Crystal structure and Hirshfeld surface analysis of the cocrystal formed between 2,3-di­amino­pyrazine and 2,3,5,6-tetra­fluoro­terephthalic acid

Bosch, E.

doi:10.1107/S2056989026001581

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ISSN: 2056-9890

Volume 82| Part 3| March 2026| Pages 289-292

https://doi.org/10.1107/S2056989026001581

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Crystal structure and Hirshfeld surface analysis of the cocrystal formed between 2,3-diaminopyrazine and 2,3,5,6-tetrafluoroterephthalic acid

Eric Bosch ^a ^*

^aDepartment of Chemistry and Biochemistry, Missouri State University, 901 South National Avenue, Springfield MO 65897, USA
^*Correspondence e-mail: [email protected]

Edited by J. Reibenspies, Texas A & M University, USA (Received 19 January 2026; accepted 13 February 2026; online 24 February 2026)

The cocrystal formed between 2,3-diaminopyrazine and 2,3,5,6-tetrafluorophthalic acid, crystallizes as the solvated salt bis(2,3-diaminopyrazin-1-ium) 2,3,5,6-tetrafluorophthalate–2,3,5,6-tetrafluorophthalic acid (1/1), 2C₄H₇N₄⁺·C₈F₄O₄²⁻·C₈H₂F₄O₄, in the triclinic space group P1 with one unique protonated 2,3-diaminopyrazinium cation, one half a tetrafluorophthalic acid molecule and one half of a tetrafluorophthalate anion. The cocrystal forms a supramolecular network with cooperative neutral and charge-assisted hydrogen bonding. In this, the linear network of alternating pyrazinium and tetrafluorophenyl moieties is crosslinked through bifurcated hydrogen bonds of two amino H atoms and a carboxyl oxygen to form a corrugated two-dimensional network.

Keywords: crystal structure; hydrogen bond; supramolecular network; pyrazinium; tetrafluorophthalic acid.

CCDC reference: 2531359

1. Chemical context

Hydrogen-bonded networks are well-established and rely on the choice of hydrogen-bond (HB) donors and HB acceptors capable of forming multiple HB's to facilitate formation of a desired network. Recent examples of this include the use of hydrogen-bonded supramolecular networks for the selective removal of perchlorate anion from aqueous media (Tian et al., 2025 ) and the application of hydrogen-bonding interactions to facilitate selective hydrogenation (Shi et al., 2023 ). Wang and coworkers investigated the formation of hydrogen-bonded supramolecular assemblies on cocrystallization with a series of aza compounds (Wang et al., 2013 ). Earlier we also reported on the cooperative charge-assisted N—H⋯O and C—H⋯N hydrogen bonding on cocrystals formed between tetrafluorobenzoic acid and 2-amino pyrazine (Bosch & Bowling, 2020 ). Here we report the cocrystallization of tetrafluorophthalic acid (TPA), formally a ditopic hydrogen-bond donor, with 2,3-diaminopyrazine (DAP), potentially a ditopic hydrogen-bond acceptor and hydrogen-bond donor, with the expectation that a linear supramolecular polymer would be formed. The 1:1 cocrystal comprises a more complex hydrogen-bonded network through neutral and charge-assisted hydrogen bonding.

2. Structural commentary

The cocrystal formed between 2,3,5,6-tetrafluoroterephthalic acid and 2,3-diaminopyrazine crystallized in the triclinic space group P $[\overline{1}]$ with one molecule of DAP and half of a TPA molecule along with one half of a deprotonated TPA molecule in the asymmetric unit as shown in Fig. 1. It is noteworthy that the C—O bond distances C9—O3 and C9—O4 are 1.257 (5) and 1.248 (5) Å respectively which is consistent with a phthalate moiety. Additionally, C—O bond distances for C5—O1 and C5—O2 are 1.305 (5) and 1.220 (5) Å respectively, consistent with the C—O single bond and double bond of phthalic acid. It is noteworthy that the carboxylate and the carboxylic acid moieties are both significantly twisted out of the plane of the tetrafluorobenzene rings at angles of 44.3 (4) and 45.0 (4)°, respectively. This rotation allows the carboxylic acid and carboxylate moieties to be almost coplanar with the central pyrazinium cation with torsional angles of only 6.5 (3) and 7.3 (2)°, respectively.

