research communications
H-benzimidazol-1-yl)methyl]benzoic acid
Hirshfeld and electronic transition analysis of 2-[(1aDepartment of Applied Chemistry, Faculty of Engineering and Technology, ZHCET, Aligarh Muslim University, Aligarh 202002 (UP), India, bFunctional Inorganic Materials Lab (FIML), Department of Chemistry, Aligarh, Muslim University, Aligarh 202002, India, cOndokuz Mayis University, Faculty of Arts and Sciences, Department of, Physics,55139 Samsun, Turkey, dDepartment of Chemistry, Institute of H. Science, Dr. Bhimrao Ambedkar, University, Agra 282002, U. P., India, and eDepartment of Pharmacy, University of Science and Technology, Ibb branch, Yemen
*Correspondence e-mail: amusheer4@gmail.com, ashraf.yemen7@gmail.com
In the title compound, C15H12N2O2, the benzimidazole ring system is inclined to the benzene ring by 78.04 (10)°. The features O—H⋯N and C—H⋯O hydrogen bonding and C—H⋯π and π–π interactions, which were investigated using Hirshfeld surface analysis.
Keywords: crystal structure; benzimidazole; Tauc plot; Hirshfeld surface analysis.
CCDC reference: 2091351
1. Chemical context
Benzimidazole is a naturally ocurring compound, being present in vitamin B12 (Crofts et al., 2014) and may also be synthesized from benzoic acid and o-phenylenediamine in presence of an excess of acid. Benzimidazole and its derivatives show biological activities such as antibacterial, antifungal (Yadav et al., 2015), antimicrobial (Shruthi et al., 2016), and anticancer (Kalalbandi et al., 2015). Cyanobenzyl compounds are used as intermediates in the synthesis of species that possess significant pharmaceutical properties. Compounds having carboxylic acid as a have shown chelating properties and thus have potential applications in the field of biology. Such groups are also helpful in building metal–organic frameworks that usually form supramolecular networks due to extensive hydrogen bonding and weak interactions. For example, 4-[(1H-benzo[d]imidazol-1-yl)methyl]benzoic acid has been used to construct coordination polymers with different metal ions (Ahmad et al., 2013). Herein, we report the title compound, 2-[(1H-benzimidazol-1-yl)methyl]benzoic acid, which was synthesized by a condensation reaction of benzimidazole and 2-(bromomethyl) benzonitrile in acetonitrile followed by a hydrolysis process.
2. Structural commentary
The . The molecule is non-planar with a dihedral angle of 78.04 (10) between the benzimidazole ring system and the benzene ring. The N1—C8—C7 angle is 113.31° and the C9—N1—C8—C7 torsion angle is −116.8 (2)°,. The C10—C15 bond length [1.408 (3) Å] is comparable to that in a similar benzimidazole derivative (Faizi et al., 2017). The C—O bond lengths [C1—O1 = 1.319 (3) and C1—O2 = 1.216 (3) Å] are in the expected range (Kamaal et al., 2019).
of the title compound is illustrated in Fig. 13. Supramolecular features
In the crystal, the molecules are connected via O—H⋯N and C—H⋯O hydrogen bonds (Table 1), forming a 1D framework along the b-axis direction (Fig. 2). C—H⋯π and π–π interactions [centroid–centroid distance = 3.6166 (15) Å] between the N1/N2/C9/C10/C15 and C2–C7 rings also occur, leading to the formation of the supramolecular structure (Fig. 3).
4. Database survey
A search of the Cambridge Structural Database (CSD, Version 5.42, November 2020; Groom et al., 2016) found five examples of similar compounds: bis(pentafluorophenyl)-(μ-{1,1′-[1,2-phenylenebis(methylene)]bis(1H-benzimidazole)})digold(I) acetone solvate (WOPLIZ; Zheng et al., 2019), 3,3′-[1,2-phenylenebis(methylene)]bis(1-ethylbenzimidazolium) dibromide (LANHAL; Haque et al., 2012), 2-[(1H-benzimidazol-1-yl)methyl]benzonitrile (JONYUJ; Akkoç et al., 2017), 1-[(2-cyanophenyl)methyl]-3-[(2-methylphenyl)methyl]-1H-benzimidazol-3-ium (JONZAQ; Akkoç et al., 2017) and 1-(2-cyanobenzyl)-3-methyl-1H-3,1-benzimidazol-3-ium bromide (MOCWAE; Ghdhayeb et al., 2014).
