research communications
of 3-methoxy-4-[2-(thiazol-2-yl)diazen-1-yl]aniline monohydrate
aDepartment of Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand, and bMaterials and Textile Technology, Faculty of Science and Technology, Thammasat, University, PathumThani 12120, Thailand
*Correspondence e-mail: fscitwd@ku.ac.th
In the title hydrated azo dye, C10H10N4OS·H2O, the benzene and thiazole, are nearly coplanar, with a dihedral angle between their mean planes of 4.69 (17)°. The aromatic rings on the –N=N– moiety exhibit a trans configuration. The features many types of intermolecular interactions involving all the functional groups – strong hydrogen bonds (N⋯H and O⋯H), weak hydrogen bonds (C—H⋯O and C—H⋯N), C—H⋯π and π–π interactions – resulting in the formation of a three-dimensional framework.
Keywords: crystal structure; azo dye; thiazole ring; hydrogen bonding; C—H⋯π interaction.
CCDC reference: 1895710
1. Chemical context
Thiazolylazo compounds contain a thiazole ring and an azo group (–N=N–). Azo dyes have wide range applications in the cosmetic, food, textile industry, chemical sensing, and pharmaceutical (Weglarz-Tomczak & Gorecki, 2012) fields. 4-(2-Thiazolylazo) resorcinol (TAR) was the first thiazolylazo dye (Jensen, 1960). Changing the substituent groups on the azo bond (Hovind, 1975) changes the coordination properties with metal ions, as in the complexation of 1-(2-thiazolylazo)-2-naphthol (TAN) with transition metals (Omar et al., 2005). Cleavage of the azo bond occurs in reductive metabolism of mammalian systems (Levine, 1991) that can decrease or increase any toxic or carcinogenic effects of the dyes. Sutthivaiyakit et al. (1998) described the preparation of a new chelating silica with 2-(2-thiazolylazo)-5-aminoanisole used for a in high-pressure In this work, we report the structure of 3-methoxy-4-[2-(thiazol-2-yl)diazen-1-yl]aniline monohydrate, also known as 2-(2-thiazolylazo)-5-aminoanisole (p-amino TAA), (I). Future work will study its complexation with metal ions.
2. Structural commentary
The molecular structure of (I) is shown in Fig. 1. The thiazole and benzene rings are arranged trans to the azo bridge (–N2=N3–). The methoxy and amino groups on the benzene ring are co-planar with the ring with atoms O1 and N4 deviating by −0.010 (2) and −0.019 (4) Å, respectively. The dihedral angle between the thiazole and benzene rings is 4.69 (17)°, nearly coplanar.
3. Supramolecular features
In the crystal, three-dimensional structure is generated by contribution of strong and weak hydrogen bonding, C—H⋯π interactions and offset π–π interaction. The strong hydrogen bonds (Fig. 2a, Table 1), which involve the amine (NH2), azo (–N=N–) and thiazole groups and the water molecule of crystallization [N4—H4B⋯O3, O3—H3A⋯N1ii, O3—H3B⋯N3iii, N4—H4A⋯N2i] are the primary interactions responsible for the formation of the three dimensional structure. In addition, the is supported by other intermolecular interactions as a secondary weak interactions, C—H⋯X (X = O and N), C—H⋯π and offset π—π interactions. The weak hydrogen bonds are formed between the C—H moieties in the benzene and thiazole rings with amine, azo, methoxy groups of adjacent molecules and water molecules [C1—H1⋯O3vii, C2—H2⋯N2v, C8—H8⋯O1vi and C9—H9⋯N4iv. The C—H⋯π interactions involve the methoxy group and ring carbon atoms [C10—H10C⋯C3ii, C10—H10A⋯C6iii and C10—H10A⋯C7iii while the offset π–π interaction is formed between benzene and thiazole rings with a centroid–centroid distance of 3.850 (5) Å, 1 − x, 2 − y, 1 − z (Fig. 2b, Table 1).
4. Hirshfeld surface analysis
Hirshfeld surfaces and fingerprint plots were generated using CrystalExplorer (Hirshfeld, 1977; McKinnon et al., 2004). Fig. 3 shows the Hirshfeld surface of compound (I) mapped over dnorm (−0.5129 to 1.1405 Å) and the shape index (−1.0 to 1.0 Å). The red spots in the Hirshfeld surface represent short N⋯H and O⋯H contacts and correspond to hydrogen-bonding interactions between (NH2)N—H⋯N(azo), (H2O)O—H⋯N(azo), (H2O)O—H⋯N(thiazole) and (NH2)N—H⋯O(H2O). The pale-red spots result from the weak C—H⋯O(H2O) and C—H⋯N(NH2) hydrogen-bonding interactions. The white spots in Fig.3a represent long contacts [C—H⋯N(azo) and C—H⋯O(OCH3)]. On the shape index surface (Fig. 3b), convex blue regions represent hydrogen-donor groups and concave red regions represent hydrogen-acceptor groups. In addition, concave red regions represent C—H⋯π and offset π–π interactions. The amino group behaves as both a donor and an acceptor. The methyl part of the methoxy group acts as a donor while the oxygen atom is an acceptor.
