research communications
and Hirshfeld surface analysis of diethyl 5-(2-cyanophenoxy)isophthalate
aDepartment of Applied Chemistry, ZHCET, Aligarh Muslim University, Aligarh, 202002, (UP), India, bCatalytic Chemistry Research Chair, Department of Chemistry, College of Science, KSU, Riyadh 11451, Saudi Arabia, and cDepartment of Chemistry, National Taras Shevchenko University, Volodymyrska Street 64, 01601 Kyiv, Ukraine
*Correspondence e-mail: amusheer4@gmail.com, plutenkom@yahoo.com
The title compound, C19H17NO5, obtained by ether bond formation between the reagents, crystallizes in the monoclinic P21/c. The compound is non-planar, subtending a dihedral angle of 82.38 (4)° between the plane of hydroxy isophthalate-based ester and that of the benzonitrile moiety. The molecule is bent at the ether linkage, with a Caryl—O—Caryl bond angle of 116.74 (11)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds and other weak interactions forming a supramolecular framework. A Hirshfeld surface analysis was performed to generate two-dimensional fingerprint plots, which reveal the type of interactions occurring in the vicinity of the molecule.
CCDC reference: 1981835
1. Chemical context
5-Hydroxyisophthalic acid and its derivatives have been used in the synthesis of several organic ligands. This type of ligand has an isophthalate moiety, which has oxygen-rich carbon chains that are sufficiently reactive to incorporate functionality, followed by conjugation with biomolecular compounds (Calderon et al., 2010; Khandare et al., 2012). Carboxylate-containing ligands have been used for the synthesis of coordination polymers because of their flexible nature. The flexibility of the ligand and hardness of metal ions improve the stability of coordination polymers (Ahmad et al., 2012). Coordination polymers have been used in various types of applications as a result of their physical properties, which include ferromagnetic behaviour, antiferromagnetic ordering, spin canting and metamagnetism (Wang et al., 2005; Liu et al., 2010). Several types of framework have been obtained, such as metal complexes, clusters, and metal–organic frameworks by linking of the flexible organic linker and metal ion, leading to interesting magnetic properties (Cheon & Suh, 2009; Wang et al., 2009). Organic ligands containing ether linkages have been used to synthesize magnetic materials because these types of organic ligands exhibit a binding ability that can efficiently transmit magnetic coupling (Coronado et al., 2000; Masciocchi et al., 2009; Yu et al., 2010).
2. Structural commentary
The molecular structure of the title compound is shown in Fig. 1. The compound crystallizes in the monoclinic P21/c. The contains one unit of 5-hydroxy-isophthalic acid diethyl ester and one unit of benzonitrile, connected by an ether bridge linkage. The molecule is non-planar, with a C12—O5—C14 bond angle of 116.74 (11)° at the ether group, and a C14—O5—C12—C13 torsion angle at the bridge of −97.37 (2)°. The C12—O5 bond length, 1.4025 (17) Å, is comparable to the C-O bond lengths obtained for similar ligands. The C3—O1 and C3—O2 bond lengths are 1.3377 (18) and 1.2061 (19) Å, respectively, and are in the expected ranges (Cambridge Structural Database; Groom et al., 2016).
3. Supramolecular features
In the crystal, the molecules are connected through C2—H2A⋯O4, C16—H16⋯O2 and C13—H13⋯O4 hydrogen bonds (Table 1, Fig. 2). They are linked by a series of C10—H10C⋯π and C3—O2⋯C16, C7—O4⋯C2 and C20—N1⋯C7 weak interactions, forming an extended supramolecular framework (Fig. 3). π–π interactions with Cg1⋯Cg2(1 − x, + y, − z) = 3.9572 (9) Å where Cg1 andCg2 are the centroids of the C4–C6/C11–C13 and C14–C19 rings, respectively, and a C—H⋯N interaction are also observed.
