4-Amino­pyridinium 4-nitro­benzoate 4-nitro­benzoic acid

Quah, C.K.; Jebas, S.R.; Fun, H.-K.

doi:10.1107/S1600536808027761

organic compounds

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ISSN: 2056-9890

Volume 64| Part 10| October 2008| Pages o1878-o1879

doi:10.1107/S1600536808027761

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4-Aminopyridinium 4-nitrobenzoate 4-nitrobenzoic acid

Ching Kheng Quah,^a Samuel Robinson Jebas ^a ‡ and Hoong-Kun Fun ^a ^*

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: hkfun@usm.my

(Received 29 August 2008; accepted 29 August 2008; online 6 September 2008)

The asymmetric unit of the title compound, C₅H₇N₂⁺·C₇H₄NO₄⁻·C₇H₅NO₄, consists of an aminopyridinium cation, a 4-nitrobenzoate anion and a neutral 4-nitrobenzoic acid molecule. The pyridine ring forms dihedral angles of 64.70 (5)° and 70.37 (5)°, respectively, with the benzene rings of 4-nitrobenzoic acid and 4-nitrobenzoate. In the crystal structure, the cations, anions and the neutral 4-nitrobenzoic acid molecules are linked by O—H⋯O and N—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (001). Adjacent networks are cross-linked via C—H⋯O hydrogen bonds and π–π stacking interactions [centroid–centroid distances 3.6339 (6) and 3.6566 (6) Å].

Related literature

For the biological activity of 4-aminopyridine, see: Judge et al. (2006 ); Schwid et al. (1997 ); Strupp et al. (2004 ). For related structures, see: Chao & Schempp (1977 ); Anderson et al. (2005 ); Andrau & White, (2003 ); Bhattacharya et al. (1994 ); Karle et al. (2003 ).

Experimental

Crystal data

C₅H₇N₂⁺·C₇H₄NO₄⁻·C₇H₅NO₄
M_r = 428.36
Triclinic, $[P \overline 1]$
a = 6.4561 (1) Å
b = 6.8598 (1) Å
c = 20.9055 (3) Å
α = 85.826 (1)°
β = 87.975 (1)°
γ = 86.188 (1)°
V = 920.92 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 100.0 (1) K
0.40 × 0.36 × 0.29 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.952, T_max = 0.965
24945 measured reflections
6647 independent reflections
5169 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.132
S = 1.05
6647 reflections
284 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.43 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3A—H1O3⋯O3Bⁱ	0.82	1.63	2.4457 (11)	170
N3—H3A⋯O3Bⁱⁱ	0.86	2.14	2.9977 (12)	172
N3—H3B⋯O4Bⁱ	0.86	2.07	2.8758 (12)	155
N2—H1N2⋯O4Aⁱⁱⁱ	0.85 (1)	1.99 (1)	2.7726 (12)	153 (1)
C2B—H2BA⋯O1B^iv	0.93	2.52	3.2187 (13)	133
C8—H8A⋯O3A^v	0.93	2.56	3.4565 (13)	161
C12—H12A⋯O1A^vi	0.93	2.55	3.4427 (13)	162
Symmetry codes: (i) -x+1, -y+2, -z+1; (ii) -x+2, -y+2, -z+1; (iii) x+1, y-1, z; (iv) -x+3, -y+1, -z+2; (v) x, y-1, z; (vi) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808027761/ci2664sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808027761/ci2664Isup2.hkl

checkCIF report

Comment top

4-Aminopyridine (Fampridine) is used clinically in Lambert-Eaton myasthenic syndrome and multiple sclerosis because by blocking potassium channels, it prolongs the action potentials thereby increasing transmitter release at the neuromuscular junction (Judge et al., 2006; Schwid et al., 1997; Strupp et al., 2004). The crystal structure of 4-aminopyridine has been reported (Chao & Schempp, 1977; Anderson et al., 2005). As an extension of our systematic study of hydrogen bonding patterns of 4-aminopyridine with aromatic carboxylic acids, we report here the crystal structure of the title compound.