The two-dimensional fingerprint plots (Fig. 4) quantify the contributions of each type of intermolecular interaction to the Hirshfeld surface (McKinnon et al., 2007). The largest contribution with 30.0% of the surface is from H⋯H contacts, which represent van der Waals interactions, followed by C⋯H contacts involved in C—H⋯π interactions (20.0%). In the N⋯H plot (18.8% contribution), the two sharp peaks correspond to strong hydrogen bonds. Finally, the O⋯H (9.3%), S⋯H (11.1%) and C⋯C (3.3%) contacts correspond to hydrogen bonds and offset π–π interactions, respectively.
5. Database survey
Related compounds to (I) are substituted thiazolylazo derivatives, for example 4-(2-thiazolylazo) resorcinol (TAR), 1-(2-thiazolylazo)-2-naphthol (TAN) and 2-(2-thiazolylazo)-4-methylphenol (TAC) (Jensen, 1960). These thiazolylazo derivatives are used as chelating agents with metal ions (Farias et al., 1992). In the of 1-(2-thiazolylazo)-2-naphthol (TAN; Kurahashi, 1976), the azo group adopts a trans configuration and the phenolic oxygen atom is linked to an azo nitrogen atom by intramolecular hydrogen bonding. The features only van der Waals interactions. To form complexes with metal ions, both thiazole and naphthol rings are rotated by 180° to coordinate to the metal through the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring and the thiazole nitrogen atom, resulting the formation of five-membered chelate rings. Complexes of TAR and TAC are formed in a similar way due to the presence of a hydroxyl group in the structure (Karipcin et al., 2010). 3-[2-(1,3-Thiazol-2-yl)diazen-1-yl]pyridine-2,6-diamine monohydrate (Chotima et al., 2018) has been used as a chelating ligand to form a complex with AuIII ion (Piyasaengthong et al., 2015). The is stabilized by hydrogen bonding between the amine group, water and the thiazole nitrogen atom along with π–π interactions between pairs of pyridine rings and pairs of thiazole rings, resulting in the formation of a layered structure. In addition, weak C—H⋯S hydrogen bonds between adjacent thiazole rings further contribute to the crystal packing, generating a three-dimensional network.
6. Synthesis and crystallization
2-Aminothiazole (9.986 mmol) was dissolved in 6 M HCl (16 ml), and 8.236 mmol of sodium nitrate solution was added slowly under stirring at low temperature 268–273 K until the diazonium salt was obtained. m-Anisidine (1.12 ml in 40 ml of 4 M HCl) was slowly dropped into the mixture and stirred at a temperature between 268 and 273 K for 1 h. After the reaction was complete, conc. NH3 was dropped into the mixture (pH 6) until the red–orange crude produce appeared. The products were filtered, washed with cold water, purified by and recrystallized from an acetonitrile–water (1:1) mixture by vapour diffusion.
1H NMR (400 MHz, DMSO-d6): δ 3.806 (3H, s, Hc), 6.364 (1H, dd, Hf, J = 8.7, 2.7 Hz) , 6.374 (1H, t, Hd, J = 2.8 Hz), 7.546 (1H, d, Hg, J = 8.9 Hz) ,7.629 (1H, d, Ha, J = 3.40 Hz), 7.697 (2H, s, He), 7.883 (1H, d, Hb, J = 3.42 Hz). m/z 235.0654 [C10H11N4OS+], 205.0548 [C9H9N4S.+], 150.0662 [C7H8N3O.+], 122.0601 [C7H8NO.+]. IR (KBr cm−1): 3,413 cm−1 (s, N—H); 821 cm−1 (w, NH2); 1,617 (m, C=N); 1,222 cm−1 (w, C—N stretch aromatic amine); 1,103 cm−1 (m, C—N stretch amine); 1,152 cm−1 (m, C—S); 1,541cm−1 (m, N=N); 1,021 cm−1 (w, C—O stretch). Elemental analysis calculated for C10H10N4OS·H2O: C, 51.27; H, 4.30; N, 23.92. Found: C, 51.34; H, 4.20; N, 23.98.
