A new tetra­kis-substituted pyrazine carb­oxy­lic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetra­yltetra­kis(methyl­ene)]tetra­kis­(sulfanedi­yl)}tetra­propionic acid: crystal structures of two triclinic polymorphs and of two potassium–organic frameworks

Pacifico, J.; Stoeckli-Evans, H.

doi:10.1107/S2056989021003479

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Volume 77| Part 5| May 2021| Pages 480-490

https://doi.org/10.1107/S2056989021003479

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A new tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetrapropionic acid: crystal structures of two triclinic polymorphs and of two potassium–organic frameworks

Jessica Pacifico ^a and Helen Stoeckli-Evans ^b ^*

^aInstitute of Chemistry, University of Neuchâtel, Av. de Bellevaux 51, CH-2000 Neuchâtel, Switzerland, and ^bInstitute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
^*Correspondence e-mail: helen.stoeckli-evans@unine.ch

Edited by S. Parkin, University of Kentucky, USA (Received 22 March 2021; accepted 1 April 2021; online 9 April 2021)

Two polymorphs of the title tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl]}tetrapropionic acid, C₂₀H₂₈N₂O₈S₄, (H₄L1), have been obtained, H₄L1_A and H₄L1_B. Each structure crystallized with half a molecule in the asymmetric unit of a triclinic P $[\overline{1}]$ unit cell. The whole molecules are generated by inversion symmetry, with the pyrazine rings being located about inversion centers. The crystals of H₄L1_B were of poor quality, but the X-ray diffraction analysis does show the change in conformation of the –CH₂—S—CH₂—CH₂– side chains compared to those in polymorph H₄L1_A. In the crystal of H₄L1_A, molecules are linked by two pairs of O—H⋯O hydrogen bonds, enclosing R²₂(8) ring motifs forming layers parallel to plane (100), which are linked by C—H⋯O hydrogen bonds to form a supramolecular framework. In the crystal of H₄L1_B, molecules are also linked by two pairs of O—H⋯O hydrogen bonds enclosing R²₂(8) ring motifs, however here, chains are formed propagating in the [001] direction and stacking up the a-axis. Reaction of H₄L1 with Hg(NO₃)₂ in the presence of a potassium acetate buffer did not produce the expected binuclear complex, instead crystals of a potassium–organic framework were obtained, poly[(μ-3-{[(3,5,6-tris{[(2-carboxyethyl)sulfanyl]methyl}pyrazin-2-yl)methyl]sulfanyl}propanoato)potassium], [K(C₂₀H₂₇N₂O₈S₄)]_n (KH₃L1). The organic mono-anion possesses inversion symmetry with the pyrazine ring being located about an inversion center. A carboxy H atom is disordered by symmetry and the charge is compensated for by a potassium ion. A similar reaction with Zn(NO₃)₂ resulted in the formation of crystals of a dipotassium-organic framework, poly[(μ-3,3′-{[(3,6-bis{[(2-carboxyethyl)sulfanyl]methyl}pyrazine-2,5-diyl)bis(methylene)]bis(sulfanediyl)}dipropionato)dipotassium], [K₂(C₂₀H₂₆N₂O₈S₄)]_n (K₂H₂L1). Here, the organic di-anion possesses inversion symmetry with the pyrazine ring being located about an inversion center. Two symmetry-related acid groups are deprotonated and the charges are compensated for by two potassium ions.

Keywords: crystal structure; pyrazine; tetrakis; carboxylate; polymorphism; hydrogen bonding; supramolecular framework; alkali metal; potassium-organic framework; Hirshfeld surface; energy framework.

CCDC references: 2074770; 2074769; 2074768; 2074767

1. Chemical context

The title tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-[(pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl)]tetrapropionic acid (H₄L1), is to the best of our knowledge, only the third pyrazine tetrakis-substituted carboxylic acid ligand to have been synthesized. The first is pyrazine-2,3,5,6-tetracarboxylic acid (pztca), which was originally synthesized by Wolff at the end of the 19th century (Wolff, 1887 , 1893 ), while the second is 4,4′,4′′,4′′′-(pyrazine-2,3,5,6-tetrayl)tetrabenzoic acid (pztba), which was first synthesized by Jiang et al. (2017 ). Pztca (Fig. 1) has been used to synthesize a number of coordination polymers, the first being poly{[(2,5-dicarboxypyrazine-3,6-dicarboxylato)transdiaquairon(II) dihydrate]} (Marioni et al., 1986 ), while pztba (Fig. 1) has been shown to form a series of metal–organic frameworks (Jiang et al., 2017; Wang et al., 2019 ).

Figure 1
Chemical diagrams for pyrazine-2,3,5,6-tetracarboxylic acid (pztca), 4,4′,4′′,4′′′-(pyrazine-2,3,5,6-tetrayl)tetrabenzoic acid (pztba), pyrazine-2,3-dicarboxylic acid (pzdca) and pyridine-2,6-dicarboxylic acid (pydca).

The title ligand was synthesized to study its coordination behaviour with various transition metal ions (Pacifico, 2003 ). Potentially the ligand can coordinate in a bis-pentadentate manner, as was shown to be the case for a similar ligand, 2,2′,2′′,2′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetrakis(ethan-1-amine) (H₄L2), for which two nickel(II) binuclear complexes, I and II, were synthesized (Pacifico, 2003; Pacifico & Stoeckli-Evans, 2020 ); see Fig. 2.

Figure 2
Chemical diagram for 2,2′,2′′,2′′′-[(pyrazine-2,3,5,6-tetrayltetrakis(methylene)tetrakis(sulfanediyl)]tetrakis(ethan-1-amine) (H₄L2) and two nickel(II) binuclear complexes, I and II (Pacifico & Stoeckli-Evans, 2020

2. Structural commentary

The title tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-[(pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl)]tetrapropionic acid (H₄L1_A), crystallized with half a molecule in the asymmetric unit (Fig. 3). The whole molecule is generated by inversion symmetry, with the pyrazine ring being located about an inversion center.

Figure 3
The molecular structure of H₄L1_A, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. Unlabelled atoms are related to labelled atoms by symmetry operator −x + 2, −y + 1, −z + 1.

In an attempt to form a co-crystal, equimolar amounts of H₄L1 and terephthalic acid were mixed in methanol. On slow evaporation of the solvent, colourless plate-like crystals were obtained. X-ray diffraction analysis revealed their structure to be that of a second triclinic P $[\overline{1}]$ polymorph, H₄L1_B (Fig. 4). It crystallized with half a molecule in the asymmetric unit and the whole molecule is generated by inversion symmetry, with the pyrazine ring being located about an inversion center. The crystals were of poor quality with one CH₂—CH₂—CO₂H side chain (atoms C8/C8B, C9/C9B, C10/C10B, O3/O3B, O4/O4B) of the centrosymmetric molecule being positionally disordered (Fig. 4b). The difference in the two polymorphs is essentially in the orientation of the –CH₂—S—CH₂—CH₂—C– side arms, as shown in Fig. 5a and b. Selected torsion angles are given in Table 1.

Table 1
Selected torsion angles (°) along the C_ar—CH₂—S—CH₂—CH₂—CO₂H side chains in compounds H₄L1_A, H₄L1_B, KH₃L1 and K₂H₂L1

Torsion angle	H₄L1_A	H₄L1_B	KH₃L1	K₂H₂L1
C1—C3—S1—C4	174.1 (2)	−72.6 (4)	−72.32)	−65.81 (15)
C3—S1—C4—C5	−155.3 (2)	−86.7 (4)	−90.3 (2)	−87.72 (15)
S1—C4—C5—C6	−167.9 (2)	−65.0 (6)	−76.4 (3)	−73.19 (18)
C2—C7—S2—C8	57.6 (2)	−66.8 (4)	−62.3 (2)	−67.34 (15)
C7—S2—C8—C9	65.7 (2)	−178.1 (5)	−77.5 (2)	97.89 (15)
S2—C8—C9—C10	174.8 (2)	−172.5 (5)	−173.8 (2)	174.51 (12)

Figure 4
(a) The molecular structure of H₄L1_B, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. (b) A view of the molecular structure of H₄L1_B with the symmetry-related disordered side chains (C8/C8B, C9/C9B, C10/C10B, O3/O3B and O4/O4B) shown with dashed bonds. Unlabelled atoms are related to labelled atoms by symmetry operator −x + 2, −y + 1, −z + 1.

Figure 5
A comparison of the orientation of the –CH₂—S—CH₂—CH₂– side chains in (a) polymorph H₄L1_A, (b) for the major disordered component of polymorph H₄L1_B, (c) KH₃L1 and (d) K₂H₂L1 [see Table 1

for further details; symmetry codes: (i) = (ii) −x + 2, −y + 1, −z + 1; (iii) −x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z; (iv) −x + $[{1\over 2}]$ , −y + $[{5\over 2}]$ , −z + 1].

Reaction of H₄L1 with Hg(NO₃)₂ in the presence a 1 M potassium acetate buffer led to the formation of colourless crystals that proved to be a potassium–organic framework (KH₃L1); see Fig. 6. The asymmetric unit consists of half a mono-deprotonated ligand molecule located about an inversion center, and half a potassium ion located on an inversion center. The carboxy H atom is disordered by symmetry. The K⁺ ion is linked to the O atoms of the acid groups and has a coordination number of eight (KO₈) and a distorted dodecahedral geometry (Fig. 7a). The K⋯O bond lengths vary between 2.682 (2) and 3.069 (3) Å (Table 2). Interestingly, here there is a significant difference between the K⋯O(C=O) and K⋯O(O⁻) distances: 2.6823 (2) and 2.828 (2) Å compared to 3.056 (3) and 3.069 (3) Å, respectively.

Table 2
Selected bond lengths (Å) for KH₃L1

K1—O1	2.828 (2)	K1—O3ⁱⁱ	2.682 (2)
K1—O2ⁱ	3.056 (3)	K1—O4ⁱⁱⁱ	3.069 (3)
Symmetry codes: (i) $[x, -y, z-{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z-{\script{1\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

Figure 6
The molecular structure of complex KH₃L1, with labels for the atoms in the asymmetric unit of the organic anion. Unlabelled atoms are related to labelled atoms by symmetry operator (i) −x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z. Displacement ellipsoids are drawn at the 50% probability level. [Further symmetry codes are: (ii) −x + 1, −y, −z: (iii) x, y + 1, z; (iv) x, y, z + 1; (v) −x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z − 1; (vi) x − $[{1\over 2}]$ , y + $[{1\over 2}]$ , z; (vii) −x + $[{1\over 2}]$ , −y − $[{1\over 2}]$ , −z.]

Figure 7
(a) Views of the coordination sphere of the potassium ion in KH₃L1 [symmetry code: (i) −x + 1, y, −z − $[{1\over 2}]$ ] and (b) views of the coordination sphere of the potassium ions in K₂H₂L1 [symmetry codes: (i) −x, y, −z + $[{3\over 2}]$ ; (ii) x, y − 1, z; (iii) x, y + 1, z; (iv) −x, y + 1, −z + $[{3\over 2}]$ ].

Reaction of H₄L1 with Zn(NO₃)₂ in the presence of a 1 M potassium acetate buffer led to the formation of colourless crystals that proved to be a dipotassium–organic framework (K₂H₂L1); see Fig. 8. The asymmetric unit consists of half a di-deprotonated ligand molecule located about an inversion center, and two half potassium ions located on inversion centers. The K⁺ ions are linked to the O atoms of the acid groups and both K⁺ ions have a coordination number of six (KO₆) and have edge-sharing bipyramidal geometries. The K⁺ ions are bridged by atoms O1 and O3, forming chains propagating along the b-axis direction (Fig. 7b). The K⋯O bond lengths vary between 2.6682 (12) and 2.8099 (14) Å (Table 3). Here, the difference between the K⋯O(C=O) and K⋯O(O⁻) bond lengths is much less significant (Table 3).

Table 3
Selected bond lengths (Å) for K₂H₂L1

K1—O1ⁱ	2.7084 (14)	K2—O1	2.7132 (13)
K1—O2	2.6682 (12)	K2—O3ⁱⁱⁱ	2.6682 (13)
K1—O3ⁱⁱ	2.8099 (14)	K2—O4ⁱⁱ	2.7209 (12)
Symmetry codes: (i) $[x, -y+2, z+{\script{1\over 2}}]$ ; (ii) $[x-{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (iii) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ .

Figure 8
The molecular structure of complex K₂H₂L1, with labels for the atoms in the asymmetric unit of the organic dianion. Unlabelled atoms are related to labelled atoms by symmetry operator (i) −x + $[{1\over 2}]$ , −y + $[{5\over 2}]$ , −z + 1. Displacement ellipsoids are drawn at the 50% probability level. [Further symmetry codes are: (ii) −x, −y + 2, −z + 1; (iii) x, y + 1, z; (iv) x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , z; (v) −x + $[{1\over 2}]$ , −y + $[{3\over 2}]$ , −z + 1; (vi) x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , z.]

The K⋯O bond lengths in the KH₃L1 and K₂H₂L1 frameworks are close to those observed for similar compounds; see §6 Database survey. The conformation of one of the –CH₂—S—CH₂—CH₂– side chains (involving atom S1) of the organic anion are similar, and similar to that in H₄L1_B (Fig. 5b), while the conformation of the second (involving atom S2) differs significantly (Fig. 5c and d, and Table 1).

3. Supramolecular features

In the crystal of H₄L1_A, molecules are linked by pairs of O—H⋯O hydrogen bonds, forming classical carboxylic acid inversion dimers enclosing R₂²(8) loops (Fig. 9 and Table 4). These interactions lead to the formation of layers lying parallel to the bc plane. The layers are linked by C—H⋯O hydrogen bonds (Table 4), forming a supramolecular framework.

