3,6-Dichloro-N-phenyl­picolinamide

The title compound, C₁₂H₈Cl₂N₂O, is found in the keto form. The mol­ecules are approximately planar (r.m.s. deviation = 0.058 Å for 17 non-H atoms) and lie in sheets. Inter­molecular N—H...O hydrogen bonds are not observed. Instead, the N—H group of the amide forms an intra­molecular N—H...N contact to the pyridyl ring and the C=O group is involved in an inter­molecular C—H...O contact.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C)= 0.004 Å
• R factor = 0.037
• wR factor = 0.100
• Data-to-parameter ratio = 13.3

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S1. Comment

Amide compounds play an important role in the development of coordination chemistry related to catalysis, magnetism and molecular architectures. As part of our studies on the synthesis and characterization of these compounds, we report here the synthesis and crystal structure of 3,6-dichloro-N-phenylpicolinamide.

The bond length of 1.345 (3) Å between atoms C7 and N2 is between the values expected for a double and single bond, because of conjugation effects in the molecule. The C═O bond length of 1.212 (3) Å indicates that the molecule is in the keto form.

In the crystal structure, the molecules are stabilized by intramolecular N—H···N hydrogen bonds and intermolecular C—H···O contacts (Table 1 and Fig. 2).

Related literature

For similar structures with an unsubstituted pyridyl group and a Cl or Br atom in the para position of the phenyl ring, see: Zhang et al. (2006); Qi et al. (2003).

S2. Experimental

A solution of 3,6-dichloropicolinoyl chloride (10 mmol) in 50 ml toluene was added to a solution of aniline (10 mmol) in 10 ml toluene. The reaction mixture was refluxed for 1 h with stirring then the resulting white precipitate was obtained by filtration, washed several times with ethanol and dried in vacuo (yield 90%). Elemental analysis calculated: C 53.96, H 3.02, Cl 26.55, N 10.49, O 5.99; found: C 53.90, H 3.08, Cl 26.50, N 10.45, O 6.08. Crystals were obtained by slow evaporation of a solution in methanol.

S3. Refinement

H atoms were placed geometrically and refined using a riding model, with C—H = 0.93 Å, N—H = 0.86 Å and U_iso(H) = 1.2 U_eq(C/N).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Bruker, 2000); program(s) used to refine structure: SHELXTL (Bruker, 2000); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures

	Fig. 1. The molecular structure of the title compound showing 50% probability displacement ellipsoids for non-H atoms.
	Fig. 2. Packing diagram (H atoms omitted).

3,6-Dichloro-N-phenylpicolinamide

Crystal data

C12H8Cl2N2O	F(000) = 544
Mr = 267.10	Dx = 1.522 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1704 reflections
a = 6.8404 (11) Å	θ = 2.2–24.2°
b = 12.2627 (19) Å	µ = 0.54 mm^−1
c = 14.156 (2) Å	T = 298 K
β = 101.044 (2)°	Block, colourless
V = 1165.4 (3) Å^3	0.42 × 0.37 × 0.35 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	2055 independent reflections
Radiation source: fine-focus sealed tube	1339 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ϕ and ω scans	θmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
Tmin = 0.805, Tmax = 0.834	k = −14→14
5729 measured reflections	l = −16→11

