2—C3	1.391 (3)
O1—S1—O2	115.38 (11)	O6—C4—C3	121.52 (19)
O1—S1—O3	111.98 (9)	C5—C4—C3	119.85 (18)
O2—S1—O3	108.58 (10)	C6—C5—C4	120.59 (18)
O1—S1—C1	107.58 (10)	C6—C5—H5	119.7
O2—S1—C1	106.66 (9)	C4—C5—H5	119.7
O3—S1—C1	106.12 (8)	C5—C6—C1	119.82 (19)
C7—O4—H4	109.5	C5—C6—H6A	120.1
C4—O6—H6	109.5	C1—C6—H6A	120.1
C9—N1—C8	111.79 (16)	O5—C7—O4	122.67 (19)
C9—N1—H1A	109.3 (15)	O5—C7—C3	124.08 (19)
C8—N1—H1A	107.1 (15)	O4—C7—C3	113.26 (16)
C9—N1—H1B	109.5 (17)	N1—C8—C9^i	110.16 (16)
C8—N1—H1B	109.5 (17)	N1—C8—H8A	109.6
H1A—N1—H1B	109.7 (14)	C9^i—C8—H8A	109.6
C2—C1—C6	120.10 (18)	N1—C8—H8B	109.6
C2—C1—S1	118.23 (14)	C9^i—C8—H8B	109.6
C6—C1—S1	121.67 (15)	H8A—C8—H8B	108.1
C1—C2—C3	120.86 (18)	N1—C9—C8^i	109.94 (16)
C1—C2—H2	119.6	N1—C9—H9A	109.7
C3—C2—H2	119.6	C8^i—C9—H9A	109.7
C2—C3—C4	118.76 (18)	N1—C9—H9B	109.7
C2—C3—C7	120.57 (17)	C8^i—C9—H9B	109.7
C4—C3—C7	120.67 (17)	H9A—C9—H9B	108.2
O6—C4—C5	118.62 (18)	H7A—O7—H7B	115.9 (17)
O1—S1—C1—C2	172.95 (15)	C7—C3—C4—C5	178.02 (18)
O2—S1—C1—C2	48.60 (18)	O6—C4—C5—C6	−178.95 (19)
O3—S1—C1—C2	−67.04 (17)	C3—C4—C5—C6	0.0 (3)
O1—S1—C1—C6	−6.4 (2)	C4—C5—C6—C1	1.1 (3)
O2—S1—C1—C6	−130.77 (17)	C2—C1—C6—C5	−0.8 (3)
O3—S1—C1—C6	113.59 (17)	S1—C1—C6—C5	178.56 (15)
C6—C1—C2—C3	−0.5 (3)	C2—C3—C7—O5	177.08 (19)
S1—C1—C2—C3	−179.92 (14)	C4—C3—C7—O5	−2.2 (3)
C1—C2—C3—C4	1.6 (3)	C2—C3—C7—O4	−3.0 (3)
C1—C2—C3—C7	−177.75 (17)	C4—C3—C7—O4	177.72 (18)
C2—C3—C4—O6	177.61 (17)	C9—N1—C8—C9^i	−57.5 (2)
C7—C3—C4—O6	−3.1 (3)	C8—N1—C9—C8^i	57.3 (2)
C2—C3—C4—C5	−1.3 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O3^ii	0.82	1.90	2.690 (2)	160
O4—H4···S1^ii	0.82	2.96	3.5926 (16)	136
N1—H1A···O7^iii	0.91 (1)	1.80 (1)	2.715 (3)	175 (2)
N1—H1B···O3^iv	0.91 (1)	2.01 (1)	2.895 (2)	166 (2)
N1—H1B···S1^iv	0.91 (1)	2.87 (2)	3.6176 (17)	140 (2)
O7—H7A···O3^v	0.85 (1)	1.94 (1)	2.750 (2)	160 (3)
O7—H7A···S1^v	0.85 (1)	3.00 (1)	3.781 (2)	154 (2)
O6—H6···O5	0.82	1.91	2.630 (2)	147
O7—H7B···O2	0.85 (1)	1.86 (1)	2.710 (2)	175 (3)

Symmetry codes: (ii) −x, −y+1, −z+2; (iii) −x+1, −y+1, −z+1; (iv) x+1, y, z; (v) x, y+1, z.