1-(1H-Benzimidazol-2-yl)ethanone

In the title compound, C₉H₈N₂O, all non-H atoms are essentially coplanar. N—H...O hydrogen bonds generate a centrosymmetric R₂²(10) dimer.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.049
• wR factor = 0.142
• Data-to-parameter ratio = 13.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.98
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

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 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
   0 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

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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 and PLATON (Spek, 2003).

1-(1H-Benzimidazol-2-yl)ethanone

Crystal data

C9H8N2O	Z = 2
Mr = 160.17	F(000) = 168
Triclinic, P1	Dx = 1.354 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.7270 (16) Å	Cell parameters from 864 reflections
b = 7.102 (2) Å	θ = 2.6–23.4°
c = 10.322 (3) Å	µ = 0.09 mm^−1
α = 95.493 (4)°	T = 293 K
β = 94.159 (4)°	Plate, colourless
γ = 108.960 (4)°	0.46 × 0.22 × 0.08 mm
V = 392.81 (19) Å^3

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	1495 independent reflections
Radiation source: fine-focus sealed tube	1194 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.013
Detector resolution: 8.33 pixels mm^-1	θmax = 26.0°, θmin = 2.0°
ω scans	h = −6→7
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −5→8
Tmin = 0.959, Tmax = 0.993	l = −12→11
2230 measured reflections

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.142	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0803P)^2 + 0.1068P] where P = (Fo^2 + 2Fc^2)/3
1495 reflections	(Δ/σ)max = 0.001
110 parameters	Δρmax = 0.21 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
O1	0.5617 (3)	0.3248 (2)	0.11628 (14)	0.0601 (5)
N1	0.2748 (3)	0.5778 (2)	0.13256 (14)	0.0440 (4)
H1A	0.3266	0.5748	0.0565	0.053*
N2	0.2149 (3)	0.5080 (2)	0.33716 (15)	0.0431 (4)
C1	−0.0451 (4)	0.7286 (3)	0.38080 (19)	0.0472 (5)
H1B	−0.0698	0.7013	0.4660	0.057*
C2	−0.1457 (4)	0.8540 (3)	0.3242 (2)	0.0534 (6)
H2	−0.2404	0.9134	0.3722	0.064*
C3	−0.1110 (4)	0.8965 (3)	0.1962 (2)	0.0553 (6)
H3	−0.1843	0.9823	0.1611	0.066*
C4	0.0287 (4)	0.8146 (3)	0.1206 (2)	0.0508 (5)
H4	0.0527	0.8434	0.0356	0.061*
C5	0.1322 (3)	0.6868 (3)	0.17810 (18)	0.0411 (5)
C6	0.0972 (3)	0.6420 (3)	0.30580 (18)	0.0403 (5)
C7	0.3180 (3)	0.4756 (3)	0.23110 (17)	0.0414 (5)
C8	0.4727 (4)	0.3449 (3)	0.21827 (19)	0.0453 (5)
C9	0.5127 (4)	0.2435 (3)	0.3333 (2)	0.0537 (6)
H9A	0.6569	0.2041	0.3262	0.081*
H9B	0.3701	0.1268	0.3357	0.081*
H9C	0.5368	0.3342	0.4121	0.081*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0741 (10)	0.0756 (11)	0.0467 (9)	0.0411 (9)	0.0242 (7)	0.0153 (7)
N1	0.0518 (9)	0.0562 (10)	0.0308 (8)	0.0237 (8)	0.0130 (7)	0.0114 (7)
N2	0.0474 (9)	0.0503 (10)	0.0372 (9)	0.0208 (8)	0.0115 (7)	0.0120 (7)
C1	0.0564 (12)	0.0532 (12)	0.0389 (10)	0.0240 (10)	0.0155 (9)	0.0113 (8)
C2	0.0600 (13)	0.0567 (13)	0.0538 (12)	0.0298 (11)	0.0170 (10)	0.0118 (10)
C3	0.0637 (13)	0.0575 (13)	0.0569 (13)	0.0329 (11)	0.0106 (10)	0.0186 (10)
C4	0.0600 (12)	0.0581 (13)	0.0413 (11)	0.0246 (10)	0.0109 (9)	0.0190 (9)
C5	0.0433 (10)	0.0452 (11)	0.0368 (10)	0.0158 (8)	0.0083 (8)	0.0090 (8)
C6	0.0429 (10)	0.0438 (11)	0.0361 (10)	0.0150 (9)	0.0079 (7)	0.0095 (8)
C7	0.0450 (10)	0.0476 (11)	0.0355 (10)	0.0184 (9)	0.0085 (8)	0.0103 (8)
C8	0.0481 (10)	0.0504 (12)	0.0406 (11)	0.0191 (9)	0.0106 (8)	0.0079 (8)
C9	0.0634 (13)	0.0594 (13)	0.0500 (12)	0.0325 (11)	0.0117 (10)	0.0160 (10)

