organic compounds
Pyridinium 3-nitrobenzoate–3-nitrobenzoic acid (1/1)
aAve Maria University, Department of Chemistry and Physics, 5050 Ave Maria Blvd, Ave Maria FL, 34142, USA, and bPurdue University, Department of Chemistry, 560 Oval Drive, West Lafayette, Indiana USA, 47907, USA
*Correspondence e-mail: Patrick.Hillesheim@avemaria.edu
The 5H6N+·C7H4NO4−·C7H5NO4. Distinct sets of hydrogen bonds link the pyridinium and benzoate ions (N—H⋯O) and the acid and benzoate moieties (O—H⋯O). The hydrogen bonding along with π–π stacking between the acid and benzoate moieties accounts for the long-range ordering of the crystal.
of the product of the neutralization reaction between 3-nitrobenzoic acid and pyridine is reported. The entities that crystallized are a pyridinium cation, a 3-nitrobenzoate anion and a 3-nitrobenzoic acid molecule in a 1:1:1 molar ratio, CKeywords: crystal structure; hydrogen bonding; carboxylate; carboxylic acid.
CCDC reference: 2088013
Structure description
The sample crystallizes in the monoclinic Pc Three discrete entities in a 1:1:1 molar ratio comprise the of this structure: 3-nitrobenzoic acid, 3-nitrobenzoate, and a pyridinium cation (Fig. 1). The structure is the result of a neutralization reaction of the carboxylic acid and pyridine (see Synthesis and crystallization section for details). The benzoic acid molecule and benzoate anion in the are nearly coplanar with a 1.16 (14)° dihedral angle. The dihedral angle between the pyridinium and the acid is 99.99 (10)° and the dihedral angle between the benzoate anion and pyridinium cation is 99.58 (10)°.
in theThe acid and benzoate moieties are linked through a short hydrogen bond between the protonated carboxylic acid oxygen atom O1 and the carboxylate anion oxygen Oatom 5 [O1—H1⋯O5, d = 1.69 (4) Å]. The other carboxylate oxygen atom, O6, accepts a hydrogen bond from the protonated pyridinium cation, N3—H3A⋯O6 at a distance of 1.81 (4) Å (Figs. 1 and 2; Table 1).
|
Parallel, offset π interactions between benzoate anions and between benzoic acid molecules account, in part, for the long-range ordering of the structure. The interactions range in distance from approximately 3.3 to 3.5 Å. Given the offset interactions of the aromatic rings, it appears that interactions are between the nitro groups and the aromatic rings in a manner similar to previously reported structures (Sánchez-Moreno et al., 2003). A depiction of these π interactions is shown in Fig. 3. No π interactions are observed from the pyridinium moiety.
Both distinct nitro groups, that is the nitro group on the acid molecule and the nitro group on the benzoate anion, interact with hydrogen atoms on the pyridinium ring. The shortest H⋯ONO2 interactions are between O7 and O8 with H19 in one of the α positions of the pyridinium ring. Both O atoms of the nitro moiety participate in a nearly symmetric, bifurcated interaction with the H19 atom at distances of 2.695 (3) and 2.714 (3) Å, respectively. The other nitro oxygen atoms (O3 and O4) also display a nearly symmetric bifurcated set of interactions with H16 in the β position of the pyridinium ring, at H⋯ONO2 distances of 2.882 (3) and 2.820 (3) Å, respectively. The H⋯ONO2 interactions observed herein are similar to those observed in some previously reported compounds (Allen et al., 1997; Gu et al., 1999; Vijayvergiya et al., 1995).
Synthesis and crystallization
The reported crystal is an impurity from residual water from an esterification reaction. A sample of 3-nitrobenzoyl chloride (1 eq.) was dissolved in dichloromethane (30 ml) with stirring. Pyridine (2 eq.) and ethanol (5 eq.) were added to the solution, the flask sealed, and the entire mixture allowed to stir overnight at room temperature. A white crystalline solid formed after several minutes of stirring. A sample of this crystalline material was collected and analyzed, yielding the structure presented herein.
