Cocrystals of pyrazine and benzene polycarb­oxy­lic acids

Dutkiewicz, G.; Dutkiewicz, E.; Kubicki, M.

doi:10.1107/S2053229618013669

Cocrystals of pyrazine and benzene polycarboxylic acids

G. Dutkiewicz, E. Dutkiewicz and M. Kubicki

The crystal structures of four cocrystals of pyrazine with benzene polycarboxylic acids were determined, namely pyrazine–phthalic (benzene-1,2-dicarboxylic) acid (1/1), C₄H₄N₂·C₈H₆O₄ (1), pyrazine–hemimellitic (benzene-1,2,3-tricarboxylic) acid (1/1), C₄H₄N₂·C₉H₆O₆ (2), pyrazine–hemimellitic acid–water (1/2/2), C₄H₄N₂·2C₉H₆O₆·2H₂O (2a), and pyrazine–pyromellitic (benzene-1,2,4,5-tetracarboxylic) acid (3/1), 3C₄H₄N₂·C₁₀H₆O₈ (3). In all cases, infinite chains of alternating acid and base molecules, bonded by O—H

N hydrogen bonds, are formed. However, the details of the supramolecular structures are different. The additional carboxylic acid groups in the tri- and tetracarboxylic acids participate in hydrogen bonding with neighbouring acid molecules (in 2), water molecules, which makes the structure more complicated (in 2a), or with additional pyrazine molecules (in 3). π–π interactions between aromatic rings help organize the crystal architectures in all cases except for hydrate 2a. In that case, the hydrogen-bond-enriched structure enforces a disposition of the rings in which no stacking is observed. The Hirshfeld surface analysis allows better visualization of the differences between the structures by fingerprint plots in particular.

Keywords: cocrystals; pyrazine; benzene carboxylic acids; hydrogen bonds; Hirshfeld surface; crystal structure.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229618013669/yp3167sup1.cif Contains datablocks 1, 2, 2a, 3
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229618013669/yp31671sup2.hkl Contains datablock 1
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229618013669/yp31672sup3.hkl Contains datablock 2
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229618013669/yp31672asup4.hkl Contains datablock 2a
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229618013669/yp31673sup5.hkl Contains datablock 3
	Portable Document Format (PDF) file https://doi.org/10.1107/S2053229618013669/yp3167sup6.pdf Fingerprint plots

CCDC references: 1869761; 1869760; 1869759; 1869758

Computing details top

For all structures, data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).

Pyrazine–benzene-1,2-dicarboxylic acid (1/1) (1) top

Crystal data top

C₄H₄N₂·C₈H₆O₄	Z = 2
M_r = 246.22	F(000) = 256
Triclinic, P1	D_x = 1.427 Mg m⁻³
a = 6.6714 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.3296 (8) Å	Cell parameters from 1538 reflections
c = 12.9870 (9) Å	θ = 3.5–27.9°
α = 90.425 (7)°	µ = 0.11 mm⁻¹
β = 96.907 (6)°	T = 100 K
γ = 114.347 (9)°	Prism, colourless
V = 573.23 (9) Å³	0.45 × 0.15 × 0.15 mm

Data collection top

Rigaku Xcalibur Eos diffractometer	2308 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2049 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
Detector resolution: 16.1544 pixels mm^-1	θ_max = 28.1°, θ_min = 3.2°
ω scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	k = −9→8
T_min = 0.821, T_max = 1.000	l = −13→15
3698 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.036	All H-atom parameters refined
wR(F²) = 0.091	w = 1/[σ²(F_o²) + (0.0416P)² + 0.1017P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max = 0.001
2308 reflections	Δρ_max = 0.25 e Å⁻³
203 parameters	Δρ_min = −0.22 e Å⁻³

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1A	0.13789 (19)	0.24741 (18)	0.69369 (9)	0.0151 (3)
C2A	0.1030 (2)	0.35787 (19)	0.77285 (9)	0.0164 (3)
C3A	−0.1055 (2)	0.2893 (2)	0.80572 (10)	0.0195 (3)
H3A	−0.131 (3)	0.371 (2)	0.8614 (12)	0.028 (4)*
C4A	−0.2757 (2)	0.1096 (2)	0.76306 (10)	0.0199 (3)
H4A	−0.416 (2)	0.063 (2)	0.7879 (11)	0.020 (4)*
C5A	−0.2405 (2)	−0.0021 (2)	0.68600 (10)	0.0192 (3)
H5A	−0.358 (2)	−0.128 (2)	0.6569 (11)	0.025 (4)*
C6A	−0.0344 (2)	0.06825 (19)	0.65114 (10)	0.0172 (3)
H6A	−0.009 (2)	−0.005 (2)	0.5946 (12)	0.023 (4)*
C7A	0.3557 (2)	0.33058 (19)	0.65184 (10)	0.0159 (3)
O71A	0.37644 (15)	0.20601 (14)	0.58360 (7)	0.0212 (2)
H71A	0.515 (4)	0.269 (3)	0.5618 (16)	0.070 (7)*
O72A	0.49732 (15)	0.49833 (14)	0.67712 (8)	0.0248 (2)
C8A	0.2823 (2)	0.5490 (2)	0.82548 (10)	0.0201 (3)
O81A	0.42988 (17)	0.51504 (16)	0.88979 (8)	0.0320 (3)
H81A	0.548 (3)	0.640 (3)	0.9188 (15)	0.056 (6)*
O82A	0.27875 (15)	0.71212 (14)	0.81401 (8)	0.0281 (3)
N1B	0.78422 (17)	0.39411 (16)	0.52281 (8)	0.0176 (2)
C2B	0.8609 (2)	0.3292 (2)	0.44645 (10)	0.0184 (3)
H2B	0.766 (2)	0.207 (2)	0.4058 (11)	0.021 (4)*
C3B	1.0753 (2)	0.4349 (2)	0.42354 (10)	0.0179 (3)
H3B	1.132 (2)	0.391 (2)	0.3694 (11)	0.018 (3)*
N1C	0.79526 (18)	0.84410 (17)	0.96575 (9)	0.0233 (3)
C2C	0.9755 (2)	0.8705 (2)	0.92202 (10)	0.0233 (3)
H2C	0.955 (2)	0.779 (2)	0.8670 (12)	0.027 (4)*
C3C	1.1790 (2)	1.0257 (2)	0.95620 (11)	0.0245 (3)
H3C	1.307 (3)	1.044 (2)	0.9244 (12)	0.031 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1A	0.0142 (6)	0.0144 (6)	0.0157 (6)	0.0052 (5)	0.0012 (5)	0.0036 (5)
C2A	0.0155 (6)	0.0145 (6)	0.0167 (6)	0.0040 (5)	0.0013 (5)	0.0027 (5)
C3A	0.0205 (7)	0.0195 (7)	0.0182 (7)	0.0076 (6)	0.0050 (5)	0.0008 (5)
C4A	0.0141 (6)	0.0214 (7)	0.0223 (7)	0.0045 (5)	0.0061 (5)	0.0063 (5)
C5A	0.0145 (6)	0.0143 (7)	0.0236 (7)	0.0017 (5)	−0.0008 (5)	0.0017 (5)
C6A	0.0176 (6)	0.0155 (6)	0.0175 (6)	0.0065 (5)	−0.0001 (5)	0.0004 (5)
C7A	0.0149 (6)	0.0147 (6)	0.0181 (6)	0.0065 (5)	0.0010 (5)	0.0025 (5)
O71A	0.0160 (5)	0.0202 (5)	0.0247 (5)	0.0040 (4)	0.0065 (4)	−0.0038 (4)
O72A	0.0173 (5)	0.0156 (5)	0.0378 (6)	0.0015 (4)	0.0099 (4)	−0.0028 (4)
C8A	0.0183 (6)	0.0207 (7)	0.0163 (6)	0.0022 (6)	0.0065 (5)	−0.0012 (5)
O81A	0.0276 (5)	0.0221 (6)	0.0277 (6)	−0.0043 (5)	−0.0110 (4)	0.0026 (4)
O82A	0.0224 (5)	0.0177 (5)	0.0409 (6)	0.0045 (4)	0.0076 (4)	−0.0070 (4)
N1B	0.0160 (5)	0.0181 (6)	0.0203 (6)	0.0084 (5)	0.0039 (4)	0.0047 (4)
C2B	0.0174 (6)	0.0174 (7)	0.0209 (7)	0.0078 (6)	0.0021 (5)	0.0009 (5)
C3B	0.0183 (6)	0.0187 (7)	0.0193 (6)	0.0097 (5)	0.0042 (5)	0.0022 (5)
N1C	0.0213 (6)	0.0212 (6)	0.0204 (6)	0.0027 (5)	−0.0004 (4)	0.0021 (5)
C2C	0.0309 (8)	0.0210 (7)	0.0171 (7)	0.0104 (6)	0.0016 (6)	−0.0023 (5)
C3C	0.0224 (7)	0.0300 (8)	0.0220 (7)	0.0107 (6)	0.0071 (6)	0.0041 (6)