Geometric parameters (Å, º)

O1—C8	1.218 (2)	C3—C4	1.376 (3)
N1—C7	1.358 (2)	C3—H3	0.93
N1—C5	1.373 (2)	C4—C5	1.389 (3)
N1—H1A	0.86	C4—H4	0.93
N2—C7	1.317 (2)	C5—C6	1.399 (3)
N2—C6	1.382 (3)	C7—C8	1.481 (3)
C1—C2	1.360 (3)	C8—C9	1.487 (3)
C1—C6	1.403 (3)	C9—H9A	0.96
C1—H1B	0.93	C9—H9B	0.96
C2—C3	1.397 (3)	C9—H9C	0.96
C2—H2	0.93
C7—N1—C5	106.58 (15)	N1—C5—C6	105.24 (16)
C7—N1—H1A	126.7	C4—C5—C6	122.33 (18)
C5—N1—H1A	126.7	N2—C6—C5	110.35 (17)
C7—N2—C6	104.08 (15)	N2—C6—C1	129.70 (17)
C2—C1—C6	117.53 (18)	C5—C6—C1	119.94 (18)
C2—C1—H1B	121.2	N2—C7—N1	113.75 (17)
C6—C1—H1B	121.2	N2—C7—C8	124.41 (17)
C1—C2—C3	122.0 (2)	N1—C7—C8	121.82 (16)
C1—C2—H2	119.0	O1—C8—C7	119.74 (18)
C3—C2—H2	119.0	O1—C8—C9	122.88 (19)
C4—C3—C2	121.7 (2)	C7—C8—C9	117.38 (17)
C4—C3—H3	119.1	C8—C9—H9A	109.5
C2—C3—H3	119.1	C8—C9—H9B	109.5
C3—C4—C5	116.45 (18)	H9A—C9—H9B	109.5
C3—C4—H4	121.8	C8—C9—H9C	109.5
C5—C4—H4	121.8	H9A—C9—H9C	109.5
N1—C5—C4	132.42 (17)	H9B—C9—H9C	109.5
C6—C1—C2—C3	0.1 (3)	C4—C5—C6—C1	−0.5 (3)
C1—C2—C3—C4	−0.5 (4)	C2—C1—C6—N2	−178.51 (19)
C2—C3—C4—C5	0.4 (3)	C2—C1—C6—C5	0.4 (3)
C7—N1—C5—C4	−178.6 (2)	C6—N2—C7—N1	−0.4 (2)
C7—N1—C5—C6	0.0 (2)	C6—N2—C7—C8	178.18 (18)
C3—C4—C5—N1	178.6 (2)	C5—N1—C7—N2	0.2 (2)
C3—C4—C5—C6	0.1 (3)	C5—N1—C7—C8	−178.37 (17)
C7—N2—C6—C5	0.4 (2)	N2—C7—C8—O1	−179.57 (18)
C7—N2—C6—C1	179.33 (19)	N1—C7—C8—O1	−1.1 (3)
N1—C5—C6—N2	−0.3 (2)	N2—C7—C8—C9	0.2 (3)
C4—C5—C6—N2	178.55 (18)	N1—C7—C8—C9	178.64 (18)
N1—C5—C6—C1	−179.32 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^i	0.86	2.05	2.868 (2)	158

Symmetry code: (i) −x+1, −y+1, −z.