Crystal structure and computational study of 2,4-di-chloro-N-[(E)-(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

The title compound, C11H6Cl2N2O2S, is a Schiff base that incorporates an N-bound 2,4-di-chloro-phenyl and a C-bound 5-nitro-thio-phene ring. The mol-ecule is approximately planar, the maximum deviation from the mean plane being 0.233 (4) Å for the C=N N atom. The dihedral angle between the benzene and thio-phene rings is 9.7 (2)°. The C=N double bond has an E configuration. The crystal structure features C-H⋯O hydrogen bonds,forming sheets parallel to (10-1), and π-π stacking inter-actions between symmetry-related thio-phene and benzene rings, in which the distance between adjacent ring centroids is 3.707 (4) Å, forming a three-dimensional supramolecular structure. Geometric parameters from quantum-chemical calculations are in good agreement with experimental X-ray diffraction results.

Chemical context

Schiff bases, which contain C=N double bonds, are well known starting materials for the synthesis of many drugs (Aydoğan et al., 2001 ▸) and often possess very important biological activities, such as anti-inflammatory and analgesic properties (Sondhi et al., 2006 ▸). In addition, nitro­thio­phene and its derivatives also exhibit many biological activities, including anti­bacterial and anti­fungal (Kalluraya et al., 1994 ▸; Kalluraya & Shetty, 1997 ▸) properties. We report the synthesis, structural analysis and theoretical calculations of the title compound, C11H6Cl2N2O2S (I), which is a new Schiff base that includes a nitro­thio­phene group.

Structural commentary

The title compound (Fig. 1 ▸) is nearly planar, the maximum deviation from the mean plane of 0.233 (4) Å is for atom N2. Schiff bases that are derived from salicyl­aldehyde show thermochromism and photochromism properties that are dependent upon planarity or non-planarity of the mol­ecules (Cohen et al., 1964 ▸; Hadjoudis et al., 1987 ▸). Since the dihedral angle between the benzene and thio­phene rings is 9.7 (2)°, the title compound may exhibit thermochromic features. The slight twist of the mol­ecule is caused by a steric repulsion of atoms H5 and H7. The C7=N2 double-bond distance is 1.267 (6)Å, which is comparable to those of reported structures (Özdemir Tarı & Işık, 2012 ▸; Ceylan et al., 2012 ▸). The C8—C7—N2—C6 torsion angle is 178.5 (5)°.

Figure 1

A view of (I), with the atom-numbering scheme and 50% probability displacement ellipsoids.

Supra­molecular features

In the crystal structure there are weak C—H⋯O hydrogen bonds (Fig. 2 ▸ and Table 1 ▸) with atom O1 acting as a bifurcated acceptor from both C5 and C7 (x − 1, y, z − 1), creating an (7) motif, and forming sheets parallel to (10). π–π stacking inter­actions are present between the benzene (centroid Cg2) and thio­phene (centroid Cg1) rings of symmetry-related mol­ecules [Cg1⋯Cg2(x,  − y,  + z) = 3.707 (4) Å, forming a three-dimensional supramolecular structure.

Figure 2

A partial packing view of (I). Dashed lines indicate the C—H⋯O hydrogen-bonding inter­actions

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1i	0.93	2.59	3.508 (8)	171
C7—H7⋯O1i	0.93	2.55	3.300 (8)	138
C2—H2⋯O2ii	0.93	2.56	3.360 (7)	144

Symmetry codes: (i) ; (ii) .

Theoretical Calculations

Quantum-chemical calculations were performed to compare with the experimental analysis. Ab initio Hartree–Fock (HF) and density functional DFT(B3LYP) methods were used with the standard basis set of 6-31+G(d) (Becke, 1993 ▸; Lee et al., 1988 ▸; Schlegel, 1982 ▸; Peng et al., 1996 ▸) using the Gaussian 03 software package (Frisch et al., 2004 ▸; Dennington et al., 2007 ▸) to obtain the optimized mol­ecular structure. The computational results are consistent with experimental crystallographic data. The C7=N2 bond length was calculated to be 1.25 and 1.28 Å using HF and DFT(B3LYP) methods, respectively. The torsion angle C8—C7—N2—C6 was calculated to be −177.98 and −176.09° by HF and DFT(B3LYP) methods, respectively.

