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N-[(E)-Quinolin-2-yl­methyl­­idene]-1,2,4-triazol-4-amine hemihydrate

aChemical Sciences, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link BE1410, Negara Brunei Darussalam, and bDepartment of Chemistry, Tennessee State University, 2500 John A. Merritt Blvd., Nashville, Tennessee, TN 37209, USA
*Correspondence e-mail: haniti.hamid@ubd.edu.bn

Edited by H. Ishida, Okayama University, Japan (Received 22 January 2020; accepted 30 January 2020; online 3 February 2020)

The title hemihydrate, C12H9N5·0.5H2O, was isolated from the condensation reaction of quinoline-2-carbaldehyde with 4-amino-4H-1,2,4-triazole. The Schiff base mol­ecule adopts an E configuration about the C=N bond and is approximately planar, with a dihedral angle between the quinoline ring system and the 1,2,4-triazole ring of 12.2 (1)°. In the crystal, one water mol­ecule bridges two Schiff base mol­ecules via O—H⋯N hydrogen bonds. The Schiff base mol­ecules are inter­connected by ππ stacking inter­actions [centroid-centroid distances of 3.7486 (7) and 3.9003 (7) Å] into columns along [1[\overline{1}]0].

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

Schiff bases containing a heterocyclic 1,2,4-triazole moiety have been investigated for their bioactivities and pharmaceutical applications (Bhalgat et al., 2014[Bhalgat, C. M., Irfan Ali, M., Ramesh, B. & Ramu, G. (2014). Arab. J. Chem, 7, 986-993.]; Saadaoui et al., 2019[Saadaoui, I., Krichen, F., Ben Salah, B., Ben Mansour, R., Miled, N., Bougatef, A. & Kossentini, M. (2019). J. Mol. Struct. 1180, 344-354.]; Zhang et al., 2019[Zhang, J., Wang, S., Ba, Y. & Xu, Z. (2019). Eur. J. Med. Chem. 174, 1-8.]; Akin et al., 2019[Akin, S., Ayaloglu, H., Gultekin, E., Colak, A., Bekircan, O. & Akatin, M. Y. (2019). Bioorg. Chem. 83, 170-179.]). Recently, the structures of Schiff bases obtained from 3-amino-1H-1,2,4-triazole have been reported in detail (Kołodziej et al., 2019[Kołodziej, B., Morawiak, M., Schilf, W. & Kamieński, B. (2019). J. Mol. Struct. 1184, 207-218.]). In the present work, we report the crystal structure of a new Schiff base, namely N-[(E)-quinolin-2-yl­methyl­idene]-1,2,4-triazol-4-amine hemihydrate.

Fig. 1[link] illustrates the mol­ecular structure of the title compound with the atomic numbering. The bond lengths and angles are within the expected range and normal values. In particular, C3—C4, C3—N4 and N3—N4 bond lengths are 1.475 (2), 1.279 (2) and 1.387 (2) Å, respectively, confirming its Schiff base structure. The title compound as a whole is a conjugated system with two aromatic fragments (quinoline and triazole) linked by the azomethine C3=N4 double bond and is approximately planar, adopting an E configuration. The azomethine (N4/C3/H3) fragment is twisted by 7.36 (9)° with respect to the quinoline ring system, and the dihedral angle between the quinoline ring system and the 1,2,4-triazole ring is 12.2 (1)°.

[Figure 1]
Figure 1
The mol­ecular structure of the title compound, showing the atom-labelling scheme and 50% probability displacement ellipsoids.

In the crystal, the O atom of water mol­ecule lies on a twofold rotation axis and also close to the plane of the adjacent quinoline ring system, deviating by 0.157 Å. As a result, the water mol­ecule forms a symmetric system of O—H⋯N hydrogen bonds (Table 1[link]) with two Schiff base mol­ecules (Fig. 2[link]); the hydrogen bonds link the water mol­ecule with the 1,2,4-triazole rings. The Schiff base mol­ecules are stacked, forming mol­ecular columns along [1[\overline{1}]0] (Fig. 3[link]) by ππ stacking inter­actions with centroid–centroid distances of 3.7486 (7) Å between the C1/N1/N2/C2/N3 and C7–C12 rings, and 3.9003 (7) Å between the C1/N1/N2/C2/N3 and N5/C4–C7/C12 rings.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1W—H1W⋯N1 0.914 (18) 1.939 (18) 2.8422 (11) 169.3 (17)
[Figure 2]
Figure 2
A partial packing diagram of the title compound, showing two Schiff base mol­ecules linked by two identical inter­molecular O—H⋯N hydrogen bonds.
[Figure 3]
Figure 3
A partial packing diagram of the title compound, showing a mol­ecular column formed by ππ stacking inter­actions.

