research communications
Synthesis and E)-{2-[(E)-(4-hydroxynaphthalen-1-yl)methylidene]hydrazin-1-yl}(methylsulfanyl)methylidene)azanium hydrogen sulfate monohydrate
of ((aLaboratoire de Chimie Inorganique et Environnement, Université de Tlemcen, BP 119, 13000 Tlemcen, Algeria, bLaboratoire de Chimie Inorganique et Environnement, Universite de Tlemcen, BP 119, 13000 Tlemcen, Algeria, and cCentre de Diffractometrie X, UMR 6226 CNRS, Unité Sciences Chimiques de Rennes, Université de Rennes I, 263 Avenue du General Leclerc, 35042 Rennes, France
*Correspondence e-mail: samhibi1@yahoo.fr
In the title hydrated molecular salt, C13H14N3S+·HSO4−·H2O, the protonation of the azomethine N atom in sulfuric acid medium involves the formation of the bisulfate anion. The molecular structure of the cation is obtained from the thiol tautomer of thiosemicarbazone wherein the naphthalene moiety and the conjugation of the bonds contribute to the planarity of the molecular skeleton. In the crystal, the cation, anion and water molecule of crystallization are linked by a series of O—H⋯O and N—H⋯O hydrogen bonds, forming a three-dimensional network. Within this network, there are also C—H⋯π interactions present involving symmetry-related naphthalene rings.
Keywords: crystal structure; thiosemicarbazone; synthesis; hydrogen bonding.
CCDC reference: 1451398
1. Chemical context
Thiosemicarbazones and their metal complexes have been widely explored because of their pharmaceutical properties (Klayman et al., 1983). These compounds present a wide variety of biological activities, such as antitumoral, fungicidal and antiviral (Tarasconi et al., 2000), and bactericidal (Abram et al., 1998). The ability of thiosemicarbazone molecules to chelate with traces of metals in biological systems is believed to be a reason for their activity (Teoh et al., 1999). The nature of the aldehyde and ketone from which the thiosemicarbazone is obtained and the nature of the substituents attached at the +NH2 N atom influence the biological activity (Beraldo & Gambinob, 2004). Thiosemicarbazones can exist as E and Z isomers and they exhibit thione–thiol as illustrated for the title compound in Fig. 1. Complexation usually takes place via dissociation of the acidic proton, resulting in the formation of a five-membered chelate ring (Pal et al., 2002). The of the title compound was determined in order to investigate the extent of electron delocalization, the ligand conformation and to explore its biological implications.
2. Structural commentary
The molecular structure of the title molecular salt is illustrated in Fig. 2. It is composed of three entities: a bisulfate anion, a thiosemicarbazone cation and a water molecule of crystallization. The cationic entity shows an E conformation with respect to the C12=N13 bond and is approximately planar, the maximum deviation from the mean plane through the 18 non-hydrogen atoms being 0.118 (2) Å for atom C12. This planarity is due to electron delocalization along the cationic entity backbone. Bond lengths and angles are close to those observed for similar (methylidene)hydrazinecarbothioamide derivatives (Gangadharan et al., 2015; Joseph et al., 2004; Houari et al., 2013.)
3. Supramolecular features
In the crystal, there is an extensive hydrogen-bonding network present. The cation, anion and water molecule of crystallization are linked by a series of O—H⋯O and N—H⋯O hydrogen bonds, forming a three-dimensional network (Table 1 and Fig. 3). Within this network there are also C—H⋯π interactions present involving symmetry-related naphthalene rings (Table 1).
4. Database survey
A search of the Cambridge Structural Database (CSD, Version 5.37, update May 2016; Groom et al., 2016) for the S-methyl (methylidene)thiosemicarbazidium cation gave two hits, viz. S-methyl-N′-(pyrrolyl-2′-methylene)isothiosemicarbazidium iodide monohydrate (JIHZUV; Bourosh et al., 1990) and 8-quinolinealdehyde S-methylthiosemicarbazone hydrochloride dihydrate (RUJXOK; Botoshansky et al., 2009). Only the coordinates for the latter structure were available. The cation in RUJXOK, is relatively planar and the bond lengths and angles in the S-methyl (methylidene)thiosemicarbazidium moiety are similar to those observed for the title compound.