Synthesis and crystallization

The compound 2,4-di­chloro-N-[(E)-(5-nitro­thio­phen-2-yl)methyl­idene]aniline was prepared by refluxing a mixture of a solution containing 5-nitro-2-thio­phene­carboxaldehyde (0.0180 g, 0.114 mmol) in 20 ml ethanol and a solution containing 2,4-di­chloro­aniline (0.0185 g, 0.114 mmol) in 20 ml ethanol. The reaction mixture was stirred for 1h under reflux. Crystals suitable for X-ray analysis were obtained from a solution in ethanol by slow evaporation (yield 65%; m.p 443–445 K).

IR (KBr/cm−1): 3102.59 (C—H), 1602.71 (C=N), 1503.00 (NO2), 1231.00 (C—N, methyl­ene), 1192.05 (C—N, thio­phene), 1039.60 (C—H, thio­phene), 1124.10 (C—H, methyl­ene), 957.96 (C—H, methyl­ene), 787.73 (C—H, 957.96)

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. All H atoms were positioned geometrically with C—H = 0.93 Å and refined with using a riding model with U iso(H) = 1.2U eq(C).

Table 2

Experimental details

Crystal data
Chemical formula	C11H6Cl2N2O2S
M r	301.14
Crystal system, space group	Monoclinic, P21/c
Temperature (K)	293
a, b, c (Å)	7.5731 (9), 22.1795 (16), 8.3093 (16)
β (°)	117.967 (10)
V (Å3)	1232.7 (3)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.69
Crystal size (mm)	0.18 × 0.15 × 0.10
Data collection
Diffractometer	Agilent SuperNova (Single source at offset) Eos
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2011)
T min, T max	0.712, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3059, 2201, 1119
R int	0.033
(sin θ/λ)max (Å−1)	0.617
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.063, 0.138, 1.09
No. of reflections	2201
No. of parameters	163
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.38, −0.32

Computer programs: CrysAlis PRO (Oxford Diffraction, 2007 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2014 (Sheldrick, 2015 ▸) and ORTEP-3 for Windows and WinGX (Farrugia, 2012 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989016011816/pk2586sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016011816/pk2586Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989016011816/pk2586Isup3.cml

CCDC reference: 1494850

Additional supporting information: crystallographic information; 3D view; checkCIF report

C11H6Cl2N2O2S	F(000) = 608
Mr = 301.14	Dx = 1.623 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.5731 (9) Å	Cell parameters from 612 reflections
b = 22.1795 (16) Å	θ = 3.2–28.4°
c = 8.3093 (16) Å	µ = 0.69 mm−1
β = 117.967 (10)°	T = 293 K
V = 1232.7 (3) Å3	Block, red
Z = 4	0.18 × 0.15 × 0.10 mm

Agilent SuperNova (Single source at offset) Eos diffractometer	2201 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	1119 reflections with I > 2σ(I)
Detector resolution: 16.0454 pixels mm-1	Rint = 0.033
ω scans	θmax = 26.0°, θmin = 3.2°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	h = −7→9
Tmin = 0.712, Tmax = 1.000	k = −27→12
3059 measured reflections	l = −10→5

Refinement on F2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.063	H-atom parameters constrained
wR(F2) = 0.138	w = 1/[σ2(Fo2) + (0.019P)2] where P = (Fo2 + 2Fc2)/3
S = 1.09	(Δ/σ)max < 0.001
2201 reflections	Δρmax = 0.38 e Å−3
163 parameters	Δρmin = −0.32 e Å−3

