3,3′-(5-Chloro-2-hydr­oxy-m-phenyl­ene­dimethyl­ene)diimidazolium oxalate

Su, X.-Y.; Wang, W.-H.; Lan, J.-B.; Mao, Z.-H.; Xie, R.-G.

doi:10.1107/S160053680704809X

3,3′-(5-Chloro-2-hydroxy-m-phenylenedimethylene)diimidazolium oxalate

X.-Y. Su, W.-H. Wang, J.-B. Lan, Z.-H. Mao and R.-G. Xie

The title compound, C₁₄H₁₅ClN₄O²⁺·C₂O₄²⁻, was obtained as a 1:1 binary ionic compound. Two cations and two anions are connected via ionic N—H

O hydrogen bonds to form an annulus with internal dimensions of about 8.5 × 9.5 Å, and these units are connected through O—H

O hydrogen bonds to form a two-dimensional porous layer. Weak C—H

π and C—Cl

π [Cl

centroid = 3.575 (2) and 3.598 (2) Å] interactions, together with strong π–π stacking interactions [centroid-to-centroid distance = 3.429 (3) Å], contribute to the stability of the structure.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680704809X/cf2146sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S160053680704809X/cf2146Isup2.hkl Contains datablock I

CCDC reference: 672793

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Key indicators

Single-crystal X-ray study
T = 294 K
Mean (C-C) = 0.005 Å
R factor = 0.069
wR factor = 0.201
Data-to-parameter ratio = 12.5

checkCIF/PLATON results

No syntax errors found



Alert level C
WEIGH01_ALERT_1_C  Extra text has been found in the
            _refine_ls_weighting_scheme field. This should be in the
            _refine_ls_weighting_details field.
            Weighting scheme given as calc w=1/[\s^2^(Fo^2^)+(0.1334P)^2^] where
            Weighting scheme identified as calc
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.35
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          6
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C15    -   C16    ...       1.56 Ang.
PLAT432_ALERT_2_C Short Inter X...Y Contact  O3     ..  C14     ..       3.00 Ang.
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C14 H15 Cl N4 O
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              C2 O4

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

The construction of organic crystals based on the hydrogen-bond interactions of organic ligands and various hydrogen bonding donors has been rapidly developed because of their fascinating structural diversity and potential applications for functional materials (MacGillivray & Atwood, 1997; Corna et al., 2004). In particular, intermolecular hydrogen bonds have been proven to be ideal and efficient tools in the design and construction of organic crystals because of their strength and directional properties (Aakeröy & Seddon, 1993). Dicarboxylic acids which can form strong and directional hydrogen bonds are frequently chosen as building blocks for crystal engineering, and a variety of cocrystals have been synthesized by assembling dicarboxylic acids and organic ligands bearing N-donors, such as pyridine-based ligands (Bhogala, 2003; Sarkar & Biradha, 2006). Imidazoles, which are also to N-donor compounds, have attracted attentions in the construction of some metal–organic frameworks in recent years (Dobrzanska et al., 2006; Zou et al., 2006; Wang et al., 2006), but only a few reports describing organic crystals composed of dicarboxylic acids and diimidazole compounds have appeared in the literature to date (Aakeröy et al., 2006; Van Roey et al., 1991; Wang et al., 2007). In further development of such interesting hydrogen-bonding supramolecular systems and as a continuation of our research in this area, we report here the crystal structure of an imidazolium oxalate salt, viz. the title compound, (I).

As depicted in Figure 1, the carboxyl protons H2N and H4N of oxalic acid have completely transferred to N2 and N4 of BICP, resulting in the formation of an imidazolium oxalate salt. Two cations and two anions form an annulus with internal dimensions of about 8.5 Å × 9.5 Å via N—H···O hydrogen bonds as illustrated in Figure 2 and Table 1. These units are further connected by O—H···O hydrogen bonds involving the hydroxy groups of the cation and the carbonyl group of oxalate to result in a 2-D porous layer as shown in Figure 3.