5. Synthesis and crystallization
The synthesis of the title molecular salt is illustrated in Fig. 4. An equimolar amount of thiosemicarbazide 10 mmol (0.91 g) and 3-hydroxy-2-naphthaldehyde 10 mmol (1.72 g) were dissolved in a mixture of methanol and water (30 ml, 50%) and refluxed for 5 h in the presence of a catalytic amount of glacial sulfuric acid. Brown crystals suitable for X-ray were obtained after slow evaporation of the solution.
6. Refinement
Crystal data, data collection and structure . The hydroxy H atom was located in a difference Fourier map and freely refined. The water and N-bound H atoms were located in difference Fourier maps and refined with distance restraints O—H = 0.84 (2) Å and N—H = 0.88 (2) Å. The C-bound H atoms were included in calculated positions and treated as riding atoms, with C—H = 0.95–0.98 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) otherwise.
details are summarized in Table 2
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Supporting information
CCDC reference: 1451398
https://doi.org/10.1107/S2056989016013232/su5320sup1.cif
contains datablocks I, Global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989016013232/su5320Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989016013232/su5320Isup3.cml
Data collection: APEX3 (Bruker, 2015); cell
SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015) and PLATON (Spek, 2009).C13H14N3OS+·HO4S−·H2O | Dx = 1.501 Mg m−3 |
Mr = 375.41 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 9907 reflections |
a = 6.3726 (5) Å | θ = 2.9–27.5° |
b = 14.2549 (11) Å | µ = 0.36 mm−1 |
c = 18.2817 (12) Å | T = 150 K |
V = 1660.7 (2) Å3 | Block, brown |
Z = 4 | 0.42 × 0.33 × 0.19 mm |
F(000) = 784 |
Bruker D8 VENTURE diffractometer | 3586 reflections with I > 2σ(I) |
Multilayer monochromator | Rint = 0.073 |
rotation images scans | θmax = 27.5°, θmin = 3.4° |
Absorption correction: multi-scan (SADABS; Bruker, 2015) | h = −8→8 |
Tmin = 0.752, Tmax = 0.935 | k = −18→18 |
19123 measured reflections | l = −23→23 |
3786 independent reflections |
Refinement on F2 | Hydrogen site location: mixed |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.039 | w = 1/[σ2(Fo2) + (0.0581P)2 + 0.4752P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.103 | (Δ/σ)max < 0.001 |
S = 1.07 | Δρmax = 0.36 e Å−3 |
3786 reflections | Δρmin = −0.33 e Å−3 |
247 parameters | Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
5 restraints | Extinction coefficient: 0.027 (5) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack x determined using 1477 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.03 (5) |