The asymmetric unit of the title compound contains one 4-aminopyridinium cation, one 4-nitrobenzoate anion and one 4-nitrobenzoic acid molecule. A proton transfer from the carboxyl group of 4-nitrobenzoic acid to atom N2 of 4-aminopyridine resulted in the formation of ions. This lead to the widening of C8—N2—C12 angle of the pyridine ring to 120.86 (9)°, compared to 115.25 (13)° in the unprotonated 4-aminopyridine (Anderson et al., 2005). This type of protonation is observed in various 4-aminopyridine acid complexes (Bhattacharya et al., 1994; Karle et al., 2003). The bond lengths and angles of the 4-aminopyridne are comparable to the values reported earlier for 4-aminopyridine (Chao & Schempp, 1977; Anderson et al., 2005). The bond lengths and angles of the 4-nitrobenzoic acid is found to be normal(Andrau & White, 2003).

The dihedral angle between the benzene rings of 4-nitrobenzoic acid (C1A-C6A) and 4-nitrobenzoate (C1B-C6B) units is 6.62 (5)°. The pyridine (N2/C8—C12) ring forms dihedral angles of 64.70 (5)° and 70.37 (5)°, respectively, with the C1A-C6A and C1B-C6B rings.

In the crystal structure, the cations, anions and the neutral 4-nitrobenzoic acid molecules are linked to form a two-dimensional network (Fig. 2) parallel to the (0 0 1) by O—H···O and N—H···O hydrogen bonds (Table 1). The adjacent networks are cross-linked via C—H···O hydrogen bonds. The crystal packing is further consolidated by π–π stacking interactions between symmetry-related C1A-C6A (centroid Cg1) and C1B-C6B (centroid Cg2) rings, with Cg1···Cg1ⁱ and Cg2···Cg2^vii distances of 3.6566 (6) Å and 3.6339 (6) Å, respectively [symmetry codes: (i) 1-x, 2-y, 1-z; (vii) 2-x, 2-y, 2-z].

Related literature top

For the biological activity of 4-aminopyridine, see: Judge et al. (2006); Schwid et al. (1997); Strupp et al. (2004). For related structures, see: Chao & Schempp (1977); Anderson et al. (2005); Andrau & White, (2003); Bhattacharya et al. (1994); Karle et al. (2003).

Experimental top

4-Aminopyridine and 4-nitrobenzoic acid were mixed in equimolar ratio in methanol and warmed in a water bath for 2 h. Colourless single crystals were obtained after a week on slow evaporation.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The asymmetric unit of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The crystal packing of the title compound, viewed along the a axis. Hydrogen bonds are shown as dashed lines.

(I) top

Crystal data top

C₅H₇N₂⁺·C₇H₄NO₄⁻·C₇H₅NO₄	Z = 2
M_r = 428.36	F(000) = 444
Triclinic, P1	D_x = 1.545 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4561 (1) Å	Cell parameters from 6200 reflections
b = 6.8598 (1) Å	θ = 2.2–29.2°
c = 20.9055 (3) Å	µ = 0.12 mm⁻¹
α = 85.826 (1)°	T = 100 K
β = 87.975 (1)°	Block, colourless
γ = 86.188 (1)°	0.40 × 0.36 × 0.29 mm
V = 920.92 (2) Å³

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	6647 independent reflections
Radiation source: fine-focus sealed tube	5169 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
ϕ and ω scans	θ_max = 32.5°, θ_min = 1.0°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −9→9
T_min = 0.952, T_max = 0.965	k = −10→10
24945 measured reflections	l = −31→31

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.132	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0736P)² + 0.1221P] where P = (F_o² + 2F_c²)/3
6647 reflections	(Δ/σ)_max = 0.001
284 parameters	Δρ_max = 0.43 e Å⁻³
1 restraint	Δρ_min = −0.39 e Å⁻³