4. Hirshfeld analysis
The Hirshfeld surface analysis (Spackman & Jayatilaka, 2009) and the associated two-dimensional fingerprint plots (McKinnon, et al., 2007) were performed with Crystal Explorer17 (Turner et al., 2017) to investigate the intermolecular interactions and surface morphology of the The Hirshfeld surface mapped over dnorm (Fig. 4) in the colour range −0.174 to 1.315 a.u. from red (shorter distance than the sum of van der Waals radii) and white to blue (longer distance than the sum of van der Waals radii). The bright red spot on the dnorm surface corresponds to a weak interaction e.g. hydrogen bonding, blue indicates close contacts and a white spot shows van der Waals interactions. In the crystal there are three major types of interaction (H⋯H = 41.2%, H⋯O = 20.5%, C⋯H = 16.3%) on the dnorm surface. The two-dimensional fingerprint plots are shown in Fig. 5. The interaction order of dnorm on the 2D fingerprint plot (H⋯H)>(H⋯O)>(C⋯H) represents the nature of the packing in the The contribution of these major interactions (H⋯H, O⋯H/H⋯O, and C⋯H/H⋯C), governs the overall packing of crystal structure.
5. Database survey
A search of the Cambridge Structural Database (CSD version 5.39, update of May 2018; Groom et al., 2016) for 5-hydroxy-isophthalic acid derivatives gave 38 hits for structures that include atomic coordinates. In most of the derivatives, the phenolic group is replaced by an alkoxy, a substituted alkoxy or a substituted phenoxy moiety. Only in three of the 5-hydroxy-isophthalic acid derivatives is the carboxyl group modified: IDIYIE (Petek et al., 2006), NUHTAM (Feng et al., 2009), EVIBOB (Yang et al., 2011). In all these compounds, the hydroxyl groups of the carboxyl moieties have been replaced by methoxy groups and the phenolic group is replaced by a substituted alkoxy or a substituted phenoxy moiety.
6. Synthesis and crystallization
5-Hydroxyisophthalic acid diethyl ester (3.7 g, 14.9 mmol) was mixed with dried K2CO3 (3.3g, 22.3 mmol) in a 100 ml round-bottom flask under an inert atmosphere and then treated with dry DMF (20 ml) . The mixture was stirred for 30 minutes at 353 K followed by addition of 2-fluoro-benzonitrile (1.8 ml, 16.6 mmol) and the resulting mixture was stirred for 24 h in an oil-bath at 353 K. After this period, the solution was allowed to cool to room temperature and then poured into ice-cold water (100 ml) with vigorous stirring, to afford a white precipitate, which was collected by filtration, washed with water, and dried under vacuum. Yield: 4.6 g (90%). Melting point 325 K. The ligand was crystallized from a solution in ethanol, the resultant solution was filtered and kept for slow evaporation. After 2–3 weeks, block-shaped colourless crystal were obtained, which were suitable for single-crystal X-ray diffraction analysis.
7. Refinement
Crytal data, data collection and structure . The H atoms were freely refined.