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. |
x | y | z | Uiso*/Ueq | ||
S1 | 0.33252 (11) | 0.30710 (5) | 0.35547 (4) | 0.0214 (2) | |
C1 | 0.6277 (5) | 0.5080 (2) | 0.06062 (17) | 0.0274 (6) | |
H1 | 0.5211 | 0.5545 | 0.0624 | 0.033* | |
C2 | 0.8011 (5) | 0.5215 (2) | 0.01485 (18) | 0.0302 (7) | |
H2 | 0.8125 | 0.5775 | −0.0130 | 0.036* | |
C3 | 0.9553 (5) | 0.4542 (2) | 0.00993 (16) | 0.0244 (6) | |
O4 | 1.1258 (4) | 0.46247 (17) | −0.03340 (14) | 0.0334 (6) | |
H4O | 1.141 (10) | 0.520 (5) | −0.059 (3) | 0.09 (2)* | |
C5 | 0.9393 (5) | 0.3697 (2) | 0.05103 (15) | 0.0210 (6) | |
C6 | 1.0925 (5) | 0.2980 (2) | 0.04354 (16) | 0.0256 (6) | |
H6 | 1.2085 | 0.3069 | 0.0117 | 0.031* | |
C7 | 1.0739 (5) | 0.2162 (2) | 0.08197 (17) | 0.0308 (7) | |
H7 | 1.1746 | 0.1678 | 0.0755 | 0.037* | |
C8 | 0.9071 (6) | 0.2033 (2) | 0.13084 (17) | 0.0299 (7) | |
H8 | 0.8977 | 0.1467 | 0.1581 | 0.036* | |
C9 | 0.7567 (5) | 0.2716 (2) | 0.13989 (16) | 0.0246 (6) | |
H9 | 0.6458 | 0.2620 | 0.1738 | 0.029* | |
C10 | 0.7656 (4) | 0.3566 (2) | 0.09897 (14) | 0.0192 (5) | |
C11 | 0.6085 (5) | 0.4279 (2) | 0.10353 (16) | 0.0215 (6) | |
C12 | 0.4268 (5) | 0.4151 (2) | 0.15100 (15) | 0.0220 (6) | |
H12A | 0.4066 | 0.3563 | 0.1744 | 0.026* | |
N13 | 0.2939 (4) | 0.48088 (17) | 0.16192 (12) | 0.0205 (5) | |
N14 | 0.1329 (4) | 0.45700 (16) | 0.20919 (13) | 0.0202 (5) | |
H14 | 0.144 (7) | 0.406 (2) | 0.234 (2) | 0.040 (11)* | |
C15 | −0.0120 (4) | 0.5212 (2) | 0.22410 (14) | 0.0182 (5) | |
N16 | −0.0075 (4) | 0.60276 (18) | 0.19085 (14) | 0.0249 (5) | |
H16B | −0.103 (5) | 0.641 (2) | 0.199 (2) | 0.032 (10)* | |
H16A | 0.084 (5) | 0.614 (3) | 0.1575 (18) | 0.036 (11)* | |
C17 | −0.3802 (5) | 0.5843 (2) | 0.28398 (18) | 0.0253 (6) | |
H17A | −0.4311 | 0.5911 | 0.2337 | 0.038* | |
H17B | −0.3101 | 0.6423 | 0.2992 | 0.038* | |
H17C | −0.4990 | 0.5718 | 0.3166 | 0.038* | |
S2 | −0.19735 (11) | 0.48825 (5) | 0.28856 (4) | 0.0245 (2) | |
O11 | 0.3992 (4) | 0.40352 (16) | 0.36112 (13) | 0.0348 (6) | |
O12 | 0.5287 (4) | 0.2471 (2) | 0.33653 (15) | 0.0442 (7) | |
H12O | 0.631 (8) | 0.246 (4) | 0.374 (3) | 0.059 (14)* | |
O13 | 0.2455 (5) | 0.2712 (2) | 0.42322 (13) | 0.0433 (7) | |
O14 | 0.1937 (4) | 0.29015 (14) | 0.29348 (11) | 0.0278 (5) | |
O1W | 0.8206 (4) | 0.2244 (2) | 0.42969 (13) | 0.0385 (6) | |
H1WA | 0.939 (6) | 0.256 (4) | 0.426 (3) | 0.060 (16)* | |
H1WB | 0.784 (8) | 0.225 (3) | 0.4750 (15) | 0.061 (15)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0240 (3) | 0.0184 (3) | 0.0220 (3) | −0.0050 (3) | −0.0028 (3) | 0.0010 (2) |