Geometric parameters (Å, º) top

C1A—C6A	1.3938 (18)	C8A—O82A	1.2156 (16)
C1A—C2A	1.4026 (17)	C8A—O81A	1.3174 (16)
C1A—C7A	1.4975 (17)	O81A—H81A	0.96 (2)
C2A—C3A	1.3922 (18)	N1B—C2B	1.3366 (16)
C2A—C8A	1.5061 (17)	N1B—C3Bⁱ	1.3403 (17)
C3A—C4A	1.3913 (19)	C2B—C3B	1.3880 (18)
C3A—H3A	1.010 (15)	C2B—H2B	0.962 (15)
C4A—C5A	1.3893 (19)	C3B—N1Bⁱ	1.3403 (17)
C4A—H4A	0.954 (15)	C3B—H3B	0.949 (15)
C5A—C6A	1.3894 (18)	N1C—C3Cⁱⁱ	1.3328 (17)
C5A—H5A	0.970 (15)	N1C—C2C	1.3340 (18)
C6A—H6A	0.974 (15)	C2C—C3C	1.382 (2)
C7A—O72A	1.2141 (15)	C2C—H2C	0.933 (15)
C7A—O71A	1.3267 (15)	C3C—N1Cⁱⁱ	1.3328 (17)
O71A—H71A	0.93 (2)	C3C—H3C	0.952 (16)

C6A—C1A—C2A	119.62 (12)	O71A—C7A—C1A	113.83 (11)
C6A—C1A—C7A	121.03 (11)	C7A—O71A—H71A	108.1 (13)
C2A—C1A—C7A	119.24 (11)	O82A—C8A—O81A	125.10 (12)
C3A—C2A—C1A	119.33 (12)	O82A—C8A—C2A	122.63 (12)
C3A—C2A—C8A	117.69 (11)	O81A—C8A—C2A	112.07 (11)
C1A—C2A—C8A	122.98 (11)	C8A—O81A—H81A	110.3 (11)
C4A—C3A—C2A	120.47 (12)	C2B—N1B—C3Bⁱ	116.79 (11)
C4A—C3A—H3A	120.3 (9)	N1B—C2B—C3B	121.49 (12)
C2A—C3A—H3A	119.2 (9)	N1B—C2B—H2B	119.6 (9)
C5A—C4A—C3A	120.33 (12)	C3B—C2B—H2B	118.9 (9)
C5A—C4A—H4A	120.3 (9)	N1Bⁱ—C3B—C2B	121.71 (12)
C3A—C4A—H4A	119.3 (9)	N1Bⁱ—C3B—H3B	115.7 (9)
C4A—C5A—C6A	119.39 (12)	C2B—C3B—H3B	122.6 (9)
C4A—C5A—H5A	120.4 (9)	C3Cⁱⁱ—N1C—C2C	116.87 (12)
C6A—C5A—H5A	120.2 (9)	N1C—C2C—C3C	121.42 (12)
C5A—C6A—C1A	120.82 (12)	N1C—C2C—H2C	116.2 (10)
C5A—C6A—H6A	120.5 (9)	C3C—C2C—H2C	122.4 (10)
C1A—C6A—H6A	118.7 (9)	N1Cⁱⁱ—C3C—C2C	121.71 (13)
O72A—C7A—O71A	123.61 (12)	N1Cⁱⁱ—C3C—H3C	117.3 (10)
O72A—C7A—C1A	122.55 (11)	C2C—C3C—H3C	121.0 (10)

C6A—C1A—C2A—C3A	−1.73 (18)	C2A—C1A—C7A—O72A	−6.63 (18)
C7A—C1A—C2A—C3A	174.55 (11)	C6A—C1A—C7A—O71A	−9.08 (16)
C6A—C1A—C2A—C8A	177.84 (11)	C2A—C1A—C7A—O71A	174.69 (10)
C7A—C1A—C2A—C8A	−5.87 (17)	C3A—C2A—C8A—O82A	−69.34 (17)
C1A—C2A—C3A—C4A	2.13 (19)	C1A—C2A—C8A—O82A	111.08 (15)
C8A—C2A—C3A—C4A	−177.47 (11)	C3A—C2A—C8A—O81A	105.91 (13)
C2A—C3A—C4A—C5A	−0.9 (2)	C1A—C2A—C8A—O81A	−73.67 (15)
C3A—C4A—C5A—C6A	−0.67 (19)	C3Bⁱ—N1B—C2B—C3B	−0.4 (2)
C4A—C5A—C6A—C1A	1.05 (19)	N1B—C2B—C3B—N1Bⁱ	0.4 (2)
C2A—C1A—C6A—C5A	0.15 (18)	C3Cⁱⁱ—N1C—C2C—C3C	0.0 (2)
C7A—C1A—C6A—C5A	−176.07 (11)	N1C—C2C—C3C—N1Cⁱⁱ	0.0 (2)
C6A—C1A—C7A—O72A	169.61 (12)