A network of intermolecular π–π and C—H···π interactions, as well as C–Cl···π interactions (Spek, 2003), provide strong packing forces in the structure of (I). A comparatively strong π–π interaction between an imidazole ring and another symmetry-related imidazole ring at (2 - x, -y, -1 - z), with their centroids separated by 3.429 (3) Å, plays an important part in the connection of adjacent porous layers. Weak C—H···π interactions also contribute to the interaction of neighboring layers. In addition, chlorine is involved in two separate C—Cl···π interactions, with C1···Cg1 = 4.623 (5) Å, Cl1···Cg1 = 3.575 (2) Å and C1—Cl1···Cg1 = 116°, and C1···Cg3 = 4.103 (4) Å, Cl1···Cg3 = 3.598 (2) Å and C1—Cl1···Cg3 = 94°, where Cg1 is the centroid of the imidazole ring of the molecule at (2 - x, -y, -z) and Cg3 is the centroid of the phenyl ring of the molecule at (1 - x, -y, -z).

Related literature top

For related literature, see: Aakeröy et al. (2006); Aakeröy & Seddon (1993); Bhogala (2003); Corna et al. (2004); Dobrzanska et al. (2006); MacGillivray & Atwood (1997); Van Roey et al. (1991); Sarkar & Biradha (2006); Wang et al. (2006, 2007); Zou et al. (2006). For structure interpretation tools, see: Spek (2003).

Experimental top

2,6-Bis[(imidazol-1-yl)methyl]-4-chlorophenol (0.05 mmol, 14.4 mg) in methanol (8 ml) and oxalic acid (0.05 mmol, 4.5 mg) in methanol (2 ml) and water (0.5 ml) were mixed and left to stand at room temperature. Colorless block crystals were obtained by slow evaporation of the solution after 8 days. Yield, 60%; ¹H NMR (400 MHz, DMSO-d6): δ 5.25 (s, 4H), 7.08 (s, 2H), 7.10 (s, 2H), 7.30 (s, 2H), 8.09 (s, 2H).

Computing details top

Data collection: DIFRAC (Gabe & White, 1993); cell refinement: DIFRAC (Gabe & White, 1993); data reduction: NRCVAX (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and Mercury (Version 1.2; Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top

	Fig. 1. The asymmetric unit of (I), showing 30% probability displacement ellipsoids and the atomic numbering.
	Fig. 2. The annulus structure of (I) formed via ionic hydrogen bonds.
	Fig. 3. A 2-D porous layer containing many annular units. Dashed lines indicate hydrogen bonds. H atoms have been omitted for clarity.

3,3'-(5-Chloro-2-hydroxy-m-phenylenedimethylene)diimidazolium oxalate top

Crystal data top

C₁₄H₁₅ClN₄O²⁺·C₂O₄²⁻	F(000) = 784
M_r = 378.77	D_x = 1.464 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 28 reflections
a = 7.3158 (18) Å	θ = 4.6–9.5°
b = 19.824 (4) Å	µ = 0.26 mm⁻¹
c = 11.901 (2) Å	T = 294 K
β = 95.18 (2)°	Block, colourless
V = 1719.0 (6) Å³	0.30 × 0.26 × 0.20 mm
Z = 4

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.007
Radiation source: fine-focus sealed tube	θ_max = 25.5°, θ_min = 2.0°
Graphite monochromator	h = −8→8
ω/2θ scans	k = 0→23
4162 measured reflections	l = −7→14
3122 independent reflections	3 standard reflections every 300 reflections
1789 reflections with I > 2σ(I)	intensity decay: 3.7%

Refinement top

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)] = 0.070	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.201	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	Calculated w = 1/[σ²(F_o²) + (0.1334P)²] where P = (F_o² + 2F_c²)/3
3122 reflections	(Δ/σ)_max < 0.001
249 parameters	Δρ_max = 0.53 e Å⁻³
0 restraints	Δρ_min = −0.39 e Å⁻³