details are summarized in Table 2
|
Supporting information
CCDC reference: 1981835
https://doi.org/10.1107/S2056989020004508/ex2031sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020004508/ex2031Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989020004508/ex2031Isup3.cml
Data collection: APEX2 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); 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).C19H17NO5 | F(000) = 712.4237 |
Mr = 339.35 | Dx = 1.345 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.3581 (5) Å | Cell parameters from 7552 reflections |
b = 10.5306 (6) Å | θ = 3.2–28.2° |
c = 17.0141 (10) Å | µ = 0.10 mm−1 |
β = 91.967 (2)° | T = 100 K |
V = 1675.69 (16) Å3 | Block, colourless |
Z = 4 | 0.39 × 0.27 × 0.16 mm |
Bruker APEXII CCD diffractometer | 3134 reflections with I ≥ 2σ(I) |
φ and ω scans | Rint = 0.062 |
Absorption correction: multi-scan (SADABS; Bruker, 2016) | θmax = 56.6°, θmin = 5.8° |
Tmin = 0.611, Tmax = 0.746 | h = −12→12 |
25974 measured reflections | k = −14→14 |
4149 independent reflections | l = −22→22 |
Refinement on F2 | 0 constraints |
Least-squares matrix: full | Primary atom site location: iterative |
R[F2 > 2σ(F2)] = 0.044 | All H-atom parameters refined |
wR(F2) = 0.110 | w = 1/[σ2(Fo2) + (0.035P)2 + 0.7212P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max = 0.001 |
4149 reflections | Δρmax = 0.30 e Å−3 |
294 parameters | Δρmin = −0.31 e Å−3 |
0 restraints |
x | y | z | Uiso*/Ueq | ||
O1 | 0.22713 (11) | 0.50496 (10) | 0.53544 (6) | 0.0229 (2) | |
O2 | 0.42747 (13) | 0.38970 (12) | 0.55579 (7) | 0.0360 (3) | |
O3 | 0.06230 (11) | 0.78631 (10) | 0.73574 (6) | 0.0213 (2) | |
O4 | 0.20643 (11) | 0.84802 (11) | 0.83720 (7) | 0.0266 (3) | |
O5 | 0.64745 (11) | 0.57614 (10) | 0.80523 (6) | 0.0232 (2) | |
N1 | 1.00269 (15) | 0.58018 (13) | 0.86616 (8) | 0.0285 (3) | |
C1 | 0.1112 (2) | 0.31216 (17) | 0.48736 (11) | 0.0312 (4) | |
H1a | 0.026 (2) | 0.3334 (18) | 0.5175 (11) | 0.036 (5)* | |
H1b | 0.174 (2) | 0.255 (2) | 0.5194 (12) | 0.044 (6)* | |
H1c | 0.079 (2) | 0.265 (2) | 0.4393 (12) | 0.045 (6)* | |
C2 | 0.19053 (19) | 0.42986 (16) | 0.46556 (9) | 0.0255 (3) | |
H2a | 0.279 (2) | 0.4097 (17) | 0.4384 (11) | 0.030 (5)* | |
H2b | 0.130 (2) | 0.4875 (19) | 0.4334 (11) | 0.036 (5)* | |
C3 | 0.34773 (16) | 0.47318 (14) | 0.57513 (9) | 0.0216 (3) | |
C4 | 0.37168 (16) | 0.55112 (13) | 0.64759 (9) | 0.0187 (3) | |
C5 | 0.26900 (15) | 0.63480 (14) | 0.67416 (9) | 0.0180 (3) | |
