N,N′-Bis(2-methyl­phen­yl)oxamide

The mol­ecule of the title compound, C₁₆H₁₆N₂O₂, lies on a crystallographically imposed center of symmetry at the midpoint of the C—C bond of the oxamide unit. An intra­molecular C—H...O hydrogen bond forms a six-membered ring, and mol­ecules are linked into ribbons along the a axis by N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.053
• wR factor = 0.155
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.14
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C7     -   C7_a   ...       1.54 Ang.
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C8

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

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 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
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 2003).

N,N'-Bis(2-methylphenyl)oxamide

Crystal data

C16H16N2O2	Z = 1
Mr = 268.31	F(000) = 142
Triclinic, P1	Dx = 1.296 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.3504 (13) Å	Cell parameters from 798 reflections
b = 6.7371 (17) Å	θ = 3.2–25.9°
c = 10.228 (3) Å	µ = 0.09 mm^−1
α = 99.582 (4)°	T = 293 K
β = 96.152 (4)°	Plate, colorless
γ = 106.527 (4)°	0.26 × 0.18 × 0.07 mm
V = 343.83 (15) Å^3

Data collection

Siemens SMART 1000 CCD area-detector diffractometer	1311 independent reflections
Radiation source: fine-focus sealed tube	1111 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.014
Detector resolution: 8.33 pixels mm^-1	θmax = 26.0°, θmin = 2.1°
ω scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −8→4
Tmin = 0.978, Tmax = 0.994	l = −12→12
1934 measured reflections

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)] = 0.053	H-atom parameters constrained
wR(F^2) = 0.156	w = 1/[σ^2(Fo^2) + (0.0866P)^2 + 0.0923P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
1311 reflections	Δρmax = 0.23 e Å^−3
92 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.14 (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
O1	−0.2945 (2)	0.3661 (2)	0.04882 (14)	0.0583 (5)
N1	0.1213 (3)	0.3400 (2)	0.09497 (16)	0.0480 (5)
H1B	0.2807	0.3942	0.0824	0.058*
C1	0.2966 (4)	0.1737 (4)	0.2557 (2)	0.0663 (7)
H1A	0.4593	0.2759	0.2632	0.080*
C2	0.2722 (5)	0.0162 (4)	0.3290 (2)	0.0717 (7)
H2A	0.4200	0.0138	0.3847	0.086*
C3	0.0348 (4)	−0.1369 (3)	0.32151 (19)	0.0557 (6)
C4	−0.1774 (4)	−0.1273 (3)	0.2366 (2)	0.0605 (6)
H4A	−0.3404	−0.2292	0.2293	0.073*
C5	−0.1573 (4)	0.0278 (3)	0.1621 (2)	0.0564 (5)
H5A	−0.3045	0.0293	0.1055	0.068*
C6	0.0817 (4)	0.1802 (3)	0.17189 (17)	0.0443 (5)
C7	−0.0598 (4)	0.4160 (3)	0.03983 (17)	0.0436 (5)
C8	0.0099 (6)	−0.3095 (4)	0.4012 (2)	0.0764 (7)
H8A	0.1778	−0.2896	0.4541	0.115*
H8B	−0.0456	−0.4449	0.3407	0.115*
H8C	−0.1184	−0.3037	0.4594	0.115*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0487 (8)	0.0613 (9)	0.0786 (10)	0.0212 (6)	0.0166 (6)	0.0409 (7)
N1	0.0460 (9)	0.0516 (9)	0.0570 (9)	0.0188 (7)	0.0152 (7)	0.0291 (7)
C1	0.0499 (11)	0.0807 (15)	0.0791 (14)	0.0181 (10)	0.0114 (10)	0.0495 (13)
C2	0.0652 (14)	0.0879 (17)	0.0748 (15)	0.0264 (12)	0.0063 (11)	0.0503 (13)
C3	0.0786 (14)	0.0511 (11)	0.0497 (11)	0.0282 (10)	0.0197 (9)	0.0237 (9)
C4	0.0630 (13)	0.0442 (11)	0.0735 (14)	0.0097 (9)	0.0087 (10)	0.0231 (10)
C5	0.0577 (12)	0.0465 (11)	0.0644 (12)	0.0134 (9)	−0.0012 (9)	0.0214 (9)
C6	0.0514 (10)	0.0454 (10)	0.0460 (9)	0.0207 (8)	0.0142 (7)	0.0220 (7)
C7	0.0472 (10)	0.0426 (9)	0.0462 (9)	0.0161 (7)	0.0097 (7)	0.0184 (7)
C8	0.112 (2)	0.0605 (14)	0.0680 (14)	0.0308 (13)	0.0183 (13)	0.0356 (11)

Geometric parameters (Å, º)

O1—C7	1.222 (2)	C3—C8	1.512 (3)
N1—C7	1.334 (2)	C4—C5	1.380 (3)
N1—C6	1.418 (2)	C4—H4A	0.9300
N1—H1B	0.8600	C5—C6	1.375 (3)
C1—C6	1.374 (3)	C5—H5A	0.9300
C1—C2	1.382 (3)	C7—C7^i	1.536 (3)
C1—H1A	0.9300	C8—H8A	0.9600
C2—C3	1.375 (3)	C8—H8B	0.9600
C2—H2A	0.9300	C8—H8C	0.9600
C3—C4	1.377 (3)
C7—N1—C6	127.64 (15)	C6—C5—C4	119.66 (18)
C7—N1—H1B	116.2	C6—C5—H5A	120.2
C6—N1—H1B	116.2	C4—C5—H5A	120.2
C6—C1—C2	120.4 (2)	C1—C6—C5	118.99 (17)
C6—C1—H1A	119.8	C1—C6—N1	117.84 (17)
C2—C1—H1A	119.8	C5—C6—N1	123.12 (17)
C3—C2—C1	121.7 (2)	O1—C7—N1	126.80 (16)
C3—C2—H2A	119.2	O1—C7—C7^i	121.19 (19)
C1—C2—H2A	119.2	N1—C7—C7^i	112.01 (19)
C2—C3—C4	116.88 (18)	C3—C8—H8A	109.5
C2—C3—C8	121.4 (2)	C3—C8—H8B	109.5
C4—C3—C8	121.7 (2)	H8A—C8—H8B	109.5
C3—C4—C5	122.43 (19)	C3—C8—H8C	109.5
C3—C4—H4A	118.8	H8A—C8—H8C	109.5
C5—C4—H4A	118.8	H8B—C8—H8C	109.5
C6—C1—C2—C3	−0.4 (4)	C2—C1—C6—N1	−177.3 (2)
C1—C2—C3—C4	0.5 (4)	C4—C5—C6—C1	0.4 (3)
C1—C2—C3—C8	179.6 (2)	C4—C5—C6—N1	177.52 (18)
C2—C3—C4—C5	−0.2 (3)	C7—N1—C6—C1	−158.5 (2)
C8—C3—C4—C5	−179.3 (2)	C7—N1—C6—C5	24.3 (3)
C3—C4—C5—C6	−0.2 (3)	C6—N1—C7—O1	2.4 (3)
C2—C1—C6—C5	0.0 (3)	C6—N1—C7—C7^i	−178.22 (18)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1^ii	0.86	2.39	3.171 (3)	151
N1—H1B···O1^i	0.86	2.26	2.676 (2)	110
C5—H5A···O1	0.93	2.42	2.953 (3)	116

Symmetry codes: (i) −x, −y+1, −z; (ii) x+1, y, z.