Crystal data top

C₁₄H₁₅ClN₄O²⁺·C₂O₄²⁻	V = 1719.0 (6) Å³
M_r = 378.77	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.3158 (18) Å	µ = 0.26 mm⁻¹
b = 19.824 (4) Å	T = 294 K
c = 11.901 (2) Å	0.30 × 0.26 × 0.20 mm
β = 95.18 (2)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.007
4162 measured reflections	3 standard reflections every 300 reflections
3122 independent reflections	intensity decay: 3.7%
1789 reflections with I > 2σ(I)

Refinement top

R[F² > 2σ(F²)] = 0.070	0 restraints
wR(F²) = 0.201	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	Δρ_max = 0.53 e Å⁻³
3122 reflections	Δρ_min = −0.39 e Å⁻³
249 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.74430 (17)	0.05960 (6)	0.08437 (11)	0.0619 (4)
O1	0.7766 (4)	−0.17156 (15)	−0.2216 (2)	0.0429 (7)
O2	0.4825 (4)	0.08021 (14)	−0.4268 (3)	0.0468 (8)
O3	0.7050 (3)	0.13828 (14)	−0.3313 (3)	0.0482 (8)
O4	0.4533 (4)	0.22842 (13)	−0.2732 (3)	0.0503 (8)
O5	0.2327 (4)	0.15468 (14)	−0.3234 (3)	0.0510 (8)
N1	0.9367 (4)	−0.03705 (14)	−0.3488 (3)	0.0328 (7)
N2	1.1907 (5)	0.00811 (19)	−0.3871 (3)	0.0427 (9)
N3	0.9597 (4)	−0.21898 (15)	0.0491 (3)	0.0364 (8)
N4	1.2236 (5)	−0.22666 (19)	0.1424 (3)	0.0481 (10)
C1	0.7455 (5)	−0.0099 (2)	−0.0058 (4)	0.0406 (9)
C2	0.7426 (5)	0.0001 (2)	−0.1197 (3)	0.0395 (9)
H2	0.7378	0.0438	−0.1484	0.047*
C3	0.7466 (4)	−0.05428 (18)	−0.1930 (3)	0.0329 (9)
C4	0.7551 (4)	−0.12011 (19)	−0.1478 (3)	0.0322 (8)
C5	0.7528 (5)	−0.1295 (2)	−0.0318 (3)	0.0358 (9)
C6	0.7471 (5)	−0.0742 (2)	0.0388 (4)	0.0417 (10)
H6	0.7443	−0.0803	0.1161	0.050*
C7	0.7489 (5)	−0.04358 (19)	−0.3167 (3)	0.0358 (9)
H71	0.6892	−0.0813	−0.3568	0.043*
H72	0.6804	−0.0030	−0.3386	0.043*
C8	1.0552 (6)	−0.0889 (2)	−0.3687 (4)	0.0451 (10)
H8	1.0305	−0.1349	−0.3652	0.054*
C9	1.2137 (6)	−0.0604 (2)	−0.3942 (4)	0.0470 (10)
H9	1.3183	−0.0828	−0.4131	0.056*
C10	1.0253 (5)	0.02073 (19)	−0.3585 (3)	0.0368 (9)
H10	0.9776	0.0634	−0.3469	0.044*
C11	0.7680 (5)	−0.1998 (2)	0.0192 (4)	0.0433 (10)
H11A	0.7019	−0.2012	0.0863	0.052*
H11B	0.7115	−0.2321	−0.0344	0.052*
C12	1.0751 (6)	−0.2505 (2)	−0.0185 (4)	0.0507 (11)
H12	1.0452	−0.2660	−0.0916	0.061*
C13	1.2387 (6)	−0.2548 (2)	0.0404 (4)	0.0562 (12)
H13	1.3442	−0.2737	0.0157	0.067*
C14	1.0532 (6)	−0.2052 (2)	0.1469 (3)	0.0409 (10)