Synthesis and crystallization

A solution of quinoline-2-carbaldehyde (1.00 g, 6.0 mmol) was mixed with an equimolar solution of 4-amino-4H-1,2,4-triazole (0.54 g, 6.0 mmol) in a mixture of absolute ethanol and chloro­form (1:1) (20 ml). Glacial acetic acid (2 drops) was added into the reaction mixture, followed by heating at 351 K for 6 h for complete conversion to the product (as confirmed by TLC analysis). The mixture was then kept in an ambient environment for two weeks. The crude product obtained was recrystallized from ethyl acetate solution, giving clear brown crystals (yield 55%) suitable for X-ray analysis. Presumably the water molecule of crystallization was absorbed from the atmosphere or as a by product during the synthesis. Analysis: C12H9N5 (%): C 64.56, H 4.06, N 31.37; found (%): C 64.74, H 4.34, N 30.67; 1H NMR (DMSO-d6): δ 9.35 (s, 2H, H-1,2), 9.27 (s, 1H, CH=N, H-3), 8.56 (d, 1H, H-5. J = 8.12 Hz 1H), 8.17 (d, 1H, H-6. J = 8.12 Hz), 8.12 (m, 2H, H-8,11), 7.89 (t, 1H, H-10, J = 6.8 Hz), 7.75 (t, 1H, H-9, J = 6.8 Hz). 13C NMR (DMSO-d6): δ 157.55 (CH=N, C3), 152.17 (C1,2), 147.83, 139.79, 137.98, 131.12, 129.63, 128.92, 128.68, 118.36. IR (KBr, cm−1): 3103 (Aryl C—H), 1597 (C=N), 1051 (N—N), 957 (C=S). EI—MS calculated for C12H9N5 [M]+: 223.24, Found: 223. m.p. 487–489 K.

The title compound was also synthesized using a green synthesis method. A solution of 4-amino-4H-1,2,4-triazole (0.11 g, 1.3 mmol) in 5 ml of distilled water was added to quinoline-2-carbaldehyde (0.20 g, 1.3 mmol) in 5 ml of distilled water. The resulting mixture was then stirred at room temperature for 1 h while the reaction progress was monitored by TLC. The clear light-brown crude product formed qu­anti­tatively after 1 h and was vacuum filtered, dried and recrystallized from ethyl acetate solution to give clear dark-brown crystals with 60% yield. The recrystallized compound from the conventional synthesis method and that from the green method were confirmed to be identical as given by the similar data from FTIR, TLC, MS, and melting-point measurements.

Refinement

Crystal data, data collection and structure refinement details of the title compound are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula C12H9N5·0.5H2O
Mr 232.25
Crystal system, space group Monoclinic, C2/c
Temperature (K) 100
a, b, c (Å) 13.7212 (12), 7.5047 (6), 21.1686 (18)
β (°) 100.524 (2)
V3) 2143.1 (3)
Z 8
Radiation type Cu Kα
μ (mm−1) 0.79
Crystal size (mm) 0.36 × 0.26 × 0.17
 
Data collection
Diffractometer Bruker D8 Venture
Absorption correction Multi-scan (SADABS; Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.626, 0.754
No. of measured, independent and observed [I > 2σ(I)] reflections 36175, 2200, 2142
Rint 0.036
(sin θ/λ)max−1) 0.625
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.090, 1.09
No. of reflections 2200
No. of parameters 164
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.22, −0.23
Computer programs: APEX3 (Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SAINT (Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2014 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Structural data


Computing details top

Data collection: APEX3 (Bruker, 2014); cell refinement: APEX3 (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