5. Hirshfeld surface analysis
A Hirshfeld surface analysis was performed and the two-dimensional fingerprint plots generated (McKinnon et al., 2007; Spackman & Jayatilaka et al., 2009) using CrystalExplorer17 (Turner et al., 2017). The Hirshfeld surface mapped over dnorm, colour-mapped from red (shorter distance than the sum of van der Waals radii) through white to blue (longer distance than the sum of the van der Waals radii). The principal weak interactions are clearly visible. The corresponding to O—H⋯N and C—H⋯O interactions are 9% and 11.8%, respectively. The dark-red spot indicates significant hydrogen bonding.
The two-dimensional finger plots are given in Fig. 4. The principal contributions to the overall surface are from H⋯H (42.4%, Fig. 4b), C⋯H/H⋯C (27.4%, Fig. 4c) and N⋯H/H⋯N 9% (Fig. 4d) interactions. The contributions of interactions such as C⋯C 4.8% are negligible.
6. Electronic transition analysis
Electro-conducting materials synthesized by conjugated organic compounds show promising electronic properties due to the availability of delocalized electrons, except for semiconducting materials such as TiO2, ZnO and other metal oxide nano-materials, which are electro-conducting in themselves (Odziomek et al., 2017). The electronic properties of organic compounds depend on the electronic transition between the highest occupied molecular orbital (HOMO) or and lowest occupied molecular orbital (LUMO) or In a simple method, the energy band gap (Eg) of organic molecule is determined by a Tauc plot from the absorption spectra (λmax = 245 nm, in this case). The band gap energy, Eg = 4.6 eV, of the title compound is very large (Fig. 5). This large band gap arises due to high π-conjugation or polarization in the title molecule system. The title molecule could be useful for developing or enhancing the organic electronic properties of conducting materials such as metal–organic frameworks.
7. Synthesis and crystallization
In an equimolar ratio, benzimidazole (2 g, 16.9 mmol) and dry K2CO3 (4.66 g, 33.85 mmol) were mixed in a round-bottom flask in acetonitrile (MeCN, 60 ml) under an inert atmosphere. The mixture was then allowed to stirred for 60 min at 363 K then treated with 2-(bromomethyl) benzonitrile (3.31 g, 16.9 mmol), and the resulting solution refluxed for 24 h. After completion of this step, the solution was allowed to cool to room temperature and the mixture was poured slowly onto ice–water (100 ml) under constant stirring. A greenish muddy crystalline precipitate was obtained and it was left to stand at 293 K for two days. After two days, a crystalline powder of 2-[(1H-benzo[d]imidazol-1-yl)methyl]benzonitrile was obtained (Ahmad et al., 2013).
The title compound was synthesized by hydrolysis of 2-[(1H-benzo[d]imidazol-1-yl)methyl]benzonitrile, 2 g being mixed with 20 equimolar of potassium hydroxide (6.86 g, 8.58 mmol) in water. The solution was refluxed at 373 K for 36 h, the resultant solution was then allowed to cool at room temperature and then poured onto ice–water, and after that acidified using 6 N HCl for protonation. The protonated solution was kept for slow evaporation. After two weeks, pale-yellow cubic crystals were obtained in good yield, which were suitable for data collection. The reaction scheme is shown in Fig. 6.
8. Refinement
Crystal data, data collection and structure .
details are summarized in Table 2
|
Supporting information
CCDC reference: 2091351
https://doi.org/10.1107/S2056989021006435/ex2044sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989021006435/ex2044Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989021006435/ex2044Isup3.cml
Data collection: APEX2 (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: olex2.solve (Bourhis et al., 2015); program(s) used to refine structure: olex2.refine (Bourhis et al., 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).