H14	1.0070	−0.1842	0.2082	0.049*
C15	0.3939 (5)	0.17246 (18)	−0.3160 (3)	0.0325 (8)
C16	0.5419 (5)	0.12589 (17)	−0.3614 (3)	0.0318 (8)
H1O	0.711 (7)	−0.203 (3)	−0.226 (4)	0.063 (16)*
H2N	1.270 (8)	0.035 (3)	−0.394 (5)	0.079 (18)*
H4N	1.312 (7)	−0.222 (2)	0.196 (4)	0.055 (13)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0567 (7)	0.0605 (8)	0.0677 (8)	0.0019 (6)	0.0008 (6)	−0.0262 (6)
O1	0.0453 (17)	0.0360 (16)	0.0483 (18)	−0.0147 (14)	0.0097 (13)	−0.0047 (13)
O2	0.0307 (15)	0.0506 (17)	0.0604 (19)	−0.0080 (13)	0.0115 (13)	−0.0209 (14)
O3	0.0237 (14)	0.0511 (17)	0.069 (2)	0.0019 (12)	−0.0003 (12)	−0.0134 (15)
O4	0.0319 (15)	0.0374 (16)	0.079 (2)	0.0125 (12)	−0.0116 (14)	−0.0118 (14)
O5	0.0290 (15)	0.0453 (16)	0.079 (2)	0.0083 (13)	0.0075 (14)	−0.0029 (15)
N1	0.0313 (16)	0.0319 (16)	0.0346 (18)	−0.0020 (13)	0.0006 (13)	0.0008 (13)
N2	0.037 (2)	0.045 (2)	0.046 (2)	−0.0123 (17)	0.0044 (15)	−0.0011 (16)
N3	0.0323 (17)	0.0364 (17)	0.0395 (19)	−0.0050 (14)	−0.0019 (14)	−0.0009 (14)
N4	0.0336 (19)	0.051 (2)	0.057 (2)	−0.0017 (16)	−0.0115 (17)	−0.0116 (18)
C1	0.0270 (19)	0.044 (2)	0.050 (3)	−0.0021 (17)	−0.0012 (17)	−0.0095 (19)
C2	0.0286 (19)	0.037 (2)	0.052 (3)	−0.0009 (16)	−0.0033 (17)	0.0011 (18)
C3	0.0141 (16)	0.038 (2)	0.046 (2)	0.0003 (14)	−0.0025 (15)	0.0015 (17)
C4	0.0160 (16)	0.037 (2)	0.043 (2)	−0.0090 (14)	−0.0020 (14)	−0.0018 (16)
C5	0.0228 (18)	0.046 (2)	0.037 (2)	−0.0080 (16)	−0.0034 (15)	0.0052 (17)
C6	0.034 (2)	0.052 (2)	0.039 (2)	−0.0021 (18)	−0.0012 (17)	−0.0040 (18)
C7	0.0267 (19)	0.036 (2)	0.043 (2)	−0.0021 (15)	−0.0029 (16)	0.0076 (17)
C8	0.042 (2)	0.036 (2)	0.058 (3)	0.0021 (18)	0.0097 (19)	−0.0064 (19)
C9	0.038 (2)	0.054 (3)	0.050 (3)	0.0035 (19)	0.0081 (19)	−0.001 (2)
C10	0.040 (2)	0.033 (2)	0.037 (2)	−0.0086 (18)	−0.0006 (17)	0.0017 (16)
C11	0.028 (2)	0.053 (2)	0.048 (2)	−0.0075 (18)	−0.0022 (17)	0.005 (2)
C12	0.043 (2)	0.056 (3)	0.054 (3)	−0.002 (2)	0.003 (2)	−0.017 (2)
C13	0.036 (2)	0.058 (3)	0.074 (3)	0.005 (2)	0.006 (2)	−0.011 (2)
C14	0.043 (2)	0.042 (2)	0.037 (2)	−0.0015 (18)	0.0009 (18)	−0.0073 (18)
C15	0.0278 (19)	0.034 (2)	0.035 (2)	0.0053 (16)	−0.0002 (15)	0.0072 (16)
C16	0.0242 (18)	0.0286 (18)	0.043 (2)	0.0010 (15)	0.0024 (15)	0.0041 (16)