7. Refinement
Crystal data, data collection and structure . Water and amino H atoms were refined freely while those of aromatic and methyl groups were placed in calculated positions (C—H = 0.93 and 0.96 Å, respectively) and included in the cycles of using a riding model with Uiso = 1.2 Ueq(C-aromatic) and 1.5Ueq (C-methyl).
details are summarized in Table 2
|
Supporting information
CCDC reference: 1895710
https://doi.org/10.1107/S205698901900207X/dx2014sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901900207X/dx2014Isup2.hkl
Data collection: APEX3 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).C10H10N4OS·H2O | F(000) = 528 |
Mr = 252.30 | Dx = 1.475 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 9.051 (5) Å | Cell parameters from 395 reflections |
b = 11.526 (5) Å | θ = 2.9–19.0° |
c = 10.893 (6) Å | µ = 0.28 mm−1 |
β = 90.345 (16)° | T = 298 K |
V = 1136.5 (10) Å3 | Block, brown |
Z = 4 | 0.14 × 0.06 × 0.06 mm |
Bruker APEXII CCD diffractometer | 2164 independent reflections |
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs | 995 reflections with I > 2σ(I) |
Mirror optics monochromator | Rint = 0.164 |
Detector resolution: 7.9 pixels mm-1 | θmax = 25.8°, θmin = 2.6° |
φ and ω scans | h = −10→11 |
Absorption correction: multi-scan (SADABS; Bruker, 2016) | k = −14→12 |
Tmin = 0.585, Tmax = 0.745 | l = −13→13 |
13093 measured 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)] = 0.055 | w = 1/[σ2(Fo2) + (0.0242P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.131 | (Δ/σ)max < 0.001 |
S = 0.93 | Δρmax = 0.26 e Å−3 |
2164 reflections | Δρmin = −0.25 e Å−3 |
172 parameters | Extinction correction: SHELXL2016 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
4 restraints | Extinction coefficient: 0.009 (2) |
Primary atom site location: dual |
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 | 0.22221 (11) | 1.00037 (9) | 0.49942 (9) | 0.0393 (4) | |
O1 | 0.4757 (3) | 0.6793 (2) | 0.5996 (2) | 0.0379 (7) | |
O3 | 0.8582 (4) | 0.3028 (3) | 0.5520 (4) | 0.0512 (9) | |
N1 | 0.3051 (4) | 1.0873 (3) | 0.2927 (3) | 0.0374 (9) | |
N2 | 0.4373 (3) | 0.9181 (3) | 0.3421 (3) | 0.0324 (8) | |
N3 | 0.4436 (3) | 0.8375 (3) | 0.4254 (3) | 0.0297 (8) | |
N4 | 0.8772 (4) | 0.5020 (3) | 0.3833 (4) | 0.0421 (9) | |
C1 | 0.1384 (4) | 1.1242 (3) | 0.4478 (4) | 0.0387 (11) | |
H1 | 0.063837 | 1.163516 | 0.488936 | 0.046* | |
C2 | 0.1954 (4) | 1.1567 (3) | 0.3399 (4) | 0.0393 (11) | |
H2 | 0.162460 | 1.222749 | 0.298950 | 0.047* | |
C3 | 0.3298 (4) | 1.0010 (3) | 0.3686 (3) | 0.0280 (9) | |
C4 | 0.5502 (4) | 0.7542 (3) | 0.4088 (3) | 0.0283 (10) | |
C5 | 0.5698 (4) | 0.6708 (3) | 0.5038 (3) | 0.0285 (9) | |
C6 | 0.6797 (4) | 0.5880 (3) | 0.4951 (3) | 0.0313 (10) | |