Refinement
Crystal data, data collection and structure . The spatial arrangement of the two nitroaromatic moieties in the with the exception of the acidic proton on the carbonyl group forming the acid versus the carboxylate group, might lead to the conclusion that a higher would exist. As such, these two molecules appear related by pseudo screw-axis symmetry; however, they are, in fact, not related by symmetry. To verify this claim, the structure was solved in the P21/c which leads to a substantial increase in the R1 and wR2 residuals (11.78% and 23.88%, respectively). The final structure solution presented is thus in the correct accounting for the subtle differences in the bonding of two nitroaromatic moieties.
details are summarized in Table 2Structural data
CCDC reference: 2088013
https://doi.org/10.1107/S2414314621005812/bh4062sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621005812/bh4062Isup3.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314621005812/bh4062Isup3.cml
Data collection: APEX3 (Bruker, 2020); cell
SAINT (Bruker, 2020); data reduction: SAINT (Bruker, 2020); program(s) used to solve structure: SHELXT2018/2 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); Mercury (Macrae et al., 2020); software used to prepare material for publication: publCIF (Westrip, 2010), CSD (Groom et al., 2016) and enCIFer (Allen et al., 2004).C5H6N+·C7H4NO4−·C7H5NO4 | F(000) = 428 |
Mr = 413.34 | Dx = 1.495 Mg m−3 |
Monoclinic, Pc | Mo Kα radiation, λ = 0.71073 Å |
a = 6.2434 (3) Å | Cell parameters from 3891 reflections |
b = 21.3584 (10) Å | θ = 3.0–28.3° |
c = 6.8938 (3) Å | µ = 0.12 mm−1 |
β = 93.118 (2)° | T = 150 K |
V = 917.92 (7) Å3 | Plate, colourless |
Z = 2 | 0.35 × 0.15 × 0.05 mm |
Bruker AXS D8 Quest diffractometer with PhotonII charge-integrating pixel array detector (CPAD) | 4437 independent reflections |
Radiation source: 1 kW fine focus sealed tube X-ray source | 3733 reflections with I > 2σ(I) |
Detector resolution: 7.4074 pixels mm-1 | Rint = 0.023 |
ω and φ scans | θmax = 28.4°, θmin = 2.9° |
Absorption correction: multi-scan (SADABS; Bruker, 2020) | h = −8→8 |
Tmin = 0.636, Tmax = 0.746 | k = −28→28 |
7895 measured reflections | l = −9→9 |
Refinement on F2 | Primary atom site location: dual |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: mixed |
wR(F2) = 0.107 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.044P)2 + 0.2733P] where P = (Fo2 + 2Fc2)/3 |
4437 reflections | (Δ/σ)max < 0.001 |
277 parameters | Δρmax = 0.25 e Å−3 |
2 restraints | Δρmin = −0.19 e Å−3 |