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

Pyrazine–benzene-1,2,3-tricarboxylic acid (1/1) (2) top

Crystal data top

C₄H₄N₂·C₉H₆O₆	Z = 2
M_r = 290.23	F(000) = 300
Triclinic, P1	D_x = 1.545 Mg m⁻³
a = 7.7184 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.9393 (10) Å	Cell parameters from 1758 reflections
c = 10.030 (1) Å	θ = 4.5–26.4°
α = 115.029 (10)°	µ = 0.13 mm⁻¹
β = 112.471 (10)°	T = 100 K
γ = 92.672 (9)°	Block, colourless
V = 624.00 (15) Å³	0.25 × 0.2 × 0.1 mm

Data collection top

Rigaku Xcalibur Eos diffractometer	2396 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2083 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.016
Detector resolution: 16.2413 pixels mm^-1	θ_max = 26.6°, θ_min = 3.3°
ω scans	h = −9→9
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	k = −12→12
T_min = 0.992, T_max = 1.000	l = −12→11
4116 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.035	All H-atom parameters refined
wR(F²) = 0.092	w = 1/[σ²(F_o²) + (0.0457P)² + 0.1205P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
2396 reflections	Δρ_max = 0.25 e Å⁻³
230 parameters	Δρ_min = −0.24 e Å⁻³

Special details top

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1A	0.77882 (19)	0.80344 (15)	0.27507 (16)	0.0137 (3)
C2A	0.63009 (19)	0.70793 (15)	0.26611 (16)	0.0130 (3)
C3A	0.62151 (19)	0.55080 (15)	0.20468 (16)	0.0134 (3)
C4A	0.7578 (2)	0.49160 (16)	0.15290 (16)	0.0155 (3)
H4A	0.750 (2)	0.3828 (19)	0.1076 (18)	0.016 (4)*
C5A	0.9085 (2)	0.58751 (17)	0.16845 (17)	0.0159 (3)
H5A	1.004 (2)	0.5487 (19)	0.140 (2)	0.023 (4)*
C6A	0.9190 (2)	0.74282 (16)	0.23014 (16)	0.0149 (3)
H6A	1.024 (2)	0.8093 (18)	0.2436 (19)	0.017 (4)*
C7A	0.78911 (19)	0.97030 (16)	0.33081 (16)	0.0145 (3)
O71A	0.93572 (14)	1.04177 (12)	0.32928 (13)	0.0205 (3)
H71A	0.938 (3)	1.152 (3)	0.368 (3)	0.071 (7)*
O72A	0.67285 (15)	1.03387 (11)	0.37084 (13)	0.0232 (3)
C8A	0.4806 (2)	0.77328 (15)	0.31933 (17)	0.0150 (3)
O81A	0.54245 (15)	0.82580 (12)	0.48002 (12)	0.0205 (3)
H81A	0.450 (3)	0.869 (2)	0.510 (3)	0.053 (6)*
O82A	0.32857 (14)	0.77818 (11)	0.22763 (12)	0.0204 (3)
C9A	0.46821 (19)	0.44580 (15)	0.19762 (16)	0.0151 (3)
O91A	0.47584 (15)	0.30072 (12)	0.13041 (13)	0.0221 (3)
H91A	0.373 (4)	0.244 (3)	0.126 (3)	0.069 (7)*
O92A	0.35251 (15)	0.48904 (12)	0.25017 (13)	0.0240 (3)
N1B	0.17076 (18)	0.11055 (14)	0.07462 (15)	0.0195 (3)
C2B	−0.0016 (2)	0.14191 (17)	0.02235 (18)	0.0190 (3)
H2B	−0.005 (2)	0.246 (2)	0.0359 (19)	0.023 (4)*
C3B	−0.1722 (2)	0.03190 (17)	−0.05225 (18)	0.0205 (3)
H3B	−0.295 (3)	0.0579 (19)	−0.089 (2)	0.027 (4)*
N1C	0.96658 (17)	1.34142 (13)	0.43213 (14)	0.0175 (3)
C2C	1.1168 (2)	1.42572 (17)	0.44258 (17)	0.0179 (3)
H2C	1.200 (2)	1.3711 (19)	0.401 (2)	0.022 (4)*
C3C	1.1493 (2)	1.58355 (17)	0.50973 (17)	0.0178 (3)
H3C	1.260 (2)	1.6428 (17)	0.5157 (18)	0.016 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1A	0.0131 (7)	0.0151 (7)	0.0122 (6)	0.0036 (5)	0.0049 (5)	0.0064 (6)
C2A	0.0121 (7)	0.0154 (7)	0.0115 (6)	0.0042 (5)	0.0044 (5)	0.0070 (5)
C3A	0.0117 (7)	0.0160 (7)	0.0114 (6)	0.0031 (5)	0.0038 (5)	0.0068 (6)
C4A	0.0162 (7)	0.0146 (7)	0.0136 (7)	0.0046 (6)	0.0055 (6)	0.0058 (6)
C5A	0.0151 (7)	0.0199 (7)	0.0165 (7)	0.0080 (6)	0.0094 (6)	0.0095 (6)
C6A	0.0134 (7)	0.0183 (7)	0.0152 (7)	0.0039 (6)	0.0069 (6)	0.0093 (6)
C7A	0.0148 (7)	0.0156 (7)	0.0126 (7)	0.0032 (5)	0.0058 (6)	0.0068 (6)
O71A	0.0199 (5)	0.0135 (5)	0.0315 (6)	0.0030 (4)	0.0162 (5)	0.0095 (5)
O72A	0.0248 (6)	0.0175 (5)	0.0352 (6)	0.0097 (4)	0.0215 (5)	0.0116 (5)
C8A	0.0158 (7)	0.0118 (7)	0.0201 (7)	0.0028 (5)	0.0095 (6)	0.0086 (6)
O81A	0.0214 (6)	0.0243 (6)	0.0200 (5)	0.0093 (5)	0.0136 (5)	0.0098 (5)
O82A	0.0146 (5)	0.0234 (6)	0.0270 (6)	0.0078 (4)	0.0102 (4)	0.0140 (5)
C9A	0.0137 (7)	0.0154 (7)	0.0149 (7)	0.0039 (5)	0.0046 (6)	0.0077 (6)
O91A	0.0185 (6)	0.0142 (5)	0.0324 (6)	0.0021 (4)	0.0128 (5)	0.0089 (5)
O92A	0.0236 (6)	0.0210 (6)	0.0353 (6)	0.0066 (5)	0.0199 (5)	0.0138 (5)
N1B	0.0197 (6)	0.0177 (6)	0.0217 (6)	0.0029 (5)	0.0088 (5)	0.0105 (5)
C2B	0.0242 (8)	0.0145 (7)	0.0214 (7)	0.0050 (6)	0.0117 (6)	0.0099 (6)
C3B	0.0193 (8)	0.0215 (8)	0.0255 (8)	0.0067 (6)	0.0102 (6)	0.0147 (7)
N1C	0.0198 (6)	0.0164 (6)	0.0153 (6)	0.0037 (5)	0.0060 (5)	0.0083 (5)
C2C	0.0192 (7)	0.0188 (7)	0.0158 (7)	0.0046 (6)	0.0067 (6)	0.0092 (6)
C3C	0.0174 (7)	0.0190 (8)	0.0173 (7)	0.0021 (6)	0.0064 (6)	0.0104 (6)