Geometric parameters (Å, º) top

Cl1—C1	1.747 (4)	C2—C3	1.389 (5)
O1—C4	1.364 (5)	C2—H2	0.930
O1—H1O	0.79 (5)	C3—C4	1.411 (5)
O2—C16	1.247 (4)	C3—C7	1.489 (5)
O3—C16	1.239 (4)	C4—C5	1.395 (5)
O4—C15	1.280 (4)	C5—C6	1.385 (6)
O5—C15	1.227 (4)	C5—C11	1.520 (5)
N1—C10	1.326 (4)	C6—H6	0.930
N1—C8	1.380 (5)	C7—H71	0.970
N1—C7	1.464 (5)	C7—H72	0.970
N2—C10	1.310 (5)	C8—C9	1.349 (6)
N2—C9	1.372 (6)	C8—H8	0.930
N2—H2N	0.80 (5)	C9—H9	0.930
N3—C14	1.325 (5)	C10—H10	0.930
N3—C12	1.369 (5)	C11—H11A	0.970
N3—C11	1.465 (5)	C11—H11B	0.970
N4—C14	1.323 (5)	C12—C13	1.334 (6)
N4—C13	1.348 (6)	C12—H12	0.930
N4—H4N	0.87 (5)	C13—H13	0.930
C1—C2	1.369 (6)	C14—H14	0.930
C1—C6	1.380 (6)	C15—C16	1.556 (5)

C4—O1—H1O	122 (4)	N1—C7—H72	109.3
C10—N1—C8	108.0 (3)	C3—C7—H72	109.3
C10—N1—C7	125.2 (3)	H71—C7—H72	108.0
C8—N1—C7	126.7 (3)	C9—C8—N1	107.0 (4)
C10—N2—C9	109.0 (4)	C9—C8—H8	126.5
C10—N2—H2N	126 (4)	N1—C8—H8	126.5
C9—N2—H2N	124 (4)	C8—C9—N2	106.8 (4)
C14—N3—C12	108.3 (3)	C8—C9—H9	126.6
C14—N3—C11	124.5 (4)	N2—C9—H9	126.6
C12—N3—C11	127.1 (3)	N2—C10—N1	109.1 (4)
C14—N4—C13	108.9 (4)	N2—C10—H10	125.4
C14—N4—H4N	125 (3)	N1—C10—H10	125.4
C13—N4—H4N	126 (3)	N3—C11—C5	111.6 (3)
C2—C1—C6	120.9 (4)	N3—C11—H11A	109.3
C2—C1—Cl1	119.6 (3)	C5—C11—H11A	109.3
C6—C1—Cl1	119.5 (3)	N3—C11—H11B	109.3
C1—C2—C3	120.6 (4)	C5—C11—H11B	109.3
C1—C2—H2	119.7	H11A—C11—H11B	108.0
C3—C2—H2	119.7	C13—C12—N3	107.0 (4)
C2—C3—C4	118.8 (4)	C13—C12—H12	126.5
C2—C3—C7	120.8 (3)	N3—C12—H12	126.5
C4—C3—C7	120.3 (3)	C12—C13—N4	107.7 (4)
O1—C4—C5	123.3 (3)	C12—C13—H13	126.1
O1—C4—C3	116.7 (3)	N4—C13—H13	126.1
C5—C4—C3	119.8 (3)	N4—C14—N3	108.2 (4)
C6—C5—C4	119.9 (4)	N4—C14—H14	125.9
C6—C5—C11	119.3 (4)	N3—C14—H14	125.9
C4—C5—C11	120.8 (3)	O5—C15—O4	124.5 (3)
C1—C6—C5	119.8 (4)	O5—C15—C16	119.9 (3)
C1—C6—H6	120.1	O4—C15—C16	115.5 (3)
C5—C6—H6	120.1	O3—C16—O2	126.6 (3)
N1—C7—C3	111.4 (3)	O3—C16—C15	117.6 (3)
N1—C7—H71	109.3	O2—C16—C15	115.7 (3)
C3—C7—H71	109.3

