2-Amino-5-chloro­pyridinium hydrogen succinate

In the title salt, C₅H₆ClN₂⁺·C₄H₅O₄⁻, the pyridine N atom is protonated. The pyridinium and amino groups associate via a pair of N—H...O hydrogen bonds to the carboxyl­ate O atoms of the singly deprotonated succinate anion. The hydrogen succinate anions self-assemble via O—H...O hydrogen bonds into chains along the b axis. The crystal structure is further stabilized by additional N—H...O hydrogen bonds involving the second amino H atoms, as well as C—H...O contacts, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.038
• wR factor = 0.082
• Data-to-parameter ratio = 20.8

checkCIF/PLATON results

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Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O1     --  C6      ..       5.07 su
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         15

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           33.24
           From the CIF: _reflns_number_total               3934
           Count of symmetry unique reflns         2342
           Completeness (_total/calc)            167.98%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1592
           Fraction of Friedel pairs measured     0.680
           Are heavy atom types Z>Si present        yes
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          4

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

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

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S1. Comment

Pyridine and its derivatives play an important role in heterocyclic chemistry (Pozharski et al., 1997; Katritzky et al., 1996). They are often involved in hydrogen-bonding interactions (Jeffrey & Saenger, 1991; Jeffrey, 1997; Scheiner, 1997). The dicarboxylic acid, succinic acid, is a precursor for many chemicals of industrial importance (Zeikus et al., 1999; Song & Lee, 2006). Succinic acid derivatives are mostly used in chemicals, food and pharmaceuticals (Sauer et al., 2008). The crystal structure of succinic acid has been reported (Gopalan et al., 2000; Leviel et al., 1981). The crystal structures of 2-amino-5-chloropyridine (Pourayoubi et al., 2007), 2-amino-5-chloropyridinium nitrate (Zaouali Zgolli et al., 2009) and bis (2-amino-5-chloropyridinium) dihydrogen diphosphate (Akriche & Rzaigui, 2005) have been reported in literature. In this paper, we present the X-ray single-crystal structure of 2-amino-5-chloropyridinium hydrogen succinate, (I).

The asymmetric unit of (I), Fig. 1, contains a 2-amino-5-chloropyridinium cation and a hydrogen succinate anion, indicating that proton transfer has occurred during the co-crystallisation experiment. In the 2-amino-5-chloropyridinium cation, a wider than normal angle (123.22 (12)°) is subtended at the protonated N1 atom.

In the crystal packing (Fig. 2), the protonated N1 atom and the 2-amino group is hydrogen-bonded to the carboxylate oxygen atoms (O1 and O2) via a pair of N–H···O hydrogen bonds forming a R₂²(8) ring motif (Bernstein et al. 1995). The hydrogen succinate anions self-assemble via O—H···O hydrogen bonds. The second amino-H atom forms a hydrogen bond with the carboxylate-O1 atom. Furthermore, the crystal structure is stabilized by C—H···O contacts, Table 1, forming a 3D-network.

Related literature

For background to the chemistry of substituted pyridines, see: Pozharski et al. (1997); Katritzky et al. (1996). For related structures, see: Pourayoubi et al. (2007); Akriche & Rzaigui (2005); Zaouali Zgolli et al. (2009). For the structure of succinic acid, see: Gopalan et al. (2000); Leviel et al. (1981). For applications of succinic acid, see: Sauer et al. (2008); Song & Lee (2006); Zeikus et al. (1999).For details of hydrogen bonding, see: Jeffrey & Saenger (1991); Jeffrey (1997); Scheiner (1997). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

S2. Experimental

A hot methanolic solution (10 ml) of 2-amino-5-chloropyridine (32 mg, Aldrich) and a hot aqueous solution (10 ml) of succinic acid (29 mg, Merck) were mixed and warmed over a water bath for 10 minutes. The resulting solution was allowed to cool slowly at room temperature. Single crystals of (I) appeared from the mother liquor after a few days.

S3. Refinement

All the H atoms were located in a difference Fourier map and allowed to refine freely [N–H = 0.83 (2) - 0.86 (2) Å, C–H = 0.944 (18) - 1.047 (19) Å, O–H = 0.822 (19) Å ].

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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) and PLATON (Spek, 2009).

Figures

	Fig. 1. The asymmetric unit of (I) showing atom labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. The crystal packing of (I), showing intermolecular interactions as dashed lines.