C1 | 0.0309 (15) | 0.0164 (14) | 0.0349 (15) | 0.0031 (12) | 0.0053 (12) | 0.0021 (11) |
C2 | 0.0386 (17) | 0.0186 (13) | 0.0333 (15) | 0.0000 (14) | 0.0083 (14) | 0.0045 (12) |
C3 | 0.0286 (15) | 0.0232 (14) | 0.0215 (13) | −0.0062 (11) | 0.0019 (12) | −0.0019 (11) |
O4 | 0.0336 (13) | 0.0323 (13) | 0.0344 (12) | 0.0011 (10) | 0.0136 (10) | 0.0079 (10) |
C5 | 0.0226 (14) | 0.0217 (14) | 0.0186 (12) | −0.0016 (11) | −0.0032 (11) | −0.0032 (10) |
C6 | 0.0250 (14) | 0.0321 (17) | 0.0196 (13) | 0.0047 (13) | 0.0002 (11) | −0.0013 (12) |
C7 | 0.0324 (17) | 0.0351 (18) | 0.0248 (14) | 0.0145 (14) | 0.0001 (13) | 0.0014 (13) |
C8 | 0.0347 (16) | 0.0299 (16) | 0.0253 (14) | 0.0108 (14) | 0.0001 (13) | 0.0084 (12) |
C9 | 0.0254 (14) | 0.0265 (14) | 0.0218 (13) | 0.0037 (11) | 0.0008 (11) | 0.0031 (11) |
C10 | 0.0202 (13) | 0.0207 (13) | 0.0166 (12) | −0.0004 (10) | −0.0020 (10) | −0.0027 (10) |
C11 | 0.0244 (14) | 0.0176 (13) | 0.0226 (13) | −0.0011 (11) | 0.0024 (11) | −0.0026 (10) |
C12 | 0.0234 (14) | 0.0192 (13) | 0.0233 (13) | −0.0003 (11) | −0.0012 (11) | −0.0009 (11) |
N13 | 0.0204 (11) | 0.0196 (11) | 0.0215 (11) | 0.0001 (10) | 0.0021 (9) | −0.0011 (9) |
N14 | 0.0212 (11) | 0.0160 (11) | 0.0233 (11) | 0.0010 (8) | 0.0028 (10) | 0.0028 (9) |
C15 | 0.0198 (12) | 0.0182 (12) | 0.0166 (11) | −0.0002 (10) | −0.0008 (9) | −0.0006 (10) |
N16 | 0.0287 (13) | 0.0187 (12) | 0.0273 (12) | 0.0058 (10) | 0.0084 (11) | 0.0056 (10) |
C17 | 0.0218 (13) | 0.0214 (13) | 0.0326 (15) | 0.0023 (11) | 0.0030 (12) | −0.0007 (12) |
S2 | 0.0264 (4) | 0.0209 (3) | 0.0263 (3) | 0.0027 (3) | 0.0080 (3) | 0.0056 (3) |
O11 | 0.0456 (14) | 0.0215 (11) | 0.0372 (12) | −0.0120 (10) | −0.0030 (11) | −0.0060 (10) |
O12 | 0.0395 (14) | 0.0493 (17) | 0.0437 (14) | 0.0146 (13) | −0.0118 (12) | −0.0185 (13) |
O13 | 0.0443 (15) | 0.0602 (17) | 0.0254 (11) | −0.0204 (13) | −0.0057 (10) | 0.0137 (11) |
O14 | 0.0353 (12) | 0.0209 (10) | 0.0271 (10) | −0.0059 (9) | −0.0089 (10) | 0.0040 (8) |
O1W | 0.0277 (12) | 0.0604 (17) | 0.0274 (11) | 0.0027 (12) | 0.0015 (10) | 0.0012 (11) |
S1—O11 | 1.442 (2) | C9—C10 | 1.425 (4) |
S1—O13 | 1.450 (2) | C9—H9 | 0.9500 |
S1—O14 | 1.458 (2) | C10—C11 | 1.429 (4) |
S1—O12 | 1.554 (3) | C11—C12 | 1.459 (4) |
C1—C11 | 1.391 (4) | C12—N13 | 1.279 (4) |
C1—C2 | 1.399 (4) | C12—H12A | 0.9500 |
C1—H1 | 0.9500 | N13—N14 | 1.384 (3) |
C2—C3 | 1.375 (4) | N14—C15 | 1.328 (4) |
C2—H2 | 0.9500 | N14—H14 | 0.86 (2) |
C3—O4 | 1.350 (4) | C15—N16 | 1.313 (4) |
C3—C5 | 1.424 (4) | C15—S2 | 1.733 (3) |
O4—H4O | 0.96 (6) | N16—H16B | 0.84 (2) |
C5—C6 | 1.420 (4) | N16—H16A | 0.86 (2) |
C5—C10 | 1.424 (4) | C17—S2 | 1.800 (3) |