Figure 1
Labelled asymmetric unit of the cocrystal formed between DAP and TPA with hydrogen bonds shown as dashed lines. Displacement ellipsoids drawn at the 50% level.

The carboxylate moiety forms a charge-assisted bifurcated hydrogen bond to the pyrazinium hydrogen and the adjacent amine hydrogen H3A with O3⋯H1 and O3⋯H3A distances of 1.73 (3) and 2.30 (7) Å, respectively. This interaction has graph set notation R₂¹(6). In contrast the carboxyl moiety, as hydrogen bond donor and acceptor, forms two cooperative hydrogen bonds to the aminopyrazine moiety as complementary hydrogen bond acceptor and donor with graph-set notation of R₂²(8). The N2⋯H1A and O2⋯H4A separations are 1.60 (8) and 2.02 (6) Å, respectively. Complete details of these HB's and others in the structure are collated in Table 1.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯F2ⁱ	0.95	2.59	3.416 (5)	145
C4—H4⋯O2ⁱⁱ	0.95	2.61	3.307 (5)	130
N4—H4A⋯O2	0.96 (6)	2.02 (6)	2.980 (4)	175 (5)
N1—H1⋯O3	0.88 (2)	1.73 (3)	2.595 (4)	165 (7)
N4—H4B⋯O4ⁱⁱⁱ	0.94 (6)	1.88 (6)	2.814 (4)	177 (5)
N3—H3A⋯F3^iv	1.01 (7)	2.54 (7)	3.027 (4)	109 (5)
N3—H3A⋯O3	1.01 (7)	2.30 (7)	3.091 (4)	134 (5)
N3—H3A⋯F4^v	1.01 (7)	2.39 (7)	3.249 (4)	143 (6)
O1—H1A⋯N2	1.02 (8)	1.60 (8)	2.589 (4)	162 (7)
N3—H3B⋯O4ⁱⁱⁱ	0.96 (6)	1.89 (6)	2.855 (5)	174 (5)
Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

3. Supramolecular features

The two hydrogen-bond networks in Fig. 1, labelled A and B in Fig. 2, result in infinite linear chains of alternating tetrafluorophthalate–pyrazinium–tetrafluorophthalic acid–pyrazinium moieties. These chains are crosslinked through a bifurcated hydrogen bond from the second carboxylate O atom, O4, to a hydrogen from each of the amino groups, H3B and H4B, with graph set notation R₂¹(7). This is shown as C in Fig. 2 which shows the resultant two-dimensional network. The oxygen–hydrogen separations are 1.98 (6) and 1.88 (6) Å for O4⋯H3B and O4⋯H4A, respectively. This crosslinking sets up two larger hydrogen-bonded rings, D and E respectively, shown in Fig. 2 with graph set notation R₄⁴(22) and R₈⁸(40). There is a close C—H⋯O contact between H4 and O2 with an H⋯O separation of 2.61Å. The two-dimensional hydrogen-bonded network is a corrugated plane with the tetrafluorophenyl rings tilted with respect to the planes of the pyrazinium moieties (Fig. 3). Complete details of the HB's in the cocrystal structure are collated in Table 1.

Figure 2
View along the a axis of the cocrystal showing four adjacent strands within the extended hydrogen-bonded network to illustrate the crosslinking between adjacent strands. The two cyclic hydrogen-bonded motifs from Fig. 1

are labelled A and B. The crosslinking bifurcated hydrogen-bond motif is labelled C. The larger hydrogen-bonded rings are labelled D and E (see text).

Figure 3
View along (110) of a portion of the packing within the unit cell of the cocrystal showing a side view of three layers of the planar hydrogen-bonded network in Fig. 2

. illustrating the twist between the tetrafluorobenzene and pyrazinium moieties.

These planar hydrogen-bonded supramolecular networks are π-stacked as shown viewed along the line (110) in Fig. 3 with offset π-stacks of each of the three components. The tetrafluorophthalic acid and tetrafluorophthalate moieties are twisted out of the plane of the pyrazinium molecules to accommodate the fluorine atoms. The perpendicular distances between the offset stacks of pyrazinium, tetrafluorophthalic acid and tetrafluorophthalate molecules are 3.243 (2), 3.430 (2) and 3.429 (2) Å with slippages of 1.671, 1.242 and 1.245 Å, respectively.

