3-Cyano-4,6-di­methyl-2-pyridone (Guareschi pyridone)

In the crystal structure of the title compound, C₈H₈N₂O, the mol­ecules form centrosymmetric dimers via N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.047
• wR factor = 0.138
• Data-to-parameter ratio = 13.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N1     -   C6       =       5.53 su
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C3     -   C31      =       1.45 Ang.

   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
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 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: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLUTON97 (Spek, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

(3)

Crystal data

C8H8N2O	Z = 2
Mr = 148.16	F(000) = 156
Triclinic, P1	Dx = 1.340 Mg m^−3
Hall symbol: -P 1	Melting point = 563–565 K
a = 3.975 (4) Å	Cu Kα radiation, λ = 1.5418 Å
b = 7.417 (4) Å	Cell parameters from 25 reflections
c = 12.820 (8) Å	θ = 22.5–27.0°
α = 76.36 (4)°	µ = 0.75 mm^−1
β = 88.54 (4)°	T = 293 K
γ = 88.62 (4)°	Cube, colourless
V = 367.1 (5) Å^3	0.30 × 0.30 × 0.30 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	Rint = 0.047
Radiation source: Fine–focus sealed tube	θmax = 69.9°, θmin = 3.6°
Graphite monochromator	h = −4→4
Non–profiled ω scans	k = −8→9
1439 measured reflections	l = 0→15
1377 independent reflections	1 standard reflections every 200 reflections
924 reflections with I > 2σ(I)	intensity decay: 1%

Refinement

Refinement on F^2	Primary atom site location: Direct
Least-squares matrix: Full	Secondary atom site location: Difmap
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: Mixed
wR(F^2) = 0.138	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0689P)^2 + 0.0196P] where P = (Fo^2 + 2Fc^2)/3
1377 reflections	(Δ/σ)max < 0.001
106 parameters	Δρmax = 0.13 e Å^−3
0 restraints	Δρmin = −0.12 e Å^−3

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

	x	y	z	Uiso*/Ueq
N1	0.2477 (4)	0.5368 (2)	0.11510 (11)	0.0537 (5)
H1	0.301 (6)	0.597 (3)	0.0447 (18)	0.066 (6)*
C2	0.3569 (5)	0.3537 (3)	0.15050 (14)	0.0527 (5)
O2	0.5248 (4)	0.27680 (19)	0.09052 (10)	0.0662 (5)
C3	0.2569 (5)	0.2712 (3)	0.25902 (13)	0.0515 (5)
C31	0.3653 (5)	0.0812 (3)	0.30173 (14)	0.0563 (5)
N31	0.4503 (6)	−0.0666 (3)	0.33703 (14)	0.0730 (6)
C4	0.0736 (5)	0.3674 (3)	0.32269 (14)	0.0527 (5)
C41	−0.0230 (6)	0.2766 (3)	0.43665 (14)	0.0617 (6)
H41A	0.1739	0.2584	0.4800	0.093*
H41B	−0.1218	0.1587	0.4392	0.093*
H41C	−0.1827	0.3545	0.4635	0.093*
C5	−0.0231 (6)	0.5533 (3)	0.27784 (14)	0.0557 (5)
H5	−0.1491	0.6202	0.3185	0.067*
C6	0.0686 (5)	0.6339 (3)	0.17500 (15)	0.0543 (5)
C61	−0.0193 (6)	0.8311 (3)	0.11969 (15)	0.0642 (6)
H61A	0.1834	0.9003	0.1011	0.096*
H61B	−0.1567	0.8862	0.1669	0.096*
H61C	−0.1406	0.8326	0.0557	0.096*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0544 (11)	0.0583 (9)	0.0492 (8)	−0.0003 (8)	−0.0037 (7)	−0.0137 (7)
C2	0.0493 (13)	0.0528 (11)	0.0592 (10)	−0.0011 (9)	−0.0056 (8)	−0.0191 (8)
O2	0.0760 (11)	0.0651 (9)	0.0596 (7)	0.0057 (8)	0.0050 (7)	−0.0200 (6)
C3	0.0503 (12)	0.0531 (10)	0.0520 (9)	−0.0015 (9)	−0.0063 (8)	−0.0137 (7)
C31	0.0544 (13)	0.0585 (12)	0.0603 (10)	0.0006 (10)	−0.0021 (9)	−0.0228 (8)
N31	0.0828 (15)	0.0620 (12)	0.0743 (10)	0.0043 (10)	0.0048 (9)	−0.0175 (8)
C4	0.0511 (13)	0.0562 (11)	0.0534 (9)	−0.0066 (9)	−0.0106 (8)	−0.0165 (7)
C41	0.0630 (15)	0.0650 (13)	0.0581 (10)	−0.0079 (11)	−0.0015 (9)	−0.0159 (9)
C5	0.0564 (13)	0.0593 (11)	0.0545 (9)	0.0016 (9)	−0.0032 (8)	−0.0195 (8)
C6	0.0486 (13)	0.0572 (11)	0.0591 (9)	−0.0040 (9)	−0.0108 (8)	−0.0165 (7)
C61	0.0669 (16)	0.0557 (12)	0.0680 (11)	0.0045 (10)	−0.0048 (10)	−0.0105 (9)

Geometric parameters (Å, º)

N1—C6	1.351 (2)	C41—H41A	0.9600
N1—C2	1.389 (2)	C41—H41B	0.9600
N1—H1	0.93 (2)	C41—H41C	0.9600
C2—O2	1.235 (2)	C5—C6	1.358 (3)
C2—C3	1.432 (3)	C5—H5	0.9300
C3—C4	1.388 (3)	C6—C61	1.504 (3)
C3—C31	1.445 (3)	C61—H61A	0.9600
C31—N31	1.130 (3)	C61—H61B	0.9600
C4—C5	1.411 (3)	C61—H61C	0.9600
C4—C41	1.502 (3)
C6—N1—C2	125.03 (16)	C4—C41—H41C	109.5
C6—N1—H1	117.2 (13)	H41A—C41—H41C	109.5
C2—N1—H1	117.7 (13)	H41B—C41—H41C	109.5
O2—C2—N1	120.56 (17)	C6—C5—C4	119.63 (17)
O2—C2—C3	125.83 (18)	C6—C5—H5	120.2
N1—C2—C3	113.62 (15)	C4—C5—H5	120.2
C4—C3—C2	122.72 (17)	N1—C6—C5	120.46 (18)
C4—C3—C31	120.59 (16)	N1—C6—C61	115.58 (17)
C2—C3—C31	116.67 (16)	C5—C6—C61	123.96 (18)
N31—C31—C3	178.69 (19)	C6—C61—H61A	109.5
C3—C4—C5	118.54 (17)	C6—C61—H61B	109.5
C3—C4—C41	121.13 (17)	H61A—C61—H61B	109.5
C5—C4—C41	120.33 (17)	C6—C61—H61C	109.5
C4—C41—H41A	109.5	H61A—C61—H61C	109.5
C4—C41—H41B	109.5	H61B—C61—H61C	109.5
H41A—C41—H41B	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2^i	0.93 (2)	1.89 (2)	2.810 (3)	171 (2)

Symmetry code: (i) −x+1, −y+1, −z.