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.100	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0324P)^2 + 0.4782P] where P = (Fo^2 + 2Fc^2)/3
2055 reflections	(Δ/σ)max < 0.001
154 parameters	Δρmax = 0.25 e Å^−3
0 restraints	Δρmin = −0.18 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	1.07918 (11)	0.66623 (7)	0.22741 (7)	0.0821 (3)
Cl2	0.29924 (11)	0.90851 (6)	0.07090 (7)	0.0838 (3)
N1	0.5113 (3)	0.73478 (17)	0.11835 (14)	0.0476 (5)
N2	0.4635 (3)	0.52408 (17)	0.12230 (15)	0.0534 (6)
H2	0.3779	0.5760	0.1103	0.064*
O1	0.7923 (3)	0.49406 (17)	0.17281 (19)	0.0927 (8)
C1	0.6531 (4)	0.5561 (2)	0.15056 (19)	0.0515 (7)
C2	0.6792 (4)	0.6782 (2)	0.15207 (17)	0.0460 (6)
C3	0.8567 (4)	0.7321 (2)	0.18511 (18)	0.0529 (7)
C4	0.8595 (4)	0.8446 (2)	0.1857 (2)	0.0618 (8)
H4	0.9772	0.8817	0.2095	0.074*
C5	0.6894 (4)	0.9011 (2)	0.1514 (2)	0.0610 (8)
H5	0.6877	0.9769	0.1506	0.073*
C6	0.5198 (4)	0.8412 (2)	0.11777 (19)	0.0536 (7)
C7	0.3836 (4)	0.41788 (19)	0.10930 (17)	0.0458 (6)
C8	0.1789 (4)	0.4101 (2)	0.07842 (18)	0.0529 (7)
H8	0.1019	0.4731	0.0685	0.063*
C9	0.0898 (4)	0.3096 (2)	0.0624 (2)	0.0617 (8)
H9	−0.0472	0.3050	0.0409	0.074*
C10	0.2011 (5)	0.2165 (2)	0.0778 (2)	0.0627 (8)
H10	0.1408	0.1485	0.0664	0.075*
C11	0.4025 (5)	0.2244 (2)	0.1103 (2)	0.0631 (8)
H11	0.4779	0.1611	0.1222	0.076*
C12	0.4958 (4)	0.3240 (2)	0.1258 (2)	0.0568 (7)
H12	0.6329	0.3280	0.1471	0.068*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0448 (4)	0.0895 (6)	0.1053 (7)	0.0040 (4)	−0.0022 (4)	−0.0149 (5)
Cl2	0.0701 (5)	0.0529 (5)	0.1224 (8)	0.0124 (4)	0.0033 (5)	0.0079 (5)
N1	0.0483 (13)	0.0439 (13)	0.0500 (13)	0.0013 (10)	0.0080 (10)	−0.0008 (10)
N2	0.0413 (12)	0.0434 (12)	0.0712 (15)	0.0087 (10)	−0.0001 (11)	0.0008 (11)
O1	0.0484 (12)	0.0600 (13)	0.162 (2)	0.0099 (11)	0.0000 (13)	0.0147 (14)
C1	0.0448 (15)	0.0530 (16)	0.0572 (17)	0.0061 (13)	0.0109 (13)	0.0036 (13)
C2	0.0414 (14)	0.0534 (16)	0.0434 (15)	0.0021 (13)	0.0090 (12)	−0.0019 (12)
C3	0.0457 (15)	0.0620 (18)	0.0507 (17)	−0.0003 (13)	0.0083 (13)	−0.0087 (14)
C4	0.0560 (18)	0.068 (2)	0.0617 (19)	−0.0163 (15)	0.0114 (15)	−0.0153 (15)
C5	0.071 (2)	0.0477 (16)	0.0650 (19)	−0.0078 (15)	0.0140 (16)	−0.0102 (14)
C6	0.0572 (17)	0.0469 (17)	0.0560 (18)	0.0006 (13)	0.0088 (14)	−0.0033 (13)
C7	0.0485 (15)	0.0419 (15)	0.0453 (15)	0.0039 (12)	0.0051 (12)	0.0019 (12)
C8	0.0507 (16)	0.0467 (16)	0.0560 (17)	0.0094 (13)	−0.0029 (13)	0.0013 (13)
C9	0.0559 (17)	0.0592 (19)	0.066 (2)	−0.0046 (15)	0.0020 (14)	−0.0045 (15)
C10	0.079 (2)	0.0469 (17)	0.0629 (19)	−0.0053 (16)	0.0149 (16)	−0.0047 (14)
C11	0.071 (2)	0.0438 (16)	0.075 (2)	0.0118 (15)	0.0164 (16)	0.0028 (14)
C12	0.0534 (16)	0.0497 (17)	0.0666 (19)	0.0106 (14)	0.0095 (14)	0.0026 (14)

Geometric parameters (Å, º)

