Piperazine-1,4-diium bis-(hydrogen 2-propyl-1H-imidazole-4,5-dicarbox-ylate) monohydrate.

The title compound, C(4)H(12)N(2) (2+)·2C(8)H(9)N(2)O(4) (-)·H(2)O, is a hydrated proton-transfer compound obtained from 2-propyl-1H-imidazole-4,5-dicarb-oxy-lic acid and piperazine. The asymmetric unit contains one half-cation, one anion and half a water mol-ecule. There is a centre of inversion at the centre of the cation ring and the water molecule O atom lies on a twofold rotation axis. In the crystal, inter-molecular N-H⋯O and N-H⋯N hydrogen bonds help to construct a three-dimensional framework. Almost symmetrical, intramolecular O-H⋯O inter-actions are also observed.

Related literature

For the structures and properties of proton-transfer compounds, see: Aghabozorg et al. (2006 ▶). For the use of multi-carboxyl­ate heterocyclic acids and n class="Chemical">piperazine in coord­ination chemistry, see: Murugavel et al. (2009 ▶); Sheshmani et al. (2006 ▶) and for piperazinium structures, see: Murugavel et al. (2009 ▶); Sheshmani et al. (2007 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C4H12N2 2+·2C8n class="Species">H9N2O4 −·H2O

M = 500.52

Monoclinic,

a = 11.288 (2) Å

b = 15.965 (3) Å

c = 14.449 (4) Å

β = 101.296 (12)°

V = 2553.6 (10) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 273 K

0.20 × 0.18 × 0.16 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 1997 ▶) T min = 0.980, T max = 0.984

6239 measured reflections

2066 independent reflections

1499 reflections with I > 2σ(I)

R int = 0.039

Refinement

R[F 2 > 2σ(F 2)] = 0.050

wR(F 2) = 0.136

S = 1.05

2066 reflections

165 parameters

13 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.43 e Å−3

Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 1997 ▶); cell refinement: SAINT (Bruker, 1997 ▶); data reduction: SAINT; 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.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810049822/jh2238sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810049822/jh2238Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C4H12N22+·2C8H9N2O4−·H2O	F(000) = 1064
Mr = 500.52	Dx = 1.302 Mg m−3
Monoclinic, I2/a	Mo Kα radiation, λ = 0.71073 Å
a = 11.288 (2) Å	Cell parameters from 1047 reflections
b = 15.965 (3) Å	θ = 0.0–0.0°
c = 14.449 (4) Å	µ = 0.10 mm−1
β = 101.296 (12)°	T = 273 K
V = 2553.6 (10) Å3	Block, colorless
Z = 4	0.20 × 0.18 × 0.16 mm

Bruker SMART CCD area-detector diffractometer	2066 independent reflections
Radiation source: fine-focus sealed tube	1499 reflections with I > 2σ(I)
graphite	Rint = 0.039
φ and ω scans	θmax = 24.3°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −10→13
Tmin = 0.980, Tmax = 0.984	k = −18→17
6239 measured reflections	l = −16→16

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.136	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.0619P)2 + 1.5738P] where P = (Fo2 + 2Fc2)/3
2066 reflections	(Δ/σ)max = 0.001
165 parameters	Δρmax = 0.43 e Å−3
13 restraints	Δρmin = −0.21 e Å−3

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.