Crystal data top

C₅H₇N₂⁺·C₇H₄NO₄⁻·C₇H₅NO₄	γ = 86.188 (1)°
M_r = 428.36	V = 920.92 (2) Å³
Triclinic, P1	Z = 2
a = 6.4561 (1) Å	Mo Kα radiation
b = 6.8598 (1) Å	µ = 0.12 mm⁻¹
c = 20.9055 (3) Å	T = 100 K
α = 85.826 (1)°	0.40 × 0.36 × 0.29 mm
β = 87.975 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	6647 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	5169 reflections with I > 2σ(I)
T_min = 0.952, T_max = 0.965	R_int = 0.031
24945 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	1 restraint
wR(F²) = 0.132	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	Δρ_max = 0.43 e Å⁻³
6647 reflections	Δρ_min = −0.39 e Å⁻³
284 parameters

Special details top

Experimental. The data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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
O1A	0.61416 (13)	0.64153 (13)	0.61139 (4)	0.02534 (18)
O1B	1.43798 (12)	0.64460 (14)	1.07244 (4)	0.02613 (19)
O2A	0.89023 (12)	0.63198 (13)	0.54960 (4)	0.02492 (18)
O2B	1.15700 (13)	0.66730 (15)	1.13139 (4)	0.02794 (19)
O3A	0.31404 (11)	0.97209 (12)	0.29069 (4)	0.02024 (16)
H1O3	0.2342	1.0163	0.2628	0.030*
O3B	0.89111 (11)	0.90736 (11)	0.80183 (4)	0.01831 (15)
O4A	0.02402 (11)	0.98398 (11)	0.35318 (4)	0.01950 (16)
O4B	0.59084 (12)	0.90329 (13)	0.85892 (4)	0.02425 (18)
N1A	0.70215 (13)	0.66162 (13)	0.55851 (4)	0.01667 (17)
N1B	1.24848 (13)	0.67136 (13)	1.07904 (4)	0.01646 (17)
N2	0.80980 (14)	0.30341 (13)	0.29153 (4)	0.01904 (18)
N3	0.73597 (13)	0.85350 (13)	0.20200 (5)	0.02020 (18)
H3A	0.8354	0.9309	0.2022	0.024*
H3B	0.6223	0.8922	0.1834	0.024*
C1A	0.24956 (15)	0.84572 (14)	0.46101 (5)	0.01507 (18)
H1AA	0.1084	0.8790	0.4667	0.018*
C1B	1.11431 (15)	0.75402 (14)	0.90711 (5)	0.01505 (18)
H1BA	1.1788	0.7482	0.8667	0.018*
C2A	0.36551 (15)	0.77640 (14)	0.51351 (5)	0.01593 (18)
H2AA	0.3048	0.7633	0.5545	0.019*
C2B	1.22778 (15)	0.70459 (14)	0.96180 (5)	0.01522 (18)
H2BA	1.3685	0.6664	0.9587	0.018*
C3B	1.12614 (14)	0.71350 (14)	1.02109 (5)	0.01397 (17)
C3A	0.57532 (15)	0.72731 (14)	0.50276 (5)	0.01424 (17)
C4A	0.67164 (15)	0.74110 (15)	0.44250 (5)	0.01592 (18)
H4AA	0.8119	0.7038	0.4369	0.019*
C4B	0.91589 (15)	0.76542 (14)	1.02843 (5)	0.01527 (18)
H4BA	0.8513	0.7667	1.0689	0.018*
C5A	0.55303 (15)	0.81214 (15)	0.39071 (5)	0.01621 (18)
H5AA	0.6142	0.8239	0.3498	0.019*
C5B	0.80500 (15)	0.81538 (14)	0.97324 (5)	0.01517 (18)
H5BA	0.6638	0.8512	0.9766	0.018*
C6A	0.34218 (14)	0.86598 (14)	0.39989 (5)	0.01412 (17)
C6B	0.90370 (14)	0.81237 (14)	0.91270 (5)	0.01388 (17)
C7A	0.21250 (15)	0.94696 (14)	0.34447 (5)	0.01498 (18)
C7B	0.78049 (15)	0.87820 (14)	0.85437 (5)	0.01578 (18)
C8	0.62995 (16)	0.35854 (16)	0.26207 (5)	0.0195 (2)