Table 4
Hydrogen-bond geometry (Å, °) for H₄L1_A

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2O⋯O1ⁱ	0.87 (2)	1.80 (2)	2.667 (3)	172 (5)
O4—H4O⋯O3ⁱⁱ	0.83 (2)	1.85 (2)	2.673 (3)	175 (5)
C5—H5A⋯O3ⁱⁱⁱ	0.97	2.55	3.405 (4)	147
C8—H8A⋯O4^iv	0.97	2.40	3.308 (4)	156
Symmetry codes: (i) ; (ii) ; (iii) ; (iv) x+1, y, z.

Figure 9
A view along the a axis of the crystal packing of H₄L1_A. The hydrogen bonds are shown as dashed lines (see Table 4

In the crystal of H₄L1_B, molecules are linked by pairs of O—H⋯O hydrogen bonds, forming chains propagating along the c-axis direction and enclosing R₂²(8) loops (Fig. 10 and Table 5). There are no other significant directional contacts present in the crystal.

Table 5
Hydrogen-bond geometry (Å, °) for H₄L1_B

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2O⋯O3ⁱ	0.82	1.94	2.66 (1)	146
O2—H2O⋯O3Bⁱ	0.82	2.20	2.77 (3)	127
O4—H4O⋯O1ⁱⁱ	0.82	1.88	2.66 (1)	158
O4B—H4OB⋯O1ⁱⁱ	0.82	1.86	2.67 (4)	170
Symmetry codes: (i) x, y, z+1; (ii) .

Figure 10
A view along the a-axis of the crystal packing of H₄L1_B. Only atoms of the major component are shown. The hydrogen bonds are shown as dashed lines (see Table 5

In both KH₃L1 and K₂H₂L1, the organic anions are arranged as rungs of parallel ladders, so forming the framework structures, as shown in Figs. 11 and 12, respectively. The frameworks are reinforced by O—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds (Tables 6 and 7, respectively).

Table 6
Hydrogen-bond geometry (Å, °) for KH₃L1

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4O⋯O1^iv	0.80 (5)	1.86 (5)	2.661 (3)	180 (7)
O2—H20⋯O2^v	1.24 (1)	1.24 (1)	2.436 (3)	159 (7)
C4—H4A⋯N1	0.99	2.52	3.340 (4)	140
C4—H4B⋯O3^vi	0.99	2.49	3.114 (4)	121
C5—H5B⋯O2ⁱ	0.99	2.60	3.467 (4)	146
C7—H7B⋯N1^vii	0.99	2.60	3.454 (4)	144
C9—H9A⋯O3^vii	0.99	2.58	3.465 (4)	149
Symmetry codes: (i) $[x, -y, z-{\script{1\over 2}}]$ ; (iv) $[x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (v) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (vi) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]$ ; (vii) $[x, -y, z+{\script{1\over 2}}]$ .

Table 7
Hydrogen-bond geometry (Å, °) for K₂H₂L1

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4O⋯O2^iv	0.85 (2)	1.61 (2)	2.4637 (16)	177 (3)
C4—H4A⋯N1	0.99	2.44	3.266 (2)	141
C8—H8A⋯O3^v	0.99	2.53	3.436 (2)	151
Symmetry codes: (iv) $[x+{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (v) $[x, -y+2, z-{\script{1\over 2}}]$ .

Figure 11
A view along the b axis of the crystal packing of complex KH₃L1. For clarity, the H atoms have been omitted.

Figure 12
A view along the b axis of the crystal packing of complex K₂H₂L1. For clarity, the H atoms have been omitted.

4. Hirshfeld surface analysis and two-dimensional fingerprint plots for H₄L1_A, and H₄L1_B

The Hirshfeld surface analysis (Spackman & Jayatilaka, 2009 ) and the associated two-dimensional fingerprint plots (McKinnon et al., 2007 ) were performed with CrystalExplorer17 (Turner et al., 2017 ) following the protocol of Tiekink and collaborators (Tan et al., 2019 ).

The Hirshfeld surfaces are colour-mapped with the normalized contact distance, d_norm, varying from red (distances shorter than the sum of the van der Waals radii) through white to blue (distances longer than the sum of the van der Waals radii). The Hirshfeld surfaces (HS) of H₄L1_A, and H₄L1_B mapped over d_norm are given in Fig. 13. The most significant short contacts in the crystal structures of the two polymorphs are given in Table 8. The large red spots in Fig. 13a and b concern the O—H⋯O hydrogen bonds in the crystal structures of both compounds.

Table 8
Short contacts (Å) in the crystal structures of H₄L1_A and H₄L1_B^a

Atom 1	Atom 2	Length	Length − VdW	Symm. op. 1	Symm. op. 2
H₄L1_A
O1	H2O	1.798	−0.922	x, y, z	−1 − x, −y, −z
O3	H4O	1.843	−0.877	x, y, z	1 − x, 1 − y, −z
O1	O2	2.667	−0.373	x, y, z	−1 − x, −y, −z
O3	O4	2.673	−0.367	x, y, z	1 − x, 1 − y, −z
O4	H8A	2.399	−0.321	x, y, z	−1 + x, y, z
O2	O4	3.015	−0.025	x, y, z	−x, 1 − y, −z
C6	H2O	2.667	−0.233	x, y, z	−1 − x, −y, −z
C10	H4O	2.668	−0.232	x, y, z	1 − x, 1 − y, −z
H5A	O3	2.549	−0.171	x, y, z	−1 + x, y, z
H4O	H4O	2.371	−0.029	x, y, z	1 − x, 1 − y, −z
H2O	H2O	2.389	−0.011	x, y, z	−1 − x, −y, −z
N1	H3A	2.807	0.057	x, y, z	1 − x, 1 − y, 1 − z
O4	C8	3.308	0.088	x, y, z	−1 + x, y, z
O2	H8A	2.820	0.100	x, y, z	1 − x, 1 − y, −z

H₄L1_B^a
H4O	O1	1.879	−0.841	x, y, z	x, y, −1 + z
O4	O1	2.658	−0.382	x, y, z	x, y, −1 + z
O3	O2	2.663	−0.377	x, y, z	x, y, −1 + z
H4O	C6	2.580	−0.320	x, y, z	x, y, −1 + z
O4	O2	2.799	−0.241	x, y, z	−1 + x, y, −1 + z
H4O	H2O	2.173	−0.227	x, y, z	x, y, −1 + z
O1	O2	2.982	−0.058	x, y, z	−1 + x, y, z
S1	H3A	2.951	−0.049	x, y, z	−1 + x, y, z
S1	S2	3.590	−0.010	x, y, z	1 − x, −y, 1 − z
O4	O3	3.041	0.001	x, y, z	−1 + x, y, z
S2	S2	3.613	0.013	x, y, z	1 − x, −y, 1 − z
H8A	O3	2.749	0.029	x, y, z	−1 + x, y, z
S1	H5A	3.047	0.047	x, y, z	−1 + x, y, z
H4O	O2	2.775	0.055	x, y, z	−1 + x, y, −1 + z
O4	H2O	2.776	0.056	x, y, z	−1 + x, y, −1 + z
C10	H2O	2.960	0.060	x, y, z	2 − x, −y, 1 − z
O3	H2O	2.796	0.076	x, y, z	2 − x, −y, 1 − z
H7B	C3	2.974	0.074	x, y, z	−1 + x, y, z
S2	H7B	3.082	0.082	x, y, z	1 − x, −y, 1 − z
O2	H5B	2.802	0.082	2 − x, 1 − y, 1 − z	−1 + x, y, −1 + z
S1	H9A	3.085	0.085	x, y, z	1 − x, −y, 1 − z
Note: (a) major component of H₄L1_B.

Figure 13
The Hirshfeld surfaces of compounds (a) H₄L1_A and (b) H₄L1_B, mapped over d_norm in the colour ranges of −0.7146 to 1.2167 and −0.6847 to 1.3548 au., respectively.

The percentage contributions of inter-atomic contacts to the HS for both compounds are compared in Table 9. The two-dimensional fingerprint plots for compounds H₄L1_A, and H₄L1_B are shown in Fig. 14. They reveal that the principal contributions to the overall HS involve H⋯H contacts at 37.2 and 36.3%, respectively, and O⋯H/H⋯O contacts at, respectively, 37.7 and 32.2%.

Table 9
Percentage contributions of inter-atomic contacts to the Hirshfeld surfaces of H₄L1_A and H₄L1_B^a

Contact	% contribution	% contribution
	H₄L1_A	H₄L1_B^a
H⋯H	37.2	36.3
O⋯H/H⋯O	37.7	32.2
S⋯H/H⋯S	13.4	16.1
C⋯H/H⋯C	4.5	4.9
N⋯H/H⋯N	3.0	2.5
C⋯N	0	0.8
C⋯O	1.0	0.7
C⋯S	1.2	0
N⋯S	0.4	0.4
O⋯O	1.3	4.9
O⋯S	0.2	0
S⋯S	0.2	1.2
Note: (a) major component of H₄L1_B.

Figure 14
The full two-dimensional fingerprint plots for compounds (a) H₄L1_A and (b) H₄L1_B, and those delineated into H⋯H, O⋯H/H⋯O and S⋯H/H⋯S contacts.

The third most important contribution to the HS is from the S⋯H/H⋯S contacts at 13.4 and 16.1%, for H₄L1_A, and H₄L1_B, respectively. These are followed by C⋯H/H⋯H contacts at, respectively, 4.5 and 4.9%. The N⋯H/H⋯N contacts contribute, respectively, 3.0 and 2.5%.

5. Energies frameworks for H₄L1_A, and H₄L1_B

The colour-coded interaction mappings within a radius of 6 Å of a central reference molecule for H₄L1_A, and H₄L1_B, are given in Fig. 15. Full details of the various contributions to the total energy (E_tot) are also included there; see Tan et al. (2019) for an explanation of the various parameters.

Figure 15
The colour-coded interaction mappings within a radius of 6 Å of a central reference molecule for (a) H₄L1_A and (b) H₄L1_B.

A comparison of the energy frameworks calculated for H₄L1_A, and H₄L1_B, showing the electrostatic potential forces (E_ele), the dispersion forces (E_dis) and the total energy diagrams (E_tot), are shown in Fig. 16. The energies were obtained by using the wave function at the HF/3-21G level of theory. The cylindrical radii are proportional to the relative strength of the corresponding energies (Turner et al., 2017; Tan et al., 2019). They have been adjusted to the same scale factor of 80 with a cut-off value of 5 kJ mol⁻¹ within a radius of 6 Å of a central reference molecule. It can be seen that for both polymorphs the major contribution to the intermolecular interactions is from electrostatic potential forces (E_ele), reflecting the presence of the classical O—H⋯O hydrogen bonds.

Figure 16
The energy frameworks calculated for (a) H₄L1_A and (b) H₄L1_B, both viewed along the b-axis direction, showing the electrostatic potential forces (E_ele), the dispersion forces (E_dis) and the total energy diagrams (E_tot).

6. Database survey

A search of the Cambridge Structural Database (CSD, Version 5.42, last update February 2021; Groom et al., 2016 ) for tetrakis-substituted pyrazine carboxylic acids gave results for only two such ligands, viz. 2,3,5,6-pyrazinetetracarboxylic acid (pztca) and 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (pztba). Ligand pztba has been shown to be extremely successful in forming metal–organic frameworks (Jiang et al., 2017; Wang et al., 2019).

Potassium salts of carboxylic acids are relatively common. A search for potassium salts of purely organic carboxylic acids and excluding hydrates, yielded over 200 hits. The potassium salt of pztca has been reported, viz. catena-[(μ₄-3,5,6-tricarboxypyrazine-2-carboxylato)potassium] (CSD refcode UBUPAK; Masci et al., 2010 ). The structure of UBUPAK is that of a potassium–organic framework (Fig. 17a). The asymmetric unit consists of half a mono-deprotonated ligand molecule located about an inversion center, and half a potassium ion. The carboxy H atom is disordered by symmetry, similar to the situation in the structure of KH₃L1. Here the K⋯O bond lengths vary from 2.7951 (11) to 2.8668 (13) Å. The K⁺ cation has a coordination number of 8 (KO₈) and a distorted dodecahedral geometry as in KH₃L1 (Fig. 7a and 11).

Figure 17
(a) A view along the a axis of the potassium–organic framework of UBUPAK (Masci et al., 2010

) and (b) a view along the c axis of the potassium–organic framework of MUMPIW (Li et al., 2020

The structure of the potassium salt of pyrazine-2,3-dicarboxylic acid (pzdca; Fig. 1), catena-[(μ₂-3-carboxypyrazine-2-carboxylato)-(μ₂-pyrazine-2,3-dicarboxylic acid)diaquapotassium], has been reported (RISYIC; Tombul et al., 2008 ). It has a polymer chain structure with the chains linked by O—H⋯O hydrogen bonds, forming a supramolecular framework. Here the K⋯O bond lengths vary from 2.8772 (14) to 3.0898 (14) Å.

The structures of two potassium salts of 2,6-pyridine-dicarboxylic acid (pydca; Fig. 1) have been reported. They include, bis(μ₂-pyridine-2,6-dicarboxylic acid-N,O,O′:O′)-hexaaquabis(6-carboxypyridine-2-carboxylato-O)dipotassium (HAMBEE; Santra et al., 2011 ; HAMBEE01; Hayati et al., 2017 ), and catena-[(μ-6-carboxypyridine-2-carboxylato)potassium] (MUMPIW; Li et al., 2020 ). HAMBEE is a binuclear complex, which is linked by O—H⋯O hydrogen bonds to form supramolecular chains. The K⋯O bond lengths vary from 2.721 (2) to 3.054 (3) Å.

