4,4,5,5-Tetra­methyl-2-(p-pyridyl)­imidazoline-1-oxyl 3-oxide

The title compound, C₁₂H₁₆N₃O₂, has axial twofold symmetry and features a twist of 23.31 (8)° between the five- and six-membered rings. The N-O bond distance is 1.2777 (13) Å.

Key indicators

• Single-crystal X-ray study
• T = 223 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.054
• wR factor = 0.152
• Data-to-parameter ratio = 22.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SHELXTL (Bruker, 2000); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHEXLTL (Bruker, 2000).

(I)

Crystal data

C12H16N3O2	F(000) = 500
Mr = 234.28	Dx = 1.303 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -C 2yc	Cell parameters from 1882 reflections
a = 11.0922 (5) Å	θ = 2.8–30.0°
b = 10.3891 (5) Å	µ = 0.09 mm^−1
c = 10.8714 (6) Å	T = 223 K
β = 107.632 (2)°	Block, brown
V = 1193.94 (10) Å^3	0.31 × 0.26 × 0.26 mm
Z = 4

Data collection

Bruker AXS SMART CCD diffractometer	1476 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 30.0°, θmin = 2.8°
ω scans	h = −15→15
4911 measured reflections	k = −14→11
1753 independent reflections	l = −13→15

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.152	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0854P)^2 + 0.5851P] where P = (Fo^2 + 2Fc^2)/3
1753 reflections	(Δ/σ)max < 0.001
79 parameters	Δρmax = 0.46 e Å^−3
0 restraints	Δρmin = −0.34 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	0.68596 (11)	0.08767 (10)	0.41872 (12)	0.0525 (4)
N1	0.5000	0.53627 (15)	0.2500	0.0373 (4)
N2	0.58806 (10)	0.04970 (10)	0.32986 (10)	0.0288 (3)
C1	0.43936 (13)	0.46832 (12)	0.14522 (13)	0.0343 (3)
H1	0.3968	0.5140	0.0699	0.041*
C2	0.43498 (11)	0.33534 (11)	0.13996 (11)	0.0282 (3)
H2	0.3892	0.2926	0.0639	0.034*
C3	0.5000	0.26593 (15)	0.2500	0.0231 (3)
C4	0.5000	0.12507 (15)	0.2500	0.0227 (3)
C5	0.56689 (11)	−0.09124 (10)	0.30036 (11)	0.0259 (3)
C6	0.67366 (14)	−0.13565 (18)	0.24908 (16)	0.0470 (4)
H6A	0.6675	−0.0912	0.1689	0.070*
H6B	0.6669	−0.2277	0.2337	0.070*
H6C	0.7545	−0.1163	0.3120	0.070*
C7	0.57626 (15)	−0.16063 (13)	0.42616 (13)	0.0389 (3)
H7A	0.5083	−0.1322	0.4586	0.058*
H7B	0.6570	−0.1412	0.4892	0.058*
H7C	0.5694	−0.2527	0.4109	0.058*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0434 (6)	0.0311 (5)	0.0567 (7)	−0.0012 (4)	−0.0243 (5)	0.0001 (4)
N1	0.0385 (8)	0.0239 (7)	0.0431 (9)	0.000	0.0025 (7)	0.000
N2	0.0279 (5)	0.0225 (5)	0.0290 (5)	−0.0012 (4)	−0.0017 (4)	0.0025 (4)
C1	0.0364 (7)	0.0252 (6)	0.0359 (7)	0.0032 (5)	0.0031 (5)	0.0051 (5)
C2	0.0296 (6)	0.0255 (5)	0.0262 (6)	0.0020 (4)	0.0033 (4)	0.0001 (4)
C3	0.0226 (7)	0.0218 (7)	0.0241 (7)	0.000	0.0056 (6)	0.000
C4	0.0232 (7)	0.0222 (7)	0.0205 (7)	0.000	0.0032 (5)	0.000
C5	0.0294 (6)	0.0212 (5)	0.0258 (5)	0.0021 (4)	0.0063 (4)	0.0000 (4)
C6	0.0342 (7)	0.0594 (10)	0.0476 (8)	0.0091 (7)	0.0128 (6)	−0.0105 (7)
C7	0.0509 (8)	0.0301 (6)	0.0313 (6)	0.0017 (6)	0.0058 (6)	0.0087 (5)

Geometric parameters (Å, º)

O1—N2	1.2777 (13)	C5—C7	1.5215 (17)
N1—C1	1.3358 (16)	C5—C6	1.5252 (18)
N2—C4	1.3444 (13)	C5—C5^i	1.555 (2)
N2—C5	1.5021 (14)	C6—H6A	0.9700
C1—C2	1.3829 (17)	C6—H6B	0.9700
C1—H1	0.9400	C6—H6C	0.9700
C2—C3	1.3959 (14)	C7—H7A	0.9700
C2—H2	0.9400	C7—H7B	0.9700
C3—C4	1.463 (2)	C7—H7C	0.9700
C1—N1—C1^i	116.19 (15)	C7—C5—C6	109.63 (12)
O1—N2—C4	126.39 (11)	N2—C5—C5^i	101.80 (6)
O1—N2—C5	120.30 (10)	C7—C5—C5^i	115.08 (12)
C4—N2—C5	113.20 (10)	C5—C6—H6A	109.5
N1—C1—C2	124.43 (12)	C5—C6—H6B	109.5
N1—C1—H1	117.8	H6A—C6—H6B	109.5
C2—C1—H1	117.8	C5—C6—H6C	109.5
C1—C2—C3	118.56 (12)	H6A—C6—H6C	109.5
C1—C2—H2	120.7	H6B—C6—H6C	109.5
C3—C2—H2	120.7	C5—C7—H7A	109.5
C2^i—C3—C2	117.79 (15)	C5—C7—H7B	109.5
C2—C3—C4	121.11 (7)	H7A—C7—H7B	109.5
N2^i—C4—N2	108.75 (14)	C5—C7—H7C	109.5
N2—C4—C3	125.63 (7)	H7A—C7—H7C	109.5
N2—C5—C7	107.83 (10)	H7B—C7—H7C	109.5
N2—C5—C6	106.52 (11)

Symmetry code: (i) −x+1, y, −z+1/2.