4-Carb-oxy-2-methyl-1H-imidazol-3-ium-5-carboxyl-ate monohydrate.

In the title compound, C(6)H(6)N(2)O(4)·H(2)O, one carboxyl group is deprotonated and one imidazole N atom is protonated. The organic mol-ecule, excluding methyl H atoms, is essentially planar, with an r.m.s. deviation of 0.0156 (1) Å. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link mol-ecules into chains along the b axis; these chains are further linked via O-H⋯O hydrogen bonds involving the water O atoms and carboxyl O atoms, generating a two-dimensional supra-molecular framework.

Related literature

For details of related structures, see: Sun et al. (2006 ▶); Nie et al. (2007 ▶). For applications as functional materials, see: Liang et al. (2002 ▶); Qin et al. (2002 ▶); Li et al. (1998 ▶). For biological activities, see: Ucucu et al. (2001 ▶); Maeda et al. (1984 ▶); Quattara et al. (1987 ▶); Seko et al. (1991 ▶). For the synthesis of the title compound, see: Anderson et al. (1989 ▶).

Experimental

Crystal data

C6H6N2O4·H2O

M = 188.14

Monoclinic,

a = 8.491 (2) Å

b = 14.280 (4) Å

c = 6.5385 (17) Å

β = 97.386 (5)°

V = 786.2 (4) Å3

Z = 4

Mo Kα radiation

μ = 0.14 mm−1

T = 295 (2) K

0.23 × 0.09 × 0.08 mm

Data collection

Bruker SMART APEX area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.969, T max = 0.995

4506 measured reflections

1538 independent reflections

1246 reflections with I > 2σ(I)

R int = 0.032

Refinement

R[F 2 > 2σ(F 2)] = 0.056

wR(F 2) = 0.131

S = 1.05

1538 reflections

128 parameters

4 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.26 e Å−3

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); 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/S1600536808040221/wn2295sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808040221/wn2295Isup2.hkl

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

C6H6N2O4·H2O	F(000) = 392
Mr = 188.14	Dx = 1.589 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 927 reflections
a = 8.491 (2) Å	θ = 2.4–24.3°
b = 14.280 (4) Å	µ = 0.14 mm−1
c = 6.5385 (17) Å	T = 295 K
β = 97.386 (5)°	Block, colorless
V = 786.2 (4) Å3	0.23 × 0.09 × 0.08 mm
Z = 4

Bruker SMART APEX area-detector diffractometer	1538 independent reflections
Radiation source: fine-focus sealed tube	1246 reflections with I > 2σ(I)
graphite	Rint = 0.032
φ and ω scans	θmax = 26.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→10
Tmin = 0.969, Tmax = 0.995	k = −17→17
4506 measured reflections	l = −8→7

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)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.131	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.0559P)2 + 0.4711P] where P = (Fo2 + 2Fc2)/3
1538 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.25 e Å−3
4 restraints	Δρmin = −0.26 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
O1	0.5312 (2)	0.88207 (11)	0.2430 (3)	0.0404 (5)
O3	0.1439 (2)	0.68027 (12)	0.1429 (3)	0.0430 (5)
H3	0.191 (3)	0.7337 (12)	0.157 (5)	0.065*
N2	0.5293 (2)	0.56877 (13)	0.2531 (3)	0.0287 (5)
H2	0.5126	0.5094	0.2501	0.034*
O2	0.2822 (2)	0.83103 (12)	0.1822 (3)	0.0436 (5)
N1	0.6490 (2)	0.70121 (13)	0.2840 (3)	0.0284 (5)
H1	0.7232	0.7424	0.3045	0.034*
C2	0.4901 (3)	0.72074 (15)	0.2375 (3)	0.0265 (5)
C3	0.4139 (3)	0.63632 (15)	0.2178 (3)	0.0265 (5)
C1	0.4314 (3)	0.81906 (15)	0.2198 (4)	0.0303 (6)
C4	0.6708 (3)	0.60933 (16)	0.2927 (4)	0.0283 (5)
C5	0.2437 (3)	0.61108 (17)	0.1680 (4)	0.0335 (6)
O4	0.2045 (2)	0.52952 (12)	0.1540 (3)	0.0506 (6)
C6	0.8249 (3)	0.56070 (18)	0.3429 (4)	0.0405 (7)
H6A	0.8557	0.5333	0.2199	0.061*
H6B	0.8148	0.5124	0.4425	0.061*
H6C	0.9043	0.6049	0.3987	0.061*
O1W	0.8762 (2)	0.83332 (13)	0.3359 (4)	0.0563 (6)
H1WA	0.961 (3)	0.827 (2)	0.419 (5)	0.084*
H1WB	0.840 (4)	0.8884 (12)	0.345 (5)	0.084*