H5 | 0.1801 (18) | 0.6472 (16) | 0.6445 (10) | 0.020 (4)* | |
C6 | 0.29409 (15) | 0.70006 (13) | 0.74438 (9) | 0.0184 (3) | |
C7 | 0.18526 (15) | 0.78627 (14) | 0.77797 (9) | 0.0193 (3) | |
C9 | −0.05528 (16) | 0.85475 (16) | 0.77059 (10) | 0.0238 (3) | |
H9a | −0.0642 (18) | 0.8230 (17) | 0.8257 (11) | 0.026 (4)* | |
H9b | −0.0293 (18) | 0.9469 (17) | 0.7713 (10) | 0.024 (4)* | |
C10 | −0.18649 (17) | 0.82704 (18) | 0.72010 (11) | 0.0282 (4) | |
H10a | −0.1759 (19) | 0.8645 (18) | 0.6671 (12) | 0.033 (5)* | |
H10b | −0.202 (2) | 0.735 (2) | 0.7152 (11) | 0.035 (5)* | |
H10c | −0.271 (2) | 0.865 (2) | 0.7460 (12) | 0.044 (6)* | |
C11 | 0.42139 (16) | 0.68242 (14) | 0.78809 (9) | 0.0198 (3) | |
H11 | 0.4401 (17) | 0.7255 (16) | 0.8374 (10) | 0.021 (4)* | |
C12 | 0.52017 (15) | 0.59670 (14) | 0.76114 (9) | 0.0193 (3) | |
C13 | 0.49852 (16) | 0.53133 (14) | 0.69155 (9) | 0.0199 (3) | |
H13 | 0.5670 (17) | 0.4739 (16) | 0.6743 (9) | 0.017 (4)* | |
C14 | 0.64157 (15) | 0.49105 (14) | 0.86643 (9) | 0.0189 (3) | |
C15 | 0.51899 (17) | 0.42882 (14) | 0.88849 (9) | 0.0216 (3) | |
H15 | 0.429 (2) | 0.4474 (18) | 0.8609 (11) | 0.034 (5)* | |
C16 | 0.52654 (18) | 0.34329 (15) | 0.95050 (9) | 0.0243 (3) | |
H16 | 0.4388 (18) | 0.2977 (16) | 0.9645 (10) | 0.025 (4)* | |
C17 | 0.65468 (18) | 0.31972 (15) | 0.99145 (9) | 0.0254 (3) | |
H17 | 0.659 (2) | 0.2606 (18) | 1.0337 (11) | 0.034 (5)* | |
C18 | 0.77621 (17) | 0.38328 (15) | 0.97039 (9) | 0.0229 (3) | |
H18 | 0.8631 (18) | 0.3700 (16) | 0.9991 (10) | 0.023 (4)* | |
C19 | 0.77115 (15) | 0.46874 (14) | 0.90750 (9) | 0.0194 (3) | |
C20 | 0.89888 (16) | 0.53164 (15) | 0.88389 (9) | 0.0218 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0265 (6) | 0.0223 (5) | 0.0195 (5) | 0.0021 (4) | −0.0050 (4) | −0.0020 (4) |
O2 | 0.0327 (7) | 0.0383 (7) | 0.0368 (7) | 0.0128 (6) | −0.0025 (5) | −0.0149 (6) |
O3 | 0.0165 (5) | 0.0264 (6) | 0.0208 (5) | 0.0056 (4) | −0.0010 (4) | −0.0018 (4) |
O4 | 0.0237 (6) | 0.0285 (6) | 0.0274 (6) | −0.0002 (5) | −0.0019 (5) | −0.0096 (5) |
O5 | 0.0154 (5) | 0.0285 (6) | 0.0252 (6) | −0.0019 (4) | −0.0048 (4) | 0.0098 (5) |
N1 | 0.0227 (7) | 0.0311 (7) | 0.0313 (8) | −0.0018 (6) | −0.0054 (6) | −0.0021 (6) |
C1 | 0.0372 (10) | 0.0299 (9) | 0.0265 (9) | −0.0063 (8) | 0.0035 (8) | −0.0051 (7) |
C2 | 0.0340 (9) | 0.0252 (8) | 0.0172 (7) | −0.0020 (7) | −0.0022 (7) | −0.0022 (6) |
C3 | 0.0219 (8) | 0.0212 (7) | 0.0218 (8) | 0.0022 (6) | 0.0006 (6) | 0.0015 (6) |
C4 | 0.0186 (7) | 0.0183 (7) | 0.0191 (7) | −0.0001 (6) | 0.0005 (6) | 0.0027 (6) |