Refinement. H atoms on the aromatic (sp2) carbons were included in calculated positions and treated as riding atoms: C—H = 0.95 Å with Uiso(H) = 1.2 × Ueq(carrier atom). H atoms H1 and H3A were located as residual electron density and allowed to refine freely with Uiso(H) = 1.5 × Ueq(O or N). |
x | y | z | Uiso*/Ueq | ||
C1 | 0.3880 (5) | 0.35185 (15) | 0.2998 (4) | 0.0229 (7) | |
C2 | 0.5147 (5) | 0.40980 (15) | 0.3404 (4) | 0.0203 (7) | |
C3 | 0.4093 (5) | 0.46720 (14) | 0.3147 (4) | 0.0190 (7) | |
H3 | 0.262180 | 0.468543 | 0.271691 | 0.023* | |
C4 | 0.5217 (5) | 0.52186 (15) | 0.3528 (4) | 0.0198 (7) | |
C5 | 0.7352 (5) | 0.52249 (16) | 0.4169 (5) | 0.0241 (7) | |
H5 | 0.809070 | 0.560736 | 0.442560 | 0.029* | |
C6 | 0.8384 (5) | 0.46494 (16) | 0.4425 (5) | 0.0261 (7) | |
H6 | 0.985232 | 0.463902 | 0.486611 | 0.031* | |
C7 | 0.7308 (5) | 0.40954 (16) | 0.4048 (5) | 0.0235 (7) | |
H7 | 0.804206 | 0.370838 | 0.422786 | 0.028* | |
N1 | 0.4075 (5) | 0.58181 (13) | 0.3261 (4) | 0.0254 (6) | |
O1 | 0.5027 (4) | 0.30049 (11) | 0.3136 (4) | 0.0325 (6) | |
H1 | 0.419 (7) | 0.2717 (19) | 0.283 (7) | 0.049* | |
O2 | 0.1965 (4) | 0.35353 (11) | 0.2591 (4) | 0.0346 (6) | |
O3 | 0.2159 (4) | 0.58001 (12) | 0.2787 (5) | 0.0421 (7) | |
O4 | 0.5076 (5) | 0.63004 (12) | 0.3523 (4) | 0.0410 (7) | |
C8 | 0.3862 (6) | 0.15289 (15) | 0.2486 (5) | 0.0246 (7) | |
C9 | 0.2590 (5) | 0.09406 (15) | 0.1956 (4) | 0.0213 (7) | |
C10 | 0.3561 (6) | 0.03643 (14) | 0.2200 (4) | 0.0208 (7) | |
H10 | 0.501855 | 0.033298 | 0.266289 | 0.025* | |
C11 | 0.2370 (5) | −0.01667 (14) | 0.1758 (4) | 0.0213 (7) | |
C12 | 0.0235 (5) | −0.01458 (16) | 0.1095 (4) | 0.0239 (7) | |
H12 | −0.055428 | −0.051872 | 0.082220 | 0.029* | |
C13 | −0.0699 (6) | 0.04316 (16) | 0.0848 (5) | 0.0275 (8) | |
H13 | −0.215401 | 0.046060 | 0.037739 | 0.033* | |
C14 | 0.0457 (6) | 0.09765 (16) | 0.1278 (5) | 0.0266 (7) | |
H14 | −0.021382 | 0.137334 | 0.110787 | 0.032* | |
N2 | 0.3439 (5) | −0.07747 (13) | 0.2017 (4) | 0.0278 (7) | |
O5 | 0.2900 (4) | 0.20430 (11) | 0.2221 (4) | 0.0343 (6) | |
O6 | 0.5729 (4) | 0.14586 (12) | 0.3167 (4) | 0.0366 (6) | |
O7 | 0.5346 (5) | −0.07837 (13) | 0.2492 (5) | 0.0448 (7) | |
O8 | 0.2350 (5) | −0.12516 (12) | 0.1741 (4) | 0.0376 (6) | |
C15 | 0.9530 (6) | 0.23917 (17) | 0.5534 (5) | 0.0337 (8) | |
H15 | 1.002933 | 0.233689 | 0.426833 | 0.040* | |
C16 | 1.0720 (6) | 0.27288 (17) | 0.6888 (6) | 0.0337 (8) | |
H16 | 1.204965 | 0.290825 | 0.657419 | 0.040* | |
C17 | 0.9967 (6) | 0.28047 (15) | 0.8709 (5) | 0.0352 (8) | |
H17 | 1.078436 | 0.303379 | 0.967064 | 0.042* | |
C18 | 0.8023 (7) | 0.25478 (17) | 0.9138 (6) | 0.0392 (9) | |
H18 | 0.747524 | 0.260163 | 1.038592 | 0.047* | |
C19 | 0.6901 (7) | 0.22142 (16) | 0.7730 (6) | 0.0372 (8) | |
H19 | 0.555815 | 0.203374 | 0.799899 | 0.045* | |