The structure of MUMPIW is that of a potassium-organic framework (Fig. 17b), with the K⋯O bonds lengths varying from 2.8197 (14) to 3.0449 (15) Å. The K⁺ ion has a coordination number of seven (KO₆N) and has an edge-sharing pentagonal antiprism geometry, forming chains (Fig. 17b). This structure can be compared to that of K₂H₂L1 where the two independent K⁺ ions, each with a coordination number of six (KO₆), have edge-sharing bipyramidal geometries, also forming chains (Fig. 7b and 12).

7. Synthesis and crystallization

The synthesis and crystal structure of the reagent tetra-2,3,5,6-bromomethyl-pyrazine (TBr) have been reported (Ferigo et al., 1994 ; Assoumatine & Stoeckli-Evans, 2014 [CSD refcode: TOJXUN]).

Synthesis of 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetrapropionic acid (H₄L1):

Mercaptopropionic acid (1.8795 g, 1.77 mol, 4 eq) was dissolved in 50 ml THF. A minimum amount of water (a few ml) was added to dissolve 1.4166 g (3.54 mol, 8 eq) of NaOH. The volume of the mixture was increased to 100 ml by adding THF and the reaction was stirred under reflux for 1 h. Then TBr (2 g, 4.42 mol, 1 eq) dissolved in 50 ml THF was added dropwise using an addition funnel. The mixture was stirred under reflux for 6 h. After drying under vacuum, the residue was dissolved in 50 ml of deionized water, and HCl puriss. was added dropwise until a clearly acid pH was obtained. This mixture was stirred at room temperature for 1–2 h. The yellow precipitate that formed was filtered off and washed with a minimum amount of water and then CHCl₃. It was then dried under vacuum conditions. Recrystallization carried out with methanol gave pale-yellow crystals of H₄L1 (yield 88%, m.p. 466 K) that X-ray diffraction analysis indicated to be triclinic polymorph H₄L1_A.

The presence of terephthalic acid in an equimolar quantity with H₄L1 in methanol gave colourless crystals of rather poor quality. However, X-ray diffraction analysis indicated that a second triclinic (P $[\overline{1}]$ ) polymorph, H₄L1_B, had been obtained.

Spectroscopic and elemental analyses:

R_f: 0.77 (solvent: CH₃OH).

¹H NMR (CD₃OD, 400 MHz), δ(ppm): 4.03 (s, 8H, H2), 2.78 (t, 8H, ³J_(3,4) = 7.0, H3), 2.62 (t, 8H, ³J_(4,3) = 7.0, H4).

¹³C NMR (CD₃OD, 50 MHz), δ(ppm): 174.54 (4C, C5), 150.12 (4C, C1), 34.29 (4C, C4), 33.64 (4C, C2), 26.65 (4C, C3).

Elemental Analysis for C₂₀H₂₈N₂O₈S₄, M_w = 552.71 g mol⁻¹: Calculated: C 43.46, H 5.11, N 5.07%. Found: C 43.40, H 5.17, N 4.87%.

ESI–MS, m/z: 591.04 [M + K]⁺; 575.06 [M + Na]⁺; 553.08 [M + H]⁺; 471.07; 449.09.

IR (KBr disc, cm⁻¹) ν: 2926(s), 2666(m), 2590(s), 1693(s), 1429(s), 1406(s), 1340(m), 1270(s), 1200(s), 1163(m), 1134(s), 1107(m), 1055(w), 918(s), 658(m), 489(m).

Synthesis of poly[(μ-3-{[(3,5,6-tris{[(2-carboxyethyl)sulfanyl]methyl}pyrazin-2-yl)methyl]sulfanyl}propanoate)potassium] (KH₃L1):

Hg(NO₃)₂ (45.0 mg, 0.109 mmol, 2 eq) and H₄L1 (30 mg, 0.054 mmol, 1 eq) were mixed together in 20 ml of a 1 M potassium acetate buffer. The mixture was left at 323 K under stirring and nitrogen conditions for 1 h. The mixture was then filtered and left to evaporate in air for six weeks. Colourless plate-like crystals were obtained, which were shown to be a potassium–organic framework.

IR (KBr disc, cm⁻¹) ν: 3422(m), 2922(m), 1713(m), 1580(s), 1399(s), 1247(m), 1190(m), 1152(m), 1114(m), 811(m), 787(m).

Synthesis of poly[(μ-3,3′-{[(3,6-bis{[(2-carboxyethyl)sulfanyl]methyl}pyrazine-2,5-diyl)bis(methylene)]bis(sulfanediyl)}dipropionato)dipotassium] (K₂H₂L1):

Zn(NO₃)₂ (28.4 mg, 0.109 mmol, 2 eq) and H₄L1 (30 mg, 0.054 mmol, 1eq) were mixed together in 20 ml of a 1M potassium acetate buffer. The mixture was left at 323 K under stirring and nitrogen for 1 h. The mixture was then filtered and left to evaporate in air for 6 weeks. Colourless plate-like crystals were obtained, which proved to be a dipotassium-organic framework.

IR (KBr disc, cm⁻¹) ν: 3401(m), 1579(s), 1401(s), 1303(m).

8. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 10.

Table 10
Experimental details

	H₄L1_A	H₄L1_B	KH₃L1	K₂H₂L1
Crystal data
Chemical formula	C₂₀H₂₈N₂O₈S₄	C₂₀H₂₈N₂O₈S₄	[K(C₂₀H₂₇N₂O₈S₄)]	[K₂(C₂₀H₂₆N₂O₈S₄)]
M_r	552.68	552.68	590.77	628.87
Crystal system, space group	Triclinic, P $[\overline{1}]$	Triclinic, P $[\overline{1}]$	Monoclinic, C2/c	Monoclinic, C2/c
Temperature (K)	293	293	153	153
a, b, c (Å)	5.5843 (8), 9.0061 (14), 12.739 (2)	4.9424 (17), 8.993 (3), 14.190 (6)	30.080 (4), 8.4716 (10), 9.5908 (12)	27.908 (2), 8.2916 (6), 11.3035 (9)
α, β, γ (°)	101.537 (18), 94.313 (18), 103.701 (17)	96.96 (3), 97.14 (3), 100.72 (3)	90, 94.717 (11), 90	90, 94.753 (6), 90
V (Å³)	604.80 (17)	608.1 (4)	2435.7 (6)	2606.7 (3)
Z	1	1	4	4
Radiation type	Mo Kα	Mo Kα	Mo Kα	Mo Kα
μ (mm⁻¹)	0.44	0.44	0.61	0.73
Crystal size (mm)	0.35 × 0.30 × 0.05	0.50 × 0.50 × 0.05	0.50 × 0.50 × 0.10	0.50 × 0.50 × 0.05

Data collection
Diffractometer	Stoe IPDS 1	Stoe IPDS 2	Stoe IPDS 2	Stoe IPDS 2
Absorption correction	Empirical (using intensity measurements) (ShxAbs; Spek, 2020 )	Empirical (using intensity measurements) (ShxAbs; Spek, 2020)	Multi-scan (MULABS; Spek, 2020)	Empirical (using intensity measurements) (ShxAbs; Spek, 2020)
T_min, T_max	0.647, 0.897	0.144, 0.616	0.640, 1.000	0.416, 0.803
No. of measured, independent and observed [I > 2σ(I)] reflections	4709, 2194, 1452	4152, 2201, 1537	10309, 2084, 1646	19423, 3646, 3175
R_int	0.058	0.080	0.064	0.042
(sin θ/λ)_max (Å⁻¹)	0.615	0.617	0.590	0.695

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.097, 0.88	0.071, 0.208, 1.05	0.039, 0.106, 1.02	0.037, 0.103, 1.05
No. of reflections	2194	2201	2084	3646
No. of parameters	162	173	165	167
No. of restraints	2	6	0	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement	H-atom parameters constrained	H atoms treated by a mixture of independent and constrained refinement	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.28	0.47, −0.39	0.26, −0.36	0.76, −0.51
Computer programs: EXPOSE, CELL and INTEGRATE in IPDS-I (Stoe & Cie, 2000 ), X-AREA and X-RED32 (Stoe & Cie, 2002 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2018/3 (Sheldrick, 2015 ), PLATON (Spek, 2020) Mercury (Macrae et al., 2020 ) and publCIF (Westrip, 2010 ).

For H₄L1_A, KH₃L1 and K₂H₂L1, the various –CO₂H H atoms were located in difference-Fourier maps and freely refined. For H₄L1_B, the –CO₂H H atoms were difficult to locate, probably due to the poor quality of the crystal and the disorder in the side chain (atoms C8/C8B, C9/C9B, C10/C10B, O3/O3B, O4/O4B; Fig. 4b). They were therefore included in calculated positions assuming the formation of carboxylic acid dimers; O—H = 0.82 Å and refined as riding with U_iso(H) = 1.5U_eq(O).

As in the K⁺ salt of pyrazine tetracarboxylic acid (UBUPAK; Masci et al., 2010), the carboxy H atom in KH₃L1 is disordered by symmetry, hence the H atom on O3 was given an occupancy factor of 0.5 to balance the charges.

For all four compounds, the C-bound H atoms were included in calculated positions and treated as riding on their parent C atom with C—H = 0.97 Å and U_iso(H) = 1.2U_eq(C).

For H₄L1_A and H₄L1_B, the alert _diffrn_reflns_point_group_measured_fraction_full value (0.94 and 0.93, respectively) below minimum (0.95) was given. For H₄L1_A it involves 131 random reflections out of a total of 2180, viz. 6.0%, while for H₄L1_B it involves 158 random reflections out of a total of 2184, viz. 7.2%.

For H₄L1_A, H₄L1_B and K₂H₂L1 the multiplicity of reflections was 2 or less and so an empirical absorption correction was applied.

Supporting information

CCDC references: 2074770; 2074769; 2074768; 2074767

Crystal structure: contains datablocks H4L1A, H4L1B, KH3L1, K2H2L1, Global. DOI: https://doi.org/10.1107/S2056989021003479/pk2656sup1.cif

Structure factors: contains datablock H4L1A. DOI: https://doi.org/10.1107/S2056989021003479/pk2656H4L1Asup2.hkl

Structure factors: contains datablock H4L1B. DOI: https://doi.org/10.1107/S2056989021003479/pk2656H4L1Bsup3.hkl

Structure factors: contains datablock KH3L1. DOI: https://doi.org/10.1107/S2056989021003479/pk2656KH3L1sup4.hkl

Structure factors: contains datablock K2H2L1. DOI: https://doi.org/10.1107/S2056989021003479/pk2656K2H2L1sup5.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989021003479/pk2656H4L1Asup6.cml

Supporting information file. DOI: https://doi.org/10.1107/S2056989021003479/pk2656H4L1Bsup7.cml

Supporting information file. DOI: https://doi.org/10.1107/S2056989021003479/pk2656KH3L1sup8.cml

Supporting information file. DOI: https://doi.org/10.1107/S2056989021003479/pk2656K2H2L1sup9.cml

checkCIF report

Computing details top

Data collection: EXPOSE in IPDS-I (Stoe & Cie, 2000) for H4L1A; X-AREA (Stoe & Cie, 2002) for H4L1B, KH3L1, K2H2L1. Cell refinement: CELL in IPDS-I (Stoe & Cie, 2000) for H4L1A; X-AREA (Stoe & Cie, 2002) for H4L1B, KH3L1, K2H2L1. Data reduction: INTEGRATE in IPDS-I (Stoe & Cie, 2000) for H4L1A; X-RED32 (Stoe & Cie, 2002) for H4L1B, KH3L1, K2H2L1. For all structures, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015). Molecular graphics: Mercury (Macrae et al., 2020) for H4L1A; PLATON (Spek, 2020) and Mercury (Macrae et al., 2020) for H4L1B, KH3L1, K2H2L1. For all structures, software used to prepare material for publication: SHELXL2018/3 (Sheldrick, 2015), PLATON (Spek, 2020) and publCIF (Westrip, 2010).