Geometric parameters (Å, º) top

C1A—C6A	1.3933 (19)	O81A—H81A	0.93 (2)
C1A—C2A	1.4052 (19)	C9A—O92A	1.2099 (17)
C1A—C7A	1.4962 (19)	C9A—O91A	1.3240 (17)
C2A—C3A	1.4028 (19)	O91A—H91A	0.93 (2)
C2A—C8A	1.5119 (19)	N1B—C2B	1.336 (2)
C3A—C4A	1.3925 (19)	N1B—C3Bⁱ	1.3377 (19)
C3A—C9A	1.5008 (19)	C2B—C3B	1.382 (2)
C4A—C5A	1.385 (2)	C2B—H2B	0.984 (17)
C4A—H4A	0.968 (16)	C3B—N1Bⁱ	1.3377 (19)
C5A—C6A	1.383 (2)	C3B—H3B	0.971 (18)
C5A—H5A	0.932 (18)	N1C—C3Cⁱⁱ	1.3377 (19)
C6A—H6A	0.948 (16)	N1C—C2C	1.3416 (19)
C7A—O72A	1.2163 (17)	C2C—C3C	1.385 (2)
C7A—O71A	1.3164 (16)	C2C—H2C	0.957 (17)
O71A—H71A	0.99 (3)	C3C—N1Cⁱⁱ	1.3378 (19)
C8A—O82A	1.2013 (17)	C3C—H3C	0.984 (15)
C8A—O81A	1.3322 (17)

C6A—C1A—C2A	120.00 (12)	O82A—C8A—O81A	125.50 (13)
C6A—C1A—C7A	118.84 (12)	O82A—C8A—C2A	123.72 (12)
C2A—C1A—C7A	121.16 (12)	O81A—C8A—C2A	110.78 (11)
C3A—C2A—C1A	118.74 (12)	C8A—O81A—H81A	108.7 (13)
C3A—C2A—C8A	120.77 (12)	O92A—C9A—O91A	123.61 (12)
C1A—C2A—C8A	120.48 (12)	O92A—C9A—C3A	123.82 (12)
C4A—C3A—C2A	120.18 (12)	O91A—C9A—C3A	112.56 (12)
C4A—C3A—C9A	119.47 (12)	C9A—O91A—H91A	106.8 (15)
C2A—C3A—C9A	120.33 (12)	C2B—N1B—C3Bⁱ	117.41 (13)
C5A—C4A—C3A	120.65 (13)	N1B—C2B—C3B	121.56 (13)
C5A—C4A—H4A	119.1 (9)	N1B—C2B—H2B	118.1 (10)
C3A—C4A—H4A	120.2 (9)	C3B—C2B—H2B	120.3 (10)
C6A—C5A—C4A	119.53 (13)	N1Bⁱ—C3B—C2B	121.03 (14)
C6A—C5A—H5A	119.8 (10)	N1Bⁱ—C3B—H3B	119.2 (10)
C4A—C5A—H5A	120.6 (10)	C2B—C3B—H3B	119.8 (10)
C5A—C6A—C1A	120.77 (12)	C3Cⁱⁱ—N1C—C2C	117.16 (13)
C5A—C6A—H6A	119.9 (10)	N1C—C2C—C3C	121.28 (14)
C1A—C6A—H6A	119.3 (10)	N1C—C2C—H2C	116.5 (10)
O72A—C7A—O71A	123.00 (13)	C3C—C2C—H2C	122.2 (10)
O72A—C7A—C1A	123.96 (12)	N1Cⁱⁱ—C3C—C2C	121.56 (13)
O71A—C7A—C1A	113.03 (12)	N1Cⁱⁱ—C3C—H3C	118.7 (9)
C7A—O71A—H71A	110.7 (14)	C2C—C3C—H3C	119.7 (9)

C6A—C1A—C2A—C3A	−2.77 (19)	C2A—C1A—C7A—O72A	−0.2 (2)
C7A—C1A—C2A—C3A	176.62 (11)	C6A—C1A—C7A—O71A	0.40 (17)
C6A—C1A—C2A—C8A	178.17 (12)	C2A—C1A—C7A—O71A	−179.00 (12)
C7A—C1A—C2A—C8A	−2.44 (19)	C3A—C2A—C8A—O82A	−86.80 (17)
C1A—C2A—C3A—C4A	−0.40 (19)	C1A—C2A—C8A—O82A	92.24 (17)
C8A—C2A—C3A—C4A	178.66 (11)	C3A—C2A—C8A—O81A	94.20 (14)
C1A—C2A—C3A—C9A	178.27 (12)	C1A—C2A—C8A—O81A	−86.75 (15)
C8A—C2A—C3A—C9A	−2.67 (19)	C4A—C3A—C9A—O92A	174.85 (12)
C2A—C3A—C4A—C5A	3.1 (2)	C2A—C3A—C9A—O92A	−3.8 (2)
C9A—C3A—C4A—C5A	−175.60 (12)	C4A—C3A—C9A—O91A	−3.90 (18)
C3A—C4A—C5A—C6A	−2.5 (2)	C2A—C3A—C9A—O91A	177.42 (11)
C4A—C5A—C6A—C1A	−0.7 (2)	C3Bⁱ—N1B—C2B—C3B	−0.1 (2)
C2A—C1A—C6A—C5A	3.4 (2)	N1B—C2B—C3B—N1Bⁱ	0.1 (2)
C7A—C1A—C6A—C5A	−176.05 (12)	C3Cⁱⁱ—N1C—C2C—C3C	−0.4 (2)
C6A—C1A—C7A—O72A	179.16 (13)	N1C—C2C—C3C—N1Cⁱⁱ	0.5 (2)

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

Pyrazine–benzene-1,2,3-tricarboxylic acid–water (1/2/2) (2a) top

Crystal data top

C₄H₄N₂·2C₉H₆O₆·2H₂O	Z = 1
M_r = 536.40	F(000) = 278
Triclinic, P1	D_x = 1.546 Mg m⁻³
a = 6.6537 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.3316 (11) Å	Cell parameters from 1276 reflections
c = 11.5433 (15) Å	θ = 4.3–26.4°
α = 73.100 (12)°	µ = 0.13 mm⁻¹
β = 75.565 (11)°	T = 295 K
γ = 73.001 (11)°	Block, colourless
V = 576.01 (14) Å³	0.3 × 0.3 × 0.2 mm