The program CrystalExplorer21 (Spackman et al., 2021 ) was used to calculate and plot the Hirshfeld surface of each molecule within the cocrystal. The surface colouration is a visual representation of the intermolecular atom-to-atom separation as compared to the sum of the van der Waals radii with close contacts coloured red. Fig. 4 shows two views of the Hirshfeld surface of the pyrazinium molecule within the cocrystal. The adjacent molecules responsible for close contacts are correlated with hydrogen bonding interactions shown. The charge-assisted hydrogen-bond interaction is labelled ‘x’ in Fig. 4(a), the bifurcated interaction between O and the two NH₂ groups labelled ‘y’ and the two-pronged carboxylic acid hydrogen-bonding interaction is labelled ‘z’ [Fig. 4(b)].

Figure 4
Two views of the Hirshfeld surface for the pyrazinium cation within the cocrystal with d_norm mapped over the surface. Red areas indicate contacts significantly closer than the sum of the respective van der Waals radii. Dashed lines showing atom-to-atom close contacts. (a) the ‘x’ label shows the carboxylate pyrazinium H⋯O contact; (b) the ‘y’ corresponds to the carboxylate hydrogen bond to the two amino groups and ‘z’ corresponds to the two-pronged hydrogen bond of the carboxylic acid to the aminopyrazine.

Fingerprint analysis of the Hirshfeld surface of the pyrazinium cation allows the interactions to be separated according to the atom within the surface and the interacting atom outside the surface as shown in Fig. 5. In these plots the most common interactions are bright green and the least common interactions are dark blue. Thus in Fig. 5(a), which shows all atom-to-atom interactions, the most common interactions are centred in the area defined by atom-to-atom separation between 3.2 to 4.0 Å typical of π-stacked aromatics. The breakdown to H⋯O, H⋯H and H⋯F contacts, shown in Fig. 5(b), (c) and (d), highlights the closest contacts as H⋯O and N⋯H with the narrow spikes.

Figure 5
Two-dimensional fingerprint plots showing the contributions of the major interactions to the total Hirshfeld surface area of the pyrazinium moiety⋯F. The first atom listed in (b) to (d) corresponds to a pyrazinium atom.

Breakdown of these contacts element-to-element to the pyrazinium cation revealed that the H⋯O interaction dominated, corresponding to 27.8% of the surface area, while the N⋯H interaction corresponds to 11.0% of the surface area of the pyrazinium cation [Fig. 5(b) and (c)]. The breakdown of atom-to-atom interactions to the surface of the two tetrafluoro moieties, collated in Table 2, highlights the dominance of O⋯H hydrogen bonding especially the carboxylate oxygen atoms. The H⋯H interactions correspond to the π-stacked pyrazinium interactions.

Table 2
Fingerprint analysis for the pyrazinium cations within the cocrystal

Interaction	H⋯O^a	N⋯H	H⋯F	H⋯H	H⋯C	N⋯C
Percentage	27.8	11.0	13.7	22.0	9.8	8.1
(a) First element corresponds to an element within the pyrazinium cation, and the second element is the close atom outside of the pyrazinium cation Hirshfeld surface.

Similar fingerprint analysis of the Hirshfeld surface of each of the tetrafluorophthalate and tetrafluorophthalic acid moieties within the cocrystal was performed and the results are collated in Table 3. As expected, the O⋯H contribution is larger for the phthalate than the phthalic acid and dominates. F⋯F and C⋯C interactions correspond to π-stacked molecules, while the F⋯H interactions are interplanar molecular interactions.

Table 3
Fingerprint analysis for each of the tetrafluorophthalate and tetrafluorophthalic acid moieties within the cocrystal.

Interaction/Moiety	O⋯H^a	F⋯F	F⋯H	C⋯C	H⋯N
Tetrafluorophalate	33.2	19.9	14.6	10.8	–
Tetrafluorophthalic acid	18.2	19.0	10.2	10.0	6.5
(a) First element corresponds to an element within the tetrafluoro moiety Hirshfeld surface, and the second element is the close atom outside of the tetrafluorophenyl moiety Hirshfeld surface.