H6 | 0.692487 | 0.534501 | 0.558164 | 0.038* | |
C7 | 0.7720 (4) | 0.5838 (3) | 0.3925 (4) | 0.0304 (10) | |
C8 | 0.7527 (4) | 0.6669 (3) | 0.2975 (3) | 0.0364 (11) | |
H8 | 0.813766 | 0.665287 | 0.229219 | 0.044* | |
C9 | 0.6462 (4) | 0.7479 (3) | 0.3060 (3) | 0.0347 (10) | |
H9 | 0.634945 | 0.801384 | 0.242785 | 0.042* | |
C10 | 0.5045 (4) | 0.6082 (3) | 0.7052 (3) | 0.0448 (12) | |
H10A | 0.495963 | 0.527893 | 0.682871 | 0.067* | |
H10B | 0.434175 | 0.625874 | 0.768158 | 0.067* | |
H10C | 0.602526 | 0.623236 | 0.735301 | 0.067* | |
H4A | 0.927 (4) | 0.496 (3) | 0.316 (2) | 0.056 (14)* | |
H4B | 0.877 (5) | 0.446 (3) | 0.437 (3) | 0.078 (18)* | |
H3A | 0.853 (7) | 0.340 (5) | 0.618 (3) | 0.15 (3)* | |
H3B | 0.776 (3) | 0.276 (4) | 0.530 (4) | 0.10 (2)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0428 (7) | 0.0371 (6) | 0.0381 (7) | 0.0005 (6) | 0.0105 (5) | 0.0034 (6) |
O1 | 0.0423 (18) | 0.0405 (16) | 0.0312 (18) | 0.0105 (14) | 0.0138 (14) | 0.0063 (14) |
O3 | 0.053 (3) | 0.0464 (19) | 0.055 (2) | −0.0033 (18) | 0.010 (2) | −0.0018 (18) |
N1 | 0.043 (2) | 0.036 (2) | 0.033 (2) | 0.0055 (18) | 0.0006 (17) | 0.0102 (18) |
N2 | 0.030 (2) | 0.0297 (19) | 0.037 (2) | 0.0021 (16) | 0.0040 (16) | 0.0022 (17) |
N3 | 0.028 (2) | 0.0277 (18) | 0.034 (2) | −0.0010 (16) | 0.0017 (15) | 0.0006 (17) |
N4 | 0.045 (2) | 0.038 (2) | 0.044 (3) | 0.010 (2) | 0.016 (2) | 0.000 (2) |
C1 | 0.036 (3) | 0.034 (2) | 0.046 (3) | 0.007 (2) | 0.003 (2) | −0.005 (2) |
C2 | 0.045 (3) | 0.028 (2) | 0.045 (3) | 0.006 (2) | −0.005 (2) | −0.001 (2) |
C3 | 0.026 (2) | 0.026 (2) | 0.032 (2) | −0.005 (2) | 0.0027 (18) | 0.000 (2) |
C4 | 0.029 (2) | 0.031 (2) | 0.026 (3) | −0.002 (2) | 0.008 (2) | −0.004 (2) |
C5 | 0.031 (2) | 0.028 (2) | 0.027 (2) | −0.006 (2) | 0.0057 (19) | −0.001 (2) |
C6 | 0.037 (3) | 0.025 (2) | 0.032 (3) | 0.001 (2) | 0.004 (2) | 0.0031 (19) |
C7 | 0.027 (2) | 0.029 (2) | 0.035 (3) | −0.003 (2) | 0.006 (2) | −0.006 (2) |
C8 | 0.038 (3) | 0.040 (2) | 0.031 (3) | −0.003 (2) | 0.010 (2) | 0.002 (2) |
C9 | 0.041 (3) | 0.033 (2) | 0.030 (3) | −0.001 (2) | −0.002 (2) | 0.0031 (19) |
C10 | 0.049 (3) | 0.055 (3) | 0.031 (3) | 0.006 (2) | 0.011 (2) | 0.009 (2) |
S1—C1 | 1.710 (4) | C1—C2 | 1.340 (5) |
S1—C3 | 1.731 (4) | C2—H2 | 0.9300 |
O1—C5 | 1.355 (4) | C4—C5 | 1.422 (5) |
O1—C10 | 1.435 (4) | C4—C9 | 1.423 (5) |
O3—H3A | 0.842 (10) | C5—C6 | 1.382 (5) |
O3—H3B | 0.840 (10) | C6—H6 | 0.9300 |
N1—C2 | 1.377 (5) | C6—C7 | 1.401 (5) |
N1—C3 | 1.312 (4) | C7—C8 | 1.420 (5) |
N2—N3 | 1.299 (4) | C8—H8 | 0.9300 |
N2—C3 | 1.396 (4) | C8—C9 | 1.345 (5) |
N3—C4 | 1.374 (4) | C9—H9 | 0.9300 |
N4—C7 | 1.344 (5) | C10—H10A | 0.9600 |
N4—H4A | 0.865 (10) | C10—H10B | 0.9600 |
