N-(2,3-Dichloro­phen­yl)acetamide

The conformation of the N-H bond in the structure of the title compound (23DCPA), C₈H₇Cl₂NO, is syn to either the ortho or meta chloro substituent. The geometric parameters of 23DCPA are similar to related amides. The amide H atom is simultaneously involved in an intra­molecular hydrogen bond with the ortho Cl atom and an inter­molecular hydrogen bond with the O atom of the carbonyl group.

Key indicators

• Single-crystal X-ray study
• T = 299 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.041
• wR factor = 0.102
• Data-to-parameter ratio = 13.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.24
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      1.239
            Tmax scaled      0.778 Tmin scaled      0.601

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

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

---

Computing details

Data collection: CAD-4-PC (Enraf–Nonius, 1996); cell refinement: CAD-4-PC; 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) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

N-(2,3-dichlorophenyl)acetamide

Crystal data

C8H7Cl2NO	F(000) = 416
Mr = 204.05	Dx = 1.557 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 4.7524 (5) Å	θ = 4.7–24.3°
b = 12.246 (1) Å	µ = 6.29 mm^−1
c = 15.140 (1) Å	T = 299 K
β = 98.915 (7)°	Needle, colourless
V = 870.5 (1) Å^3	0.28 × 0.06 × 0.04 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1072 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.033
Graphite monochromator	θmax = 66.9°, θmin = 4.7°
ω/2θ scans	h = 0→5
Absorption correction: ψ scan (North et al., 1968)	k = −14→1
Tmin = 0.485, Tmax = 0.627	l = −18→17
1923 measured reflections	3 standard reflections every 120 min
1560 independent reflections	intensity decay: 4.3%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.102	w = 1/[σ^2(Fo^2) + (0.0415P)^2 + 0.0972P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.002
1560 reflections	Δρmax = 0.27 e Å^−3
113 parameters	Δρmin = −0.24 e Å^−3
1 restraint	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0062 (6)

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
C1	0.0128 (7)	−0.3229 (3)	−0.0294 (2)	0.0495 (9)
H1A	−0.0168	−0.3908	−0.0006	0.059*
H1B	0.2123	−0.3134	−0.0312	0.059*
H1C	−0.0898	−0.3236	−0.0893	0.059*
C2	−0.0917 (7)	−0.2313 (3)	0.0215 (2)	0.0404 (8)
C5	0.0701 (6)	−0.0852 (3)	0.1298 (2)	0.0359 (7)
C6	0.2434 (6)	−0.0729 (3)	0.2121 (2)	0.0358 (7)
C7	0.2093 (8)	0.0171 (3)	0.2651 (2)	0.0425 (8)
C8	0.0025 (8)	0.0941 (3)	0.2378 (2)	0.0510 (9)
H8	−0.0199	0.1542	0.2737	0.061*
C9	−0.1704 (8)	0.0808 (3)	0.1567 (3)	0.0523 (9)
H9	−0.3120	0.1319	0.1382	0.063*
C10	−0.1366 (7)	−0.0070 (3)	0.1027 (2)	0.0443 (8)
H10	−0.2532	−0.0141	0.0477	0.053*
N4	0.1139 (5)	−0.1758 (2)	0.07566 (18)	0.0389 (6)
H4N	0.286 (3)	−0.197 (3)	0.079 (2)	0.047*
O3	−0.3435 (5)	−0.2085 (2)	0.01501 (18)	0.0601 (8)
Cl11	0.49749 (19)	−0.17057 (7)	0.24850 (6)	0.0466 (3)
Cl12	0.4238 (2)	0.03476 (8)	0.36764 (6)	0.0625 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0390 (19)	0.055 (2)	0.053 (2)	−0.0027 (18)	0.0024 (16)	−0.0118 (18)
C2	0.0310 (17)	0.048 (2)	0.0413 (18)	−0.0029 (15)	0.0018 (14)	0.0052 (15)
C5	0.0319 (16)	0.0365 (16)	0.0401 (16)	−0.0003 (15)	0.0074 (13)	0.0003 (15)
C6	0.0311 (16)	0.0354 (17)	0.0416 (17)	−0.0012 (14)	0.0081 (13)	0.0036 (14)
C7	0.0440 (19)	0.043 (2)	0.0417 (18)	−0.0076 (16)	0.0102 (15)	−0.0009 (15)
C8	0.055 (2)	0.041 (2)	0.061 (2)	0.0029 (19)	0.0212 (18)	−0.0035 (17)
C9	0.047 (2)	0.044 (2)	0.069 (2)	0.0127 (18)	0.0208 (18)	0.0090 (19)
C10	0.0368 (19)	0.051 (2)	0.0444 (18)	0.0086 (16)	0.0054 (15)	0.0074 (16)
N4	0.0231 (13)	0.0485 (16)	0.0432 (15)	0.0051 (13)	−0.0008 (11)	−0.0042 (13)
O3	0.0255 (13)	0.0772 (19)	0.0760 (19)	−0.0016 (12)	0.0026 (12)	−0.0145 (15)
Cl11	0.0419 (4)	0.0454 (4)	0.0487 (5)	0.0050 (4)	−0.0052 (3)	0.0029 (4)
Cl12	0.0705 (7)	0.0662 (6)	0.0486 (5)	−0.0100 (5)	0.0022 (4)	−0.0136 (5)