3,3',3'',3'''-{[Pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl]}tetrapropionic acid (H4L1A) top

Crystal data top

C₂₀H₂₈N₂O₈S₄	Z = 1
M_r = 552.68	F(000) = 290
Triclinic, P1	D_x = 1.517 Mg m⁻³
a = 5.5843 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.0061 (14) Å	Cell parameters from 3225 reflections
c = 12.739 (2) Å	θ = 2.4–25.9°
α = 101.537 (18)°	µ = 0.44 mm⁻¹
β = 94.313 (18)°	T = 293 K
γ = 103.701 (17)°	Plate, pale-yellow
V = 604.80 (17) Å³	0.35 × 0.30 × 0.05 mm

Data collection top

STOE IPDS 1 diffractometer	2194 independent reflections
Radiation source: fine-focus sealed tube	1452 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.058
φ rotation scans	θ_max = 25.9°, θ_min = 2.4°
Absorption correction: empirical (using intensity measurements) (ShxAbs; Spek, 2020)	h = −6→6
T_min = 0.647, T_max = 0.897	k = −11→11
4709 measured reflections	l = −14→15

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)] = 0.041	Hydrogen site location: mixed
wR(F²) = 0.097	H atoms treated by a mixture of independent and constrained refinement
S = 0.88	w = 1/[σ²(F_o²) + (0.0478P)²] where P = (F_o² + 2F_c²)/3
2194 reflections	(Δ/σ)_max < 0.001
162 parameters	Δρ_max = 0.35 e Å⁻³
2 restraints	Δρ_min = −0.28 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
S1	0.40170 (15)	0.39121 (9)	0.29698 (6)	0.0312 (2)
S2	1.27548 (15)	0.86290 (9)	0.37908 (6)	0.0288 (2)
O1	−0.3381 (5)	0.0716 (3)	0.12207 (17)	0.0435 (6)
O2	−0.2098 (5)	0.1064 (3)	−0.03567 (17)	0.0409 (6)
H2O	−0.363 (5)	0.052 (5)	−0.059 (4)	0.098 (19)*
O3	0.7761 (4)	0.5277 (3)	0.08084 (16)	0.0379 (6)
O4	0.5045 (5)	0.6736 (3)	0.09232 (19)	0.0422 (6)
H4O	0.422 (8)	0.607 (4)	0.039 (3)	0.087 (17)*
N1	0.8353 (4)	0.5540 (3)	0.44074 (17)	0.0198 (5)
C1	0.7859 (5)	0.4024 (3)	0.4451 (2)	0.0194 (6)
C2	1.0447 (5)	0.6523 (3)	0.4952 (2)	0.0183 (6)
C3	0.5460 (5)	0.2957 (3)	0.3850 (2)	0.0248 (6)
H3A	0.434405	0.264980	0.436177	0.030*
H3B	0.577409	0.201607	0.342827	0.030*
C4	0.1473 (6)	0.2234 (4)	0.2308 (2)	0.0328 (7)
H4A	0.202811	0.128008	0.222673	0.039*
H4B	0.011542	0.214305	0.274306	0.039*
C5	0.0600 (6)	0.2449 (4)	0.1219 (2)	0.0347 (8)
H5A	0.041788	0.350865	0.129466	0.042*
H5B	0.186183	0.233148	0.074799	0.042*
C6	−0.1807 (6)	0.1321 (3)	0.0698 (2)	0.0291 (7)
C7	1.0877 (6)	0.8196 (3)	0.4857 (2)	0.0239 (6)
H7A	1.170302	0.887935	0.554088	0.029*
H7B	0.928434	0.841937	0.471163	0.029*
C8	1.0935 (6)	0.7220 (4)	0.2615 (2)	0.0277 (7)
H8A	1.187763	0.725553	0.200717	0.033*
H8B	1.068152	0.617707	0.275367	0.033*
C9	0.8427 (6)	0.7491 (3)	0.2307 (2)	0.0290 (7)
H9A	0.742172	0.735720	0.288698	0.035*
H9B	0.866452	0.856524	0.223186	0.035*
C10	0.7046 (6)	0.6407 (4)	0.1277 (2)	0.0283 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0292 (5)	0.0246 (4)	0.0348 (4)	−0.0018 (3)	−0.0101 (3)	0.0109 (3)
S2	0.0243 (5)	0.0241 (4)	0.0376 (4)	−0.0013 (3)	0.0027 (3)	0.0156 (3)
O1	0.0333 (15)	0.0501 (14)	0.0362 (13)	−0.0022 (12)	−0.0093 (10)	0.0054 (11)
O2	0.0322 (16)	0.0486 (14)	0.0345 (13)	0.0001 (13)	−0.0099 (10)	0.0099 (10)
O3	0.0400 (15)	0.0425 (13)	0.0341 (12)	0.0216 (12)	−0.0002 (10)	0.0039 (10)
O4	0.0345 (15)	0.0519 (15)	0.0396 (13)	0.0217 (13)	−0.0064 (11)	0.0004 (12)
N1	0.0182 (14)	0.0159 (11)	0.0242 (11)	0.0010 (10)	−0.0009 (9)	0.0072 (9)
C1	0.0184 (16)	0.0158 (13)	0.0222 (13)	0.0006 (12)	0.0005 (10)	0.0055 (10)
C2	0.0182 (16)	0.0125 (12)	0.0226 (13)	0.0011 (12)	0.0009 (10)	0.0047 (10)
C3	0.0191 (17)	0.0189 (14)	0.0327 (15)	−0.0025 (13)	−0.0028 (11)	0.0085 (11)
C4	0.0259 (19)	0.0290 (16)	0.0359 (16)	−0.0069 (14)	−0.0053 (13)	0.0097 (13)
C5	0.032 (2)	0.0279 (16)	0.0404 (18)	0.0008 (15)	−0.0080 (14)	0.0114 (13)
C6	0.0228 (19)	0.0264 (16)	0.0360 (17)	0.0048 (15)	−0.0074 (13)	0.0083 (13)
C7	0.0251 (18)	0.0155 (13)	0.0313 (15)	0.0028 (13)	0.0021 (12)	0.0088 (11)
C8	0.0263 (18)	0.0316 (16)	0.0293 (15)	0.0092 (14)	0.0066 (12)	0.0132 (12)
C9	0.0281 (19)	0.0276 (16)	0.0324 (16)	0.0074 (15)	0.0008 (12)	0.0097 (12)
C10	0.0262 (18)	0.0385 (17)	0.0254 (15)	0.0125 (15)	0.0068 (12)	0.0129 (13)

Geometric parameters (Å, º) top

S1—C3	1.796 (3)	C3—H3B	0.9700
S1—C4	1.818 (3)	C4—C5	1.500 (4)
S2—C8	1.813 (3)	C4—H4A	0.9700
S2—C7	1.825 (3)	C4—H4B	0.9700
O1—C6	1.233 (4)	C5—C6	1.493 (4)
O2—C6	1.307 (4)	C5—H5A	0.9700
O2—H2O	0.87 (2)	C5—H5B	0.9700
O3—C10	1.240 (4)	C7—H7A	0.9700
O4—C10	1.294 (4)	C7—H7B	0.9700
O4—H4O	0.830 (19)	C8—C9	1.514 (4)
N1—C2	1.332 (3)	C8—H8A	0.9700
N1—C1	1.341 (3)	C8—H8B	0.9700
C1—C2ⁱ	1.406 (3)	C9—C10	1.499 (4)
C1—C3	1.499 (4)	C9—H9A	0.9700
C2—C7	1.500 (3)	C9—H9B	0.9700
C3—H3A	0.9700

C3—S1—C4	97.53 (13)	C4—C5—H5B	108.8
C8—S2—C7	101.68 (14)	H5A—C5—H5B	107.7
C6—O2—H2O	108 (3)	O1—C6—O2	123.6 (3)
C10—O4—H4O	113 (3)	O1—C6—C5	122.7 (3)
C2—N1—C1	119.1 (2)	O2—C6—C5	113.7 (3)
N1—C1—C2ⁱ	120.3 (2)	C2—C7—S2	112.8 (2)
N1—C1—C3	117.7 (2)	C2—C7—H7A	109.0
C2ⁱ—C1—C3	122.0 (2)	S2—C7—H7A	109.0
N1—C2—C1ⁱ	120.6 (2)	C2—C7—H7B	109.0
N1—C2—C7	115.9 (2)	S2—C7—H7B	109.0
C1ⁱ—C2—C7	123.4 (2)	H7A—C7—H7B	107.8
C1—C3—S1	110.88 (18)	C9—C8—S2	114.2 (2)
C1—C3—H3A	109.5	C9—C8—H8A	108.7
S1—C3—H3A	109.5	S2—C8—H8A	108.7
C1—C3—H3B	109.5	C9—C8—H8B	108.7
S1—C3—H3B	109.5	S2—C8—H8B	108.7
H3A—C3—H3B	108.1	H8A—C8—H8B	107.6
C5—C4—S1	109.2 (2)	C10—C9—C8	113.5 (2)
C5—C4—H4A	109.8	C10—C9—H9A	108.9
S1—C4—H4A	109.8	C8—C9—H9A	108.9
C5—C4—H4B	109.8	C10—C9—H9B	108.9
S1—C4—H4B	109.8	C8—C9—H9B	108.9
H4A—C4—H4B	108.3	H9A—C9—H9B	107.7
C6—C5—C4	113.8 (3)	O3—C10—O4	122.8 (3)
C6—C5—H5A	108.8	O3—C10—C9	122.4 (3)
C4—C5—H5A	108.8	O4—C10—C9	114.8 (3)
C6—C5—H5B	108.8

C2—N1—C1—C2ⁱ	−1.2 (4)	C4—C5—C6—O1	26.8 (4)
C2—N1—C1—C3	178.6 (2)	C4—C5—C6—O2	−154.4 (3)
C1—N1—C2—C1ⁱ	1.2 (4)	N1—C2—C7—S2	−94.0 (3)
C1—N1—C2—C7	179.6 (2)	C1ⁱ—C2—C7—S2	84.3 (3)
N1—C1—C3—S1	11.3 (3)	C8—S2—C7—C2	57.6 (2)
C2ⁱ—C1—C3—S1	−168.8 (2)	C7—S2—C8—C9	65.7 (2)
C4—S1—C3—C1	174.1 (2)	S2—C8—C9—C10	174.8 (2)
C3—S1—C4—C5	−155.3 (2)	C8—C9—C10—O3	8.8 (4)
S1—C4—C5—C6	−167.9 (2)	C8—C9—C10—O4	−171.8 (3)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O1ⁱⁱ	0.87 (2)	1.80 (2)	2.667 (3)	172 (5)
O4—H4O···O3ⁱⁱⁱ	0.83 (2)	1.85 (2)	2.673 (3)	175 (5)
C5—H5A···O3^iv	0.97	2.55	3.405 (4)	147
C8—H8A···O4^v	0.97	2.40	3.308 (4)	156

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

3,3',3'',3'''-{[Pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl]}tetrapropionic acid (H4L1B) top

Crystal data top

C₂₀H₂₈N₂O₈S₄	Z = 1
M_r = 552.68	F(000) = 290
Triclinic, P1	D_x = 1.509 Mg m⁻³
a = 4.9424 (17) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.993 (3) Å	Cell parameters from 5563 reflections
c = 14.190 (6) Å	θ = 2.4–25.5°
α = 96.96 (3)°	µ = 0.44 mm⁻¹
β = 97.14 (3)°	T = 293 K
γ = 100.72 (3)°	Plate, colourless
V = 608.1 (4) Å³	0.50 × 0.50 × 0.05 mm

Data collection top

STOE IPDS 2 diffractometer	2201 independent reflections
Radiation source: fine-focus sealed tube	1537 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.080
φ + ω scans	θ_max = 26.0°, θ_min = 2.3°
Absorption correction: empirical (using intensity measurements) (ShxAbs; Spek, 2020)	h = −5→5
T_min = 0.144, T_max = 0.616	k = −11→9
4152 measured reflections	l = −17→17