Cl1—C3	1.725 (3)	C5—C6	1.378 (4)
Cl2—C6	1.736 (3)	C5—H5	0.930
N1—C6	1.307 (3)	C7—C12	1.378 (3)
N1—C2	1.349 (3)	C7—C8	1.388 (3)
N2—C1	1.341 (3)	C8—C9	1.374 (3)
N2—C7	1.411 (3)	C8—H8	0.930
N2—H2	0.860	C9—C10	1.367 (4)
O1—C1	1.212 (3)	C9—H9	0.930
C1—C2	1.508 (4)	C10—C11	1.370 (4)
C2—C3	1.382 (3)	C10—H10	0.930
C3—C4	1.380 (4)	C11—C12	1.376 (4)
C4—C5	1.362 (4)	C11—H11	0.930
C4—H4	0.930	C12—H12	0.930
C6—N1—C2	118.7 (2)	N1—C6—Cl2	116.1 (2)
C1—N2—C7	129.6 (2)	C5—C6—Cl2	119.4 (2)
C1—N2—H2	115.2	C12—C7—C8	119.5 (2)
C7—N2—H2	115.2	C12—C7—N2	124.0 (2)
O1—C1—N2	124.1 (3)	C8—C7—N2	116.5 (2)
O1—C1—C2	122.3 (2)	C9—C8—C7	120.1 (2)
N2—C1—C2	113.6 (2)	C9—C8—H8	119.9
N1—C2—C3	120.5 (2)	C7—C8—H8	119.9
N1—C2—C1	114.5 (2)	C10—C9—C8	120.5 (3)
C3—C2—C1	125.0 (2)	C10—C9—H9	119.8
C4—C3—C2	119.3 (2)	C8—C9—H9	119.8
C4—C3—Cl1	117.1 (2)	C9—C10—C11	119.2 (3)
C2—C3—Cl1	123.6 (2)	C9—C10—H10	120.4
C5—C4—C3	119.8 (3)	C11—C10—H10	120.4
C5—C4—H4	120.1	C10—C11—C12	121.5 (3)
C3—C4—H4	120.1	C10—C11—H11	119.3
C4—C5—C6	117.2 (3)	C12—C11—H11	119.3
C4—C5—H5	121.4	C11—C12—C7	119.2 (3)
C6—C5—H5	121.4	C11—C12—H12	120.4
N1—C6—C5	124.5 (3)	C7—C12—H12	120.4
C7—N2—C1—O1	−2.0 (5)	C2—N1—C6—C5	−1.4 (4)
C7—N2—C1—C2	177.8 (2)	C2—N1—C6—Cl2	178.61 (18)
C6—N1—C2—C3	−0.1 (4)	C4—C5—C6—N1	1.3 (4)
C6—N1—C2—C1	179.4 (2)	C4—C5—C6—Cl2	−178.8 (2)
O1—C1—C2—N1	175.3 (3)	C1—N2—C7—C12	0.8 (4)
N2—C1—C2—N1	−4.6 (3)	C1—N2—C7—C8	−179.6 (2)
O1—C1—C2—C3	−5.2 (4)	C12—C7—C8—C9	−1.5 (4)
N2—C1—C2—C3	175.0 (2)	N2—C7—C8—C9	178.9 (2)
N1—C2—C3—C4	1.7 (4)	C7—C8—C9—C10	0.8 (4)
C1—C2—C3—C4	−177.8 (2)	C8—C9—C10—C11	0.6 (4)
N1—C2—C3—Cl1	−178.81 (19)	C9—C10—C11—C12	−1.4 (4)
C1—C2—C3—Cl1	1.7 (4)	C10—C11—C12—C7	0.8 (4)
C2—C3—C4—C5	−1.9 (4)	C8—C7—C12—C11	0.6 (4)
Cl1—C3—C4—C5	178.7 (2)	N2—C7—C12—C11	−179.7 (3)
C3—C4—C5—C6	0.4 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N1	0.86	2.14	2.606 (3)	113
C4—H4···O1^i	0.93	2.48	3.349 (3)	156

Symmetry code: (i) −x+2, y+1/2, −z+1/2.