C5 | 0.0156 (7) | 0.0185 (7) | 0.0199 (7) | −0.0004 (6) | −0.0015 (6) | 0.0039 (6) |
C6 | 0.0173 (7) | 0.0179 (7) | 0.0200 (7) | −0.0004 (5) | 0.0002 (6) | 0.0036 (6) |
C7 | 0.0174 (7) | 0.0194 (7) | 0.0212 (7) | −0.0007 (6) | −0.0006 (6) | 0.0008 (6) |
C9 | 0.0203 (8) | 0.0280 (8) | 0.0232 (8) | 0.0073 (6) | 0.0019 (6) | −0.0025 (7) |
C10 | 0.0185 (8) | 0.0373 (10) | 0.0288 (9) | 0.0051 (7) | 0.0011 (7) | −0.0033 (8) |
C11 | 0.0196 (7) | 0.0212 (7) | 0.0185 (7) | −0.0034 (6) | −0.0012 (6) | 0.0024 (6) |
C12 | 0.0139 (7) | 0.0218 (7) | 0.0220 (8) | −0.0019 (6) | −0.0026 (6) | 0.0070 (6) |
C13 | 0.0180 (7) | 0.0192 (7) | 0.0226 (8) | 0.0017 (6) | 0.0034 (6) | 0.0048 (6) |
C14 | 0.0192 (7) | 0.0170 (7) | 0.0204 (7) | 0.0020 (6) | −0.0029 (6) | 0.0001 (6) |
C15 | 0.0192 (7) | 0.0229 (7) | 0.0225 (8) | 0.0002 (6) | −0.0024 (6) | 0.0001 (6) |
C16 | 0.0274 (8) | 0.0217 (7) | 0.0241 (8) | −0.0002 (6) | 0.0025 (6) | 0.0009 (6) |
C17 | 0.0334 (9) | 0.0241 (8) | 0.0187 (8) | 0.0049 (7) | −0.0005 (6) | 0.0024 (6) |
C18 | 0.0245 (8) | 0.0252 (8) | 0.0184 (7) | 0.0060 (6) | −0.0058 (6) | −0.0033 (6) |
C19 | 0.0185 (7) | 0.0197 (7) | 0.0199 (7) | 0.0018 (6) | −0.0024 (6) | −0.0041 (6) |
C20 | 0.0194 (8) | 0.0232 (7) | 0.0222 (8) | 0.0032 (6) | −0.0072 (6) | −0.0029 (6) |
O1—C2 | 1.4588 (18) | C9—H9a | 1.002 (18) |
O1—C3 | 1.3377 (18) | C9—H9b | 1.001 (17) |
O2—C3 | 1.2061 (19) | C9—C10 | 1.503 (2) |
O3—C7 | 1.3355 (17) | C10—H10a | 0.992 (19) |
O3—C9 | 1.4583 (17) | C10—H10b | 0.99 (2) |
O4—C7 | 1.2100 (18) | C10—H10c | 1.00 (2) |
O5—C12 | 1.4025 (17) | C11—H11 | 0.964 (17) |
O5—C14 | 1.3763 (18) | C11—C12 | 1.382 (2) |
N1—C20 | 1.147 (2) | C12—C13 | 1.379 (2) |
C1—H1a | 0.99 (2) | C13—H13 | 0.936 (17) |
C1—H1b | 0.99 (2) | C14—C15 | 1.384 (2) |
C1—H1c | 1.00 (2) | C14—C19 | 1.399 (2) |
C1—C2 | 1.498 (2) | C15—H15 | 0.973 (19) |
C2—H2a | 0.988 (19) | C15—C16 | 1.387 (2) |
C2—H2b | 0.98 (2) | C16—H16 | 0.988 (17) |
C3—C4 | 1.492 (2) | C16—C17 | 1.388 (2) |
C4—C5 | 1.391 (2) | C17—H17 | 0.950 (19) |
C4—C13 | 1.397 (2) | C17—C18 | 1.378 (2) |
C5—H5 | 0.967 (17) | C18—H18 | 0.945 (17) |
C5—C6 | 1.391 (2) | C18—C19 | 1.398 (2) |
C6—C7 | 1.493 (2) | C19—C20 | 1.436 (2) |
C6—C11 | 1.395 (2) | ||
C3—O1—C2 | 116.50 (12) | C10—C9—H9b | 112.9 (10) |
C9—O3—C7 | 115.44 (11) | H10a—C10—C9 | 109.7 (11) |
C14—O5—C12 | 116.74 (11) | H10b—C10—C9 | 110.6 (11) |
H1b—C1—H1a | 108.8 (16) | H10b—C10—H10a | 109.5 (15) |
H1c—C1—H1a | 108.1 (16) | H10c—C10—C9 | 108.3 (12) |