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	0.4933 (2)	0.69183 (7)	0.38617 (19)	0.0450 (4)
Cl1	0.3105 (3)	0.89412 (7)	0.2025 (2)	0.0612 (5)
Cl2	−0.2711 (3)	0.95859 (7)	−0.4521 (2)	0.0720 (6)
C6	0.0675 (8)	0.8117 (2)	−0.0461 (7)	0.0369 (14)
C7	0.1939 (9)	0.7153 (3)	0.0411 (7)	0.0473 (16)
H7	0.1199	0.7042	−0.0806	0.057*
C5	−0.0926 (8)	0.7988 (3)	−0.2169 (7)	0.0443 (15)
H5	−0.1307	0.7588	−0.2472	0.053*
C2	0.0113 (9)	0.9185 (3)	−0.1289 (7)	0.0468 (16)
H2	0.0445	0.9588	−0.0990	0.056*
C4	−0.1955 (9)	0.8429 (3)	−0.3414 (7)	0.0446 (15)
H4	−0.3005	0.8328	−0.4545	0.053*
O1	0.8046 (7)	0.6438 (2)	0.7224 (6)	0.0768 (15)
N2	0.1847 (7)	0.7692 (2)	0.0870 (6)	0.0429 (12)
C10	0.4560 (10)	0.5791 (3)	0.3021 (8)	0.0499 (16)
H10	0.4750	0.5376	0.3102	0.060*
N1	0.7237 (8)	0.6023 (2)	0.6127 (7)	0.0538 (14)
C1	0.1141 (8)	0.8726 (2)	−0.0056 (7)	0.0395 (14)
O2	0.7734 (7)	0.5493 (2)	0.6444 (6)	0.0761 (15)
C9	0.3146 (9)	0.6094 (3)	0.1475 (7)	0.0495 (17)
H9	0.2288	0.5902	0.0393	0.059*
C11	0.5608 (9)	0.6182 (3)	0.4372 (8)	0.0450 (15)
C8	0.3165 (9)	0.6706 (3)	0.1730 (7)	0.0445 (15)
C3	−0.1422 (9)	0.9020 (3)	−0.2976 (7)	0.0436 (15)

	U11	U22	U33	U12	U13	U23
S1	0.0440 (10)	0.0394 (9)	0.0480 (9)	0.0004 (8)	0.0184 (8)	0.0007 (7)
Cl1	0.0617 (12)	0.0609 (11)	0.0451 (9)	−0.0060 (9)	0.0118 (9)	−0.0096 (8)
Cl2	0.0749 (15)	0.0527 (10)	0.0616 (11)	0.0061 (10)	0.0096 (11)	0.0135 (9)
C6	0.041 (4)	0.038 (3)	0.036 (3)	0.004 (3)	0.022 (3)	0.004 (3)
C7	0.051 (4)	0.050 (4)	0.037 (3)	0.000 (3)	0.017 (3)	0.002 (3)
C5	0.037 (4)	0.039 (3)	0.046 (3)	0.003 (3)	0.009 (3)	0.002 (3)
C2	0.051 (4)	0.042 (4)	0.053 (4)	−0.009 (3)	0.029 (4)	−0.003 (3)
C4	0.041 (4)	0.047 (4)	0.033 (3)	0.001 (3)	0.007 (3)	0.001 (3)
O1	0.069 (4)	0.067 (3)	0.060 (3)	−0.008 (3)	0.001 (3)	−0.003 (3)
N2	0.042 (3)	0.037 (3)	0.045 (3)	−0.005 (2)	0.016 (3)	−0.001 (2)
C10	0.064 (5)	0.036 (3)	0.060 (4)	0.006 (3)	0.038 (4)	0.003 (3)
N1	0.049 (4)	0.055 (4)	0.061 (4)	0.004 (3)	0.029 (3)	0.007 (3)
C1	0.037 (4)	0.044 (4)	0.036 (3)	−0.006 (3)	0.016 (3)	−0.004 (3)
O2	0.086 (4)	0.053 (3)	0.082 (3)	0.028 (3)	0.033 (3)	0.021 (2)
C9	0.052 (5)	0.053 (4)	0.036 (3)	−0.001 (3)	0.014 (3)	−0.001 (3)
C11	0.049 (4)	0.039 (3)	0.049 (4)	−0.004 (3)	0.025 (4)	0.002 (3)
C8	0.042 (4)	0.042 (3)	0.046 (4)	0.003 (3)	0.018 (3)	0.003 (3)
C3	0.041 (4)	0.049 (4)	0.033 (3)	0.003 (3)	0.011 (3)	0.005 (3)