Data collection top

Rigaku Xcalibur Eos diffractometer	2179 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	1736 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
Detector resolution: 16.2413 pixels mm^-1	θ_max = 26.5°, θ_min = 3.5°
ω scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	k = −10→10
T_min = 0.905, T_max = 1.000	l = −13→14
3622 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F² > 2σ(F²)] = 0.053	w = 1/[σ²(F_o²) + (0.0997P)² + 0.0693P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.160	(Δ/σ)_max < 0.001
S = 1.04	Δρ_max = 0.38 e Å⁻³
2179 reflections	Δρ_min = −0.21 e Å⁻³
213 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.080 (15)

Special details top

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1A	0.8047 (3)	0.6697 (3)	0.22031 (18)	0.0340 (5)
C2A	0.7430 (3)	0.7000 (2)	0.33845 (17)	0.0308 (5)
C3A	0.7530 (3)	0.5595 (2)	0.44108 (17)	0.0311 (5)
C4A	0.8212 (3)	0.3923 (3)	0.4238 (2)	0.0377 (5)
H4A	0.828 (4)	0.297 (3)	0.489 (2)	0.050 (7)*
C5A	0.8848 (4)	0.3629 (3)	0.3068 (2)	0.0433 (5)
H5A	0.938 (4)	0.245 (4)	0.292 (2)	0.061 (7)*
C6A	0.8769 (3)	0.5005 (3)	0.2059 (2)	0.0389 (5)
H6A	0.923 (3)	0.485 (3)	0.125 (2)	0.041 (6)*
C7A	0.7833 (4)	0.8169 (3)	0.11065 (18)	0.0415 (5)
O71A	0.8710 (3)	0.7743 (2)	0.00575 (14)	0.0559 (5)
H71A	0.838 (6)	0.862 (5)	−0.052 (3)	0.094 (12)*
O72A	0.6895 (4)	0.9610 (2)	0.11759 (16)	0.0915 (9)
C8A	0.6790 (3)	0.8824 (2)	0.35543 (17)	0.0353 (5)
O81A	0.4703 (2)	0.94641 (19)	0.37352 (14)	0.0451 (4)
H81A	0.441 (4)	1.049 (4)	0.384 (2)	0.054 (7)*
O82A	0.8079 (3)	0.95864 (19)	0.35354 (16)	0.0533 (5)
C9A	0.6933 (3)	0.5865 (2)	0.56852 (18)	0.0337 (5)
O91A	0.7045 (3)	0.44251 (19)	0.65358 (13)	0.0458 (5)
H91A	0.658 (5)	0.470 (4)	0.734 (3)	0.094 (11)*
O92A	0.6407 (3)	0.72808 (18)	0.59098 (13)	0.0460 (5)
N1B	0.5795 (3)	0.4852 (2)	0.88038 (15)	0.0442 (5)
C2B	0.4811 (4)	0.6368 (3)	0.9069 (2)	0.0484 (6)
H2B	0.469 (4)	0.732 (4)	0.840 (3)	0.065 (8)*
C3B	0.4014 (4)	0.6525 (3)	1.0256 (2)	0.0462 (6)
H3B	0.340 (4)	0.760 (4)	1.045 (2)	0.059 (7)*
O1W	0.1942 (4)	0.9683 (2)	0.18795 (16)	0.0569 (5)
H1W1	0.083 (6)	0.948 (4)	0.247 (3)	0.085 (11)*
H1W2	0.312 (7)	0.949 (5)	0.215 (4)	0.116 (15)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1A	0.0367 (10)	0.0326 (10)	0.0301 (10)	−0.0060 (8)	−0.0024 (8)	−0.0089 (8)
C2A	0.0330 (10)	0.0269 (10)	0.0315 (10)	−0.0062 (7)	−0.0027 (8)	−0.0088 (8)
C3A	0.0322 (9)	0.0293 (10)	0.0306 (10)	−0.0070 (7)	−0.0032 (8)	−0.0075 (8)
C4A	0.0466 (12)	0.0252 (10)	0.0360 (11)	−0.0065 (8)	−0.0042 (9)	−0.0036 (8)
C5A	0.0564 (13)	0.0274 (10)	0.0438 (12)	−0.0060 (9)	−0.0032 (10)	−0.0140 (9)
C6A	0.0481 (12)	0.0345 (11)	0.0330 (11)	−0.0073 (9)	−0.0015 (9)	−0.0136 (9)
C7A	0.0529 (13)	0.0354 (11)	0.0308 (11)	−0.0070 (9)	−0.0019 (9)	−0.0079 (8)
O71A	0.0809 (13)	0.0454 (10)	0.0284 (9)	−0.0044 (8)	0.0012 (8)	−0.0089 (7)
O72A	0.164 (2)	0.0379 (10)	0.0353 (10)	0.0157 (11)	−0.0033 (11)	−0.0045 (8)
C8A	0.0481 (12)	0.0287 (10)	0.0245 (10)	−0.0081 (9)	−0.0013 (8)	−0.0047 (7)
O81A	0.0509 (9)	0.0315 (8)	0.0493 (9)	0.0051 (7)	−0.0117 (7)	−0.0167 (7)
O82A	0.0607 (10)	0.0392 (9)	0.0614 (11)	−0.0221 (8)	0.0086 (8)	−0.0204 (8)
C9A	0.0339 (10)	0.0321 (10)	0.0319 (10)	−0.0049 (8)	−0.0041 (8)	−0.0074 (8)
O91A	0.0681 (11)	0.0343 (8)	0.0284 (8)	−0.0087 (7)	−0.0047 (7)	−0.0046 (6)
O92A	0.0641 (10)	0.0325 (8)	0.0368 (8)	−0.0013 (7)	−0.0065 (7)	−0.0132 (6)
N1B	0.0566 (12)	0.0425 (10)	0.0298 (9)	−0.0084 (9)	−0.0053 (8)	−0.0082 (8)
C2B	0.0696 (16)	0.0360 (12)	0.0327 (12)	−0.0095 (11)	−0.0087 (11)	−0.0010 (9)
C3B	0.0617 (14)	0.0362 (12)	0.0356 (12)	−0.0055 (10)	−0.0080 (10)	−0.0077 (9)
O1W	0.0590 (12)	0.0608 (12)	0.0392 (10)	−0.0093 (9)	−0.0031 (9)	−0.0038 (8)

Geometric parameters (Å, º) top

C1A—C6A	1.395 (3)	C8A—O82A	1.201 (3)
C1A—C2A	1.397 (3)	C8A—O81A	1.320 (3)
C1A—C7A	1.487 (3)	O81A—H81A	0.86 (3)
C2A—C3A	1.402 (3)	C9A—O92A	1.213 (2)
C2A—C8A	1.510 (3)	C9A—O91A	1.307 (2)
C3A—C4A	1.390 (3)	O91A—H91A	0.97 (4)
C3A—C9A	1.491 (3)	N1B—C2B	1.326 (3)
C4A—C5A	1.382 (3)	N1B—C3Bⁱ	1.330 (3)
C4A—H4A	0.92 (3)	C2B—C3B	1.371 (3)
C5A—C6A	1.375 (3)	C2B—H2B	0.94 (3)
C5A—H5A	0.99 (3)	C3B—N1Bⁱ	1.330 (3)
C6A—H6A	0.94 (2)	C3B—H3B	0.93 (3)
C7A—O72A	1.196 (3)	O1W—H1W1	0.89 (4)
C7A—O71A	1.307 (2)	O1W—H1W2	0.87 (4)
O71A—H71A	0.85 (4)