N3 | 0.7677 (5) | 0.21406 (13) | 0.5984 (5) | 0.0321 (7) | |
H3A | 0.694 (7) | 0.198 (2) | 0.498 (6) | 0.048* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0250 (17) | 0.0217 (15) | 0.0224 (15) | 0.0023 (13) | 0.0047 (13) | 0.0001 (12) |
C2 | 0.0209 (16) | 0.0212 (15) | 0.0189 (15) | 0.0001 (12) | 0.0026 (12) | 0.0000 (11) |
C3 | 0.0177 (17) | 0.0205 (15) | 0.0188 (15) | 0.0009 (12) | 0.0017 (12) | −0.0010 (11) |
C4 | 0.0218 (17) | 0.0199 (14) | 0.0178 (14) | 0.0021 (12) | 0.0021 (12) | −0.0021 (11) |
C5 | 0.0260 (19) | 0.0249 (16) | 0.0215 (16) | −0.0050 (13) | 0.0023 (13) | −0.0017 (12) |
C6 | 0.0149 (16) | 0.0374 (19) | 0.0259 (16) | 0.0000 (13) | −0.0005 (12) | −0.0001 (13) |
C7 | 0.0201 (17) | 0.0264 (16) | 0.0241 (16) | 0.0062 (13) | 0.0019 (13) | 0.0034 (12) |
N1 | 0.0302 (16) | 0.0175 (13) | 0.0286 (15) | 0.0028 (12) | 0.0018 (12) | −0.0019 (11) |
O1 | 0.0352 (14) | 0.0188 (11) | 0.0432 (15) | 0.0014 (10) | −0.0021 (11) | 0.0014 (10) |
O2 | 0.0270 (13) | 0.0249 (12) | 0.0516 (15) | −0.0031 (10) | 0.0005 (11) | −0.0095 (11) |
O3 | 0.0301 (14) | 0.0248 (13) | 0.0699 (19) | 0.0093 (12) | −0.0115 (13) | −0.0070 (13) |
O4 | 0.0391 (16) | 0.0209 (12) | 0.0625 (18) | −0.0042 (11) | −0.0030 (13) | −0.0034 (12) |
C8 | 0.0320 (19) | 0.0172 (15) | 0.0247 (15) | −0.0062 (13) | 0.0027 (13) | −0.0059 (12) |
C9 | 0.0243 (17) | 0.0204 (15) | 0.0195 (15) | −0.0018 (12) | 0.0035 (13) | −0.0024 (11) |
C10 | 0.0202 (17) | 0.0229 (16) | 0.0192 (15) | −0.0023 (13) | 0.0003 (12) | −0.0037 (11) |
C11 | 0.0275 (18) | 0.0193 (15) | 0.0175 (14) | −0.0003 (13) | 0.0041 (12) | −0.0008 (12) |
C12 | 0.0230 (18) | 0.0285 (17) | 0.0204 (15) | −0.0072 (13) | 0.0025 (13) | −0.0034 (13) |
C13 | 0.0222 (18) | 0.0349 (19) | 0.0251 (17) | −0.0019 (13) | −0.0001 (13) | −0.0003 (13) |
C14 | 0.0314 (19) | 0.0235 (16) | 0.0249 (16) | 0.0013 (13) | −0.0001 (14) | 0.0005 (13) |
N2 | 0.0353 (18) | 0.0204 (13) | 0.0274 (15) | −0.0017 (13) | −0.0003 (13) | −0.0049 (11) |
O5 | 0.0388 (14) | 0.0184 (11) | 0.0454 (15) | −0.0015 (10) | −0.0008 (12) | −0.0011 (10) |
O6 | 0.0296 (14) | 0.0266 (13) | 0.0529 (16) | −0.0034 (11) | −0.0054 (12) | −0.0146 (11) |
O7 | 0.0380 (16) | 0.0282 (14) | 0.066 (2) | 0.0069 (13) | −0.0156 (14) | −0.0071 (13) |
O8 | 0.0461 (16) | 0.0173 (11) | 0.0493 (15) | −0.0075 (11) | 0.0033 (13) | −0.0027 (11) |
C15 | 0.037 (2) | 0.0301 (16) | 0.0328 (18) | 0.0057 (15) | −0.0043 (15) | 0.0010 (14) |
C16 | 0.0286 (18) | 0.0296 (17) | 0.042 (2) | −0.0019 (14) | −0.0051 (15) | 0.0037 (14) |
C17 | 0.041 (2) | 0.0240 (16) | 0.0384 (19) | 0.0009 (15) | −0.0174 (16) | −0.0036 (14) |