Geometric parameters (Å, º)

C1—C2	1.490 (5)	C6—Cl11	1.728 (3)
C1—H1A	0.9600	C7—C8	1.379 (5)
C1—H1B	0.9600	C7—Cl12	1.734 (3)
C1—H1C	0.9600	C8—C9	1.377 (5)
C2—O3	1.217 (4)	C8—H8	0.9300
C2—N4	1.357 (4)	C9—C10	1.376 (5)
C5—C10	1.387 (4)	C9—H9	0.9300
C5—C6	1.391 (4)	C10—H10	0.9300
C5—N4	1.414 (4)	N4—H4N	0.850 (10)
C6—C7	1.387 (4)
C2—C1—H1A	109.5	C8—C7—C6	120.8 (3)
C2—C1—H1B	109.5	C8—C7—Cl12	118.4 (3)
H1A—C1—H1B	109.5	C6—C7—Cl12	120.8 (3)
C2—C1—H1C	109.5	C9—C8—C7	119.0 (3)
H1A—C1—H1C	109.5	C9—C8—H8	120.5
H1B—C1—H1C	109.5	C7—C8—H8	120.5
O3—C2—N4	122.7 (3)	C10—C9—C8	120.9 (3)
O3—C2—C1	122.2 (3)	C10—C9—H9	119.5
N4—C2—C1	115.0 (3)	C8—C9—H9	119.5
C10—C5—C6	119.0 (3)	C9—C10—C5	120.4 (3)
C10—C5—N4	122.1 (3)	C9—C10—H10	119.8
C6—C5—N4	119.0 (3)	C5—C10—H10	119.8
C7—C6—C5	119.9 (3)	C2—N4—C5	125.9 (3)
C7—C6—Cl11	120.3 (3)	C2—N4—H4N	119 (2)
C5—C6—Cl11	119.9 (2)	C5—N4—H4N	115 (2)
C10—C5—C6—C7	−0.7 (5)	Cl12—C7—C8—C9	−179.6 (3)
N4—C5—C6—C7	178.1 (3)	C7—C8—C9—C10	−0.8 (6)
C10—C5—C6—Cl11	178.6 (2)	C8—C9—C10—C5	1.1 (5)
N4—C5—C6—Cl11	−2.6 (4)	C6—C5—C10—C9	−0.3 (5)
C5—C6—C7—C8	1.0 (5)	N4—C5—C10—C9	−179.1 (3)
Cl11—C6—C7—C8	−178.3 (3)	O3—C2—N4—C5	−1.1 (5)
C5—C6—C7—Cl12	−179.6 (2)	C1—C2—N4—C5	179.2 (3)
Cl11—C6—C7—Cl12	1.1 (4)	C10—C5—N4—C2	−36.0 (5)
C6—C7—C8—C9	−0.2 (5)	C6—C5—N4—C2	145.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4N···Cl11	0.85 (1)	2.63 (3)	2.949 (3)	104 (2)
N4—H4N···O3^i	0.85 (1)	2.14 (2)	2.896 (4)	148 (3)

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