H8A	0.5260	0.2709	0.2623	0.023*
C9	0.59889 (15)	0.54066 (15)	0.23204 (5)	0.01760 (19)
H9A	0.4736	0.5775	0.2126	0.021*
C10	0.75805 (15)	0.67391 (15)	0.23052 (5)	0.01566 (18)
C11	0.94501 (15)	0.60896 (15)	0.26128 (5)	0.01670 (19)
H11A	1.0538	0.6914	0.2611	0.020*
C12	0.96496 (16)	0.42621 (16)	0.29097 (5)	0.0186 (2)
H12A	1.0877	0.3849	0.3113	0.022*
H1N2	0.839 (2)	0.1892 (15)	0.3080 (7)	0.029 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1A	0.0250 (4)	0.0384 (5)	0.0118 (4)	−0.0024 (3)	−0.0008 (3)	0.0048 (3)
O1B	0.0158 (3)	0.0428 (5)	0.0191 (4)	0.0041 (3)	−0.0028 (3)	−0.0013 (3)
O2A	0.0172 (3)	0.0361 (5)	0.0207 (4)	0.0016 (3)	−0.0036 (3)	0.0012 (3)
O2B	0.0228 (4)	0.0485 (5)	0.0115 (4)	0.0012 (3)	0.0006 (3)	0.0003 (3)
O3A	0.0183 (3)	0.0303 (4)	0.0116 (3)	−0.0013 (3)	−0.0025 (3)	0.0027 (3)
O3B	0.0174 (3)	0.0258 (4)	0.0114 (3)	−0.0009 (3)	−0.0003 (3)	0.0006 (3)
O4A	0.0158 (3)	0.0236 (4)	0.0182 (4)	0.0011 (3)	−0.0016 (3)	0.0026 (3)
O4B	0.0145 (3)	0.0368 (5)	0.0198 (4)	0.0011 (3)	−0.0020 (3)	0.0071 (3)
N1A	0.0179 (4)	0.0178 (4)	0.0145 (4)	−0.0016 (3)	−0.0034 (3)	−0.0001 (3)
N1B	0.0167 (4)	0.0194 (4)	0.0131 (4)	0.0003 (3)	−0.0014 (3)	−0.0010 (3)
N2	0.0213 (4)	0.0188 (4)	0.0161 (4)	0.0014 (3)	0.0009 (3)	0.0017 (3)
N3	0.0160 (4)	0.0212 (4)	0.0224 (5)	0.0005 (3)	−0.0014 (3)	0.0045 (3)
C1A	0.0146 (4)	0.0166 (4)	0.0140 (4)	−0.0011 (3)	−0.0003 (3)	−0.0006 (3)
C1B	0.0156 (4)	0.0177 (4)	0.0114 (4)	0.0009 (3)	0.0001 (3)	−0.0004 (3)
C2A	0.0172 (4)	0.0180 (4)	0.0127 (4)	−0.0030 (3)	0.0005 (3)	−0.0001 (3)
C2B	0.0139 (4)	0.0175 (4)	0.0140 (4)	0.0009 (3)	−0.0001 (3)	−0.0010 (3)
C3B	0.0151 (4)	0.0154 (4)	0.0114 (4)	−0.0001 (3)	−0.0023 (3)	−0.0003 (3)
C3A	0.0168 (4)	0.0143 (4)	0.0118 (4)	−0.0017 (3)	−0.0030 (3)	0.0002 (3)
C4A	0.0141 (4)	0.0193 (4)	0.0143 (4)	−0.0007 (3)	−0.0005 (3)	−0.0013 (3)
C4B	0.0158 (4)	0.0175 (4)	0.0125 (4)	−0.0018 (3)	0.0009 (3)	−0.0007 (3)
C5A	0.0163 (4)	0.0206 (4)	0.0117 (4)	−0.0015 (3)	0.0000 (3)	−0.0013 (3)
C5B	0.0131 (4)	0.0180 (4)	0.0142 (4)	−0.0005 (3)	−0.0002 (3)	0.0001 (3)
C6A	0.0154 (4)	0.0147 (4)	0.0125 (4)	−0.0018 (3)	−0.0021 (3)	−0.0006 (3)
C6B	0.0143 (4)	0.0151 (4)	0.0122 (4)	−0.0013 (3)	−0.0014 (3)	0.0005 (3)
C7A	0.0173 (4)	0.0153 (4)	0.0125 (4)	−0.0026 (3)	−0.0018 (3)	0.0002 (3)
C7B	0.0157 (4)	0.0167 (4)	0.0149 (4)	−0.0007 (3)	−0.0022 (3)	−0.0001 (3)
C8	0.0175 (4)	0.0233 (5)	0.0178 (5)	−0.0023 (4)	0.0008 (4)	−0.0016 (4)
C9	0.0138 (4)	0.0231 (5)	0.0156 (5)	−0.0006 (3)	−0.0012 (3)	−0.0001 (4)
C10	0.0144 (4)	0.0199 (4)	0.0123 (4)	0.0012 (3)	0.0005 (3)	−0.0009 (3)
C11	0.0151 (4)	0.0203 (4)	0.0148 (4)	−0.0004 (3)	−0.0020 (3)	−0.0015 (4)
C12	0.0178 (4)	0.0232 (5)	0.0143 (5)	0.0029 (3)	−0.0023 (3)	−0.0010 (4)