C18 | 0.051 (2) | 0.0314 (18) | 0.0358 (19) | 0.0082 (17) | 0.0066 (17) | 0.0024 (15) |
C19 | 0.0296 (18) | 0.0252 (16) | 0.057 (2) | −0.0014 (14) | 0.0043 (16) | 0.0026 (16) |
N3 | 0.0319 (16) | 0.0193 (12) | 0.0431 (17) | 0.0009 (11) | −0.0152 (13) | −0.0053 (11) |
C1—C2 | 1.488 (4) | C10—C11 | 1.381 (4) |
C1—O1 | 1.311 (4) | C11—C12 | 1.386 (5) |
C1—O2 | 1.214 (4) | C11—N2 | 1.467 (4) |
C2—C3 | 1.398 (4) | C12—H12 | 0.9500 |
C2—C7 | 1.397 (4) | C12—C13 | 1.371 (5) |
C3—H3 | 0.9500 | C13—H13 | 0.9500 |
C3—C4 | 1.380 (4) | C13—C14 | 1.393 (5) |
C4—C5 | 1.382 (4) | C14—H14 | 0.9500 |
C4—N1 | 1.472 (4) | N2—O7 | 1.217 (4) |
C5—H5 | 0.9500 | N2—O8 | 1.234 (4) |
C5—C6 | 1.395 (4) | C15—H15 | 0.9500 |
C6—H6 | 0.9500 | C15—C16 | 1.366 (5) |
C6—C7 | 1.378 (5) | C15—N3 | 1.327 (5) |
C7—H7 | 0.9500 | C16—H16 | 0.9500 |
N1—O3 | 1.223 (4) | C16—C17 | 1.374 (6) |
N1—O4 | 1.213 (4) | C17—H17 | 0.9500 |
O1—H1 | 0.83 (4) | C17—C18 | 1.379 (6) |
C8—C9 | 1.520 (4) | C18—H18 | 0.9500 |
C8—O5 | 1.260 (4) | C18—C19 | 1.366 (6) |
C8—O6 | 1.242 (4) | C19—H19 | 0.9500 |
C9—C10 | 1.378 (4) | C19—N3 | 1.331 (5) |
C9—C14 | 1.389 (5) | N3—H3A | 0.88 (4) |
C10—H10 | 0.9500 | ||
O1—C1—C2 | 113.5 (3) | C10—C11—C12 | 122.9 (3) |
O2—C1—C2 | 121.8 (3) | C10—C11—N2 | 117.6 (3) |
O2—C1—O1 | 124.7 (3) | C12—C11—N2 | 119.5 (3) |
C3—C2—C1 | 117.6 (3) | C11—C12—H12 | 121.2 |
C7—C2—C1 | 123.4 (3) | C13—C12—C11 | 117.7 (3) |
C7—C2—C3 | 118.9 (3) | C13—C12—H12 | 121.2 |
C2—C3—H3 | 120.4 | C12—C13—H13 | 119.6 |
C4—C3—C2 | 119.1 (3) | C12—C13—C14 | 120.9 (3) |
C4—C3—H3 | 120.4 | C14—C13—H13 | 119.6 |
C3—C4—C5 | 122.7 (3) | C9—C14—C13 | 120.1 (3) |
C3—C4—N1 | 118.3 (3) | C9—C14—H14 | 119.9 |
C5—C4—N1 | 118.9 (3) | C13—C14—H14 | 119.9 |
C4—C5—H5 | 121.2 | O7—N2—C11 | 118.6 (3) |
C4—C5—C6 | 117.6 (3) | O7—N2—O8 | 123.4 (3) |
C6—C5—H5 | 121.2 | O8—N2—C11 | 117.9 (3) |
C5—C6—H6 | 119.5 | C16—C15—H15 | 119.9 |
C7—C6—C5 | 121.0 (3) | N3—C15—H15 | 119.9 |
C7—C6—H6 | 119.5 | N3—C15—C16 | 120.1 (4) |
C2—C7—H7 | 119.7 | C15—C16—H16 | 120.5 |
C6—C7—C2 | 120.6 (3) | C15—C16—C17 | 119.1 (4) |
C6—C7—H7 | 119.7 | C17—C16—H16 | 120.5 |
O3—N1—C4 | 117.8 (3) | C16—C17—H17 | 120.1 |
O4—N1—C4 | 118.5 (3) | C16—C17—C18 | 119.9 (3) |
O4—N1—O3 | 123.7 (3) | C18—C17—H17 | 120.1 |
C1—O1—H1 | 105 (3) | C17—C18—H18 | 120.7 |
O5—C8—C9 | 116.6 (3) | C19—C18—C17 | 118.6 (4) |
O6—C8—C9 | 117.3 (3) | C19—C18—H18 | 120.7 |
O6—C8—O5 | 126.2 (3) | C18—C19—H19 | 119.8 |
C10—C9—C8 | 119.2 (3) | N3—C19—C18 | 120.4 (4) |
C10—C9—C14 | 119.8 (3) | N3—C19—H19 | 119.8 |
C14—C9—C8 | 120.9 (3) | C15—N3—C19 | 121.9 (3) |
C9—C10—H10 | 120.7 | C15—N3—H3A | 113 (3) |
C9—C10—C11 | 118.6 (3) | C19—N3—H3A | 124 (3) |
C11—C10—H10 | 120.7 | ||