H1c—C1—H1b | 107.9 (17) | H10c—C10—H10a | 110.4 (16) |
C2—C1—H1a | 110.9 (11) | H10c—C10—H10b | 108.3 (16) |
C2—C1—H1b | 110.5 (12) | H11—C11—C6 | 121.8 (10) |
C2—C1—H1c | 110.5 (12) | C12—C11—C6 | 118.62 (14) |
C1—C2—O1 | 110.56 (13) | C12—C11—H11 | 119.5 (10) |
H2a—C2—O1 | 108.7 (10) | C11—C12—O5 | 119.28 (13) |
H2a—C2—C1 | 111.7 (11) | C13—C12—O5 | 118.64 (13) |
H2b—C2—O1 | 103.5 (11) | C13—C12—C11 | 122.08 (13) |
H2b—C2—C1 | 111.8 (11) | C12—C13—C4 | 118.85 (14) |
H2b—C2—H2a | 110.3 (16) | H13—C13—C4 | 120.5 (10) |
O2—C3—O1 | 124.32 (14) | H13—C13—C12 | 120.7 (10) |
C4—C3—O1 | 112.32 (12) | C15—C14—O5 | 124.64 (13) |
C4—C3—O2 | 123.35 (14) | C19—C14—O5 | 115.53 (13) |
C5—C4—C3 | 122.10 (13) | C19—C14—C15 | 119.83 (14) |
C13—C4—C3 | 117.47 (13) | H15—C15—C14 | 119.3 (11) |
C13—C4—C5 | 120.30 (14) | C16—C15—C14 | 119.51 (14) |
H5—C5—C4 | 120.5 (10) | C16—C15—H15 | 121.2 (11) |
C6—C5—C4 | 119.60 (13) | H16—C16—C15 | 118.6 (10) |
C6—C5—H5 | 119.9 (10) | C17—C16—C15 | 121.22 (15) |
C7—C6—C5 | 122.14 (13) | C17—C16—H16 | 120.2 (10) |
C11—C6—C5 | 120.52 (14) | H17—C17—C16 | 120.5 (11) |
C11—C6—C7 | 117.28 (13) | C18—C17—C16 | 119.28 (15) |
O4—C7—O3 | 124.15 (13) | C18—C17—H17 | 120.3 (11) |
C6—C7—O3 | 112.38 (12) | H18—C18—C17 | 119.8 (10) |
C6—C7—O4 | 123.46 (13) | C19—C18—C17 | 120.36 (14) |
H9a—C9—O3 | 107.7 (10) | C19—C18—H18 | 119.8 (10) |
H9b—C9—O3 | 107.3 (10) | C18—C19—C14 | 119.78 (14) |
H9b—C9—H9a | 109.9 (14) | C20—C19—C14 | 119.90 (13) |
C10—C9—O3 | 106.54 (13) | C20—C19—C18 | 120.31 (13) |
C10—C9—H9a | 112.2 (10) | C19—C20—N1 | 178.46 (16) |
Cg1 is the centroid of the C4–C6/C11–C13 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2B···O4i | 0.98 (2) | 2.50 (2) | 3.2071 (2) | 128 (1) |
C13—H13···O4ii | 0.936 (16) | 2.514 (16) | 3.4179 (2) | 163.5 (12) |
C16—H16···O2iii | 0.997 (17) | 2.516 (17) | 3.1941 (2) | 125.7 (13) |
C18—H18···N1iv | 0.945 (17) | 2.629 (17) | 3.430 (2) | 143.0 (13) |
C10—H10C···Cg1v | 1.00 (2) | 2.96 (2) | 3.7893 (19) | 140 (2) |
Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) −x+1, y−1/2, −z+3/2; (iii) x, −y+1/2, z+1/2; (iv) −x+2, −y+1, −z+2; (v) −x, y+1/2, −z+3/2. |
Acknowledgements
The Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, UP, India, and Deanship of Scientific Research, Research Chair, King Saud University, Riyadh, KSA, are gratefully acknowledged for providing laboratory facilities. TEQIP-III, ZHCET, Aligarh Muslim University, is thanked for extensive help to procure chemicals.