N4—H4B | 0.868 (10) | C10—H10C | 0.9600 |
C1—H1 | 0.9300 | ||
C1—S1—C3 | 88.6 (2) | O1—C5—C4 | 115.8 (3) |
C5—O1—C10 | 117.7 (3) | O1—C5—C6 | 123.9 (3) |
H3A—O3—H3B | 112 (5) | C6—C5—C4 | 120.2 (3) |
C3—N1—C2 | 109.0 (3) | C5—C6—H6 | 119.6 |
N3—N2—C3 | 111.9 (3) | C5—C6—C7 | 120.8 (3) |
N2—N3—C4 | 115.8 (3) | C7—C6—H6 | 119.6 |
C7—N4—H4A | 120 (3) | N4—C7—C6 | 120.7 (4) |
C7—N4—H4B | 118 (3) | N4—C7—C8 | 120.2 (4) |
H4A—N4—H4B | 121 (4) | C6—C7—C8 | 119.1 (3) |
S1—C1—H1 | 124.8 | C7—C8—H8 | 119.9 |
C2—C1—S1 | 110.5 (3) | C9—C8—C7 | 120.2 (4) |
C2—C1—H1 | 124.8 | C9—C8—H8 | 119.9 |
N1—C2—H2 | 121.7 | C4—C9—H9 | 119.0 |
C1—C2—N1 | 116.6 (3) | C8—C9—C4 | 122.1 (4) |
C1—C2—H2 | 121.7 | C8—C9—H9 | 119.0 |
N1—C3—S1 | 115.3 (3) | O1—C10—H10A | 109.5 |
N1—C3—N2 | 120.4 (3) | O1—C10—H10B | 109.5 |
N2—C3—S1 | 124.3 (3) | O1—C10—H10C | 109.5 |
N3—C4—C5 | 117.5 (3) | H10A—C10—H10B | 109.5 |
N3—C4—C9 | 124.9 (3) | H10A—C10—H10C | 109.5 |
C5—C4—C9 | 117.6 (3) | H10B—C10—H10C | 109.5 |
S1—C1—C2—N1 | 0.2 (5) | C3—S1—C1—C2 | −0.2 (3) |
O1—C5—C6—C7 | 179.3 (3) | C3—N1—C2—C1 | −0.1 (5) |
N2—N3—C4—C5 | 174.2 (3) | C3—N2—N3—C4 | −177.8 (3) |
N2—N3—C4—C9 | −3.2 (5) | C4—C5—C6—C7 | −0.8 (5) |
N3—N2—C3—S1 | 2.3 (4) | C5—C4—C9—C8 | −0.2 (5) |
N3—N2—C3—N1 | −178.1 (3) | C5—C6—C7—N4 | −178.9 (3) |
N3—C4—C5—O1 | 2.8 (5) | C5—C6—C7—C8 | 0.8 (5) |
N3—C4—C5—C6 | −177.0 (3) | C6—C7—C8—C9 | −0.5 (6) |
N3—C4—C9—C8 | 177.1 (3) | C7—C8—C9—C4 | 0.2 (6) |
N4—C7—C8—C9 | 179.2 (4) | C9—C4—C5—O1 | −179.6 (3) |
C1—S1—C3—N1 | 0.2 (3) | C9—C4—C5—C6 | 0.5 (5) |
C1—S1—C3—N2 | 179.7 (3) | C10—O1—C5—C4 | −171.3 (3) |
C2—N1—C3—S1 | −0.1 (4) | C10—O1—C5—C6 | 8.6 (5) |
C2—N1—C3—N2 | −179.7 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H4A···N2i | 0.87 (1) | 2.30 (2) | 3.137 (5) | 162 (3) |
N4—H4B···O3 | 0.87 (1) | 2.08 (1) | 2.946 (5) | 173 (4) |
O3—H3A···N1ii | 0.84 (1) | 2.12 (2) | 2.954 (5) | 169 (6) |
O3—H3B···N3iii | 0.84 (1) | 2.43 (3) | 3.186 (5) | 150 (5) |
C9—H9···N4iv | 0.93 | 2.69 | 3.587 (5) | 162 |
C2—H2···N2v | 0.93 | 2.87 | 3.798 (5) | 176 |
C8—H8···O1vi | 0.93 | 2.72 | 3.452 (5) | 136 |
C1—H1···O3vii | 0.93 | 2.56 | 3.463 (5) | 165 |
C10—H10C···C3ii | 0.96 | 2.89 | 3.655 (5) | 137 |
C10—H10A···C6iii | 0.96 | 2.83 | 3.551 (5) | 132 |
C10—H10A···C7iii | 0.96 | 2.86 | 3.502 (5) | 125 |
Symmetry codes: (i) −x+3/2, y−1/2, −z+1/2; (ii) x+1/2, −y+3/2, z+1/2; (iii) −x+1, −y+1, −z+1; (iv) −x+3/2, y+1/2, −z+1/2; (v) −x+1/2, y+1/2, −z+1/2; (vi) x+1/2, −y+3/2, z−1/2; (vii) x−1, y+1, z. |
Acknowledgements
We would like to thank the Department of Chemistry, Faculty of Science, Kasetsart University, for support to facilitate our research.
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