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)] = 0.071	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.208	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.1049P)² + 0.4241P] where P = (F_o² + 2F_c²)/3
2201 reflections	(Δ/σ)_max = 0.001
173 parameters	Δρ_max = 0.47 e Å⁻³
6 restraints	Δρ_min = −0.39 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	Occ. (<1)
S1	0.7886 (3)	0.28919 (12)	0.71512 (9)	0.0583 (4)
S2	0.6227 (3)	0.07568 (12)	0.39724 (10)	0.0682 (5)
N1	1.2114 (8)	0.5110 (4)	0.5754 (3)	0.0500 (9)
C1	0.9965 (9)	0.3908 (4)	0.5566 (3)	0.0467 (10)
C2	0.7852 (9)	0.3796 (4)	0.4821 (3)	0.0469 (10)
C3	1.0020 (10)	0.2707 (4)	0.6214 (3)	0.0537 (11)
H3A	1.192760	0.277226	0.650755	0.064*
H3B	0.937959	0.170470	0.583113	0.064*
C4	0.9971 (12)	0.4560 (5)	0.7916 (4)	0.0644 (13)
H4A	1.087916	0.524956	0.752231	0.077*
H4B	0.876729	0.509027	0.826037	0.077*
C5	1.2177 (12)	0.4158 (6)	0.8638 (4)	0.0682 (14)
H5A	1.332589	0.358948	0.829232	0.082*
H5B	1.337009	0.509683	0.898069	0.082*
C6	1.0984 (14)	0.3238 (6)	0.9345 (4)	0.0728 (15)
O1	0.8532 (10)	0.3158 (5)	0.9473 (3)	0.0828 (12)
O2	1.2630 (12)	0.2603 (9)	0.9826 (5)	0.136 (2)
H2O	1.173990	0.186783	1.001978	0.204*
C7	0.5410 (10)	0.2468 (5)	0.4572 (4)	0.0559 (11)
H7A	0.394220	0.276430	0.416093	0.067*
H7B	0.470023	0.224151	0.515671	0.067*
C8	0.6926 (16)	0.1494 (6)	0.2872 (5)	0.0604 (17)	0.821 (6)
H8A	0.530565	0.183752	0.258819	0.072*	0.821 (6)
H8B	0.847467	0.236521	0.301719	0.072*	0.821 (6)
C9	0.7607 (15)	0.0292 (6)	0.2173 (5)	0.0657 (16)	0.821 (6)
H9A	0.597449	−0.051856	0.196091	0.079*	0.821 (6)
H9B	0.906849	−0.014697	0.248293	0.079*	0.821 (6)
C10	0.8546 (16)	0.0963 (7)	0.1325 (5)	0.0622 (15)	0.821 (6)
O3	1.0881 (16)	0.0900 (11)	0.1127 (6)	0.132 (3)	0.821 (6)
O4	0.6974 (19)	0.1598 (10)	0.0858 (6)	0.117 (3)	0.821 (6)
H4O	0.785351	0.212989	0.052298	0.175*	0.821 (6)
C8B	0.834 (7)	0.112 (3)	0.3062 (18)	0.0604 (17)	0.179 (6)
H8B1	0.957385	0.212176	0.321614	0.072*	0.179 (6)
H8B2	0.941870	0.034250	0.294752	0.072*	0.179 (6)
C9B	0.609 (6)	0.106 (3)	0.2219 (19)	0.0657 (16)	0.179 (6)
H9B1	0.490282	0.005115	0.207464	0.079*	0.179 (6)
H9B2	0.494650	0.179949	0.237286	0.079*	0.179 (6)
C10B	0.748 (6)	0.143 (4)	0.137 (2)	0.0622 (15)	0.179 (6)
O3B	0.998 (6)	0.188 (6)	0.137 (3)	0.132 (3)	0.179 (6)
O4B	0.576 (9)	0.176 (6)	0.073 (3)	0.117 (3)	0.179 (6)
H4OB	0.660348	0.228397	0.038152	0.175*	0.179 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0546 (9)	0.0462 (6)	0.0762 (8)	0.0041 (5)	0.0158 (6)	0.0205 (5)
S2	0.0868 (11)	0.0329 (5)	0.0834 (9)	−0.0047 (5)	0.0293 (7)	0.0119 (5)
N1	0.045 (2)	0.0322 (16)	0.075 (2)	0.0074 (14)	0.0141 (17)	0.0146 (15)
C1	0.048 (3)	0.0259 (16)	0.071 (3)	0.0081 (15)	0.017 (2)	0.0160 (16)
C2	0.045 (3)	0.0292 (17)	0.070 (3)	0.0054 (15)	0.017 (2)	0.0152 (16)
C3	0.051 (3)	0.0350 (19)	0.080 (3)	0.0097 (17)	0.015 (2)	0.0220 (19)
C4	0.073 (4)	0.043 (2)	0.083 (3)	0.009 (2)	0.026 (3)	0.022 (2)
C5	0.063 (4)	0.061 (3)	0.077 (3)	−0.001 (2)	0.015 (3)	0.017 (2)
C6	0.064 (4)	0.066 (3)	0.090 (4)	0.003 (2)	0.013 (3)	0.033 (3)
O1	0.079 (3)	0.086 (3)	0.093 (3)	0.019 (2)	0.029 (2)	0.034 (2)
O2	0.085 (4)	0.190 (6)	0.162 (5)	0.031 (4)	0.031 (3)	0.122 (5)
C7	0.051 (3)	0.042 (2)	0.073 (3)	−0.0032 (18)	0.012 (2)	0.0155 (19)
C8	0.078 (5)	0.034 (3)	0.074 (4)	0.010 (2)	0.023 (3)	0.017 (2)
C9	0.084 (5)	0.040 (3)	0.079 (4)	0.011 (3)	0.026 (3)	0.022 (3)
C10	0.068 (5)	0.048 (3)	0.080 (4)	0.019 (3)	0.024 (3)	0.020 (3)
O3	0.096 (5)	0.194 (8)	0.145 (6)	0.052 (5)	0.052 (4)	0.113 (6)
O4	0.132 (8)	0.140 (5)	0.131 (5)	0.087 (5)	0.067 (5)	0.090 (4)
C8B	0.078 (5)	0.034 (3)	0.074 (4)	0.010 (2)	0.023 (3)	0.017 (2)
C9B	0.084 (5)	0.040 (3)	0.079 (4)	0.011 (3)	0.026 (3)	0.022 (3)
C10B	0.068 (5)	0.048 (3)	0.080 (4)	0.019 (3)	0.024 (3)	0.020 (3)
O3B	0.096 (5)	0.194 (8)	0.145 (6)	0.052 (5)	0.052 (4)	0.113 (6)
O4B	0.132 (8)	0.140 (5)	0.131 (5)	0.087 (5)	0.067 (5)	0.090 (4)

Geometric parameters (Å, º) top

S1—C4	1.801 (5)	C7—H7A	0.9700
S1—C3	1.808 (5)	C7—H7B	0.9700
S2—C8B	1.78 (3)	C8—C9	1.490 (8)
S2—C7	1.804 (5)	C8—H8A	0.9700
S2—C8	1.816 (6)	C8—H8B	0.9700
N1—C1	1.342 (5)	C9—C10	1.496 (8)
N1—C2ⁱ	1.351 (5)	C9—H9A	0.9700
C1—C2	1.371 (6)	C9—H9B	0.9700
C1—C3	1.503 (5)	C10—O4	1.224 (8)
C2—C7	1.504 (6)	C10—O3	1.231 (9)
C3—H3A	0.9700	O4—H4O	0.8200
C3—H3B	0.9700	C8B—C9B	1.516 (19)
C4—C5	1.526 (8)	C8B—H8B1	0.9700
C4—H4A	0.9700	C8B—H8B2	0.9700
C4—H4B	0.9700	C9B—C10B	1.505 (19)
C5—C6	1.485 (7)	C9B—H9B1	0.9700
C5—H5A	0.9700	C9B—H9B2	0.9700
C5—H5B	0.9700	C10B—O3B	1.226 (19)
C6—O1	1.238 (7)	C10B—O4B	1.265 (19)
C6—O2	1.258 (8)	O4B—H4OB	0.8200
O2—H2O	0.8200

C4—S1—C3	100.2 (2)	C2—C7—H7B	108.8
C8B—S2—C7	112.9 (9)	S2—C7—H7B	108.8
C7—S2—C8	96.8 (2)	H7A—C7—H7B	107.7
C1—N1—C2ⁱ	117.9 (4)	C9—C8—S2	110.8 (4)
N1—C1—C2	121.2 (4)	C9—C8—H8A	109.5
N1—C1—C3	116.3 (4)	S2—C8—H8A	109.5
C2—C1—C3	122.5 (4)	C9—C8—H8B	109.5
N1ⁱ—C2—C1	120.9 (4)	S2—C8—H8B	109.5
N1ⁱ—C2—C7	115.7 (4)	H8A—C8—H8B	108.1
C1—C2—C7	123.5 (4)	C8—C9—C10	110.3 (5)
C1—C3—S1	113.3 (3)	C8—C9—H9A	109.6
C1—C3—H3A	108.9	C10—C9—H9A	109.6
S1—C3—H3A	108.9	C8—C9—H9B	109.6
C1—C3—H3B	108.9	C10—C9—H9B	109.6
S1—C3—H3B	108.9	H9A—C9—H9B	108.1
H3A—C3—H3B	107.7	O4—C10—O3	121.6 (7)
C5—C4—S1	112.3 (3)	O4—C10—C9	118.5 (7)
C5—C4—H4A	109.2	O3—C10—C9	119.8 (6)
S1—C4—H4A	109.2	C10—O4—H4O	109.5
C5—C4—H4B	109.2	C9B—C8B—S2	99.9 (19)
S1—C4—H4B	109.2	C9B—C8B—H8B1	111.8
H4A—C4—H4B	107.9	S2—C8B—H8B1	111.8
C6—C5—C4	113.3 (5)	C9B—C8B—H8B2	111.8
C6—C5—H5A	108.9	S2—C8B—H8B2	111.8
C4—C5—H5A	108.9	H8B1—C8B—H8B2	109.5
C6—C5—H5B	108.9	C10B—C9B—C8B	108 (2)
C4—C5—H5B	108.9	C10B—C9B—H9B1	110.0
H5A—C5—H5B	107.7	C8B—C9B—H9B1	110.0
O1—C6—O2	122.4 (5)	C10B—C9B—H9B2	110.0
O1—C6—C5	121.3 (5)	C8B—C9B—H9B2	110.0
O2—C6—C5	116.3 (6)	H9B1—C9B—H9B2	108.4
C6—O2—H2O	109.5	O3B—C10B—O4B	119 (3)
C2—C7—S2	113.8 (3)	O3B—C10B—C9B	126 (3)
C2—C7—H7A	108.8	O4B—C10B—C9B	110 (3)
S2—C7—H7A	108.8	C10B—O4B—H4OB	109.5

C2ⁱ—N1—C1—C2	−0.6 (6)	N1ⁱ—C2—C7—S2	103.4 (4)
C2ⁱ—N1—C1—C3	179.3 (4)	C1—C2—C7—S2	−75.4 (5)
N1—C1—C2—N1ⁱ	0.6 (7)	C8B—S2—C7—C2	−43.7 (10)
C3—C1—C2—N1ⁱ	−179.3 (4)	C8—S2—C7—C2	−66.8 (4)
N1—C1—C2—C7	179.3 (4)	C7—S2—C8—C9	−178.1 (5)
C3—C1—C2—C7	−0.6 (6)	S2—C8—C9—C10	−172.5 (5)
N1—C1—C3—S1	98.8 (4)	C8—C9—C10—O4	−57.8 (10)
C2—C1—C3—S1	−81.3 (5)	C8—C9—C10—O3	120.5 (9)
C4—S1—C3—C1	−72.6 (4)	C7—S2—C8B—C9B	−87.0 (16)
C3—S1—C4—C5	−86.7 (4)	S2—C8B—C9B—C10B	177 (2)
S1—C4—C5—C6	−65.0 (6)	C8B—C9B—C10B—O3B	−8 (5)
C4—C5—C6—O1	−17.0 (8)	C8B—C9B—C10B—O4B	−164 (3)
C4—C5—C6—O2	165.7 (6)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O3ⁱⁱ	0.82	1.94	2.66 (1)	146
O2—H2O···O3Bⁱⁱ	0.82	2.20	2.77 (3)	127
O4—H4O···O1ⁱⁱⁱ	0.82	1.88	2.66 (1)	158
O4B—H4OB···O1ⁱⁱⁱ	0.82	1.86	2.67 (4)	170

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

Poly[(µ-3-{[(3,5,6-tris{[(2-carboxyethyl)sulfanyl]methyl}pyrazin-2-yl)methyl]sulfanyl}propanoato)potassium] (KH3L1) top

Crystal data top

[K(C₂₀H₂₇N₂O₈S₄)]	F(000) = 1232
M_r = 590.77	D_x = 1.611 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 30.080 (4) Å	Cell parameters from 7965 reflections
b = 8.4716 (10) Å	θ = 1.4–25.0°
c = 9.5908 (12) Å	µ = 0.61 mm⁻¹
β = 94.717 (11)°	T = 153 K
V = 2435.7 (6) Å³	Plate, colourless
Z = 4	0.50 × 0.50 × 0.10 mm

Data collection top

STOE IPDS 2 diffractometer	2084 independent reflections
Radiation source: fine-focus sealed tube	1646 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.064
φ + ω scans	θ_max = 24.8°, θ_min = 2.5°
Absorption correction: multi-scan (MULABS; Spek, 2020)	h = −35→35
T_min = 0.640, T_max = 1.000	k = −9→9
10309 measured reflections	l = −11→11

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)] = 0.039	Hydrogen site location: mixed
wR(F²) = 0.106	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ²(F_o²) + (0.0648P)² + 1.5958P] where P = (F_o² + 2F_c²)/3
2084 reflections	(Δ/σ)_max = 0.002
165 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.36 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
K1	0.500000	−0.28423 (13)	−0.250000	0.0357 (3)
S1	0.34409 (2)	−0.03261 (9)	0.17646 (7)	0.0305 (2)
S2	0.18978 (2)	−0.11089 (9)	0.16606 (8)	0.0342 (2)
O1	0.46781 (7)	−0.2235 (3)	0.0136 (2)	0.0404 (5)
O2	0.46330 (7)	−0.0466 (3)	0.1860 (2)	0.0402 (6)
H20	0.500000	−0.073 (9)	0.250000	0.12 (3)*
O3	0.06245 (6)	0.1153 (3)	−0.0544 (2)	0.0363 (5)
O4	0.03178 (7)	0.1057 (3)	0.1493 (2)	0.0472 (7)
H4O	0.0125 (17)	0.157 (7)	0.109 (5)	0.097 (19)*
N1	0.28457 (7)	0.2024 (3)	−0.0774 (2)	0.0240 (5)
C1	0.27160 (8)	0.1117 (3)	0.0267 (3)	0.0240 (6)
C2	0.23661 (8)	0.1606 (3)	0.1047 (3)	0.0229 (6)
C3	0.29578 (8)	−0.0422 (3)	0.0500 (3)	0.0280 (6)
H3A	0.305554	−0.079313	−0.040443	0.034*
H3B	0.274689	−0.121452	0.082227	0.034*
C4	0.38202 (9)	0.0765 (4)	0.0748 (3)	0.0352 (7)
H4A	0.364384	0.148969	0.010857	0.042*
H4B	0.401718	0.141946	0.139218	0.042*
C5	0.41100 (9)	−0.0265 (4)	−0.0116 (3)	0.0335 (7)
H5A	0.391756	−0.108161	−0.059355	0.040*
H5B	0.422744	0.040143	−0.084955	0.040*
C6	0.44979 (9)	−0.1079 (4)	0.0676 (3)	0.0326 (7)
C7	0.22055 (9)	0.0650 (3)	0.2220 (3)	0.0283 (6)
H7A	0.201211	0.132352	0.275893	0.034*
H7B	0.246620	0.033583	0.285664	0.034*
C8	0.14217 (9)	−0.0295 (4)	0.0628 (3)	0.0329 (7)
H8A	0.152427	0.055219	0.002031	0.039*
H8B	0.128312	−0.113189	0.001607	0.039*
C9	0.10744 (9)	0.0371 (4)	0.1528 (3)	0.0350 (7)
H9A	0.099826	−0.044379	0.220895	0.042*
H9B	0.120475	0.128185	0.206358	0.042*
C10	0.06542 (9)	0.0895 (4)	0.0702 (3)	0.0307 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0254 (4)	0.0547 (6)	0.0267 (5)	0.000	−0.0009 (3)	0.000
S1	0.0189 (3)	0.0428 (5)	0.0297 (4)	0.0034 (3)	0.0011 (3)	0.0042 (3)
S2	0.0224 (4)	0.0335 (4)	0.0466 (5)	−0.0003 (3)	0.0027 (3)	0.0034 (3)
O1	0.0302 (11)	0.0590 (15)	0.0320 (11)	0.0130 (10)	0.0022 (9)	−0.0023 (10)
O2	0.0246 (10)	0.0633 (15)	0.0319 (11)	0.0051 (10)	−0.0024 (9)	−0.0077 (10)
O3	0.0259 (10)	0.0554 (15)	0.0278 (11)	0.0021 (9)	0.0032 (8)	0.0038 (9)
O4	0.0266 (12)	0.0804 (19)	0.0356 (13)	0.0138 (12)	0.0085 (10)	0.0044 (12)
N1	0.0156 (10)	0.0304 (13)	0.0255 (12)	−0.0007 (9)	−0.0019 (9)	−0.0021 (10)
C1	0.0152 (12)	0.0299 (16)	0.0256 (14)	0.0007 (11)	−0.0048 (10)	−0.0038 (11)
C2	0.0159 (11)	0.0278 (15)	0.0239 (14)	−0.0009 (11)	−0.0036 (10)	−0.0026 (11)
C3	0.0187 (13)	0.0317 (16)	0.0331 (15)	0.0022 (11)	−0.0012 (11)	−0.0003 (12)
C4	0.0210 (13)	0.0424 (19)	0.0421 (18)	−0.0024 (13)	0.0018 (12)	0.0070 (14)
C5	0.0213 (13)	0.051 (2)	0.0280 (15)	−0.0009 (12)	0.0017 (12)	0.0039 (13)
C6	0.0185 (13)	0.053 (2)	0.0268 (15)	−0.0019 (13)	0.0047 (11)	0.0024 (14)
C7	0.0229 (14)	0.0366 (16)	0.0251 (14)	−0.0005 (12)	0.0013 (11)	0.0024 (12)
C8	0.0224 (14)	0.0422 (19)	0.0338 (16)	−0.0034 (12)	0.0011 (12)	−0.0009 (13)
C9	0.0208 (14)	0.056 (2)	0.0280 (15)	0.0017 (13)	0.0037 (12)	0.0032 (14)
C10	0.0217 (13)	0.0388 (18)	0.0321 (16)	−0.0033 (12)	0.0052 (12)	−0.0013 (13)