S1—C11	1.703 (6)	C2—C1	1.394 (7)
S1—C8	1.711 (6)	C2—H2	0.9300
Cl1—C1	1.737 (5)	C4—C3	1.370 (7)
Cl2—C3	1.732 (6)	C4—H4	0.9300
C6—C5	1.397 (7)	O1—N1	1.237 (6)
C6—C1	1.398 (7)	C10—C11	1.344 (7)
C6—N2	1.407 (6)	C10—C9	1.399 (7)
C7—N2	1.267 (6)	C10—H10	0.9300
C7—C8	1.446 (7)	N1—O2	1.226 (6)
C7—H7	0.9300	N1—C11	1.445 (7)
C5—C4	1.371 (7)	C9—C8	1.372 (7)
C5—H5	0.9300	C9—H9	0.9300
C2—C3	1.386 (7)
C11—S1—C8	89.5 (3)	C9—C10—H10	124.6
C5—C6—C1	116.3 (5)	O2—N1—O1	124.1 (6)
C5—C6—N2	126.1 (5)	O2—N1—C11	118.8 (5)
C1—C6—N2	117.6 (5)	O1—N1—C11	117.1 (5)
N2—C7—C8	121.7 (5)	C2—C1—C6	122.5 (5)
N2—C7—H7	119.2	C2—C1—Cl1	117.0 (4)
C8—C7—H7	119.2	C6—C1—Cl1	120.4 (4)
C4—C5—C6	122.5 (6)	C8—C9—C10	112.6 (5)
C4—C5—H5	118.8	C8—C9—H9	123.7
C6—C5—H5	118.8	C10—C9—H9	123.7
C3—C2—C1	117.8 (5)	C10—C11—N1	125.2 (6)
C3—C2—H2	121.1	C10—C11—S1	114.8 (5)
C1—C2—H2	121.1	N1—C11—S1	120.0 (4)
C3—C4—C5	119.3 (5)	C9—C8—C7	127.2 (6)
C3—C4—H4	120.3	C9—C8—S1	112.2 (4)
C5—C4—H4	120.3	C7—C8—S1	120.6 (5)
C7—N2—C6	119.9 (5)	C4—C3—C2	121.6 (5)
C11—C10—C9	110.8 (6)	C4—C3—Cl2	120.2 (4)
C11—C10—H10	124.6	C2—C3—Cl2	118.2 (5)
C1—C6—C5—C4	2.0 (8)	O1—N1—C11—C10	−179.9 (6)
N2—C6—C5—C4	−177.9 (5)	O2—N1—C11—S1	−177.9 (5)
C6—C5—C4—C3	−0.7 (9)	O1—N1—C11—S1	2.2 (7)
C8—C7—N2—C6	178.5 (5)	C8—S1—C11—C10	−0.3 (5)
C5—C6—N2—C7	22.1 (9)	C8—S1—C11—N1	177.9 (5)
C1—C6—N2—C7	−157.7 (5)	C10—C9—C8—C7	178.5 (5)
C3—C2—C1—C6	−0.2 (8)	C10—C9—C8—S1	0.6 (7)
C3—C2—C1—Cl1	178.2 (4)	N2—C7—C8—C9	168.4 (6)
C5—C6—C1—C2	−1.5 (8)	N2—C7—C8—S1	−13.8 (8)
N2—C6—C1—C2	178.4 (5)	C11—S1—C8—C9	−0.2 (5)
C5—C6—C1—Cl1	−179.9 (3)	C11—S1—C8—C7	−178.3 (5)
N2—C6—C1—Cl1	0.0 (7)	C5—C4—C3—C2	−1.2 (9)
C11—C10—C9—C8	−0.8 (8)	C5—C4—C3—Cl2	−179.6 (4)
C9—C10—C11—N1	−177.4 (5)	C1—C2—C3—C4	1.6 (8)
C9—C10—C11—S1	0.6 (7)	C1—C2—C3—Cl2	−180.0 (4)
O2—N1—C11—C10	0.0 (9)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1i	0.93	2.59	3.508 (8)	171
C7—H7···O1i	0.93	2.55	3.300 (8)	138
C2—H2···O2ii	0.93	2.56	3.360 (7)	144