2-Amino-5-chloropyridinium hydrogen succinate

Crystal data

C5H6ClN2^+·C4H5O4^−	F(000) = 512
Mr = 246.65	Dx = 1.547 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3633 reflections
a = 5.2263 (1) Å	θ = 2.7–33.2°
b = 13.5997 (3) Å	µ = 0.36 mm^−1
c = 14.9019 (3) Å	T = 100 K
V = 1059.17 (4) Å^3	Blcok, yellow
Z = 4	0.41 × 0.15 × 0.10 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	3934 independent reflections
Radiation source: fine-focus sealed tube	3581 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
φ and ω scans	θmax = 33.2°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −8→6
Tmin = 0.866, Tmax = 0.965	k = −17→20
11594 measured reflections	l = −21→22

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)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.082	w = 1/[σ^2(Fo^2) + (0.0404P)^2 + 0.0588P] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max = 0.001
3934 reflections	Δρmax = 0.33 e Å^−3
189 parameters	Δρmin = −0.27 e Å^−3
0 restraints	Absolute structure: Flack (1983), 1604 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.05 (5)

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) k.

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 > 2sigma(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
Cl1	−0.16471 (6)	0.66417 (3)	0.01385 (3)	0.02344 (8)
N1	0.3976 (2)	0.47974 (9)	−0.04334 (8)	0.0152 (2)
N2	0.5510 (2)	0.33552 (9)	0.01762 (9)	0.0194 (2)
C1	0.3838 (2)	0.40861 (10)	0.02044 (9)	0.0152 (2)
C2	0.1897 (3)	0.41668 (10)	0.08661 (9)	0.0170 (2)
C3	0.0245 (3)	0.49419 (11)	0.08409 (10)	0.0183 (3)
C4	0.0469 (2)	0.56603 (10)	0.01630 (10)	0.0180 (2)
C5	0.2340 (3)	0.55775 (10)	−0.04688 (10)	0.0168 (2)
O1	0.42571 (19)	0.16607 (8)	0.11491 (6)	0.0208 (2)
O2	0.24386 (19)	0.03548 (7)	0.17729 (7)	0.0184 (2)
O3	0.8289 (2)	0.36179 (8)	0.25630 (8)	0.0232 (2)
O4	0.4478 (2)	0.29887 (8)	0.29328 (8)	0.0277 (3)
C6	0.4118 (2)	0.10302 (9)	0.17571 (9)	0.0142 (2)
C7	0.6061 (3)	0.10441 (10)	0.25145 (10)	0.0179 (3)
C8	0.7907 (2)	0.19017 (10)	0.24860 (10)	0.0181 (3)
C9	0.6663 (3)	0.28792 (10)	0.26836 (8)	0.0158 (2)
H2	0.180 (3)	0.3686 (13)	0.1322 (11)	0.020 (4)*
H3	−0.110 (3)	0.4991 (12)	0.1279 (11)	0.020 (4)*
H5	0.262 (3)	0.6021 (12)	−0.0964 (12)	0.016 (4)*
H7A	0.713 (4)	0.0395 (14)	0.2466 (13)	0.029 (5)*
H7B	0.504 (4)	0.1041 (13)	0.3078 (13)	0.033 (5)*
H8A	0.925 (4)	0.1818 (13)	0.2917 (12)	0.026 (5)*
H8B	0.883 (4)	0.1978 (13)	0.1893 (12)	0.023 (5)*
H1O3	0.764 (4)	0.4144 (14)	0.2709 (13)	0.026 (5)*
H1N1	0.517 (4)	0.4729 (13)	−0.0823 (13)	0.026 (5)*
H1N2	0.667 (4)	0.3364 (14)	−0.0209 (13)	0.029 (5)*
H2N2	0.538 (4)	0.2904 (14)	0.0544 (13)	0.027 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.01978 (14)	0.01782 (15)	0.03271 (18)	0.00423 (12)	0.00071 (13)	−0.00177 (14)
N1	0.0162 (5)	0.0134 (5)	0.0162 (5)	−0.0010 (4)	0.0012 (4)	0.0015 (4)
N2	0.0200 (5)	0.0154 (5)	0.0227 (6)	0.0009 (5)	0.0046 (5)	0.0071 (5)
C1	0.0156 (5)	0.0133 (5)	0.0168 (6)	−0.0035 (4)	−0.0024 (4)	0.0009 (5)
C2	0.0188 (6)	0.0168 (6)	0.0154 (6)	−0.0038 (5)	0.0007 (5)	0.0013 (5)
C3	0.0177 (6)	0.0193 (6)	0.0180 (6)	−0.0033 (5)	0.0013 (5)	−0.0030 (5)
C4	0.0176 (5)	0.0154 (6)	0.0209 (6)	0.0001 (5)	−0.0026 (5)	−0.0021 (5)
C5	0.0175 (5)	0.0124 (6)	0.0205 (7)	−0.0014 (5)	−0.0030 (5)	0.0008 (5)
O1	0.0257 (5)	0.0174 (5)	0.0194 (5)	−0.0048 (4)	−0.0037 (4)	0.0068 (4)
O2	0.0197 (4)	0.0132 (4)	0.0222 (5)	−0.0027 (4)	−0.0035 (4)	0.0039 (4)
O3	0.0242 (5)	0.0129 (5)	0.0326 (6)	−0.0011 (4)	0.0082 (5)	−0.0048 (4)
O4	0.0192 (5)	0.0251 (6)	0.0387 (6)	−0.0001 (4)	0.0062 (4)	−0.0112 (5)
C6	0.0153 (5)	0.0118 (5)	0.0154 (6)	0.0024 (4)	0.0000 (4)	−0.0013 (5)
C7	0.0226 (6)	0.0140 (6)	0.0169 (6)	−0.0011 (5)	−0.0027 (5)	0.0027 (5)
C8	0.0169 (6)	0.0156 (6)	0.0218 (7)	0.0014 (5)	−0.0023 (5)	−0.0016 (5)
C9	0.0184 (5)	0.0153 (6)	0.0138 (6)	0.0011 (5)	−0.0014 (5)	−0.0017 (5)