Geometric parameters (Å, º) top

O1A—N1A	1.2278 (12)	C2A—H2AA	0.93
O1B—N1B	1.2294 (11)	C2B—C3B	1.3851 (14)
O2A—N1A	1.2276 (11)	C2B—H2BA	0.93
O2B—N1B	1.2244 (12)	C3B—C4B	1.3863 (13)
O3A—C7A	1.2877 (12)	C3A—C4A	1.3848 (14)
O3A—H1O3	0.8200	C4A—C5A	1.3888 (14)
O3B—C7B	1.2993 (12)	C4A—H4AA	0.93
O4A—C7A	1.2362 (12)	C4B—C5B	1.3890 (14)
O4B—C7B	1.2263 (12)	C4B—H4BA	0.93
N1A—C3A	1.4743 (12)	C5A—C6A	1.3969 (13)
N1B—C3B	1.4702 (13)	C5A—H5AA	0.93
N2—C12	1.3502 (14)	C5B—C6B	1.3977 (14)
N2—C8	1.3523 (14)	C5B—H5BA	0.93
N2—H1N2	0.844 (9)	C6A—C7A	1.5049 (13)
N3—C10	1.3301 (13)	C6B—C7B	1.5047 (13)
N3—H3A	0.86	C8—C9	1.3626 (15)
N3—H3B	0.86	C8—H8A	0.93
C1A—C2A	1.3877 (14)	C9—C10	1.4180 (14)
C1A—C6A	1.3930 (14)	C9—H9A	0.93
C1A—H1AA	0.93	C10—C11	1.4180 (13)
C1B—C2B	1.3888 (13)	C11—C12	1.3580 (15)
C1B—C6B	1.3949 (13)	C11—H11A	0.93
C1B—H1BA	0.93	C12—H12A	0.93
C2A—C3A	1.3884 (13)