Geometric parameters (Å, º) top

K1—O1	2.828 (2)	C1—C2	1.403 (4)
K1—O1ⁱ	2.828 (2)	C1—C3	1.501 (4)
K1—O2ⁱⁱ	3.056 (3)	C2—C7	1.498 (4)
K1—O2ⁱⁱⁱ	3.056 (3)	C3—H3A	0.9900
K1—O3^iv	2.682 (2)	C3—H3B	0.9900
K1—O3^v	2.682 (2)	C4—C5	1.525 (4)
K1—O4^vi	3.069 (3)	C4—H4A	0.9900
K1—O4^vii	3.069 (3)	C4—H4B	0.9900
S1—C4	1.814 (3)	C5—C6	1.506 (4)
S1—C3	1.816 (3)	C5—H5A	0.9900
S2—C8	1.809 (3)	C5—H5B	0.9900
S2—C7	1.812 (3)	C7—H7A	0.9900
O1—C6	1.252 (4)	C7—H7B	0.9900
O2—C6	1.284 (4)	C8—C9	1.517 (4)
O2—H20	1.239 (15)	C8—H8A	0.9900
O3—C10	1.211 (3)	C8—H8B	0.9900
O4—C10	1.321 (3)	C9—C10	1.502 (4)
O4—H4O	0.80 (5)	C9—H9A	0.9900
N1—C2^viii	1.339 (4)	C9—H9B	0.9900
N1—C1	1.343 (4)

O3^iv—K1—O3^v	143.00 (11)	C1—C2—C7	122.9 (3)
O3^iv—K1—O1	114.30 (6)	C1—C3—S1	114.31 (19)
O3^v—K1—O1	72.78 (6)	C1—C3—H3A	108.7
O3^iv—K1—O1ⁱ	72.78 (6)	S1—C3—H3A	108.7
O3^v—K1—O1ⁱ	114.30 (6)	C1—C3—H3B	108.7
O1—K1—O1ⁱ	159.05 (11)	S1—C3—H3B	108.7
O3^iv—K1—O2ⁱⁱ	130.71 (7)	H3A—C3—H3B	107.6
O3^v—K1—O2ⁱⁱ	85.98 (6)	C5—C4—S1	114.4 (2)
O1—K1—O2ⁱⁱ	78.37 (7)	C5—C4—H4A	108.7
O1ⁱ—K1—O2ⁱⁱ	82.42 (6)	S1—C4—H4A	108.7
O3^iv—K1—O2ⁱⁱⁱ	85.98 (6)	C5—C4—H4B	108.7
O3^v—K1—O2ⁱⁱⁱ	130.71 (7)	S1—C4—H4B	108.7
O1—K1—O2ⁱⁱⁱ	82.42 (6)	H4A—C4—H4B	107.6
O1ⁱ—K1—O2ⁱⁱⁱ	78.37 (7)	C6—C5—C4	116.2 (2)
O2ⁱⁱ—K1—O2ⁱⁱⁱ	46.99 (8)	C6—C5—H5A	108.2
O3^iv—K1—O4^vi	73.54 (7)	C4—C5—H5A	108.2
O3^v—K1—O4^vi	73.75 (7)	C6—C5—H5B	108.2
O1—K1—O4^vi	125.54 (7)	C4—C5—H5B	108.2
O1ⁱ—K1—O4^vi	75.02 (7)	H5A—C5—H5B	107.4
O2ⁱⁱ—K1—O4^vi	139.50 (6)	O1—C6—O2	124.5 (3)
O2ⁱⁱⁱ—K1—O4^vi	150.17 (6)	O1—C6—C5	119.6 (3)
O3^iv—K1—O4^vii	73.75 (7)	O2—C6—C5	115.9 (3)
O3^v—K1—O4^vii	73.54 (7)	C2—C7—S2	114.24 (19)
O1—K1—O4^vii	75.02 (7)	C2—C7—H7A	108.7
O1ⁱ—K1—O4^vii	125.54 (7)	S2—C7—H7A	108.7
O2ⁱⁱ—K1—O4^vii	150.17 (6)	C2—C7—H7B	108.7
O2ⁱⁱⁱ—K1—O4^vii	139.50 (6)	S2—C7—H7B	108.7
O4^vi—K1—O4^vii	54.87 (9)	H7A—C7—H7B	107.6
C4—S1—C3	99.68 (14)	C9—C8—S2	112.4 (2)
C8—S2—C7	102.17 (14)	C9—C8—H8A	109.1
C6—O1—K1	134.73 (19)	S2—C8—H8A	109.1
C6—O2—K1ⁱⁱ	129.17 (19)	C9—C8—H8B	109.1
C6—O2—H20	125 (2)	S2—C8—H8B	109.1
K1ⁱⁱ—O2—H20	77 (4)	H8A—C8—H8B	107.9
C10—O3—K1^ix	137.58 (18)	C10—C9—C8	113.5 (2)
C10—O4—K1^vii	111.2 (2)	C10—C9—H9A	108.9
C10—O4—H4O	110 (4)	C8—C9—H9A	108.9
K1^vii—O4—H4O	114 (4)	C10—C9—H9B	108.9
C2^viii—N1—C1	118.6 (2)	C8—C9—H9B	108.9
N1—C1—C2	120.3 (2)	H9A—C9—H9B	107.7
N1—C1—C3	116.2 (2)	O3—C10—O4	123.4 (3)
C2—C1—C3	123.5 (2)	O3—C10—C9	124.3 (2)
N1^viii—C2—C1	121.1 (2)	O4—C10—C9	112.3 (2)
N1^viii—C2—C7	116.0 (2)

C2^viii—N1—C1—C2	−0.1 (4)	K1ⁱⁱ—O2—C6—C5	−60.6 (3)
C2^viii—N1—C1—C3	178.5 (2)	C4—C5—C6—O1	161.6 (3)
N1—C1—C2—N1^viii	0.1 (4)	C4—C5—C6—O2	−21.4 (4)
C3—C1—C2—N1^viii	−178.4 (2)	N1^viii—C2—C7—S2	107.9 (2)
N1—C1—C2—C7	180.0 (2)	C1—C2—C7—S2	−72.0 (3)
C3—C1—C2—C7	1.5 (4)	C8—S2—C7—C2	−62.3 (2)
N1—C1—C3—S1	91.6 (3)	C7—S2—C8—C9	−77.5 (2)
C2—C1—C3—S1	−89.8 (3)	S2—C8—C9—C10	−173.8 (2)
C4—S1—C3—C1	−72.3 (2)	K1^ix—O3—C10—O4	1.7 (5)
C3—S1—C4—C5	−90.3 (2)	K1^ix—O3—C10—C9	−177.7 (2)
S1—C4—C5—C6	−76.4 (3)	K1^vii—O4—C10—O3	110.5 (3)
K1—O1—C6—O2	−127.8 (3)	K1^vii—O4—C10—C9	−70.0 (3)
K1—O1—C6—C5	48.8 (4)	C8—C9—C10—O3	−17.9 (5)
K1ⁱⁱ—O2—C6—O1	116.1 (3)	C8—C9—C10—O4	162.6 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O1^ix	0.80 (5)	1.86 (5)	2.661 (3)	180 (7)
O2—H20···O2^x	1.24 (1)	1.24 (1)	2.436 (3)	159 (7)
C4—H4A···N1	0.99	2.52	3.340 (4)	140
C4—H4B···O3^viii	0.99	2.49	3.114 (4)	121
C5—H5B···O2ⁱⁱⁱ	0.99	2.60	3.467 (4)	146
C7—H7B···N1^xi	0.99	2.60	3.454 (4)	144
C9—H9A···O3^xi	0.99	2.58	3.465 (4)	149

Symmetry codes: (iii) x, −y, z−1/2; (viii) −x+1/2, −y+1/2, −z; (ix) x−1/2, y+1/2, z; (x) −x+1, y, −z+1/2; (xi) x, −y, z+1/2.

Poly[(µ-3,3'-{[(3,6-bis{[(2-carboxyethyl)sulfanyl]methyl}pyrazine-2,5-diyl)bis(methylene)]bis(sulfanediyl)}dipropionato)dipotassium] (K2H2L1) top

Crystal data top

[K₂(C₂₀H₂₆N₂O₈S₄)]	F(000) = 1304
M_r = 628.87	D_x = 1.602 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 27.908 (2) Å	Cell parameters from 20250 reflections
b = 8.2916 (6) Å	θ = 1.8–29.6°
c = 11.3035 (9) Å	µ = 0.73 mm⁻¹
β = 94.753 (6)°	T = 153 K
V = 2606.7 (3) Å³	Plate, colourless
Z = 4	0.50 × 0.50 × 0.05 mm

Data collection top

STOE IPDS 2 diffractometer	3646 independent reflections
Radiation source: fine-focus sealed tube	3175 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.042
φ + ω scans	θ_max = 29.6°, θ_min = 2.6°
Absorption correction: empirical (using intensity measurements) (ShxAbs; Spek, 2020)	h = −38→38
T_min = 0.416, T_max = 0.803	k = −11→11
19423 measured reflections	l = −15→15