C15H12N2O2 | Dx = 1.411 Mg m−3 |
Mr = 252.28 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 1209 reflections |
a = 6.5690 (8) Å | θ = 2.9–22.1° |
b = 12.7956 (15) Å | µ = 0.10 mm−1 |
c = 14.1278 (16) Å | T = 100 K |
V = 1187.5 (2) Å3 | Block, colourless |
Z = 4 | 0.38 × 0.21 × 0.14 mm |
F(000) = 528.253 |
Bruker APEXII CCD diffractometer | 1759 reflections with I ≥ 2u(I) |
Detector resolution: X-ray pixels mm-1 | Rint = 0.107 |
φ and ω scans | θmax = 25.1°, θmin = 3.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2014) | h = −8→8 |
k = −17→17 | |
18798 measured reflections | l = −18→18 |
2095 independent reflections |
Refinement on F2 | 21 constraints |
Least-squares matrix: full | Primary atom site location: iterative |
R[F2 > 2σ(F2)] = 0.044 | All H-atom parameters refined |
wR(F2) = 0.091 | w = 1/[σ2(Fo2) + (0.0284P)2 + 0.3178P] where P = (Fo2 + 2Fc2)/3 |
S = 1.09 | (Δ/σ)max = 0.004 |
2095 reflections | Δρmax = 0.24 e Å−3 |
176 parameters | Δρmin = −0.28 e Å−3 |
1 restraint |
x | y | z | Uiso*/Ueq | ||
C1 | 0.2861 (4) | 0.82904 (18) | 0.71973 (18) | 0.0170 (6) | |
C2 | 0.4789 (4) | 0.81263 (19) | 0.66504 (18) | 0.0166 (6) | |
C3 | 0.5267 (4) | 0.88501 (19) | 0.59451 (17) | 0.0186 (6) | |
H3 | 0.4333 (4) | 0.93965 (19) | 0.58083 (17) | 0.0223 (8)* | |
C4 | 0.7074 (4) | 0.8790 (2) | 0.54393 (18) | 0.0213 (6) | |
H4 | 0.7359 (4) | 0.9282 (2) | 0.49537 (18) | 0.0256 (8)* | |
C5 | 0.8447 (4) | 0.80132 (19) | 0.56462 (18) | 0.0204 (7) | |
H5 | 0.9705 (4) | 0.79769 (19) | 0.53166 (18) | 0.0245 (8)* | |
C6 | 0.7985 (4) | 0.7280 (2) | 0.63408 (18) | 0.0196 (6) | |
H6 | 0.8941 (4) | 0.6743 (2) | 0.64778 (18) | 0.0235 (7)* | |
C7 | 0.6164 (4) | 0.7311 (2) | 0.68391 (17) | 0.0163 (6) | |
C8 | 0.5804 (4) | 0.6465 (2) | 0.75638 (17) | 0.0179 (6) | |
H8a | 0.7114 (4) | 0.6115 (2) | 0.77035 (17) | 0.0215 (7)* | |
H8b | 0.5313 (4) | 0.6790 (2) | 0.81572 (17) | 0.0215 (7)* | |
C9 | 0.2503 (4) | 0.54778 (19) | 0.76721 (18) | 0.0197 (6) | |
H9 | 0.2023 (4) | 0.58470 (19) | 0.82111 (18) | 0.0236 (7)* | |
C10 | 0.2677 (4) | 0.43913 (19) | 0.65142 (17) | 0.0176 (6) | |
C11 | 0.2311 (4) | 0.3622 (2) | 0.58413 (19) | 0.0229 (6) | |
H11 | 0.1089 (4) | 0.3224 (2) | 0.58480 (19) | 0.0274 (8)* | |
C12 | 0.3793 (4) | 0.3456 (2) | 0.51608 (19) | 0.0248 (7) | |
H12 | 0.3580 (4) | 0.2940 (2) | 0.46874 (19) | 0.0297 (8)* | |
C13 | 0.5601 (4) | 0.40366 (19) | 0.51595 (18) | 0.0223 (7) | |
H13 | 0.6590 (4) | 0.39013 (19) | 0.46844 (18) | 0.0267 (8)* | |
C14 | 0.5993 (4) | 0.4801 (2) | 0.58275 (18) | 0.0197 (6) | |
H14 | 0.7226 (4) | 0.5188 (2) | 0.58240 (18) | 0.0236 (8)* | |
C15 | 0.4494 (4) | 0.49744 (19) | 0.65048 (17) | 0.0156 (6) | |
N1 | 0.4321 (3) | 0.56758 (15) | 0.72553 (14) | 0.0158 (5) | |