	x	y	z	Uiso*/Ueq
C1	0.0849 (2)	0.71261 (16)	0.09103 (17)	0.0422 (6)
C2	0.1935 (2)	0.67934 (14)	0.15314 (16)	0.0364 (6)
C3	0.2144 (2)	0.64165 (14)	0.24013 (16)	0.0363 (6)
C4	0.1292 (2)	0.62027 (16)	0.30292 (18)	0.0424 (6)
C5	0.5184 (2)	0.6485 (2)	0.1969 (2)	0.0611 (8)
H5A	0.5649	0.6478	0.2609	0.073*
H5B	0.5409	0.6984	0.1661	0.073*
C6	0.5505 (3)	0.5713 (3)	0.1446 (4)	0.1233 (18)
H6A	0.5028	0.5710	0.0810	0.148*
H6B	0.5308	0.5212	0.1765	0.148*
C7	0.6847 (4)	0.5704 (3)	0.1403 (5)	0.171 (3)
H7A	0.7039	0.6195	0.1078	0.205*
H7B	0.7024	0.5213	0.1072	0.205*
H7C	0.7320	0.5699	0.2032	0.205*
C8	0.5499 (2)	0.57768 (16)	0.47554 (19)	0.0483 (7)
H8A	0.5643	0.6370	0.4872	0.058*
H8B	0.5864	0.5617	0.4227	0.058*
C9	0.3930 (2)	0.47110 (16)	0.43879 (17)	0.0456 (7)
H9A	0.4231	0.4509	0.3845	0.055*
H9B	0.3062	0.4627	0.4267	0.055*
C12	0.3877 (2)	0.65313 (16)	0.20022 (17)	0.0429 (6)
H2	−0.004 (2)	0.6647 (18)	0.195 (2)	0.103 (11)*
H1W	0.8140	0.7443	0.0209	0.31 (5)*
N1	0.30493 (17)	0.68560 (13)	0.12993 (13)	0.0410 (5)
H1	0.3196	0.7069	0.0787	0.049*
N2	0.33568 (18)	0.62552 (13)	0.26903 (14)	0.0426 (5)
N3	0.42026 (17)	0.56200 (13)	0.45216 (14)	0.0426 (5)
H3A	0.3883	0.5897	0.3989	0.051*
H3B	0.3856	0.5818	0.4988	0.051*
O1	−0.01641 (15)	0.70340 (13)	0.11795 (13)	0.0582 (6)
O2	0.09473 (15)	0.74761 (12)	0.01667 (12)	0.0510 (5)
O3	0.01637 (15)	0.63600 (13)	0.27299 (13)	0.0566 (5)
O4	0.16861 (16)	0.58907 (12)	0.38055 (12)	0.0537 (5)
O5	0.7500	0.7747 (3)	0.0000	0.170 (3)

	U11	U22	U33	U12	U13	U23
C1	0.0499 (16)	0.0430 (15)	0.0338 (14)	0.0040 (12)	0.0083 (12)	−0.0025 (12)
C2	0.0403 (13)	0.0379 (14)	0.0322 (13)	0.0010 (10)	0.0101 (10)	−0.0008 (10)
C3	0.0388 (13)	0.0379 (14)	0.0331 (13)	0.0015 (10)	0.0092 (10)	0.0022 (10)
C4	0.0480 (15)	0.0419 (15)	0.0390 (15)	0.0021 (11)	0.0124 (12)	0.0047 (12)
C5	0.0471 (17)	0.088 (2)	0.0514 (17)	0.0117 (15)	0.0188 (14)	0.0195 (16)
C6	0.090 (3)	0.089 (3)	0.215 (5)	0.042 (2)	0.089 (3)	0.042 (3)
C7	0.130 (4)	0.149 (5)	0.268 (7)	0.062 (4)	0.126 (5)	0.072 (5)
C8	0.0438 (15)	0.0455 (16)	0.0572 (17)	0.0039 (12)	0.0138 (13)	0.0078 (13)
C9	0.0408 (14)	0.0511 (17)	0.0438 (16)	0.0050 (12)	0.0055 (11)	−0.0065 (12)
C12	0.0437 (14)	0.0530 (16)	0.0335 (14)	0.0049 (12)	0.0110 (11)	0.0054 (12)
N1	0.0469 (12)	0.0483 (13)	0.0307 (11)	0.0027 (10)	0.0150 (9)	0.0058 (9)
N2	0.0437 (12)	0.0494 (13)	0.0366 (12)	0.0059 (9)	0.0127 (9)	0.0089 (9)
N3	0.0448 (12)	0.0479 (13)	0.0354 (11)	0.0108 (9)	0.0090 (9)	0.0058 (9)
O1	0.0429 (11)	0.0824 (15)	0.0487 (12)	0.0088 (9)	0.0075 (9)	0.0143 (10)
O2	0.0610 (12)	0.0601 (12)	0.0334 (10)	0.0150 (9)	0.0132 (9)	0.0053 (8)
O3	0.0427 (11)	0.0766 (14)	0.0527 (12)	0.0031 (9)	0.0146 (9)	0.0180 (10)
O4	0.0540 (11)	0.0682 (13)	0.0426 (11)	0.0087 (9)	0.0189 (9)	0.0200 (9)
O5	0.084 (3)	0.089 (3)	0.315 (8)	0.000	−0.015 (4)	0.000