N-[(E)-Quinolin-2-ylmethylidene]-1,2,4-triazol-4-amine hemihydrate top
Crystal data top
C12H9N5·0.5H2OF(000) = 968
Mr = 232.25Dx = 1.440 Mg m3
Monoclinic, C2/cCu Kα radiation, λ = 1.54178 Å
a = 13.7212 (12) ÅCell parameters from 9219 reflections
b = 7.5047 (6) Åθ = 4.3–74.4°
c = 21.1686 (18) ŵ = 0.79 mm1
β = 100.524 (2)°T = 100 K
V = 2143.1 (3) Å3Block, brown
Z = 80.36 × 0.26 × 0.17 mm
Data collection top
Bruker D8 Venture
diffractometer
2142 reflections with I > 2σ(I)
Radiation source: Sealed Microfocus SourceRint = 0.036
φ and ω scansθmax = 74.5°, θmin = 4.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
h = 1717
Tmin = 0.626, Tmax = 0.754k = 99
36175 measured reflectionsl = 2526
2200 independent reflections
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.0426P)2 + 1.6998P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.090(Δ/σ)max < 0.001
S = 1.09Δρmax = 0.22 e Å3
2200 reflectionsΔρmin = 0.22 e Å3
164 parametersExtinction correction: SHELXL2014 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0104 (4)
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.14712 (7)0.46460 (13)0.69779 (5)0.0216 (2)
N20.22716 (7)0.56151 (14)0.73141 (5)0.0234 (2)
N30.24350 (6)0.54032 (12)0.63061 (4)0.0168 (2)
N40.27388 (7)0.54247 (12)0.57163 (4)0.0172 (2)
N50.46063 (6)0.73766 (12)0.50056 (4)0.0156 (2)
C10.15910 (8)0.45416 (15)0.63833 (5)0.0188 (2)
H10.11520.39490.60500.023*
C20.28338 (8)0.60519 (16)0.69030 (5)0.0207 (3)
H20.34300.67200.70030.025*
C30.35238 (8)0.62997 (14)0.56723 (5)0.0164 (2)
H30.38800.69320.60300.020*
C40.38588 (7)0.62967 (14)0.50486 (5)0.0155 (2)
C50.33874 (8)0.51790 (15)0.45428 (5)0.0176 (2)
H50.28560.44230.46020.021*
C60.37095 (8)0.52081 (14)0.39711 (5)0.0173 (2)
H60.33980.44850.36240.021*
C70.45134 (7)0.63285 (14)0.38995 (5)0.0150 (2)
C80.49101 (8)0.63959 (14)0.33287 (5)0.0176 (2)
H80.46520.56360.29790.021*
C90.56649 (8)0.75496 (15)0.32765 (5)0.0181 (2)
H90.59230.75980.28900.022*
C100.60599 (8)0.86659 (15)0.37961 (5)0.0181 (2)
H100.65710.94850.37510.022*
C110.57180 (8)0.85879 (14)0.43664 (5)0.0167 (2)
H110.60080.93190.47170.020*
C120.49343 (7)0.74173 (13)0.44309 (5)0.0145 (2)
O1W0.00000.27774 (16)0.75000.0257 (3)
H1W0.0437 (13)0.351 (3)0.7347 (9)0.053 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0192 (5)0.0245 (5)0.0230 (5)0.0016 (4)0.0086 (4)0.0027 (4)
N20.0225 (5)0.0295 (5)0.0201 (5)0.0004 (4)0.0087 (4)0.0000 (4)
N30.0151 (4)0.0211 (5)0.0154 (4)0.0012 (3)0.0059 (3)0.0007 (3)
N40.0163 (4)0.0227 (5)0.0138 (4)0.0030 (3)0.0056 (3)0.0015 (3)
N50.0146 (4)0.0177 (4)0.0147 (4)0.0019 (3)0.0031 (3)0.0003 (3)
C10.0155 (5)0.0203 (5)0.0218 (5)0.0016 (4)0.0062 (4)0.0021 (4)
C20.0194 (5)0.0269 (6)0.0167 (5)0.0003 (4)0.0060 (4)0.0016 (4)
C30.0153 (5)0.0184 (5)0.0155 (5)0.0026 (4)0.0033 (4)0.0007 (4)
C40.0133 (5)0.0181 (5)0.0150 (5)0.0035 (4)0.0024 (4)0.0022 (4)
C50.0136 (5)0.0209 (5)0.0178 (5)0.0017 (4)0.0018 (4)0.0024 (4)
C60.0164 (5)0.0190 (5)0.0153 (5)0.0005 (4)0.0001 (4)0.0002 (4)
C70.0144 (5)0.0165 (5)0.0135 (5)0.0022 (4)0.0008 (4)0.0018 (4)