4. Database survey

A search of the Cambridge Structural Database (CSD, Version 6.0.1, Nov 2025; Groom et al., 2016 ) using Conquest (Version 2025.3.0, Build 466532; Bruno et al., 2002 ) for structures containing the 2,3-diaminopyrazine did not yield any structures. Indeed, there were only four structures that include the 2,3-diaminopyrazine core. These include a structure of the dicyano derivative 5,6-diaminopyrazine-2,3-dicarbonitrile (refcode NUZMON; Semenov et al., 2020 ) as well as three structures with substituted 2,3-diaminoquinoxaline core. Interestingly one of these structures (refcode DURSER; Yuan et al., 2020 ) is a 1:1 cocrystal salt formed between 2,3-diaminquinoxaline and benzene-1,3,5-tricarboxylic acid in which the quinoxaline is protonated and one carboxylic acid moiety deprotonated. A search of the database for organic only structures that include tetrafluorophthallate and tetrafluorophthallic acid yielded seven unique structures [refcodes AGIJEJ (Mali et al., 2023 ), HIQVUC (Xiao et al., 2023 ), REXMUE, REXNIT, REXNOZ (Wang et al., 2013), YOCZOH and YOCZUN (Wang et al., 2014 )]. The carboxylate C—O bond distances range from 1.212 to 1.273 Å with an average of 1.246 Å while the carboxylic acid C—O distances range from 1.285 to 1.306 Å with an average of 1.296 Å and C=O distances range from 1.196 to 1.214 Å with an average of 1.206 Å. The C—O distances reported herein are consistent with this data.

5. Synthesis and crystallization

2,3-Diaminopyrazine and 2,3,5,6-tetrafluoroterephthalic acid were used as supplied. An equimolar amount (0.1 mmol) of each component was added to a screw-capped vial and 4 mL of ethanol added and the solution was gently heated, resulting in the formation of a homogeneous mass of crystals after 2 weeks.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4. All hydrogen atoms were observed in the difference maps during refinement and added to C as riding atoms in geometrically idealized positions. The pyrazinium proton was restrained in the refinement with N—H = 0.87 (2) Å and with U_iso(H) = 1.2U_eq(N). The carboxylic acid proton was restrained in the refinement with O—H = 0.84 (2) Å and with U_iso(H) = 1.2U_eq(O). In the difference map of the final solution, the residual peaks correspond to a minor disorder component. Attempts to resolve this disorder with a free variable were unsuccessful.

Table 4
Experimental details

Crystal data
Chemical formula	2C₄H₇N₄⁺·C₈F₄O₄²⁻·C₈H₂F₄O₄
M_r	696.45
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	100
a, b, c (Å)	3.6482 (9), 6.851 (2), 24.959 (6)
α, β, γ (°)	88.125 (5), 88.452 (3), 86.426 (3)
V (Å³)	622.0 (3)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	0.18
Crystal size (mm)	0.47 × 0.40 × 0.10

Data collection
Diffractometer	Bruker APEXI CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.649, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	7403, 2824, 2661
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.647

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.086, 0.212, 1.21
No. of reflections	2824
No. of parameters	241
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)	0.96, −0.53
Computer programs: APEX2 and SAINT (Bruker, 2014 ), SHELXT2018/2 (Sheldrick, 2015a ), SHELXL2019/2 (Sheldrick, 2015b ) and X-SEED4 (Barbour, 2020 ).

Supporting information

CCDC reference: 2531359

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989026001581/jy2069sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989026001581/jy2069Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989026001581/jy2069Isup3.cdx

checkCIF report

Computing details top

(I) top

Crystal data top

2C₄H₇N₄⁺·C₈F₄O₄²⁻·C₈H₂F₄O₄	Z = 1
M_r = 696.45	F(000) = 352
Triclinic, P1	D_x = 1.859 Mg m⁻³
a = 3.6482 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 6.851 (2) Å	Cell parameters from 3862 reflections
c = 24.959 (6) Å	θ = 2.5–27.4°
α = 88.125 (5)°	µ = 0.18 mm⁻¹
β = 88.452 (3)°	T = 100 K
γ = 86.426 (3)°	Irregular block, clear colourless
V = 622.0 (3) Å³	0.47 × 0.40 × 0.10 mm