C6—C7 | 1.366 (5) | C17—H17A | 0.9800 |
C6—H6 | 0.9500 | C17—H17B | 0.9800 |
C7—C8 | 1.400 (5) | C17—H17C | 0.9800 |
C7—H7 | 0.9500 | O12—H12O | 0.94 (5) |
C8—C9 | 1.376 (4) | O1W—H1WA | 0.89 (3) |
C8—H8 | 0.9500 | O1W—H1WB | 0.86 (2) |
O11—S1—O13 | 112.83 (16) | C10—C9—H9 | 119.6 |
O11—S1—O14 | 113.10 (14) | C5—C10—C9 | 117.7 (3) |
O13—S1—O14 | 111.92 (14) | C5—C10—C11 | 119.2 (3) |
O11—S1—O12 | 107.66 (17) | C9—C10—C11 | 123.1 (3) |
O13—S1—O12 | 107.67 (18) | C1—C11—C10 | 119.3 (3) |
O14—S1—O12 | 102.94 (13) | C1—C11—C12 | 120.5 (3) |
C11—C1—C2 | 121.3 (3) | C10—C11—C12 | 120.1 (3) |
C11—C1—H1 | 119.4 | N13—C12—C11 | 121.8 (3) |
C2—C1—H1 | 119.4 | N13—C12—H12A | 119.1 |
C3—C2—C1 | 120.5 (3) | C11—C12—H12A | 119.1 |
C3—C2—H2 | 119.7 | C12—N13—N14 | 114.1 (2) |
C1—C2—H2 | 119.7 | C15—N14—N13 | 118.3 (2) |
O4—C3—C2 | 123.5 (3) | C15—N14—H14 | 122 (3) |
O4—C3—C5 | 116.2 (3) | N13—N14—H14 | 118 (3) |
C2—C3—C5 | 120.3 (3) | N16—C15—N14 | 120.0 (3) |
C3—O4—H4O | 117 (4) | N16—C15—S2 | 124.7 (2) |
C6—C5—C10 | 120.0 (3) | N14—C15—S2 | 115.3 (2) |
C6—C5—C3 | 120.6 (3) | C15—N16—H16B | 119 (3) |
C10—C5—C3 | 119.4 (3) | C15—N16—H16A | 120 (3) |
C7—C6—C5 | 120.3 (3) | H16B—N16—H16A | 120 (4) |
C7—C6—H6 | 119.9 | S2—C17—H17A | 109.5 |
C5—C6—H6 | 119.9 | S2—C17—H17B | 109.5 |
C6—C7—C8 | 120.4 (3) | H17A—C17—H17B | 109.5 |
C6—C7—H7 | 119.8 | S2—C17—H17C | 109.5 |
C8—C7—H7 | 119.8 | H17A—C17—H17C | 109.5 |
C9—C8—C7 | 120.8 (3) | H17B—C17—H17C | 109.5 |
C9—C8—H8 | 119.6 | C15—S2—C17 | 101.74 (14) |
C7—C8—H8 | 119.6 | S1—O12—H12O | 114 (3) |
C8—C9—C10 | 120.7 (3) | H1WA—O1W—H1WB | 108 (5) |
C8—C9—H9 | 119.6 | ||
C11—C1—C2—C3 | 1.5 (5) | C8—C9—C10—C5 | −2.5 (4) |
C1—C2—C3—O4 | 179.6 (3) | C8—C9—C10—C11 | 176.9 (3) |
C1—C2—C3—C5 | 0.5 (5) | C2—C1—C11—C10 | −2.0 (5) |
O4—C3—C5—C6 | −2.3 (4) | C2—C1—C11—C12 | 179.9 (3) |
C2—C3—C5—C6 | 176.9 (3) | C5—C10—C11—C1 | 0.6 (4) |
O4—C3—C5—C10 | 178.9 (3) | C9—C10—C11—C1 | −178.9 (3) |
C2—C3—C5—C10 | −1.9 (4) | C5—C10—C11—C12 | 178.6 (3) |
C10—C5—C6—C7 | 0.2 (4) | C9—C10—C11—C12 | −0.8 (4) |
C3—C5—C6—C7 | −178.6 (3) | C1—C11—C12—N13 | −8.9 (4) |
C5—C6—C7—C8 | −2.0 (5) | C10—C11—C12—N13 | 173.1 (3) |
C6—C7—C8—C9 | 1.5 (5) | C11—C12—N13—N14 | −179.2 (2) |
C7—C8—C9—C10 | 0.9 (5) | C12—N13—N14—C15 | 179.6 (2) |
C6—C5—C10—C9 | 2.0 (4) | N13—N14—C15—N16 | 4.2 (4) |
C3—C5—C10—C9 | −179.2 (3) | N13—N14—C15—S2 | −175.70 (19) |
C6—C5—C10—C11 | −177.5 (3) | N16—C15—S2—C17 | 7.7 (3) |
C3—C5—C10—C11 | 1.4 (4) | N14—C15—S2—C17 | −172.4 (2) |
Cg1 and Cg2 are the centroids of rings C1–C3/C5/C10/C11 and C5–C10, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O13i | 0.89 (3) | 1.96 (3) | 2.791 (4) | 155 (5) |