C6A—C1A—C2A	119.69 (18)	O72A—C7A—C1A	122.92 (19)
C6A—C1A—C7A	120.14 (18)	O71A—C7A—C1A	114.19 (18)
C2A—C1A—C7A	120.10 (17)	C7A—O71A—H71A	108 (2)
C1A—C2A—C3A	119.42 (17)	O82A—C8A—O81A	124.30 (19)
C1A—C2A—C8A	120.25 (17)	O82A—C8A—C2A	122.28 (19)
C3A—C2A—C8A	120.22 (17)	O81A—C8A—C2A	113.41 (18)
C4A—C3A—C2A	119.56 (18)	C8A—O81A—H81A	110.2 (17)
C4A—C3A—C9A	119.45 (18)	O92A—C9A—O91A	123.40 (18)
C2A—C3A—C9A	120.99 (17)	O92A—C9A—C3A	123.34 (18)
C5A—C4A—C3A	120.84 (19)	O91A—C9A—C3A	113.26 (17)
C5A—C4A—H4A	117.3 (15)	C9A—O91A—H91A	109 (2)
C3A—C4A—H4A	121.8 (15)	C2B—N1B—C3Bⁱ	117.16 (19)
C6A—C5A—C4A	119.74 (19)	N1B—C2B—C3B	122.0 (2)
C6A—C5A—H5A	118.1 (15)	N1B—C2B—H2B	116.1 (17)
C4A—C5A—H5A	122.2 (15)	C3B—C2B—H2B	122.0 (17)
C5A—C6A—C1A	120.72 (19)	N1Bⁱ—C3B—C2B	120.9 (2)
C5A—C6A—H6A	121.6 (14)	N1Bⁱ—C3B—H3B	117.1 (17)
C1A—C6A—H6A	117.7 (14)	C2B—C3B—H3B	121.9 (17)
O72A—C7A—O71A	122.9 (2)	H1W1—O1W—H1W2	114 (3)

Symmetry code: (i) −x+1, −y+1, −z+2.

Pyrazine–benzene-1,2,4,5-tetracarboxylic acid (3/1) (3) top

Crystal data top

3C₄H₄N₂·C₁₀H₆O₈	F(000) = 512
M_r = 494.42	D_x = 1.455 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.0481 (7) Å	Cell parameters from 1334 reflections
b = 22.365 (2) Å	θ = 3.9–26.1°
c = 7.2120 (7) Å	µ = 0.11 mm⁻¹
β = 96.967 (9)°	T = 295 K
V = 1128.44 (19) Å³	Block, colourless
Z = 2	0.35 × 0.3 × 0.3 mm

Data collection top

Rigaku Xcalibur Eos diffractometer	2160 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	1695 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.020
Detector resolution: 16.2413 pixels mm^-1	θ_max = 26.6°, θ_min = 3.4°
ω scans	h = −8→7
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	k = −27→21
T_min = 0.933, T_max = 1.000	l = −8→9
4092 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F² > 2σ(F²)] = 0.041	w = 1/[σ²(F_o²) + (0.0431P)² + 0.2031P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.103	(Δ/σ)_max < 0.001
S = 1.02	Δρ_max = 0.26 e Å⁻³
2160 reflections	Δρ_min = −0.19 e Å⁻³
200 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.080 (5)

Special details top

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1A	0.9329 (2)	0.55829 (7)	0.4697 (2)	0.0295 (4)
C2A	0.8159 (2)	0.50981 (7)	0.41165 (19)	0.0291 (4)
C3A	0.8842 (2)	0.45193 (7)	0.4433 (2)	0.0307 (4)
H3A	0.804 (2)	0.4189 (7)	0.400 (2)	0.033 (4)*
C7A	0.8682 (2)	0.62210 (7)	0.4430 (2)	0.0365 (4)
O71A	0.7576 (2)	0.63877 (6)	0.56779 (18)	0.0572 (4)
H71A	0.699 (4)	0.6754 (13)	0.532 (4)	0.107 (9)*
O72A	0.92066 (19)	0.65422 (5)	0.32535 (19)	0.0563 (4)
C8A	0.6212 (2)	0.52010 (7)	0.3092 (2)	0.0335 (4)
O81A	0.51999 (17)	0.47085 (5)	0.28590 (19)	0.0494 (4)
H81A	0.393 (4)	0.4780 (11)	0.214 (3)	0.099 (8)*
O82A	0.56530 (17)	0.56850 (6)	0.25342 (19)	0.0565 (4)
N1B	0.2733 (3)	0.82069 (8)	0.3447 (3)	0.0652 (5)
C2B	0.2324 (4)	0.76279 (11)	0.3326 (3)	0.0630 (6)
H2B	0.106 (4)	0.7544 (11)	0.277 (4)	0.098 (9)*
C3B	0.3631 (4)	0.71991 (9)	0.3897 (3)	0.0573 (6)
H3B	0.330 (3)	0.6799 (11)	0.377 (3)	0.075 (7)*
N4B	0.5391 (3)	0.73355 (7)	0.4642 (2)	0.0535 (4)
C5B	0.5803 (3)	0.79119 (9)	0.4780 (3)	0.0558 (5)
H5B	0.702 (3)	0.8009 (10)	0.534 (3)	0.073 (7)*
C6B	0.4483 (3)	0.83400 (9)	0.4175 (3)	0.0580 (6)
H6B	0.482 (3)	0.8755 (10)	0.425 (3)	0.076 (7)*
N1C	0.82260 (18)	0.51111 (7)	0.90302 (18)	0.0405 (4)
C2C	0.8834 (2)	0.45569 (9)	0.9402 (2)	0.0414 (4)
H2C	0.799 (3)	0.4240 (8)	0.894 (2)	0.051 (5)*
C3C	1.0598 (3)	0.44473 (9)	1.0369 (2)	0.0421 (4)
H3C	1.100 (3)	0.4049 (9)	1.062 (3)	0.057 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1A	0.0271 (8)	0.0299 (8)	0.0307 (7)	0.0024 (7)	0.0006 (6)	0.0020 (6)
C2A	0.0234 (7)	0.0324 (8)	0.0305 (8)	0.0003 (7)	−0.0005 (6)	0.0016 (6)
C3A	0.0260 (8)	0.0296 (8)	0.0349 (8)	−0.0026 (7)	−0.0022 (6)	−0.0012 (6)
C7A	0.0286 (8)	0.0334 (9)	0.0449 (9)	0.0012 (7)	−0.0055 (7)	0.0017 (7)
O71A	0.0679 (9)	0.0445 (8)	0.0609 (9)	0.0265 (7)	0.0144 (7)	0.0061 (6)
O72A	0.0534 (8)	0.0397 (7)	0.0768 (9)	0.0015 (6)	0.0119 (7)	0.0189 (7)
C8A	0.0259 (8)	0.0377 (9)	0.0351 (8)	0.0017 (7)	−0.0034 (6)	0.0018 (7)
O81A	0.0293 (7)	0.0404 (7)	0.0728 (9)	−0.0026 (5)	−0.0170 (6)	−0.0013 (6)
O82A	0.0389 (7)	0.0447 (8)	0.0792 (9)	0.0016 (6)	−0.0200 (7)	0.0176 (7)
N1B	0.0644 (12)	0.0521 (11)	0.0770 (12)	0.0121 (9)	−0.0004 (10)	0.0085 (9)
C2B	0.0560 (13)	0.0649 (15)	0.0661 (14)	−0.0088 (12)	−0.0007 (11)	0.0042 (11)
C3B	0.0769 (16)	0.0378 (11)	0.0581 (12)	−0.0077 (11)	0.0115 (11)	−0.0027 (9)
N4B	0.0641 (12)	0.0404 (9)	0.0574 (10)	0.0131 (8)	0.0126 (8)	0.0033 (7)
C5B	0.0557 (13)	0.0494 (12)	0.0607 (13)	−0.0002 (10)	0.0013 (11)	−0.0022 (10)
C6B	0.0712 (15)	0.0334 (10)	0.0684 (13)	0.0005 (11)	0.0051 (11)	−0.0012 (10)
N1C	0.0259 (7)	0.0553 (10)	0.0383 (8)	−0.0001 (7)	−0.0039 (6)	−0.0008 (7)
C2C	0.0327 (9)	0.0498 (11)	0.0404 (9)	−0.0067 (9)	−0.0014 (7)	−0.0010 (8)
C3C	0.0372 (10)	0.0443 (11)	0.0432 (9)	0.0023 (9)	−0.0021 (7)	0.0016 (8)