Data collection top

Bruker APEXI CCD diffractometer	2661 reflections with I > 2σ(I)
Detector resolution: 8.3660 pixels mm^-1	R_int = 0.022
φ and ω scans	θ_max = 27.4°, θ_min = 0.8°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −4→4
T_min = 0.649, T_max = 0.746	k = −8→8
7403 measured reflections	l = −32→32
2824 independent reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.086	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.212	w = 1/[σ²(F_o²) + (0.0607P)² + 3.3965P] where P = (F_o² + 2F_c²)/3
S = 1.21	(Δ/σ)_max < 0.001
2824 reflections	Δρ_max = 0.96 e Å⁻³
241 parameters	Δρ_min = −0.53 e Å⁻³
1 restraint

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
F1	−0.1924 (7)	0.3798 (3)	0.47161 (10)	0.0222 (6)
O1	0.3060 (9)	0.3062 (4)	0.38931 (12)	0.0220 (7)
N1	0.8293 (9)	0.6531 (5)	0.21239 (13)	0.0160 (7)
C1	0.6976 (10)	0.4784 (6)	0.20518 (15)	0.0138 (7)
F2	−0.3079 (8)	0.2526 (4)	0.57192 (10)	0.0242 (6)
O2	0.0792 (9)	0.0469 (5)	0.35073 (11)	0.0221 (7)
N2	0.5555 (9)	0.4571 (5)	0.30018 (13)	0.0161 (7)
C2	0.5525 (10)	0.3755 (6)	0.25301 (15)	0.0143 (7)
F3	1.1916 (6)	1.2914 (3)	0.06106 (9)	0.0153 (5)
O3	1.1367 (8)	0.7643 (4)	0.12248 (11)	0.0184 (6)
N3	0.7061 (10)	0.4043 (5)	0.15676 (14)	0.0180 (7)
C3	0.6878 (11)	0.6381 (6)	0.30526 (16)	0.0170 (8)
H3	0.684989	0.694550	0.339537	0.020*
F4	1.3660 (6)	1.3695 (3)	−0.04072 (9)	0.0145 (5)
O4	1.3969 (8)	1.0346 (4)	0.14728 (11)	0.0189 (6)
N4	0.4156 (10)	0.1996 (5)	0.24889 (14)	0.0166 (7)
C4	0.8238 (11)	0.7386 (6)	0.26166 (16)	0.0169 (8)
H4	0.912708	0.864770	0.265250	0.020*
C5	0.1481 (11)	0.1404 (6)	0.38960 (15)	0.0148 (7)
C6	0.0608 (11)	0.0680 (6)	0.44630 (15)	0.0154 (8)
C7	−0.0908 (11)	0.1937 (6)	0.48501 (15)	0.0167 (8)
C8	−0.1498 (11)	0.1265 (6)	0.53729 (15)	0.0168 (8)
C9	1.3066 (10)	0.9167 (5)	0.11367 (14)	0.0123 (7)
C10	1.4083 (9)	0.9592 (5)	0.05484 (13)	0.0092 (7)
C11	1.3511 (10)	1.1444 (5)	0.03174 (14)	0.0099 (7)
C12	1.4395 (10)	1.1867 (5)	−0.02154 (14)	0.0099 (7)
H4A	0.301 (16)	0.145 (8)	0.281 (2)	0.032 (15)*
H1	0.919 (19)	0.711 (9)	0.1833 (18)	0.06 (2)*
