2,2-Dichloro-N-(2,3-dichloro­phen­yl)acetamide

The conformation of the N—H bond in the title compound, C₈H₅Cl₄NO, is syn to the 2-chloro substituent in the aromatic ring, similar to that of the 2-chloro substituent in 2,2-dichloro-N-(2-chloro­phen­yl)acetamide, the 3-chloro substituent in 2,2-dichloro-N-(3,4-dichloro­phen­yl)acetamide and the 2- and 3-chloro substituents in N-(2,3-dichloro­phen­yl)acetamide, but in contrast to the anti conformation observed with respect to the 3-chloro substituent in 2,2-dichloro-N-(3-chloro­phen­yl)acetamide. The bond parameters are similar to those in 2,2-dichloro-N-phenyl­acetamide and other acetanilides. The mol­ecules are linked into chains through N—H...O hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 299 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.046
• wR factor = 0.129
• Data-to-parameter ratio = 15.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C8
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

In the present work, the structure of N-(2,3-dichlorophenyl)-2,2- dichloroacetamide (23DCPDCA) has been determined to study the substituent effects on the structures of N-aromatic amides (Gowda et al., 2001, 2006; 2007a, b). The conformation of the N—H bond in 23DCPDCA is syn to both the 2-chloro and 3-chloro substituent (Fig. 1), similar to that of 2-chloro substituent in N-(2-chlorophenyl)-2,2- dichloroacetamide (2CPDCA)(Gowda et al., 2001), 3-chloro substituent in N-(3,4-dichlorophenyl)-2,2-dichloroacetamide (34DCPDCA) (Gowda et al., 2007b), and 2- and 3-chloro substituents in N-(2,3-dichlorophenyl)-acetamide (23DCPA)(Gowda et al., 2007a), but in contrast to the anti conformation observed with respect to the 3-chloro substituent in the N-(3-chlorophenyl)- 2,2-dichloroacetamide (3CPDCA)(Gowda et al., 2006)·The bond parameters in 23DCPDCA are similar to those in N-(phenyl)-2,2-dichloroacetamide, 2CPDCA, 3CPDCA, 34DCPDCA, 23DCPA and other acetanilides (Gowda et al., 2001, 2006; 2007a, b). The molecules in 23DCPDCA are linked into chains through N—H···O hydrogen bonding (Table 1 and Fig.2).

Related literature

For related literature, see: Gowda et al. (2001, 2006, 2007a,b); Shilpa & Gowda (2007).

S2. Experimental

The title compound was prepared according to the literature method (Shilpa and Gowda, 2007). The purity of the compound was checked by determining its melting point. It was characterized by recording its infrared and NMR spectra (Shilpa and Gowda, 2007). Single crystals of the title compound were obtained from an ethanolic solution and used for X-ray diffraction studies at room temperature.

S3. Refinement

The H atoms were positioned with idealized geometry using a riding model with N—H = 0.86 Å and C—H = 0.93–0.98 Å. U_iso(H) values were set equal to 1.2 U_eq of the parent atom.

Computing details

Data collection: CAD-4-PC Software (Enraf–Nonius, 1996); cell refinement: CAD-4-PC Software (Enraf–Nonius, 1996); data reduction: REDU4 (Stoe & Cie, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. Molecular structure of the title compound showing the atom labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.
	Fig. 2. Molecular packing of the title compound with hydrogen bonding shown as dashed lines.