C1—C2—C3—C4 | 179.4 (3) | C9—C10—C11—N2 | 179.6 (3) |
C1—C2—C7—C6 | −179.1 (3) | C10—C9—C14—C13 | 0.1 (5) |
C2—C3—C4—C5 | −0.4 (5) | C10—C11—C12—C13 | 1.1 (5) |
C2—C3—C4—N1 | −179.6 (3) | C10—C11—N2—O7 | −4.4 (5) |
C3—C2—C7—C6 | 0.0 (5) | C10—C11—N2—O8 | 175.5 (3) |
C3—C4—C5—C6 | 0.2 (5) | C11—C12—C13—C14 | −0.9 (5) |
C3—C4—N1—O3 | 2.8 (4) | C12—C11—N2—O7 | 175.8 (3) |
C3—C4—N1—O4 | −177.3 (3) | C12—C11—N2—O8 | −4.2 (4) |
C4—C5—C6—C7 | 0.1 (5) | C12—C13—C14—C9 | 0.4 (5) |
C5—C4—N1—O3 | −176.4 (3) | C14—C9—C10—C11 | 0.0 (5) |
C5—C4—N1—O4 | 3.5 (4) | N2—C11—C12—C13 | −179.2 (3) |
C5—C6—C7—C2 | −0.2 (5) | O5—C8—C9—C10 | 179.5 (3) |
C7—C2—C3—C4 | 0.3 (4) | O5—C8—C9—C14 | −2.1 (5) |
N1—C4—C5—C6 | 179.4 (3) | O6—C8—C9—C10 | −1.7 (5) |
O1—C1—C2—C3 | 175.3 (3) | O6—C8—C9—C14 | 176.7 (3) |
O1—C1—C2—C7 | −5.6 (4) | C15—C16—C17—C18 | −0.7 (5) |
O2—C1—C2—C3 | −5.1 (5) | C16—C15—N3—C19 | 1.1 (5) |
O2—C1—C2—C7 | 174.0 (3) | C16—C17—C18—C19 | 0.8 (5) |
C8—C9—C10—C11 | 178.4 (3) | C17—C18—C19—N3 | 0.0 (5) |
C8—C9—C14—C13 | −178.3 (3) | C18—C19—N3—C15 | −1.0 (5) |
C9—C10—C11—C12 | −0.6 (5) | N3—C15—C16—C17 | −0.2 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O5 | 0.83 (4) | 1.69 (4) | 2.508 (3) | 169 (5) |
N3—H3A···O6 | 0.88 (4) | 1.81 (4) | 2.667 (4) | 164 (4) |
Acknowledgements
Parts of this work is supported by the National Science Foundation through the Major Research Instrumentation Program under grant No. CHE 1919785 (funding for the single-crystal X-ray diffractometer). The authors would also like to thank the reviewers for their assistance with structure solution and
and related fruitful discussions.Funding information
Funding for this research was provided by: Ave Maria University Department of Chemistry and Physics; National Science Foundation (grant No. 1919785).
References
Allen, F. H., Baalham, C. A., Lommerse, J. P. M., Raithby, P. R. & Sparr, E. (1997). Acta Cryst. B53, 1017–1024. Web of Science CrossRef CAS IUCr Journals Google Scholar
Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bruker (2020). APEX3, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. 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
Gu, Y., Kar, T. & Scheiner, S. (1999). J. Am. Chem. Soc. 121, 9411–9422. Web of Science CrossRef CAS 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
Sánchez-Moreno, M. J., Choquesillo-Lazarte, D., González-Pérez, J. M., Carballo, R., Mart\?ín-Ramos, J. D., Castiñeiras, A. & Niclós-Gutiérrez, J. (2003). Polyhedron, 22, 1039–1049. 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
Vijayvergiya, V., Padmanabhan, B. & Singh, T. P. (1995). Acta Cryst. C51, 2235–2238. CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.