N2 | 0.1467 (3) | 0.47270 (16) | 0.72598 (15) | 0.0195 (5) | |
O1 | 0.1923 (3) | 0.91615 (15) | 0.69535 (13) | 0.0228 (5) | |
O2 | 0.2246 (3) | 0.77045 (13) | 0.78116 (12) | 0.0227 (4) | |
H1 | 0.078 (4) | 0.924 (3) | 0.727 (2) | 0.077 (13)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0165 (14) | 0.0131 (13) | 0.0214 (14) | −0.0029 (12) | −0.0021 (12) | −0.0043 (12) |
C2 | 0.0186 (14) | 0.0126 (13) | 0.0184 (14) | −0.0064 (11) | −0.0017 (12) | −0.0040 (11) |
C3 | 0.0246 (16) | 0.0118 (14) | 0.0193 (14) | 0.0002 (12) | −0.0039 (12) | −0.0027 (11) |
C4 | 0.0257 (16) | 0.0207 (14) | 0.0175 (14) | −0.0068 (13) | 0.0054 (13) | −0.0014 (12) |
C5 | 0.0217 (15) | 0.0172 (14) | 0.0223 (16) | −0.0060 (12) | 0.0068 (12) | −0.0042 (12) |
C6 | 0.0187 (14) | 0.0166 (13) | 0.0235 (15) | 0.0024 (12) | −0.0007 (12) | −0.0050 (12) |
C7 | 0.0166 (13) | 0.0158 (14) | 0.0164 (13) | −0.0037 (12) | −0.0020 (11) | −0.0056 (11) |
C8 | 0.0166 (13) | 0.0181 (14) | 0.0190 (14) | −0.0010 (12) | −0.0033 (12) | −0.0009 (12) |
C9 | 0.0241 (15) | 0.0163 (14) | 0.0186 (14) | 0.0038 (12) | 0.0022 (13) | 0.0027 (12) |
C10 | 0.0210 (14) | 0.0149 (13) | 0.0170 (13) | 0.0010 (12) | −0.0025 (12) | 0.0032 (11) |
C11 | 0.0235 (15) | 0.0183 (14) | 0.0268 (15) | −0.0006 (13) | −0.0034 (13) | 0.0007 (12) |
C12 | 0.0339 (17) | 0.0159 (14) | 0.0244 (16) | 0.0026 (14) | −0.0028 (14) | −0.0030 (13) |
C13 | 0.0295 (17) | 0.0185 (15) | 0.0188 (14) | 0.0077 (12) | 0.0031 (13) | 0.0007 (12) |
C14 | 0.0201 (15) | 0.0178 (14) | 0.0212 (14) | −0.0002 (12) | 0.0010 (12) | 0.0031 (12) |
C15 | 0.0198 (15) | 0.0117 (13) | 0.0153 (13) | 0.0008 (11) | −0.0027 (12) | 0.0017 (11) |
N1 | 0.0160 (12) | 0.0144 (11) | 0.0170 (11) | −0.0010 (9) | −0.0006 (10) | 0.0000 (10) |
N2 | 0.0222 (12) | 0.0136 (12) | 0.0226 (12) | −0.0009 (10) | 0.0014 (11) | 0.0032 (10) |
O1 | 0.0170 (11) | 0.0199 (10) | 0.0316 (11) | 0.0030 (9) | 0.0012 (9) | 0.0042 (9) |
O2 | 0.0250 (10) | 0.0171 (9) | 0.0259 (11) | 0.0012 (8) | 0.0075 (9) | 0.0031 (9) |
C1—C2 | 1.499 (3) | C9—H9 | 0.950 (4) |
C1—O1 | 1.319 (3) | C9—N1 | 1.356 (3) |
C1—O2 | 1.216 (3) | C9—N2 | 1.313 (3) |
C2—C3 | 1.396 (3) | C10—C11 | 1.390 (3) |
C2—C7 | 1.405 (3) | C10—C15 | 1.408 (3) |
C3—H3 | 0.950 (4) | C10—N2 | 1.388 (3) |
C3—C4 | 1.388 (3) | C11—H11 | 0.9501 (4) |
C4—H4 | 0.950 (4) | C11—C12 | 1.385 (4) |
C4—C5 | 1.373 (4) | C12—H12 | 0.950 (4) |
C5—H5 | 0.950 (4) | C12—C13 | 1.401 (4) |
C5—C6 | 1.391 (4) | C13—H13 | 0.950 (4) |
C6—H6 | 0.951 (4) | C13—C14 | 1.383 (3) |
C6—C7 | 1.389 (4) | C14—H14 | 0.949 (4) |
C7—C8 | 1.508 (3) | C14—C15 | 1.391 (4) |
C8—H8a | 0.990 (4) | C15—N1 | 1.394 (3) |
C8—H8b | 0.990 (3) | O1—H1 | 0.878 (18) |
C8—N1 | 1.469 (3) | ||
O1—C1—C2 | 112.3 (2) | N1—C9—H9 | 123.20 (14) |
O2—C1—C2 | 124.2 (2) | N2—C9—H9 | 123.20 (15) |