	U11	U22	U33	U12	U13	U23
O1	0.0417 (11)	0.0175 (8)	0.0613 (13)	−0.0014 (7)	0.0041 (9)	−0.0002 (8)
O3	0.0293 (10)	0.0278 (10)	0.0697 (14)	−0.0004 (7)	−0.0020 (9)	0.0000 (9)
N2	0.0313 (11)	0.0172 (9)	0.0371 (12)	0.0002 (8)	0.0025 (9)	−0.0009 (8)
O2	0.0360 (11)	0.0272 (9)	0.0664 (14)	0.0062 (8)	0.0025 (9)	0.0008 (8)
N1	0.0287 (11)	0.0206 (10)	0.0351 (11)	−0.0044 (8)	0.0016 (8)	−0.0009 (8)
C2	0.0288 (12)	0.0229 (11)	0.0275 (13)	0.0001 (9)	0.0028 (10)	−0.0002 (9)
C3	0.0330 (13)	0.0200 (11)	0.0267 (12)	0.0015 (9)	0.0042 (10)	0.0005 (9)
C1	0.0380 (14)	0.0214 (12)	0.0315 (14)	0.0013 (10)	0.0046 (10)	0.0005 (9)
C4	0.0304 (13)	0.0230 (12)	0.0311 (13)	−0.0008 (9)	0.0028 (10)	−0.0005 (9)
C5	0.0307 (13)	0.0278 (14)	0.0413 (15)	−0.0016 (10)	0.0023 (11)	0.0009 (10)
O4	0.0399 (11)	0.0261 (10)	0.0835 (16)	−0.0082 (8)	−0.0013 (10)	−0.0008 (9)
C6	0.0346 (14)	0.0309 (13)	0.0551 (18)	0.0050 (11)	0.0019 (12)	0.0018 (12)
O1W	0.0395 (12)	0.0292 (10)	0.0942 (18)	−0.0035 (8)	−0.0148 (11)	0.0009 (11)

O1—C1	1.232 (3)	C2—C3	1.367 (3)
O3—C5	1.299 (3)	C2—C1	1.489 (3)
O3—H3	0.861 (10)	C3—C5	1.484 (3)
N2—C4	1.329 (3)	C4—C6	1.481 (3)
N2—C3	1.373 (3)	C5—O4	1.212 (3)
N2—H2	0.8600	C6—H6A	0.9600
O2—C1	1.271 (3)	C6—H6B	0.9600
N1—C4	1.325 (3)	C6—H6C	0.9600
N1—C2	1.373 (3)	O1W—H1WA	0.849 (10)
N1—H1	0.8600	O1W—H1WB	0.850 (10)
C5—O3—H3	112 (2)	O2—C1—C2	117.2 (2)
C4—N2—C3	109.54 (19)	N1—C4—N2	107.8 (2)
C4—N2—H2	125.2	N1—C4—C6	126.1 (2)
C3—N2—H2	125.2	N2—C4—C6	126.2 (2)
C4—N1—C2	109.81 (19)	O4—C5—O3	123.6 (2)
C4—N1—H1	125.1	O4—C5—C3	120.0 (2)
C2—N1—H1	125.1	O3—C5—C3	116.4 (2)
C3—C2—N1	106.37 (19)	C4—C6—H6A	109.5
C3—C2—C1	132.4 (2)	C4—C6—H6B	109.5
N1—C2—C1	121.2 (2)	H6A—C6—H6B	109.5
C2—C3—N2	106.5 (2)	C4—C6—H6C	109.5
C2—C3—C5	132.1 (2)	H6A—C6—H6C	109.5
N2—C3—C5	121.3 (2)	H6B—C6—H6C	109.5
O1—C1—O2	125.4 (2)	H1WA—O1W—H1WB	110 (2)
O1—C1—C2	117.4 (2)
C4—N1—C2—C3	0.1 (3)	C3—C2—C1—O2	1.2 (4)
C4—N1—C2—C1	179.5 (2)	N1—C2—C1—O2	−178.0 (2)
N1—C2—C3—N2	0.0 (2)	C2—N1—C4—N2	−0.1 (3)
C1—C2—C3—N2	−179.3 (2)	C2—N1—C4—C6	−178.7 (2)
N1—C2—C3—C5	−179.6 (2)	C3—N2—C4—N1	0.1 (3)
C1—C2—C3—C5	1.1 (4)	C3—N2—C4—C6	178.7 (2)
C4—N2—C3—C2	−0.1 (3)	C2—C3—C5—O4	178.1 (3)
C4—N2—C3—C5	179.6 (2)	N2—C3—C5—O4	−1.4 (4)
C3—C2—C1—O1	−178.9 (2)	C2—C3—C5—O3	−2.3 (4)
N1—C2—C1—O1	1.9 (3)	N2—C3—C5—O3	178.2 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WB···O4i	0.85 (1)	2.05 (1)	2.887 (3)	168 (4)
O1W—H1WA···O3ii	0.85 (1)	2.00 (1)	2.839 (3)	173 (4)
N2—H2···O1iii	0.86	1.86	2.716 (3)	176
N1—H1···O1W	0.86	1.83	2.689 (3)	177
O3—H3···O2	0.86 (1)	1.59 (2)	2.447 (2)	179 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WB⋯O4i	0.85 (1)	2.05 (1)	2.887 (3)	168 (4)
O1W—H1WA⋯O3ii	0.85 (1)	2.00 (1)	2.839 (3)	173 (4)
N2—H2⋯O1iii	0.86	1.86	2.716 (3)	176
N1—H1⋯O1W	0.86	1.83	2.689 (3)	177
O3—H3⋯O2	0.86 (1)	1.59 (2)	2.447 (2)	179 (3)

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