H4B	0.412 (16)	0.140 (8)	0.216 (2)	0.031 (14)*
H3A	0.79 (2)	0.494 (10)	0.127 (3)	0.06 (2)*
H1A	0.36 (2)	0.358 (11)	0.351 (3)	0.07 (2)*
H3B	0.613 (15)	0.278 (8)	0.152 (2)	0.028 (14)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.0313 (14)	0.0155 (12)	0.0203 (12)	−0.0040 (10)	−0.0026 (10)	−0.0021 (9)
O1	0.0314 (17)	0.0217 (15)	0.0140 (14)	−0.0128 (12)	−0.0002 (12)	0.0038 (11)
N1	0.0175 (16)	0.0169 (16)	0.0134 (15)	−0.0036 (12)	0.0005 (12)	0.0048 (12)
C1	0.0140 (18)	0.0150 (18)	0.0120 (17)	0.0024 (14)	0.0001 (13)	0.0011 (14)
F2	0.0352 (15)	0.0218 (13)	0.0158 (12)	−0.0024 (11)	0.0042 (10)	−0.0075 (10)
O2	0.0299 (17)	0.0268 (16)	0.0104 (13)	−0.0079 (13)	0.0010 (11)	−0.0028 (11)
N2	0.0172 (16)	0.0185 (16)	0.0122 (15)	−0.0004 (13)	0.0019 (12)	0.0021 (12)
C2	0.0119 (17)	0.0164 (18)	0.0142 (17)	−0.0011 (14)	−0.0005 (14)	0.0033 (14)
F3	0.0218 (12)	0.0115 (11)	0.0121 (10)	0.0038 (9)	0.0042 (9)	−0.0046 (8)
O3	0.0210 (14)	0.0193 (14)	0.0149 (13)	−0.0053 (11)	0.0029 (11)	0.0061 (11)
N3	0.0255 (18)	0.0158 (16)	0.0127 (15)	−0.0027 (13)	0.0042 (13)	0.0001 (12)
C3	0.0198 (19)	0.0178 (19)	0.0132 (18)	−0.0006 (15)	−0.0009 (15)	−0.0006 (14)
F4	0.0233 (12)	0.0063 (10)	0.0135 (10)	0.0012 (8)	0.0002 (9)	0.0034 (8)
O4	0.0254 (15)	0.0230 (15)	0.0088 (12)	−0.0024 (12)	−0.0010 (11)	−0.0031 (11)
N4	0.0235 (18)	0.0143 (16)	0.0123 (15)	−0.0043 (13)	0.0015 (13)	−0.0006 (12)
C4	0.0180 (19)	0.0149 (18)	0.0175 (19)	−0.0006 (14)	0.0005 (15)	0.0016 (14)
C5	0.0143 (18)	0.0190 (18)	0.0108 (17)	−0.0023 (14)	0.0015 (14)	0.0023 (14)
C6	0.0185 (19)	0.0205 (19)	0.0080 (16)	−0.0087 (15)	0.0003 (14)	−0.0008 (14)
C7	0.023 (2)	0.0159 (18)	0.0120 (17)	−0.0093 (15)	0.0001 (15)	−0.0010 (14)
C8	0.023 (2)	0.0171 (19)	0.0111 (17)	−0.0070 (15)	0.0007 (15)	−0.0046 (14)
C9	0.0130 (17)	0.0143 (17)	0.0093 (16)	0.0009 (13)	0.0010 (13)	0.0014 (13)
C10	0.0085 (15)	0.0137 (17)	0.0057 (15)	−0.0028 (13)	0.0005 (12)	−0.0003 (12)
C11	0.0109 (16)	0.0093 (16)	0.0097 (16)	−0.0010 (12)	0.0013 (13)	−0.0039 (12)
C12	0.0120 (16)	0.0072 (15)	0.0108 (16)	−0.0022 (12)	−0.0027 (13)	0.0026 (12)