O2—C1—O1 | 123.5 (2) | N2—C9—N1 | 113.6 (2) |
C3—C2—C1 | 117.7 (2) | C15—C10—C11 | 121.1 (2) |
C7—C2—C1 | 123.3 (2) | N2—C10—C11 | 129.7 (2) |
C7—C2—C3 | 118.9 (2) | N2—C10—C15 | 109.2 (2) |
H3—C3—C2 | 119.23 (15) | H11—C11—C10 | 121.25 (15) |
C4—C3—C2 | 121.5 (2) | C12—C11—C10 | 117.5 (3) |
C4—C3—H3 | 119.23 (15) | C12—C11—H11 | 121.25 (16) |
H4—C4—C3 | 120.26 (15) | H12—C12—C11 | 119.48 (16) |
C5—C4—C3 | 119.5 (2) | C13—C12—C11 | 121.0 (2) |
C5—C4—H4 | 120.26 (15) | C13—C12—H12 | 119.48 (15) |
H5—C5—C4 | 120.16 (15) | H13—C13—C12 | 118.94 (15) |
C6—C5—C4 | 119.7 (2) | C14—C13—C12 | 122.1 (2) |
C6—C5—H5 | 120.16 (16) | C14—C13—H13 | 118.94 (16) |
H6—C6—C5 | 119.13 (16) | H14—C14—C13 | 121.59 (16) |
C7—C6—C5 | 121.7 (2) | C15—C14—C13 | 116.8 (3) |
C7—C6—H6 | 119.13 (16) | C15—C14—H14 | 121.59 (16) |
C6—C7—C2 | 118.6 (2) | C14—C15—C10 | 121.5 (2) |
C8—C7—C2 | 124.1 (2) | N1—C15—C10 | 105.3 (2) |
C8—C7—C6 | 117.3 (2) | N1—C15—C14 | 133.2 (2) |
H8a—C8—C7 | 108.91 (14) | C9—N1—C8 | 125.7 (2) |
H8b—C8—C7 | 108.91 (13) | C15—N1—C8 | 127.9 (2) |
H8b—C8—H8a | 107.7 (3) | C15—N1—C9 | 106.4 (2) |
N1—C8—C7 | 113.31 (19) | C10—N2—C9 | 105.4 (2) |
N1—C8—H8a | 108.91 (12) | H1—O1—C1 | 111 (2) |
N1—C8—H8b | 108.91 (12) | ||
C1—C2—C3—C4 | 176.5 (2) | C8—N1—C9—N2 | −179.6 (2) |
C1—C2—C7—C6 | −174.8 (2) | C8—N1—C15—C10 | 179.7 (3) |
C1—C2—C7—C8 | 4.3 (3) | C8—N1—C15—C14 | −1.3 (3) |
C2—C3—C4—C5 | −1.2 (3) | C9—N1—C15—C10 | 1.0 (2) |
C2—C7—C6—C5 | −1.9 (3) | C9—N1—C15—C14 | 179.9 (2) |
C2—C7—C8—N1 | 75.2 (3) | C9—N2—C10—C11 | −179.2 (2) |
C3—C4—C5—C6 | 1.8 (3) | C9—N2—C10—C15 | 0.4 (2) |
C4—C5—C6—C7 | −0.2 (3) | C10—C11—C12—C13 | 0.6 (3) |
C5—C6—C7—C8 | 178.9 (2) | C10—C15—C14—C13 | 0.7 (3) |
C6—C7—C8—N1 | −105.6 (2) | C11—C12—C13—C14 | −0.3 (3) |
C7—C8—N1—C9 | −116.8 (2) | C12—C13—C14—C15 | −0.4 (3) |
C7—C8—N1—C15 | 64.7 (3) | C13—C14—C15—N1 | −178.1 (2) |
Cg1, Cg2, Cg3 and Cg4 are the centroids of the N1/N2/C9/C10/C15, C2–C7, C10–C15 and N1/N2/C9–15 rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N2i | 0.88 (3) | 1.73 (3) | 2.592 (3) | 164 (4) |
C8—H8A···O1ii | 0.99 (1) | 2.62 (1) | 3.374 (3) | 133 (1) |
C3—H3···O1 | 0.95 (1) | 2.28 (1) | 2.648 (3) | 102 (1) |
C8—H8B···O2 | 0.99 (1) | 2.38 (1) | 2.846 (3) | 108 (1) |
C9—H9···O2 | 0.95 (1) | 2.45 (1) | 2.861 (3) | 106 (1) |
C4—H4···Cg1iii | 0.95 (1) | 2.99 (1) | 3.865 (3) | 155 (1) |
C4—H4···Cg3iii | 0.95 (1) | 2.51 (1) | 3.408 (3) | 157 (1) |
C4—H4···Cg4iii | 0.95 (1) | 2.51 (1) | 3.454 (3) | 170 (1) |
C5—H5···Cg2iii | 0.95 (1) | 2.76 (1) | 3.554 (3) | 142 (1) |
Symmetry codes: (i) −x, y+1/2, −z+3/2; (ii) −x+1, y−1/2, −z+3/2; (iii) x+1/2, −y+3/2, −z+1. |
Acknowledgements