C6—C1—C2—C3	−1.9 (6)	C7—N1—C8—C9	−179.2 (3)
Cl1—C1—C2—C3	178.9 (3)	N1—C8—C9—N2	1.3 (5)
C1—C2—C3—C4	−0.4 (5)	C10—N2—C9—C8	0.0 (5)
C1—C2—C3—C7	−178.2 (3)	C9—N2—C10—N1	−1.3 (5)
C2—C3—C4—O1	−173.9 (3)	C8—N1—C10—N2	2.1 (4)
C7—C3—C4—O1	3.9 (4)	C7—N1—C10—N2	179.3 (3)
C2—C3—C4—C5	2.3 (5)	C14—N3—C11—C5	87.6 (5)
C7—C3—C4—C5	−180.0 (3)	C12—N3—C11—C5	−89.1 (5)
O1—C4—C5—C6	174.1 (3)	C6—C5—C11—N3	−87.1 (4)
C3—C4—C5—C6	−1.7 (5)	C4—C5—C11—N3	89.2 (4)
O1—C4—C5—C11	−2.1 (5)	C14—N3—C12—C13	−0.5 (5)
C3—C4—C5—C11	−178.0 (3)	C11—N3—C12—C13	176.6 (4)
C2—C1—C6—C5	2.5 (6)	N3—C12—C13—N4	0.3 (5)
Cl1—C1—C6—C5	−178.4 (3)	C14—N4—C13—C12	0.0 (5)
C4—C5—C6—C1	−0.6 (5)	C13—N4—C14—N3	−0.3 (5)
C11—C5—C6—C1	175.7 (3)	C12—N3—C14—N4	0.5 (5)
C10—N1—C7—C3	−93.7 (4)	C11—N3—C14—N4	−176.7 (3)
C8—N1—C7—C3	83.0 (5)	O5—C15—C16—O3	−164.8 (3)
C2—C3—C7—N1	88.7 (4)	O4—C15—C16—O3	15.6 (5)
C4—C3—C7—N1	−89.1 (4)	O5—C15—C16—O2	16.5 (5)
C10—N1—C8—C9	−2.1 (5)	O4—C15—C16—O2	−163.0 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O4ⁱ	0.79 (5)	1.81 (5)	2.597 (4)	174 (5)
N2—H2N···O2ⁱⁱ	0.80 (5)	1.86 (6)	2.647 (4)	166 (6)
N2—H2N···O5ⁱⁱ	0.80 (5)	2.53 (6)	3.012 (5)	119 (5)
N4—H4N···O3ⁱⁱⁱ	0.87 (5)	2.33 (5)	2.861 (5)	120 (4)
N4—H4N···O4ⁱⁱⁱ	0.87 (5)	1.88 (5)	2.710 (4)	160 (4)
C8—H8···Cg2	0.93	2.83	3.664 (4)	149

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

Experimental details

Crystal data
Chemical formula	C₁₄H₁₅ClN₄O²⁺·C₂O₄²⁻
M_r	378.77
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	294
a, b, c (Å)	7.3158 (18), 19.824 (4), 11.901 (2)
β (°)	95.18 (2)
V (Å³)	1719.0 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.26
Crystal size (mm)	0.30 × 0.26 × 0.20

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	4162, 3122, 1789
R_int	0.007
(sin θ/λ)_max (Å⁻¹)	0.605

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.070, 0.201, 0.96
No. of reflections	3122
No. of parameters	249
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.39

Computer programs: DIFRAC (Gabe & White, 1993), NRCVAX (Gabe et al., 1989), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996) and Mercury (Version 1.2; Macrae et al., 2006).