Geometric parameters (Å, º)

Cl1—C4	1.7336 (13)	C5—H5	0.965 (17)
N1—C1	1.3580 (17)	O1—C6	1.2496 (16)
N1—C5	1.3636 (18)	O2—C6	1.2708 (16)
N1—H1N1	0.86 (2)	O3—C9	1.3281 (17)
N2—C1	1.3242 (17)	O3—H1O3	0.822 (19)
N2—H1N2	0.83 (2)	O4—C9	1.2100 (17)
N2—H2N2	0.83 (2)	C6—C7	1.5183 (19)
C1—C2	1.4189 (18)	C7—C8	1.5141 (19)
C2—C3	1.363 (2)	C7—H7A	1.047 (19)
C2—H2	0.944 (18)	C7—H7B	0.99 (2)
C3—C4	1.410 (2)	C8—C9	1.5090 (19)
C3—H3	0.961 (17)	C8—H8A	0.959 (19)
C4—C5	1.362 (2)	C8—H8B	1.010 (18)
C1—N1—C5	123.22 (12)	N1—C5—H5	115.0 (10)
C1—N1—H1N1	115.7 (12)	C9—O3—H1O3	110.9 (14)
C5—N1—H1N1	121.0 (12)	O1—C6—O2	123.33 (12)
C1—N2—H1N2	119.3 (14)	O1—C6—C7	119.44 (11)
C1—N2—H2N2	118.7 (13)	O2—C6—C7	117.21 (11)
H1N2—N2—H2N2	122.0 (19)	C8—C7—C6	114.51 (11)
N2—C1—N1	118.52 (12)	C8—C7—H7A	107.9 (10)
N2—C1—C2	123.49 (12)	C6—C7—H7A	107.2 (10)
N1—C1—C2	117.99 (12)	C8—C7—H7B	111.6 (11)
C3—C2—C1	119.57 (13)	C6—C7—H7B	105.6 (12)
C3—C2—H2	121.4 (11)	H7A—C7—H7B	109.9 (15)
C1—C2—H2	119.0 (11)	C9—C8—C7	113.48 (11)
C2—C3—C4	120.21 (13)	C9—C8—H8A	106.9 (11)
C2—C3—H3	119.8 (10)	C7—C8—H8A	110.9 (11)
C4—C3—H3	119.9 (10)	C9—C8—H8B	106.5 (10)
C5—C4—C3	119.81 (12)	C7—C8—H8B	114.0 (10)
C5—C4—Cl1	120.47 (11)	H8A—C8—H8B	104.4 (14)
C3—C4—Cl1	119.71 (11)	O4—C9—O3	123.52 (13)
C4—C5—N1	119.20 (13)	O4—C9—C8	125.11 (13)
C4—C5—H5	125.8 (10)	O3—C9—C8	111.36 (12)
C5—N1—C1—N2	179.59 (12)	Cl1—C4—C5—N1	−179.96 (10)
C5—N1—C1—C2	−0.30 (18)	C1—N1—C5—C4	0.21 (19)
N2—C1—C2—C3	−179.60 (13)	O1—C6—C7—C8	4.56 (19)
N1—C1—C2—C3	0.29 (18)	O2—C6—C7—C8	−176.50 (12)
C1—C2—C3—C4	−0.2 (2)	C6—C7—C8—C9	69.12 (16)
C2—C3—C4—C5	0.1 (2)	C7—C8—C9—O4	7.3 (2)
C2—C3—C4—Cl1	179.95 (11)	C7—C8—C9—O3	−173.70 (12)
C3—C4—C5—N1	−0.10 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O2^i	0.821 (19)	1.819 (19)	2.5891 (15)	156 (2)
N1—H1N1···O2^ii	0.86 (2)	1.85 (2)	2.7023 (15)	172.4 (19)
N2—H1N2···O1^ii	0.84 (2)	1.95 (2)	2.7814 (15)	177 (2)
N2—H2N2···O1	0.826 (19)	2.004 (19)	2.8002 (16)	162 (2)
C5—H5···O4^iii	0.964 (17)	2.391 (17)	3.2216 (18)	144.0 (13)

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