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)] = 0.037	Hydrogen site location: mixed
wR(F²) = 0.103	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0541P)² + 3.5192P] where P = (F_o² + 2F_c²)/3
3646 reflections	(Δ/σ)_max < 0.001
167 parameters	Δρ_max = 0.76 e Å⁻³
1 restraint	Δρ_min = −0.51 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
K1	0.000000	0.82906 (7)	0.750000	0.02908 (13)
K2	0.000000	0.64758 (6)	0.250000	0.02585 (12)
S1	0.15530 (2)	0.94369 (6)	0.36528 (5)	0.03200 (12)
S2	0.31454 (2)	0.91861 (6)	0.30731 (4)	0.02972 (12)
O1	0.03202 (5)	0.90961 (16)	0.37679 (12)	0.0288 (3)
O2	0.03173 (4)	0.75961 (15)	0.53962 (10)	0.0251 (2)
O3	0.44445 (5)	1.07891 (16)	0.64145 (11)	0.0264 (3)
O4	0.45504 (4)	1.14483 (16)	0.45457 (11)	0.0246 (2)
H4O	0.4811 (7)	1.187 (3)	0.485 (2)	0.037*
N1	0.22122 (5)	1.18192 (18)	0.58094 (13)	0.0226 (3)
C1	0.23166 (6)	1.10103 (19)	0.48370 (15)	0.0214 (3)
C2	0.26072 (6)	1.1694 (2)	0.40166 (14)	0.0214 (3)
C3	0.20952 (6)	0.9373 (2)	0.46641 (17)	0.0261 (3)
H3A	0.201509	0.894439	0.544105	0.031*
H3B	0.233073	0.863252	0.434300	0.031*
C4	0.11775 (7)	1.0635 (2)	0.4543 (2)	0.0344 (4)
H4A	0.138286	1.142471	0.500499	0.041*
H4B	0.094632	1.125024	0.400576	0.041*
C5	0.08989 (6)	0.9666 (2)	0.53952 (18)	0.0301 (4)
H5A	0.112007	0.889825	0.583250	0.036*
H5B	0.077277	1.040676	0.598231	0.036*
C6	0.04848 (6)	0.8740 (2)	0.47738 (14)	0.0215 (3)
C7	0.27238 (6)	1.0859 (2)	0.28997 (15)	0.0260 (3)
H7A	0.285609	1.166910	0.237196	0.031*
H7B	0.241998	1.045256	0.249183	0.031*
C8	0.37036 (6)	1.0182 (3)	0.35882 (16)	0.0295 (4)
H8A	0.397073	0.966995	0.320275	0.035*
H8B	0.368597	1.132425	0.333262	0.035*
C9	0.38174 (6)	1.0126 (2)	0.49202 (15)	0.0243 (3)
H9A	0.380284	0.899037	0.518480	0.029*
H9B	0.356583	1.073093	0.530128	0.029*
C10	0.43036 (6)	1.08130 (19)	0.53492 (14)	0.0216 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0442 (3)	0.0240 (2)	0.0186 (2)	0.000	−0.0001 (2)	0.000
K2	0.0356 (3)	0.0230 (2)	0.0189 (2)	0.000	0.00191 (18)	0.000
S1	0.0250 (2)	0.0304 (2)	0.0399 (3)	−0.00503 (16)	−0.00202 (17)	−0.00557 (18)
S2	0.0236 (2)	0.0297 (2)	0.0355 (2)	−0.00158 (16)	0.00042 (16)	−0.00746 (17)
O1	0.0311 (6)	0.0272 (6)	0.0269 (6)	−0.0064 (5)	−0.0040 (5)	0.0023 (5)
O2	0.0235 (5)	0.0282 (6)	0.0233 (5)	−0.0027 (5)	0.0009 (4)	0.0005 (5)
O3	0.0276 (6)	0.0300 (6)	0.0217 (5)	−0.0011 (5)	0.0019 (4)	0.0021 (5)
O4	0.0228 (5)	0.0299 (6)	0.0212 (5)	−0.0051 (5)	0.0024 (4)	0.0004 (5)
N1	0.0196 (6)	0.0235 (6)	0.0242 (6)	−0.0010 (5)	−0.0004 (5)	0.0030 (5)
C1	0.0173 (6)	0.0206 (7)	0.0256 (7)	−0.0002 (5)	−0.0027 (5)	0.0020 (6)
C2	0.0183 (7)	0.0230 (7)	0.0223 (7)	0.0002 (5)	−0.0022 (5)	0.0019 (6)
C3	0.0214 (7)	0.0213 (7)	0.0353 (9)	−0.0017 (6)	0.0007 (6)	0.0016 (6)
C4	0.0220 (8)	0.0231 (8)	0.0576 (12)	−0.0023 (6)	−0.0009 (8)	−0.0060 (8)
C5	0.0230 (8)	0.0295 (9)	0.0368 (9)	−0.0023 (6)	−0.0035 (7)	−0.0092 (7)
C6	0.0180 (7)	0.0212 (7)	0.0250 (7)	0.0004 (5)	0.0006 (5)	−0.0046 (6)
C7	0.0250 (8)	0.0290 (8)	0.0237 (7)	−0.0007 (6)	−0.0005 (6)	−0.0005 (6)
C8	0.0211 (7)	0.0402 (10)	0.0271 (8)	−0.0049 (7)	0.0021 (6)	−0.0020 (7)
C9	0.0218 (7)	0.0250 (8)	0.0261 (7)	−0.0017 (6)	0.0025 (6)	−0.0010 (6)
C10	0.0224 (7)	0.0205 (7)	0.0220 (7)	0.0019 (5)	0.0031 (6)	−0.0003 (5)

Geometric parameters (Å, º) top

K1—O1ⁱ	2.7084 (14)	O1—C6	1.227 (2)
K1—O1ⁱⁱ	2.7084 (14)	O4—C10	1.296 (2)
K1—O2	2.6682 (12)	O4—H4O	0.855 (16)
K1—O2ⁱⁱⁱ	2.6683 (12)	O3—C10	1.236 (2)
K1—O3^iv	2.8099 (14)	N1—C1	1.340 (2)
K1—O3^v	2.8099 (13)	N1—C2^xi	1.341 (2)
K1—C6ⁱⁱⁱ	3.4864 (17)	C1—C2	1.401 (2)
K1—C6	3.4865 (17)	C1—C3	1.498 (2)
K1—K2^vi	3.9521 (8)	C2—C7	1.499 (2)
K1—K2ⁱⁱ	4.3395 (8)	C3—H3A	0.9900
K2—O1^vii	2.7131 (13)	C3—H3B	0.9900
K2—O1	2.7132 (13)	C4—C5	1.518 (3)
K2—O3^viii	2.6683 (13)	C4—H4A	0.9900
K2—O3^ix	2.6682 (13)	C4—H4B	0.9900
K2—O4^x	2.7209 (12)	C5—C6	1.511 (2)
K2—O4^iv	2.7209 (12)	C5—H5A	0.9900
K2—C6^vii	3.3739 (16)	C5—H5B	0.9900
K2—C6	3.3739 (16)	C7—H7A	0.9900
K2—C10^viii	3.5364 (16)	C7—H7B	0.9900
K2—C10^ix	3.5364 (16)	C8—C9	1.513 (2)
S1—C4	1.809 (2)	C8—H8A	0.9900
S1—C3	1.8200 (18)	C8—H8B	0.9900
S2—C8	1.8159 (18)	C9—C10	1.514 (2)
S2—C7	1.8190 (19)	C9—H9A	0.9900
O2—C6	1.291 (2)	C9—H9B	0.9900

O2—K1—O2ⁱⁱⁱ	155.07 (6)	O3^ix—K2—K1^vi	45.27 (3)
O2—K1—O1ⁱ	121.67 (4)	O1^vii—K2—K1^vi	143.21 (3)
O2ⁱⁱⁱ—K1—O1ⁱ	79.65 (4)	O1—K2—K1^vi	143.21 (3)
O2—K1—O1ⁱⁱ	79.65 (4)	O4^x—K2—K1^vi	89.52 (3)
O2ⁱⁱⁱ—K1—O1ⁱⁱ	121.67 (4)	O4^iv—K2—K1^vi	89.52 (3)
O1ⁱ—K1—O1ⁱⁱ	73.73 (6)	C6^vii—K2—K1^vi	123.80 (3)
O2—K1—O3^iv	70.32 (4)	C6—K2—K1^vi	123.80 (3)
O2ⁱⁱⁱ—K1—O3^iv	91.03 (4)	C10^viii—K2—K1^vi	57.55 (3)
O1ⁱ—K1—O3^iv	165.36 (4)	C10^ix—K2—K1^vi	57.55 (3)
O1ⁱⁱ—K1—O3^iv	102.33 (4)	O3^viii—K2—K1ⁱⁱ	134.73 (3)
O2—K1—O3^v	91.03 (4)	O3^ix—K2—K1ⁱⁱ	134.73 (3)
O2ⁱⁱⁱ—K1—O3^v	70.32 (4)	O1^vii—K2—K1ⁱⁱ	36.79 (3)
O1ⁱ—K1—O3^v	102.33 (4)	O1—K2—K1ⁱⁱ	36.79 (3)
O1ⁱⁱ—K1—O3^v	165.36 (4)	O4^x—K2—K1ⁱⁱ	90.48 (3)
O3^iv—K1—O3^v	84.85 (5)	O4^iv—K2—K1ⁱⁱ	90.48 (3)
O2—K1—C6ⁱⁱⁱ	172.97 (4)	C6^vii—K2—K1ⁱⁱ	56.20 (3)
O2ⁱⁱⁱ—K1—C6ⁱⁱⁱ	18.84 (4)	C6—K2—K1ⁱⁱ	56.20 (3)
O1ⁱ—K1—C6ⁱⁱⁱ	65.30 (4)	C10^viii—K2—K1ⁱⁱ	122.45 (3)
O1ⁱⁱ—K1—C6ⁱⁱⁱ	104.31 (4)	C10^ix—K2—K1ⁱⁱ	122.45 (3)
O3^iv—K1—C6ⁱⁱⁱ	102.96 (4)	K1^vi—K2—K1ⁱⁱ	180.0
O3^v—K1—C6ⁱⁱⁱ	86.17 (4)	C4—S1—C3	99.00 (9)
O2—K1—C6	18.84 (4)	C8—S2—C7	102.58 (9)
O2ⁱⁱⁱ—K1—C6	172.97 (4)	C6—O2—K1	119.28 (10)
O1ⁱ—K1—C6	104.31 (4)	C6—O1—K1ⁱⁱ	139.92 (11)
O1ⁱⁱ—K1—C6	65.30 (4)	C6—O1—K2	112.22 (11)
O3^iv—K1—C6	86.17 (4)	K1ⁱⁱ—O1—K2	106.34 (4)
O3^v—K1—C6	102.96 (4)	C10—O4—K2^xii	155.24 (11)
C6ⁱⁱⁱ—K1—C6	167.74 (6)	C10—O4—H4O	111.3 (17)
O2—K1—K2^vi	77.54 (3)	K2^xii—O4—H4O	84.7 (17)
O2ⁱⁱⁱ—K1—K2^vi	77.54 (3)	C10—O3—K2^ix	125.83 (11)
O1ⁱ—K1—K2^vi	143.13 (3)	C10—O3—K1^xii	122.23 (11)
O1ⁱⁱ—K1—K2^vi	143.13 (3)	K2^ix—O3—K1^xii	92.31 (4)
O3^iv—K1—K2^vi	42.42 (3)	C1—N1—C2^xi	118.43 (14)
O3^v—K1—K2^vi	42.42 (3)	N1—C1—C2	121.17 (15)
C6ⁱⁱⁱ—K1—K2^vi	96.13 (3)	N1—C1—C3	116.44 (15)
C6—K1—K2^vi	96.13 (3)	C2—C1—C3	122.37 (15)
O2—K1—K2ⁱⁱ	102.46 (3)	N1^xi—C2—C1	120.40 (15)
O2ⁱⁱⁱ—K1—K2ⁱⁱ	102.46 (3)	N1^xi—C2—C7	116.30 (15)
O1ⁱ—K1—K2ⁱⁱ	36.87 (3)	C1—C2—C7	123.28 (15)
O1ⁱⁱ—K1—K2ⁱⁱ	36.87 (3)	C1—C3—S1	111.60 (12)
O3^iv—K1—K2ⁱⁱ	137.58 (3)	C1—C3—H3A	109.3
O3^v—K1—K2ⁱⁱ	137.58 (3)	S1—C3—H3A	109.3
C6ⁱⁱⁱ—K1—K2ⁱⁱ	83.87 (3)	C1—C3—H3B	109.3
C6—K1—K2ⁱⁱ	83.87 (3)	S1—C3—H3B	109.3
K2^vi—K1—K2ⁱⁱ	180.0	H3A—C3—H3B	108.0
O3^viii—K2—O3^ix	90.54 (6)	C5—C4—S1	114.41 (14)
O3^viii—K2—O1^vii	99.63 (4)	C5—C4—H4A	108.7
O3^ix—K2—O1^vii	163.72 (4)	S1—C4—H4A	108.7
O3^viii—K2—O1	163.72 (4)	C5—C4—H4B	108.7
O3^ix—K2—O1	99.63 (4)	S1—C4—H4B	108.7
O1^vii—K2—O1	73.59 (6)	H4A—C4—H4B	107.6
O3^viii—K2—O4^x	83.95 (4)	C6—C5—C4	112.73 (16)
O3^ix—K2—O4^x	95.38 (4)	C6—C5—H5A	109.0
O1^vii—K2—O4^x	73.30 (4)	C4—C5—H5A	109.0
O1—K2—O4^x	107.50 (4)	C6—C5—H5B	109.0
O3^viii—K2—O4^iv	95.38 (4)	C4—C5—H5B	109.0
O3^ix—K2—O4^iv	83.95 (4)	H5A—C5—H5B	107.8
O1^vii—K2—O4^iv	107.50 (4)	O1—C6—O2	123.88 (15)
O1—K2—O4^iv	73.30 (4)	O1—C6—C5	121.42 (16)
O4^x—K2—O4^iv	179.04 (6)	O2—C6—C5	114.67 (15)
O3^viii—K2—C6^vii	81.96 (4)	O1—C6—K2	48.11 (8)
O3^ix—K2—C6^vii	157.35 (4)	O2—C6—K2	82.31 (9)
O1^vii—K2—C6^vii	19.67 (4)	C5—C6—K2	151.60 (11)
O1—K2—C6^vii	92.90 (4)	O1—C6—K1	134.60 (11)
O4^x—K2—C6^vii	62.69 (4)	O2—C6—K1	41.88 (8)
O4^iv—K2—C6^vii	117.91 (4)	C5—C6—K1	88.93 (10)
O3^viii—K2—C6	157.35 (4)	K2—C6—K1	116.96 (5)
O3^ix—K2—C6	81.96 (4)	C2—C7—S2	116.42 (12)
O1^vii—K2—C6	92.90 (4)	C2—C7—H7A	108.2
O1—K2—C6	19.67 (4)	S2—C7—H7A	108.2
O4^x—K2—C6	117.91 (4)	C2—C7—H7B	108.2
O4^iv—K2—C6	62.69 (4)	S2—C7—H7B	108.2
C6^vii—K2—C6	112.40 (6)	H7A—C7—H7B	107.3
O3^viii—K2—C10^viii	16.46 (4)	C9—C8—S2	114.13 (13)
O3^ix—K2—C10^viii	101.75 (4)	C9—C8—H8A	108.7
O1^vii—K2—C10^viii	85.89 (4)	S2—C8—H8A	108.7
O1—K2—C10^viii	158.61 (4)	C9—C8—H8B	108.7
O4^x—K2—C10^viii	71.16 (4)	S2—C8—H8B	108.7
O4^iv—K2—C10^viii	108.29 (4)	H8A—C8—H8B	107.6
C6^vii—K2—C10^viii	67.17 (4)	C8—C9—C10	114.57 (14)
C6—K2—C10^viii	170.09 (4)	C8—C9—H9A	108.6
O3^viii—K2—C10^ix	101.75 (4)	C10—C9—H9A	108.6
O3^ix—K2—C10^ix	16.46 (4)	C8—C9—H9B	108.6
O1^vii—K2—C10^ix	158.61 (4)	C10—C9—H9B	108.6
O1—K2—C10^ix	85.89 (4)	H9A—C9—H9B	107.6
O4^x—K2—C10^ix	108.29 (4)	O3—C10—O4	122.99 (16)
O4^iv—K2—C10^ix	71.16 (4)	O3—C10—C9	120.71 (15)
C6^vii—K2—C10^ix	170.09 (4)	O4—C10—C9	116.27 (14)
C6—K2—C10^ix	67.17 (4)	O3—C10—K2^ix	37.72 (8)
C10^viii—K2—C10^ix	115.09 (5)	O4—C10—K2^ix	113.96 (10)
O3^viii—K2—K1^vi	45.27 (3)	C9—C10—K2^ix	116.44 (10)