Geometric parameters (Å, º) top

C1A—C3Aⁱ	1.382 (2)	C2B—C3B	1.359 (3)
C1A—C2A	1.396 (2)	C2B—H2B	0.95 (3)
C1A—C7A	1.504 (2)	C3B—N4B	1.326 (3)
C2A—C3A	1.390 (2)	C3B—H3B	0.93 (2)
C2A—C8A	1.495 (2)	N4B—C5B	1.323 (3)
C3A—C1Aⁱ	1.383 (2)	C5B—C6B	1.369 (3)
C3A—H3A	0.960 (16)	C5B—H5B	0.93 (2)
C7A—O72A	1.2036 (19)	C6B—H6B	0.96 (2)
C7A—O71A	1.314 (2)	N1C—C3Cⁱⁱ	1.328 (2)
O71A—H71A	0.94 (3)	N1C—C2C	1.328 (2)
C8A—O82A	1.2043 (19)	C2C—C3C	1.372 (2)
C8A—O81A	1.3119 (19)	C2C—H2C	0.960 (19)
O81A—H81A	0.99 (3)	C3C—N1Cⁱⁱ	1.328 (2)
N1B—C6B	1.314 (3)	C3C—H3C	0.95 (2)
N1B—C2B	1.327 (3)

C3Aⁱ—C1A—C2A	119.49 (14)	N1B—C2B—H2B	113.9 (16)
C3Aⁱ—C1A—C7A	117.84 (14)	C3B—C2B—H2B	123.8 (16)
C2A—C1A—C7A	122.67 (13)	N4B—C3B—C2B	121.8 (2)
C3A—C2A—C1A	119.60 (14)	N4B—C3B—H3B	118.3 (15)
C3A—C2A—C8A	120.21 (14)	C2B—C3B—H3B	119.9 (15)
C1A—C2A—C8A	120.15 (14)	C5B—N4B—C3B	116.17 (19)
C1Aⁱ—C3A—C2A	120.90 (14)	N4B—C5B—C6B	121.5 (2)
C1Aⁱ—C3A—H3A	120.0 (9)	N4B—C5B—H5B	116.4 (14)
C2A—C3A—H3A	119.1 (9)	C6B—C5B—H5B	122.1 (14)
O72A—C7A—O71A	124.89 (16)	N1B—C6B—C5B	122.5 (2)
O72A—C7A—C1A	122.85 (15)	N1B—C6B—H6B	117.1 (14)
O71A—C7A—C1A	112.18 (14)	C5B—C6B—H6B	120.3 (14)
C7A—O71A—H71A	109.9 (16)	C3Cⁱⁱ—N1C—C2C	117.07 (15)
O82A—C8A—O81A	124.12 (14)	N1C—C2C—C3C	121.31 (17)
O82A—C8A—C2A	123.15 (15)	N1C—C2C—H2C	116.6 (11)
O81A—C8A—C2A	112.73 (13)	C3C—C2C—H2C	122.1 (11)
C8A—O81A—H81A	111.9 (14)	N1Cⁱⁱ—C3C—C2C	121.61 (17)
C6B—N1B—C2B	115.7 (2)	N1Cⁱⁱ—C3C—H3C	118.5 (12)
N1B—C2B—C3B	122.3 (2)	C2C—C3C—H3C	119.9 (12)

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

Selected geometrical data (Å, °). A and B denote the least-squares planes of the phenyl and pyrazine ring, respectively. top

	1	2	2a	3
C—O	1.3267 (15)	1.3164 (16)	1.308 (3)	1.314 (2)
	1.3174 (16)	1.3322 (17)	1.320 (3)	1.3119 (19)
		1.3240 (17)	1.307 (2)
C═O	1.2141 (15)	1.2163 (17)	1.196 (3)	1.2036 (19)
	1.2156 (16)	1.2013 (17)	1.201 (3)	1.2043 (19)
		1.2099 (17)	1.213 (2)
O—C═O	123.61 (12)	123.00 (13)	122.9 (2)	124.89 (16)
	125.10 (12)	125.50 (13)	124.30 (19)	124.12 (14)
		123.61 (12)	123.40 (18)
C—N—C	116.79 (11)	117.41 (13)	117.16 (19)	115.7 (2)
	116.87 (12)	117.16 (13)		116.17 (19)
				117.07 (15)
A/COO	8.88 (18)	4.25 (15)	11.74 (8)	77.53 (6)
	72.45 (8)	85.85 (10)	84.50 (8)	10.2 (2)
		5.8 (2)	3.38 (2)
A/B	4.10 (10)	36.34 (5)	8.76 (4)	3.44 (8)
	6.20 (10)	3.38 (10)		3.65 (9)