C7A—O3A—H1O3	109.5	C3B—C4B—H4BA	121.2
O2A—N1A—O1A	123.62 (9)	C5B—C4B—H4BA	121.2
O2A—N1A—C3A	118.18 (9)	C4A—C5A—C6A	120.21 (9)
O1A—N1A—C3A	118.20 (8)	C4A—C5A—H5AA	119.9
O2B—N1B—O1B	123.36 (9)	C6A—C5A—H5AA	119.9
O2B—N1B—C3B	118.43 (8)	C4B—C5B—C6B	120.61 (9)
O1B—N1B—C3B	118.20 (9)	C4B—C5B—H5BA	119.7
C12—N2—C8	120.86 (9)	C6B—C5B—H5BA	119.7
C12—N2—H1N2	115.2 (11)	C1A—C6A—C5A	119.99 (9)
C8—N2—H1N2	123.7 (11)	C1A—C6A—C7A	119.15 (8)
C10—N3—H3A	120.0	C5A—C6A—C7A	120.86 (9)
C10—N3—H3B	120.0	C1B—C6B—C5B	120.08 (9)
H3A—N3—H3B	120.0	C1B—C6B—C7B	121.02 (9)
C2A—C1A—C6A	120.74 (9)	C5B—C6B—C7B	118.88 (8)
C2A—C1A—H1AA	119.6	O4A—C7A—O3A	125.63 (9)
C6A—C1A—H1AA	119.6	O4A—C7A—C6A	119.65 (9)
C2B—C1B—C6B	120.04 (9)	O3A—C7A—C6A	114.72 (8)
C2B—C1B—H1BA	120.0	O4B—C7B—O3B	125.05 (9)
C6B—C1B—H1BA	120.0	O4B—C7B—C6B	120.18 (9)
C1A—C2A—C3A	117.70 (9)	O3B—C7B—C6B	114.75 (8)
C1A—C2A—H2AA	121.2	N2—C8—C9	120.94 (10)
C3A—C2A—H2AA	121.2	N2—C8—H8A	119.5
C3B—C2B—C1B	118.35 (9)	C9—C8—H8A	119.5
C3B—C2B—H2BA	120.8	C8—C9—C10	119.85 (9)
C1B—C2B—H2BA	120.8	C8—C9—H9A	120.1
C2B—C3B—C4B	123.20 (9)	C10—C9—H9A	120.1
C2B—C3B—N1B	118.36 (8)	N3—C10—C11	120.35 (9)
C4B—C3B—N1B	118.42 (9)	N3—C10—C9	122.38 (9)
C4A—C3A—C2A	123.18 (9)	C11—C10—C9	117.27 (9)
C4A—C3A—N1A	118.57 (8)	C12—C11—C10	119.88 (9)
C2A—C3A—N1A	118.23 (9)	C12—C11—H11A	120.1
C3A—C4A—C5A	118.16 (9)	C10—C11—H11A	120.1
C3A—C4A—H4AA	120.9	N2—C12—C11	121.19 (9)
C5A—C4A—H4AA	120.9	N2—C12—H12A	119.4
C3B—C4B—C5B	117.67 (9)	C11—C12—H12A	119.4