C2^xi—N1—C1—C2	0.0 (2)	C4—C5—C6—O1	−18.7 (2)
C2^xi—N1—C1—C3	−178.32 (14)	C4—C5—C6—O2	162.94 (15)
N1—C1—C2—N1^xi	0.0 (3)	C4—C5—C6—K2	40.3 (3)
C3—C1—C2—N1^xi	178.22 (14)	C4—C5—C6—K1	−162.96 (14)
N1—C1—C2—C7	−178.30 (15)	N1^xi—C2—C7—S2	108.63 (15)
C3—C1—C2—C7	−0.1 (2)	C1—C2—C7—S2	−72.98 (19)
N1—C1—C3—S1	97.64 (16)	C8—S2—C7—C2	−67.34 (15)
C2—C1—C3—S1	−80.62 (18)	C7—S2—C8—C9	97.89 (15)
C4—S1—C3—C1	−65.81 (15)	S2—C8—C9—C10	174.51 (12)
C3—S1—C4—C5	−87.72 (15)	K2^ix—O3—C10—O4	−87.24 (18)
S1—C4—C5—C6	−73.29 (18)	K1^xii—O3—C10—O4	33.7 (2)
K1ⁱⁱ—O1—C6—O2	128.23 (16)	K2^ix—O3—C10—C9	94.51 (17)
K2—O1—C6—O2	−35.0 (2)	K1^xii—O3—C10—C9	−144.57 (12)
K1ⁱⁱ—O1—C6—C5	−49.9 (3)	K1^xii—O3—C10—K2^ix	120.92 (16)
K2—O1—C6—C5	146.80 (13)	K2^xii—O4—C10—O3	125.1 (2)
K1ⁱⁱ—O1—C6—K2	163.2 (2)	K2^xii—O4—C10—C9	−56.6 (3)
K1ⁱⁱ—O1—C6—K1	74.9 (2)	K2^xii—O4—C10—K2^ix	83.1 (3)
K2—O1—C6—K1	−88.34 (15)	C8—C9—C10—O3	−177.68 (16)
K1—O2—C6—O1	−121.20 (15)	C8—C9—C10—O4	3.9 (2)
K1—O2—C6—C5	57.09 (17)	C8—C9—C10—K2^ix	−134.75 (13)
K1—O2—C6—K2	−146.73 (7)

Symmetry codes: (i) x, −y+2, z+1/2; (ii) −x, −y+2, −z+1; (iii) −x, y, −z+3/2; (iv) x−1/2, y−1/2, z; (v) −x+1/2, y−1/2, −z+3/2; (vi) −x, −y+1, −z+1; (vii) −x, y, −z+1/2; (viii) x−1/2, −y+3/2, z−1/2; (ix) −x+1/2, −y+3/2, −z+1; (x) −x+1/2, y−1/2, −z+1/2; (xi) −x+1/2, −y+5/2, −z+1; (xii) x+1/2, y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O2^xii	0.85 (2)	1.61 (2)	2.4637 (16)	177 (3)
C4—H4A···N1	0.99	2.44	3.266 (2)	141
C8—H8A···O3^xiii	0.99	2.53	3.436 (2)	151

Symmetry codes: (xii) x+1/2, y+1/2, z; (xiii) x, −y+2, z−1/2.

Selected torsion angles (°) along the C_ar—CH₂—S—CH₂—CH₂—CO₂H side chains in compounds H₄L1_A, H₄L1_B, H₃L1K and H₂L1K2 top

Torsion angle	H₄L1_A	H₄L1_B	H₃L1K	H₂L1K2
C1—C3—S1—C4	174.1 (2)	-72.6 (4)	-72.32)	-65.81 (15)
C3—S1—C4—C5	-155.3 (2)	-86.7 (4)	-90.3 (2)	-87.72 (15)
S1—C4—C5—C6	-167.9 (2)	-65.0 (6)	-76.4 (3)	-73.19 (18)
C2—C7—S2—C8	57.6 (2)	-66.8 (4)	-62.3 (2)	-67.34 (15)
C7—C2—S2—C9	65.7 (2)	-178.1 (5)	-77.5 (2)	97.89 (15)
S2—C8—C9—C10	174.8 (2)	-172.5 (5)	-173.8 (2)	174.51 (12)

Short contacts (Å) in the crystal structures of H₄L1_A and H₄L1_B^a top

Atom 1	Atom 2	Length	Length - VdW	Symm. op. 1	Symm. op. 2
H₄L1_A
O1	H2O	1.798	-0.922	x, y, z	-1 - x, -y, -z
O3	H4O	1.843	-0.877	x, y, z	1 - x, 1 - y, -z
O1	O2	2.667	-0.373	x, y, z	-1 - x, -y, -z
O3	O4	2.673	-0.367	x, y, z	1 - x, 1 - y, -z
O4	H8A	2.399	-0.321	x, y, z	-1 + x, y, z
O2	O4	3.015	-0.025	x, y, z	-x, 1 - y, -z
C6	H2O	2.667	-0.233	x, y, z	-1 - x, -y, -z
C10	H4O	2.668	-0.232	x, y, z	1 - x, 1 - y, -z
H5A	O3	2.549	-0.171	x, y, z	-1 + x, y, z
H4O	H4O	2.371	-0.029	x, y, z	1 - x, 1 - y, -z
H2O	H2O	2.389	-0.011	x, y, z	-1 - x, -y, -z
N1	H3A	2.807	0.057	x, y, z	1 - x, 1 - y, 1 - z
O4	C8	3.308	0.088	x, y, z	-1 + x, y, z
O2	H8A	2.820	0.100	x, y, z	1 - x, 1 - y, -z

H₄L1_B^a
H4O	O1	1.879	-0.841	x, y, z	x, y, -1 + z
O4	O1	2.658	-0.382	x, y, z	x, y, -1 + z
O3	O2	2.663	-0.377	x, y, z	x, y, -1 + z
H4O	C6	2.580	-0.320	x, y, z	x, y, -1 + z
O4	O2	2.799	-0.241	x, y, z	-1 + x, y, -1 + z
H4O	H2O	2.173	-0.227	x, y, z	x, y, -1 + z
O1	O2	2.982	-0.058	x, y, z	-1 + x, y, z
S1	H3A	2.951	-0.049	x, y, z	-1 + x, y, z
S1	S2	3.590	-0.010	x, y, z	1 - x, -y, 1 - z
O4	O3	3.041	0.001	x, y, z	-1 + x, y, z
S2	S2	3.613	0.013	x, y, z	1 - x, -y, 1 - z
H8A	O3	2.749	0.029	x, y, z	-1 + x, y, z
S1	H5A	3.047	0.047	x, y, z	-1 + x, y, z
H4O	O2	2.775	0.055	x, y, z	-1 + x, y, -1 + z
O4	H2O	2.776	0.056	x, y, z	-1 + x, y, -1 + z
C10	H2O	2.960	0.060	x, y, z	2 - x, -y, 1 - z
O3	H2O	2.796	0.076	x, y, z	2 - x, -y, 1 - z
H7B	C3	2.974	0.074	x, y, z	-1 + x, y, z
S2	H7B	3.082	0.082	x, y, z	1 - x, -y, 1 - z
O2	H5B	2.802	0.082	2 - x, 1 - y, 1 - z	-1 + x, y, -1 + z
S1	H9A	3.085	0.085	x, y, z	1 - x, -y, 1 - z

Note: (a) major component of H₄L1_B.

Percentage contributions of inter-atomic contacts to the Hirshfeld surfaces of H₄L1_A and H₄L1_B^a top

Contact	% contribution	% contribution
	H₄L1_A	H₄L1_B^a
H···H	37.2	36.3
O···H/H···O	37.7	32.3
S···H/H···S	13.4	16.1
C···H/H···C	4.5	4.9
C···N	0	0.8
C···O	1.0	0.7
C···S	1.2	0
N···S	0.4	0.4
O···O	1.3	4.9
O···S	0.2	0
S···S	0.2	1.2

Note: (a) major component of H₄L1_B.

Acknowledgements

HSE is grateful to the University of Neuchâtel for their support over the years.

Funding information

Funding for this research was provided by: Swiss National Science Foundation; University of Neuchâtel.

References

Assoumatine, T. & Stoeckli-Evans, H. (2014). Acta Cryst. E70, 51–53. CSD CrossRef CAS IUCr Journals Google Scholar
Ferigo, M., Bonhôte, P., Marty, W. & Stoeckli-Evans, H. (1994). J. Chem. Soc. Dalton Trans. pp. 1549–1554. CSD CrossRef Web of Science 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
Hayati, P., Rezvani, A. R., Morsali, A. & Retailleau, P. (2017). Ultrason. Sonochem. 34, 195–205. Web of Science CSD CrossRef CAS PubMed Google Scholar
Jiang, Y., Sun, L., Du, J., Liu, Y., Shi, H., Liang, Z. & Li, J. (2017). Cryst. Growth Des. 17, 2090–2096. Web of Science CSD CrossRef CAS Google Scholar
Li, C., Wang, K., Li, J. & Zhang, Q. (2020). Nanoscale, 12, 7870-7874. Web of Science CSD CrossRef CAS PubMed Google Scholar
Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226–235. Web of Science CrossRef CAS IUCr Journals Google Scholar
Marioni, P.-A., Stoeckli-Evans, H., Marty, W., Güdel, H.-U. & Williams, A. F. (1986). Helv. Chim. Acta, 69, 1004–1011. CSD CrossRef CAS Web of Science Google Scholar
Masci, B., Pasquale, S. & Thuéry, P. (2010). Cryst. Growth Des. 10, 2004–2010. Web of Science CSD CrossRef CAS Google Scholar
McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. 3814–3816. Google Scholar
Pacifico, J. (2003). PhD Thesis, University of Neuchâtel, Switzerland. Google Scholar
Pacifico, J. & Stoeckli-Evans, H. (2020). Private communications (CCDC 2036276, 2041654 and 2041655). CCDC, Cambridge, England. Google Scholar
Santra, S., Das, B. & Baruah, J. B. (2011). J. Chem. Crystallogr. 41, 1981–1987. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19–32. Web of Science CrossRef CAS Google Scholar
Spek, A. L. (2020). Acta Cryst. E76, 1–11. Web of Science CrossRef IUCr Journals Google Scholar
Stoe & Cie (2000). IPDSI Bedienungshandbuch. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar
Stoe & Cie. (2002). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar
Tan, S. L., Jotani, M. M. & Tiekink, E. R. T. (2019). Acta Cryst. E75, 308–318. Web of Science CrossRef IUCr Journals Google Scholar
Tombul, M., Güven, K. & Svoboda, I. (2008). Acta Cryst. E64, m246–m247. Web of Science CSD CrossRef IUCr Journals Google Scholar
Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). CrystalExplorer17. University of Western Australia. https://hirshfeldsurface.net Google Scholar
Wang, L., Zou, R., Guo, W., Gao, S., Meng, W., Yang, J., Chen, X. & Zou, R. (2019). Inorg. Chem. Commun. 104, 78–82. Web of Science CSD CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wolff, L. (1887). Ber. Dtsch. Chem. Ges. 20, 425–433. CrossRef Google Scholar
Wolff, L. (1893). Ber. Dtsch. Chem. Ges. 26, 721–725. CrossRef Google Scholar

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research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

A new tetra­kis-substituted pyrazine carb­­oxy­lic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetra­yltetra­kis(methyl­ene)]tetra­kis­(sulfanedi­yl)}tetra­propionic acid: crystal structures of two triclinic polymorphs and of two potassium–organic frameworks

1. Chemical context

2. Structural commentary

3. Supra­molecular features

4. Hirshfeld surface analysis and two-dimensional fingerprint plots for H4L1_A, and H4L1_B

5. Energies frameworks for H4L1_A, and H4L1_B

6. Database survey

7. Synthesis and crystallization

8. Refinement

Supporting information

Acknowledgements

Funding information

References

research communications

A new tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetrapropionic acid: crystal structures of two triclinic polymorphs and of two potassium–organic frameworks

3. Supramolecular features

4. Hirshfeld surface analysis and two-dimensional fingerprint plots for H₄L1_A, and H₄L1_B

5. Energies frameworks for H₄L1_A, and H₄L1_B