Geometric parameters (Å, º) top

F1—C7	1.339 (5)	N3—H3B	0.96 (6)
O1—C5	1.305 (5)	C3—C4	1.367 (5)
O1—H1A	1.02 (8)	C3—H3	0.9500
N1—C1	1.336 (5)	F4—C12	1.340 (4)
N1—C4	1.378 (5)	O4—C9	1.248 (5)
N1—H1	0.88 (2)	N4—H4A	0.96 (6)
C1—N3	1.325 (5)	N4—H4B	0.94 (6)
C1—C2	1.470 (5)	C4—H4	0.9500
F2—C8	1.336 (5)	C5—C6	1.516 (5)
O2—C5	1.220 (5)	C6—C7	1.396 (6)
N2—C2	1.320 (5)	C6—C8ⁱ	1.403 (6)
N2—C3	1.369 (5)	C7—C8	1.385 (5)
C2—N4	1.341 (5)	C9—C10	1.528 (5)
F3—C11	1.357 (4)	C10—C11	1.383 (5)
O3—C9	1.257 (5)	C10—C12ⁱⁱ	1.399 (5)
N3—H3A	1.01 (7)	C11—C12	1.386 (5)

C5—O1—H1A	112 (5)	O2—C5—C6	121.6 (3)
C1—N1—C4	122.7 (3)	O1—C5—C6	111.4 (3)
C1—N1—H1	115 (5)	C7—C6—C8ⁱ	117.2 (3)
C4—N1—H1	122 (5)	C7—C6—C5	121.7 (4)
N3—C1—N1	120.1 (3)	C8ⁱ—C6—C5	121.0 (4)
N3—C1—C2	123.0 (4)	F1—C7—C8	119.1 (4)
N1—C1—C2	116.9 (3)	F1—C7—C6	120.2 (3)
C2—N2—C3	121.0 (3)	C8—C7—C6	120.6 (4)
N2—C2—N4	119.9 (3)	F2—C8—C7	117.6 (4)
N2—C2—C1	119.8 (3)	F2—C8—C6ⁱ	120.2 (3)
N4—C2—C1	120.3 (3)	C7—C8—C6ⁱ	122.1 (4)
C1—N3—H3A	115 (4)	O4—C9—O3	127.3 (3)
C1—N3—H3B	120 (3)	O4—C9—C10	117.6 (3)
H3A—N3—H3B	124 (5)	O3—C9—C10	115.0 (3)
C4—C3—N2	120.9 (4)	C11—C10—C12ⁱⁱ	116.6 (3)
C4—C3—H3	119.6	C11—C10—C9	121.4 (3)
N2—C3—H3	119.6	C12ⁱⁱ—C10—C9	122.0 (3)
C2—N4—H4A	117 (3)	F3—C11—C10	119.9 (3)
C2—N4—H4B	121 (3)	F3—C11—C12	117.5 (3)
H4A—N4—H4B	122 (5)	C10—C11—C12	122.5 (3)
C3—C4—N1	118.7 (4)	F4—C12—C11	118.3 (3)
C3—C4—H4	120.7	F4—C12—C10ⁱⁱ	120.9 (3)
N1—C4—H4	120.7	C11—C12—C10ⁱⁱ	120.8 (3)
O2—C5—O1	126.9 (4)

C4—N1—C1—N3	179.2 (4)	C5—C6—C7—C8	−176.5 (4)
C4—N1—C1—C2	−1.7 (6)	F1—C7—C8—F2	0.2 (6)
C3—N2—C2—N4	−178.8 (4)	C6—C7—C8—F2	−177.7 (3)
C3—N2—C2—C1	0.8 (6)	F1—C7—C8—C6ⁱ	178.0 (4)
N3—C1—C2—N2	179.4 (4)	C6—C7—C8—C6ⁱ	0.1 (7)
N1—C1—C2—N2	0.3 (5)	O4—C9—C10—C11	−45.5 (5)
N3—C1—C2—N4	−1.0 (6)	O3—C9—C10—C11	134.2 (4)
N1—C1—C2—N4	180.0 (4)	O4—C9—C10—C12ⁱⁱ	135.1 (4)
C2—N2—C3—C4	−0.6 (6)	O3—C9—C10—C12ⁱⁱ	−45.3 (5)
N2—C3—C4—N1	−0.7 (6)	C12ⁱⁱ—C10—C11—F3	177.5 (3)
C1—N1—C4—C3	2.0 (6)	C9—C10—C11—F3	−2.0 (5)
O2—C5—C6—C7	−137.7 (4)	C12ⁱⁱ—C10—C11—C12	−0.3 (6)
O1—C5—C6—C7	43.6 (5)	C9—C10—C11—C12	−179.7 (3)
O2—C5—C6—C8ⁱ	46.1 (6)	F3—C11—C12—F4	0.6 (5)
O1—C5—C6—C8ⁱ	−132.6 (4)	C10—C11—C12—F4	178.4 (3)
C8ⁱ—C6—C7—F1	−177.9 (3)	F3—C11—C12—C10ⁱⁱ	−177.5 (3)
C5—C6—C7—F1	5.7 (6)	C10—C11—C12—C10ⁱⁱ	0.3 (6)
C8ⁱ—C6—C7—C8	−0.1 (6)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···F2ⁱⁱⁱ	0.95	2.59	3.416 (5)	145
C4—H4···O2^iv	0.95	2.61	3.307 (5)	130
N4—H4A···O2	0.96 (6)	2.02 (6)	2.980 (4)	175 (5)
N1—H1···O3	0.88 (2)	1.73 (3)	2.595 (4)	165 (7)
N4—H4B···O4^v	0.94 (6)	1.88 (6)	2.814 (4)	177 (5)
N3—H3A···F3^vi	1.01 (7)	2.54 (7)	3.027 (4)	109 (5)
N3—H3A···O3	1.01 (7)	2.30 (7)	3.091 (4)	134 (5)
N3—H3A···F4^vii	1.01 (7)	2.39 (7)	3.249 (4)	143 (6)
O1—H1A···N2	1.02 (8)	1.60 (8)	2.589 (4)	162 (7)
N3—H3B···O4^v	0.96 (6)	1.89 (6)	2.855 (5)	174 (5)