C6A—C1A—C2A—C3A	−0.39 (14)	C4A—C5A—C6A—C1A	−0.97 (14)
C6B—C1B—C2B—C3B	0.50 (14)	C4A—C5A—C6A—C7A	178.78 (9)
C1B—C2B—C3B—C4B	1.38 (15)	C2B—C1B—C6B—C5B	−1.98 (14)
C1B—C2B—C3B—N1B	−176.79 (9)	C2B—C1B—C6B—C7B	176.30 (9)
O2B—N1B—C3B—C2B	−175.56 (9)	C4B—C5B—C6B—C1B	1.65 (14)
O1B—N1B—C3B—C2B	5.40 (14)	C4B—C5B—C6B—C7B	−176.66 (9)
O2B—N1B—C3B—C4B	6.18 (14)	C1A—C6A—C7A—O4A	−4.01 (14)
O1B—N1B—C3B—C4B	−172.86 (9)	C5A—C6A—C7A—O4A	176.24 (9)
C1A—C2A—C3A—C4A	−1.18 (15)	C1A—C6A—C7A—O3A	175.76 (8)
C1A—C2A—C3A—N1A	177.40 (8)	C5A—C6A—C7A—O3A	−3.99 (13)
O2A—N1A—C3A—C4A	3.87 (13)	C1B—C6B—C7B—O4B	170.01 (9)
O1A—N1A—C3A—C4A	−176.87 (9)	C5B—C6B—C7B—O4B	−11.69 (14)
O2A—N1A—C3A—C2A	−174.77 (9)	C1B—C6B—C7B—O3B	−11.13 (13)
O1A—N1A—C3A—C2A	4.48 (13)	C5B—C6B—C7B—O3B	167.17 (9)
C2A—C3A—C4A—C5A	1.64 (15)	C12—N2—C8—C9	−1.21 (16)
N1A—C3A—C4A—C5A	−176.93 (8)	N2—C8—C9—C10	1.08 (16)
C2B—C3B—C4B—C5B	−1.70 (15)	C8—C9—C10—N3	−179.88 (10)
N1B—C3B—C4B—C5B	176.47 (9)	C8—C9—C10—C11	−0.23 (15)
C3A—C4A—C5A—C6A	−0.53 (14)	N3—C10—C11—C12	179.16 (10)
C3B—C4B—C5B—C6B	0.15 (14)	C9—C10—C11—C12	−0.50 (15)
C2A—C1A—C6A—C5A	1.44 (14)	C8—N2—C12—C11	0.45 (16)
C2A—C1A—C6A—C7A	−178.30 (9)	C10—C11—C12—N2	0.41 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3A—H1O3···O3Bⁱ	0.82	1.63	2.4457 (11)	170
N3—H3A···O3Bⁱⁱ	0.86	2.14	2.9977 (12)	172
N3—H3B···O4Bⁱ	0.86	2.07	2.8758 (12)	155
N2—H1N2···O4Aⁱⁱⁱ	0.85 (1)	1.99 (1)	2.7726 (12)	153 (1)
C2B—H2BA···O1B^iv	0.93	2.52	3.2187 (13)	133
C8—H8A···O3A^v	0.93	2.56	3.4565 (13)	161
C12—H12A···O1A^vi	0.93	2.55	3.4427 (13)	162

Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+2, −y+2, −z+1; (iii) x+1, y−1, z; (iv) −x+3, −y+1, −z+2; (v) x, y−1, z; (vi) −x+2, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₅H₇N₂⁺·C₇H₄NO₄⁻·C₇H₅NO₄
M_r	428.36
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	6.4561 (1), 6.8598 (1), 20.9055 (3)
α, β, γ (°)	85.826 (1), 87.975 (1), 86.188 (1)
V (Å³)	920.92 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.40 × 0.36 × 0.29

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.952, 0.965
No. of measured, independent and observed [I > 2σ(I)] reflections	24945, 6647, 5169
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.757

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.132, 1.05
No. of reflections	6647
No. of parameters	284
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.43, −0.39

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3A—H1O3···O3Bⁱ	0.82	1.63	2.4457 (11)	170
N3—H3A···O3Bⁱⁱ	0.86	2.14	2.9977 (12)	172
N3—H3B···O4Bⁱ	0.86	2.07	2.8758 (12)	155
N2—H1N2···O4Aⁱⁱⁱ	0.85 (1)	1.99 (1)	2.7726 (12)	153 (1)
C2B—H2BA···O1B^iv	0.93	2.52	3.2187 (13)	133
C8—H8A···O3A^v	0.93	2.56	3.4565 (13)	161
C12—H12A···O1A^vi	0.93	2.55	3.4427 (13)	162

Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+2, −y+2, −z+1; (iii) x+1, y−1, z; (iv) −x+3, −y+1, −z+2; (v) x, y−1, z; (vi) −x+2, −y+1, −z+1.

Footnotes

‡Permanent address: Department of Physics, Karunya University, Karunya Nagar, Coimbatore 641 114, India.

Acknowledgements

HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post-doctoral research fellowship. CKQ thanks Universiti Sains Malaysia for a student assistanceship.

References

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