Hydrogen-bond data (Å, °) top

D	H	A	D—H	H···A	D···A	D—H···A
1
O71A	H71A	N1B	0.93 (2)	1.79 (2)	2.7139 (14)	179 (2)
O81A	H81A	N1C	0.96 (2)	1.75 (2)	2.6965 (15)	168.7 (17)
C3B	H3B	O72Aⁱ	0.949 (15)	2.419 (14)	3.1358 (16)	132.2 (11)
C2C	H2C	O82Aⁱⁱ	0.933 (15)	2.570 (15)	3.1628 (17)	121.9 (11)
2
O71A	H71A	N1C	0.99 (3)	1.68 (3)	2.6717 (16)	174 (2)
O81A	H81A	O72Aⁱⁱⁱ	0.93 (2)	1.80 (2)	2.7010 (14)	162 (2)
O91A	H91A	N1B	0.93 (2)	1.75 (3)	2.6672 (16)	168 (2)
C3B	H3B	O82A^iv	0.971 (18)	2.517 (17)	3/0844 (18)	117.2 (12)
2a
O71A	H71A	O1W^v	0.85 (4)	1.79 (4)	2.634 (2)	171 (4)
O81A	H81A	O92A^vi	0.86 (3)	1.86 (3)	2.719 (2)	176 (3)
O91A	H91A	N1B	0.97 (4)	1.68 (4)	2.637 (2)	171 (3)
O1W	H1W1	O82A^vii	0.89 (4)	1.93 (4)	2.802 (3)	166 (3)
O1W	H1W2	O81A	0.87 (4)	2.32 (4)	3.088 (3)	147 (4)
O1W	H1W2	O72A	0.87 (4)	2.50 (4)	3.178 (4)	135 (3)
3
O71A	H71A	N4B	0.94 (3)	1.75 (3)	2.673 (2)	166 (3)
O81A	H81A	N1C	0.99 (3)	1.66 (3)	2.6554 (17)	178 (2)

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

Comparison of the chain structures from similar cocrystals. D is the distance between subsequent acid molecules, A is the angle formed by three subsequent acid molecules, and `direction' of a chain, repetition parameter, space group top

Refcode	Acceptor	Stoichiometry	D	A	T	Direction	Reference
NANPOI	2,5-Bis(pyridin-3-yl)-1,3,4-oxadiazole	1:1 (1/2:1/2)	19.023	32.20 23.74	180	[010] 10.550 Pnna 12.679	1
NANPUO	2,5-Bis(pyridin-4-yl)-1,3,4-oxadiazole	1:1	20.833	29.33	180	[010] 10.547 C2/c 13.296	1
ONAQIE	1,2-Bis(pyridin-4-yl)ethane	1:1 (1/2:1/2)	21.331	73.49	180	[101] 25.522 C2/c 12.784	2
SUXVOW	4,4'-Bipyridine	1:1 (1/2:1/2)	19.344	69.56	180	[101] 22.070 C2/c 9.973	3
SUXVUC	4,4'-Dipyridyl-acetylene	1:1 (1/2:1/2)	21.777	73.59	180	[101] 26.088 C2/c 12.424	3
VAXVUN	Pyrazine	1:1	15.001	53.90	180	[010] 13.597 P2₁/c 6.279	4
XOGFIK	Tetramethylpyrazine	1:1 (1:2 × 1/2)	14.706 15.207	51.00	180	[001] 12.885 P1 6.500 6.581	5
XOGFOQ	Tetramethylpyrazine	2:1 (1:1/2)	9.602 15.385	54.95	180	[110] 12.618 P2₁/n 6.603	5
	Pyrazine	1:1 (1:2 × 1/2)	15.046 15.203	58.87	180	[011] 14.865 P1 6.267 6.357	6a
	Pyrazine	1:1 (1:2 × 1/2)	15.153 14.986	142.33		[103] 28.525	6b

References: (1) Du et al. (2005a,b); (2) Ebenezer & Muthiah (2011); (3) Tomura & Yamashita (2001); (4) Arhangelskis et al. (2012); (5) Wang et al. (2014); (6a)/(6b) this work.

PLEASE PROVIDE A TABLE CAPTION top

	1			2			2a		3
	Pyr_B	Pyr_C	A	Pyr_B	Pyr_C	A	Pyr	A	Pyr_B	Pyr_C	A
C···C	9.4	7.1	5.2	0	8.4	6.8	0.5	4.5	4.7	10.1	4.9
C···H	6.6	14.0	12.4	9.5	11.4	10.8	13.3	11.7	9.9	6.0	7.8
C···O	3.3	0.3	1.6	5.2	1.4	8.7	5.6	9.2	0.2	2.3	5.0
C···N	6.2	2.8	3.2	0.4	3.2	1.2	2.1	1.0	4.3	6.9	3.9
H···H	35.1	39.8	29.3	37.9	24.2	19.0	28.4	17.8	35.8	30.4	16.3
H···O	22.5	17.5	39.0	23.4	28.7	42.2	30.1	50.3	21.4	21.2	42.6
H···N	14.9	15.6	7.8	19.0	21.9	7.8	19.9	4.7	22.1	21.8	14.3
O···N	2.1	3.0	1.5	4.6	0.8	1.4	0.0	0.8	0.3	1.3	0.8
O···O						2.1					4.2
N···N									1.3

Comparison of the chain structures from selected cocrystals of phtalic acid (cf. text) top

D is the distance between the centroids of the phenyl rings of subsequent acid molecules, A is the angle formed by three subsequent centroids, T is the dihedral angle made by four centroids, and the `direction' column shows a direction of a chain in the crystal structure, the repetition parameter along the chain and the space group.

No	Refcode	acceptor	stoichiometry	D	A	T	direction	reference
1	NANPOI	2,5-Bis(pyrid-3-yl)-1,3,4-oxadiazole	1:1 (1/2:1/2)	19.023	32.20	180	[010] 10.550 Pnna	1
2	NANPUO	2,5-Bis(pyrid-4-yl)-1,3,4-oxadiazole	1:1	20.833	29.33	180	[010] 10.547 C2/c	1
3	ONAQIE	1,2-Bis(pyridin-4-yl)ethane	1:1 (1/2:1/2)	21.331	73.49	180	[101] 25.522 C2/c	2
4	SUXVOW	4,4'-Bipyridine	1:1 (1/2:1/2)	19.344	69.56	180	[101] 22.070 C2/c	3
5	SUXVUC	4,4'-Dipyridylacetylene	1:1 (1/2:1/2)	21.777	73.59	180	[101] 26.088 C2/c	3
6	VAXVUN	Pyrazine	1:1	15.001	53.90	180	[010] 13.597 P2₁/c	4
7	XOGFIK	Tetramethyl-pyrazine	1:1(1:2x1/2)	14.706 15.207	51.00	180	[001] 12.885 P1	5
8	XOGFOQ	Tetramethyl-pyrazine	2:1 (1:1/2)	9.602 15.385	54.95	180	[110] 12.618 P2₁/n	5
9		Pyrazine	1:1(1:2x1/2)	15.046 15.203	58.87	180	[011] 14.865 P1	6a

References: (1) Du et al. (2005b), (2) Ebenezer & Muthiah (2011); (3) Tomura & Yamashita (2001); (4) Arhangelskis et al. (2012); (5) Wang et al. (2014); (6a) this work, 1.

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Cocrystals of pyrazine and benzene polycarb­oxy­lic acids

Supporting information

Cocrystals of pyrazine and benzene polycarboxylic acids