O1W—H1WB···O13ii | 0.86 (2) | 1.88 (3) | 2.732 (3) | 172 (5) |
O4—H4O···O11iii | 0.96 (6) | 1.84 (6) | 2.719 (3) | 153 (6) |
O12—H12O···O1W | 0.94 (5) | 1.61 (5) | 2.543 (4) | 168 (5) |
N14—H14···O14 | 0.86 (2) | 2.00 (2) | 2.860 (3) | 176 (4) |
N16—H16A···O1Wiv | 0.86 (2) | 2.32 (3) | 3.046 (4) | 142 (4) |
N16—H16B···O14v | 0.84 (2) | 2.20 (3) | 2.937 (3) | 147 (4) |
C6—H6···Cg2vi | 0.95 | 2.67 | 3.451 (3) | 140 |
C7—H7···Cg1vi | 0.95 | 2.94 | 3.622 (3) | 130 |
Symmetry codes: (i) x+1, y, z; (ii) x+1/2, −y+1/2, −z+1; (iii) −x+3/2, −y+1, z−1/2; (iv) −x+1, y+1/2, −z+1/2; (v) −x, y+1/2, −z+1/2; (vi) x+1/2, −y+1/2, −z. |
Acknowledgements
The authors are grateful for the support provided by the Algerian Ministry for Education and Research.
References
Abram, S., Maichle-Mössmer, C. & Abram, U. (1998). Polyhedron, 17, 131–143. CSD CrossRef CAS Web of Science Google Scholar
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Beraldo, H. & Gambinob, D. (2004). Mini Rev. Med. Chem. 4, 159–165. Google Scholar
Botoshansky, M., Bourosh, P. N., Revenco, M. D., Korja, I. D., Simonov, Yu. A. & Panfilie, T. (2009). Zh. Strukt. Khim. 50, 188–191. Google Scholar
Bourosh, P. N., Jampolskaia, M. A., Dvorkin, A. A., Gerbeleu, N. V., Simonov, Yu. A. & Malinovskii, T. I. (1990). Dokl. Akad. Nauk SSSR, 311, 1119–1122. Google Scholar
Bruker (2015). APEX3, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Gangadharan, R., Haribabu, J., Karvembu, R. & Sethusankar, K. (2015). Acta Cryst. E71, 305–308. Web of Science CSD CrossRef 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 CSD CrossRef IUCr Journals Google Scholar
Houari, B., Louhibi, S., Boukli-Hacene, L., Roisnel, T. & Taleb, M. (2013). Acta Cryst. E69, o1469. CSD CrossRef IUCr Journals Google Scholar
Joseph, M., Suni, V., Nayar, C. R., Kurup, M. R. P. & Fun, H.-K. (2004). J. Mol. Struct. 705, 63–70. Web of Science CSD CrossRef CAS Google Scholar
Klayman, D. L., Scovill, J. P., Bartosevich, J. F. & Bruce, J. J. (1983). J. Med. Chem. 26, 35–39. CrossRef CAS PubMed Google Scholar
Pal, I., Basuli, F. & Bhattacharya, S. (2002). J. Chem Sci 114, 255–268. CrossRef CAS Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tarasconi, P., Capacchi, S., Pelosi, G., Cornia, M., Albertini, R., Bonati, A., Dall'Aglio, P. P., Lunghi, P. & Pinelli, S. (2000). Bioorg. Med. Chem. 8, 157–162. Web of Science CrossRef PubMed CAS Google Scholar
Teoh, S.-G., Ang, S.-H., Fun, H.-K. & Ong, C.-W. (1999). J. Organomet. Chem. 580, 17–21. CSD CrossRef CAS Google Scholar
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