The authors are grateful to the Department of Applied Chemistry, Aligarh Muslim University, for providing laboratory facilities. Author contribution are as follows. Conceptualization, MA and AM; methodology, AA and MS; investigation, MM, SK, SJ and JAK; writing (original draft), AA and ND; writing (review and editing of the manuscript), AAfall and ADA; visualization, MA, AA and AM; funding acquisition, AM; resources, ND and MA; supervision, MA and AM.
Funding information
MA acknowledges the start-up grant received from UGC, India. AA, MM and SK also thank the UGC for the Non-NET scheme. AM acknowledges support from the Department of Pharmacy, University of Science and Technology, Ibb Branch, Yemen.
References
Ahmad, M. & Bharadwaj, P. K. (2013). Polyhedron, 52, 1145–1152. Web of Science CSD CrossRef CAS Google Scholar
Akkoç, S., Kayser, V., İlhan, I. O., Hibbs, D. E., Gök, Y., Williams, P. A., Hawkins, B. & Lai, F. (2017). J. Organomet. Chem. 839, 98–107. Google Scholar
Bourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59–75. Web of Science CrossRef IUCr Journals Google Scholar
Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Crofts, T. S., Men, Y., Alvarez-Cohen, L. & Taga, M. E. (2014). Front. Microbiol. 5, PMID 25431570. 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
Faizi, M. S. H., Dege, N. & Malinkin, S. (2017). Acta Cryst. E73, 1180–1183. CrossRef IUCr Journals Google Scholar
Ghdhayeb, M. Z., Haque, R. A. & Budagumpi, S. (2014). J. Organomet. Chem. 757, 42–50. CrossRef CAS 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
Haque, R. A., Iqbal, M. A., Budagumpi, S., Hemamalini, M. & Fun, H.-K. (2012). Acta Cryst. E68, o573. CSD CrossRef IUCr Journals Google Scholar
Kalalbandi, V. K. A. & Seetharamappa, J. (2015). Med. Chem. Commun. 6, 1942–1953. CrossRef CAS Google Scholar
Kamaal, S., Faizi, M. S. H., Ali, A., Ahmad, M., Gupta, M., Dege, N. & Iskenderov, T. (2019). Acta Cryst. E75, 159–162. CrossRef IUCr Journals Google Scholar
McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. 3814–3816. Google Scholar
Odziomek, K., Ushizima, D., Oberbek, P., KurzydŁowski, K. J., Puzyn, T. & Haranczyk, M. (2017). J. Microsc. 265, 34–50. CrossRef CAS PubMed Google Scholar
Shruthi, N., Poojary, B., Kumar, V., Hussain, M. M., Rai, V. M., Pai, V. R., Bhat, M. & Revannasiddappa, B. C. (2016). RSC Adv. 6, 8303–8316. CrossRef CAS Google Scholar
Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19–32. Web of Science CrossRef CAS 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
Yadav, G. & Ganguly, S. (2015). Eur. J. Med. Chem. 97, 419–443. Web of Science CrossRef CAS PubMed Google Scholar
Zheng, Q., Borsley, S., Nichol, G. S., Duarte, F. & Cockroft, S. L. (2019). Angew. Chem. Int. Ed. 58, 12617–12623. CrossRef CAS Google Scholar
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