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

Fingerprint analysis for the pyrazinium cations within the cocrystal top

Interaction	H···O^a	N···H	H···F	H···H	H···C	N···C
Percentage	27.8	11.0	13.7	22.0	9.8	8.1

(a) First element corresponds to an element within the pyrazinium cation, and the second element is the close atom outside of the pyrazinium cation Hirshfeld surface.

Fingerprint analysis for each of the tetrafluorophthallate and tetrafluorophthalic acid moieties within the cocrystal. top

Interaction/Moiety	O···H^a	F···F	F···H	C···C	H···N
Tetrafluorophallate	33.2	19.9	14.6	10.8	–
Tetrafluorophthalic acid	18.2	19.0	10.2	10.0	6.5

(a) First element corresponds to an element within tetrafluoro moiety Hirshfeld surface, and the second element is the close atom outside of the tetrafluorophenyl moiety Hirshfeld surface.

Acknowledgements

EB acknowledges the Missouri State University Provost Incentive Fund for the purchase of the X-ray diffractometer used in this contribution.

Funding information

Funding for this research was provided by: National Science Foundation (grant No. CHE1606556).

References

Barbour, L. J. (2020). J. Appl. Cryst. 53, 1141–1146. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bosch, E. & Bowling, N. P. (2020). Cryst. Growth Des. 20, 1565–1571. CrossRef Google Scholar
Bruker (2014). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389–397. Web of Science CrossRef CAS IUCr Journals Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Mali, B. P., Dash, S. R., Annadhasan, M., Biswas, A., Manoj, K., Vanka, K. & Gonnade R. G. (2023). Cryst. Growth Des. 23, 5052–5065. CrossRef Google Scholar
Semenov, N. A., Radiush, E. A., Chulanova, E. A., Slawin, A. M. Z., Woollins, J. D., Kadilenko, E. M., Bagryanskaya, I. Y., Irtegova, I. G., Bogomyakov, A. S., Shindrin, L. A., Gritsan, N. P. & Zibarev, A. V. (2020). CSD Communication (refcode NUZMON). CCDC, Cambridge, England. Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Shi, S., Yang, P., Dun, C., Zheng, W., Urban, J. J. & Vlachos, D. G. (2023). Nat. Commun. 14, 429. CrossRef PubMed Google Scholar
Spackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006–1011. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tian, J., Han, X., Yang, H. R., Liu, J., Chen, J. F., Wei, T. B., Yao, H., Qu, W. J., Shi, B. & Lin, Q. (2025). Nat. Commun. 16, 6481. CrossRef PubMed Google Scholar
Wang, L., Hu, Y., Wang, W., Liu, F. & Huang, K. (2014). CrystEngComm 16, 4142–4161. CrossRef Google Scholar
Wang, L., Zhao, L., Hu, Y., Wang, W., Chen, R. & Yang, Y. (2013). CrystEngComm 15, 2835–2852. CrossRef Google Scholar
Xiao, G., Ma, Y. J., Fang, X., Xu, C. & Yan, D. (2023). Chem. Commun. 59, 10113–10116. CrossRef Google Scholar
Yuan, Y., Lo, K. C., Szeto, L. & Chan, W. K. (2020). J. Org. Chem. 85, 6372–6379. CrossRef PubMed Google Scholar

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