C1—O2	1.235 (3)	C7—H7C	0.9600
C1—O1	1.286 (3)	C8—N3	1.458 (3)
C1—C2	1.469 (3)	C8—C9i	1.497 (3)
C2—N1	1.368 (3)	C8—H8A	0.9700
C2—C3	1.372 (3)	C8—H8B	0.9700
C3—N2	1.375 (3)	C9—N3	1.488 (3)
C3—C4	1.486 (3)	C9—C8i	1.497 (3)
C4—O4	1.228 (3)	C9—H9A	0.9700
C4—O3	1.287 (3)	C9—H9B	0.9700
C5—C12	1.487 (3)	C12—N2	1.325 (3)
C5—C6	1.526 (5)	C12—N1	1.342 (3)
C5—H5A	0.9700	N1—H1	0.8600
C5—H5B	0.9700	N3—H3A	0.9000
C6—C7	1.528 (5)	N3—H3B	0.9000
C6—H6A	0.9700	O1—H2	1.26 (3)
C6—H6B	0.9700	O3—H2	1.19 (3)
C7—H7A	0.9600	O5—H1W	0.8739
C7—H7B	0.9600
O2—C1—O1	123.5 (2)	H7B—C7—H7C	109.5
O2—C1—C2	119.2 (2)	N3—C8—C9i	110.6 (2)
O1—C1—C2	117.3 (2)	N3—C8—H8A	109.5
N1—C2—C3	104.8 (2)	C9i—C8—H8A	109.5
N1—C2—C1	121.4 (2)	N3—C8—H8B	109.5
C3—C2—C1	133.8 (2)	C9i—C8—H8B	109.5
C2—C3—N2	110.1 (2)	H8A—C8—H8B	108.1
C2—C3—C4	130.1 (2)	N3—C9—C8i	110.8 (2)
N2—C3—C4	119.8 (2)	N3—C9—H9A	109.5
O4—C4—O3	122.9 (2)	C8i—C9—H9A	109.5
O4—C4—C3	119.3 (2)	N3—C9—H9B	109.5
O3—C4—C3	117.8 (2)	C8i—C9—H9B	109.5
C12—C5—C6	112.9 (3)	H9A—C9—H9B	108.1
C12—C5—H5A	109.0	N2—C12—N1	110.5 (2)
C6—C5—H5A	109.0	N2—C12—C5	126.6 (2)
C12—C5—H5B	109.0	N1—C12—C5	122.9 (2)
C6—C5—H5B	109.0	C12—N1—C2	108.89 (19)
H5A—C5—H5B	107.8	C12—N1—H1	125.6
C5—C6—C7	111.2 (4)	C2—N1—H1	125.6
C5—C6—H6A	109.4	C12—N2—C3	105.7 (2)
C7—C6—H6A	109.4	C8—N3—C9	111.74 (18)
C5—C6—H6B	109.4	C8—N3—H3A	109.3
C7—C6—H6B	109.4	C9—N3—H3A	109.3
H6A—C6—H6B	108.0	C8—N3—H3B	109.3
C6—C7—H7A	109.5	C9—N3—H3B	109.3
C6—C7—H7B	109.5	H3A—N3—H3B	107.9
H7A—C7—H7B	109.5	C1—O1—H2	112.1 (11)
C6—C7—H7C	109.5	C4—O3—H2	112.9 (12)
H7A—C7—H7C	109.5

D—H···A	D—H	H···A	D···A	D—H···A
O3—H2···O1	1.19 (3)	1.26 (3)	2.447 (3)	172 (3)
O5—H1W···O1ii	0.87	2.24	3.065 (3)	158.
N1—H1···O2iii	0.86	1.94	2.773 (3)	162.
N3—H3A···N2	0.90	1.94	2.820 (3)	165.
N3—H3B···O4iv	0.90	1.96	2.826 (3)	161.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H2⋯O1	1.19 (3)	1.26 (3)	2.447 (3)	172 (3)
O5—H1W⋯O1i	0.87	2.24	3.065 (3)	158
N1—H1⋯O2ii	0.86	1.94	2.773 (3)	162
N3—H3A⋯N2	0.90	1.94	2.820 (3)	165
N3—H3B⋯O4iii	0.90	1.96	2.826 (3)	161

Symmetry codes: (i) ; (ii) ; (iii) .