2,2-Dichloro-N-(2,3-dichlorophenyl)acetamide

Crystal data

C8H5Cl4NO	F(000) = 544
Mr = 272.93	Dx = 1.663 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 4.674 (1) Å	θ = 5.8–20.3°
b = 11.804 (2) Å	µ = 9.60 mm^−1
c = 19.833 (3) Å	T = 299 K
β = 95.05 (1)°	Needle, colourless
V = 1090.0 (3) Å^3	0.60 × 0.08 × 0.03 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1421 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.025
Graphite monochromator	θmax = 66.9°, θmin = 4.4°
ω/2θ scans	h = 0→5
Absorption correction: ψ scan (North et al., 1968)	k = −14→2
Tmin = 0.322, Tmax = 0.750	l = −23→23
2435 measured reflections	3 standard reflections every 120 min
1950 independent reflections	intensity decay: 1.0%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.129	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0721P)^2 + 0.5313P] where P = (Fo^2 + 2Fc^2)/3
1950 reflections	(Δ/σ)max < 0.001
127 parameters	Δρmax = 0.31 e Å^−3
0 restraints	Δρmin = −0.44 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.8086 (2)	−0.02347 (8)	0.21645 (5)	0.0564 (3)
Cl2	0.6830 (3)	−0.03704 (9)	0.36898 (5)	0.0763 (4)
Cl3	0.4053 (3)	0.33369 (10)	−0.00199 (6)	0.0782 (4)
Cl4	0.2454 (3)	0.10696 (11)	−0.04307 (5)	0.0761 (4)
O1	0.0589 (5)	0.1713 (3)	0.09146 (13)	0.0714 (9)
N1	0.5159 (5)	0.1646 (2)	0.13964 (13)	0.0395 (6)
H1N	0.6933	0.1633	0.1312	0.047*
C1	0.4524 (6)	0.1571 (3)	0.20853 (15)	0.0365 (7)
C2	0.5814 (7)	0.0733 (3)	0.24928 (15)	0.0378 (7)
C3	0.5257 (8)	0.0668 (3)	0.31709 (17)	0.0474 (8)
C4	0.3431 (9)	0.1429 (4)	0.34292 (17)	0.0572 (10)
H4	0.3052	0.1382	0.3881	0.069*
C5	0.2162 (9)	0.2260 (4)	0.30237 (19)	0.0587 (10)
H5	0.0922	0.2773	0.3203	0.070*
C6	0.2705 (8)	0.2346 (3)	0.23480 (18)	0.0478 (8)
H6	0.1856	0.2918	0.2076	0.057*
C7	0.3169 (7)	0.1735 (3)	0.08749 (16)	0.0414 (7)
C8	0.4369 (7)	0.1891 (3)	0.01915 (16)	0.0454 (8)
H8	0.6398	0.1671	0.0227	0.054*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0591 (6)	0.0535 (5)	0.0558 (5)	0.0144 (4)	−0.0003 (4)	−0.0054 (4)
Cl2	0.1161 (10)	0.0611 (6)	0.0478 (5)	−0.0047 (6)	−0.0142 (6)	0.0150 (5)
Cl3	0.1027 (9)	0.0732 (7)	0.0587 (6)	−0.0169 (6)	0.0076 (6)	0.0143 (5)
Cl4	0.0814 (8)	0.0907 (8)	0.0537 (5)	−0.0051 (6)	−0.0080 (5)	−0.0211 (5)
O1	0.0236 (12)	0.143 (3)	0.0475 (14)	−0.0033 (14)	0.0037 (10)	0.0094 (17)
N1	0.0253 (12)	0.0599 (17)	0.0337 (13)	0.0029 (12)	0.0044 (10)	0.0049 (12)
C1	0.0301 (15)	0.0456 (17)	0.0337 (15)	−0.0059 (13)	0.0026 (12)	0.0014 (13)
C2	0.0359 (16)	0.0404 (16)	0.0366 (16)	−0.0065 (13)	−0.0003 (13)	−0.0046 (13)
C3	0.057 (2)	0.0499 (19)	0.0335 (15)	−0.0115 (17)	−0.0036 (15)	0.0044 (15)
C4	0.066 (2)	0.074 (3)	0.0332 (17)	−0.008 (2)	0.0136 (17)	−0.0058 (17)
C5	0.056 (2)	0.073 (3)	0.049 (2)	0.007 (2)	0.0141 (17)	−0.014 (2)
C6	0.0415 (18)	0.055 (2)	0.0468 (18)	0.0075 (16)	0.0043 (15)	0.0019 (16)
C7	0.0292 (15)	0.059 (2)	0.0363 (16)	0.0010 (14)	0.0048 (12)	0.0036 (15)
C8	0.0332 (16)	0.069 (2)	0.0340 (16)	0.0006 (15)	0.0031 (13)	0.0016 (16)

Geometric parameters (Å, º)

Cl1—C2	1.726 (3)	C2—C3	1.394 (4)
Cl2—C3	1.723 (4)	C3—C4	1.369 (5)
Cl3—C8	1.761 (4)	C4—C5	1.370 (6)
Cl4—C8	1.752 (4)	C4—H4	0.9300
O1—C7	1.216 (4)	C5—C6	1.389 (5)
N1—C7	1.333 (4)	C5—H5	0.9300
N1—C1	1.426 (4)	C6—H6	0.9300
N1—H1N	0.8600	C7—C8	1.523 (4)
C1—C2	1.382 (4)	C8—H8	0.9800
C1—C6	1.382 (5)
C7—N1—C1	123.9 (3)	C4—C5—C6	120.8 (4)
C7—N1—H1N	118.0	C4—C5—H5	119.6
C1—N1—H1N	118.0	C6—C5—H5	119.6
C2—C1—C6	120.3 (3)	C1—C6—C5	119.1 (3)
C2—C1—N1	119.2 (3)	C1—C6—H6	120.5
C6—C1—N1	120.5 (3)	C5—C6—H6	120.5
C1—C2—C3	119.6 (3)	O1—C7—N1	125.2 (3)
C1—C2—Cl1	120.3 (2)	O1—C7—C8	120.4 (3)
C3—C2—Cl1	120.1 (3)	N1—C7—C8	114.4 (3)
C4—C3—C2	120.0 (3)	C7—C8—Cl4	110.8 (2)
C4—C3—Cl2	119.4 (3)	C7—C8—Cl3	107.4 (2)
C2—C3—Cl2	120.6 (3)	Cl4—C8—Cl3	109.98 (19)
C3—C4—C5	120.1 (3)	C7—C8—H8	109.5
C3—C4—H4	119.9	Cl4—C8—H8	109.5
C5—C4—H4	119.9	Cl3—C8—H8	109.5
C7—N1—C1—C2	131.1 (3)	Cl2—C3—C4—C5	180.0 (3)
C7—N1—C1—C6	−50.7 (5)	C3—C4—C5—C6	−0.1 (6)
C6—C1—C2—C3	0.4 (5)	C2—C1—C6—C5	−0.9 (5)
N1—C1—C2—C3	178.6 (3)	N1—C1—C6—C5	−179.1 (3)
C6—C1—C2—Cl1	−180.0 (3)	C4—C5—C6—C1	0.8 (6)
N1—C1—C2—Cl1	−1.8 (4)	C1—N1—C7—O1	−3.4 (6)
C1—C2—C3—C4	0.3 (5)	C1—N1—C7—C8	175.7 (3)
Cl1—C2—C3—C4	−179.3 (3)	O1—C7—C8—Cl4	−42.7 (4)
C1—C2—C3—Cl2	179.9 (2)	N1—C7—C8—Cl4	138.2 (3)
Cl1—C2—C3—Cl2	0.3 (4)	O1—C7—C8—Cl3	77.5 (4)
C2—C3—C4—C5	−0.4 (6)	N1—C7—C8—Cl3	−101.6 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1^i	0.86	1.95	2.790 (3)	167

Symmetry code: (i) x+1, y, z.