C80.0193 (5)0.0205 (5)0.0125 (5)0.0000 (4)0.0015 (4)0.0002 (4)
C90.0174 (5)0.0241 (6)0.0132 (5)0.0009 (4)0.0037 (4)0.0022 (4)
C100.0149 (5)0.0210 (6)0.0182 (5)0.0021 (4)0.0027 (4)0.0021 (4)
C110.0160 (5)0.0184 (5)0.0153 (5)0.0010 (4)0.0012 (4)0.0009 (4)
C120.0136 (5)0.0164 (5)0.0132 (5)0.0032 (4)0.0020 (4)0.0010 (4)
O1W0.0228 (6)0.0227 (6)0.0356 (7)0.0000.0153 (5)0.000
Geometric parameters (Å, º) top
N1—C11.3011 (14)C5—H50.9500
N1—N21.3985 (14)C6—C71.4169 (15)
N2—C21.3057 (14)C6—H60.9500
N3—C11.3621 (14)C7—C81.4140 (14)
N3—C21.3714 (14)C7—C121.4245 (14)
N3—N41.3866 (12)C8—C91.3698 (15)
N4—C31.2793 (14)C8—H80.9500
N5—C41.3233 (14)C9—C101.4099 (15)
N5—C121.3724 (13)C9—H90.9500
C1—H10.9500C10—C111.3739 (14)
C2—H20.9500C10—H100.9500
C3—C41.4752 (14)C11—C121.4143 (14)
C3—H30.9500C11—H110.9500
C4—C51.4196 (15)O1W—H1W0.914 (18)
C5—C61.3623 (15)
C1—N1—N2107.30 (9)C5—C6—C7119.32 (10)
C2—N2—N1107.22 (9)C5—C6—H6120.3
C1—N3—C2105.24 (9)C7—C6—H6120.3
C1—N3—N4121.04 (9)C8—C7—C6122.77 (9)
C2—N3—N4133.67 (9)C8—C7—C12119.37 (9)
C3—N4—N3117.85 (9)C6—C7—C12117.86 (9)
C4—N5—C12117.27 (9)C9—C8—C7120.42 (10)
N1—C1—N3110.36 (10)C9—C8—H8119.8
N1—C1—H1124.8C7—C8—H8119.8
N3—C1—H1124.8C8—C9—C10120.08 (10)
N2—C2—N3109.88 (10)C8—C9—H9120.0
N2—C2—H2125.1C10—C9—H9120.0
N3—C2—H2125.1C11—C10—C9121.06 (10)
N4—C3—C4117.94 (9)C11—C10—H10119.5
N4—C3—H3121.0C9—C10—H10119.5
C4—C3—H3121.0C10—C11—C12119.93 (10)
N5—C4—C5124.21 (10)C10—C11—H11120.0
N5—C4—C3115.64 (9)C12—C11—H11120.0
C5—C4—C3120.16 (9)N5—C12—C11118.53 (9)
C6—C5—C4118.91 (10)N5—C12—C7122.41 (9)
C6—C5—H5120.5C11—C12—C7119.06 (9)
C4—C5—H5120.5
C1—N1—N2—C20.18 (12)C4—C5—C6—C70.96 (15)
C1—N3—N4—C3178.11 (10)C5—C6—C7—C8178.09 (10)
C2—N3—N4—C34.93 (17)C5—C6—C7—C121.59 (15)
N2—N1—C1—N30.19 (12)C6—C7—C8—C9177.65 (10)
C2—N3—C1—N10.12 (12)C12—C7—C8—C92.68 (15)
N4—N3—C1—N1177.84 (9)C7—C8—C9—C100.74 (16)
N1—N2—C2—N30.11 (13)C8—C9—C10—C111.74 (16)
C1—N3—C2—N20.00 (13)C9—C10—C11—C122.19 (16)
N4—N3—C2—N2177.30 (10)C4—N5—C12—C11178.64 (9)
N3—N4—C3—C4178.88 (8)C4—N5—C12—C71.26 (14)
C12—N5—C4—C50.58 (15)C10—C11—C12—N5179.70 (9)
C12—N5—C4—C3179.61 (8)C10—C11—C12—C70.21 (15)
N4—C3—C4—N5172.73 (9)C8—C7—C12—N5177.90 (9)
N4—C3—C4—C57.45 (15)C6—C7—C12—N51.78 (15)
N5—C4—C5—C60.45 (16)C8—C7—C12—C112.20 (15)
C3—C4—C5—C6179.75 (9)C6—C7—C12—C11178.12 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···N10.914 (18)1.939 (18)2.8422 (11)169.3 (17)
 

Acknowledgements

We are thankful to the Chemical Sciences, Faculty of Science, Universiti Brunei Darussalam for supporting this research work. We also thank the National University of Singapore for the data collection and analysis of the single-crystal X-ray diffraction and the analytical data. We also thank Tennessee State University for collecting the NMR spectroscopic data.

References

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First citationZhang, J., Wang, S., Ba, Y. & Xu, Z. (2019). Eur. J. Med. Chem. 174, 1–8.  Web of Science CrossRef PubMed Google Scholar

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