Funding information
Musheer Ahmad acknowledges a start-up grant from the UGC, India. Mohd Afzal acknowledges support from the Deanship of Scientific Research, King Saud University, Riyadh, Saudi Arabia. AA, SK and MM thank the UGC for Non-NET Fellowships.
References
Ahmad, M., Das, R., Lama, P., Poddar, P. & Bharadwaj, P. K. (2012). Cryst. Growth Des. 12, 4624–4632. CrossRef CAS 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 (2016). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Calderón, M., Quadir, M. A., Sharma, S. K. & Haag, R. (2010). Adv. Mater. 22, 190–218. CrossRef PubMed Google Scholar
Cheon, Y. E. & Suh, M. P. (2009). Chem. Commun. pp. 2296–2298. CrossRef Google Scholar
Coronado, E., Galán-Mascarós, J. R., Gómez-García, C. J. & Laukhin, V. (2000). Nature, 408, 447–449. Web of Science CSD CrossRef PubMed CAS 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
Feng, Y., Liu, Z.-T., Liu, J., He, Y.-M., Zheng, Q.-Y. & Fan, Q.-H. (2009). J. Am. Chem. Soc. 131, 7950–7951. CrossRef PubMed 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
Khandare, J., Calderón, M., Dagia, N. M. & Haag, R. (2012). Chem. Soc. Rev. 41, 2824–2848. CrossRef CAS PubMed Google Scholar
Liu, Q.-Y., Wang, Y.-L., Shan, Z.-M., Cao, R., Jiang, Y.-L., Wang, Z.-J. & Yang, E.-L. (2010). Inorg. Chem. 49, 8191–8193. Web of Science CSD CrossRef CAS PubMed Google Scholar
Masciocchi, N., Galli, S., Tagliabue, G., Sironi, A., Castillo, O., Luque, A., Beobide, G., Wang, W., Romero, M. A., Barea, E. & Navarro, J. A. R. (2009). Inorg. Chem. 48, 3087–3094. CrossRef PubMed CAS Google Scholar
McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. pp. 3814–3814. CrossRef Google Scholar
Petek, H., Akdemir, N., Ağar, E., Gümrükçüoğlu, İ. E. & Şenel, İ. (2006). Acta Cryst. E62, o2111–o2112. CrossRef IUCr Journals 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
Wang, X.-L., Qin, C., Wang, E.-B., Li, Y.-G., Su, Z.-M., Xu, L. & Carlucci, L. (2005). Angew. Chem. Int. Ed. 44, 5824–5827. Web of Science CSD CrossRef CAS Google Scholar
Wang, X.-T., Wang, X.-H., Wang, Z.-M. & Gao, S. (2009). Inorg. Chem. 48, 1301–1308. Web of Science CSD CrossRef PubMed CAS Google Scholar
Yang, F., Meng, F., Zhang, X. & Bai, M. (2011). Acta Cryst. E67, o1836. CrossRef IUCr Journals Google Scholar
Yu, Q., Zeng, Y.-F., Zhao, J.-P., Yang, Q., Hu, B.-W., Chang, Z. & Bu, X.-H. (2010). Inorg. Chem. 49, 4301–4306. Web of Science CSD CrossRef CAS PubMed 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.