N,N'-Bis(6-methyl-2-pyridyl)­urea

The title compound, C₁₃H₁₄N₄O, has been synthesized as an ADDA (D: hydrogen-bond donor; A: hydrogen-bond acceptor) recognition unit for quadruple hydrogen bonds. In the solid state, it crystallizes as a centrosymmetric dimer connecting one N-H group with one pyridyl N atom. Furthermore, an intramolecular hydrogen bond is formed connecting two N atoms.

Key indicators

• Single-crystal X-ray study
• T = 133 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.036
• wR factor = 0.094
• Data-to-parameter ratio = 15.2

checkCIF results

No syntax errors found



ADDSYM reports no extra symmetry

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Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1991).

(lue5)

Crystal data

C13H14N4O	F(000) = 512
Mr = 242.28	Dx = 1.248 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.1142 (2) Å	Cell parameters from 6371 reflections
b = 11.0127 (3) Å	θ = 1.0–25.0°
c = 16.4630 (4) Å	µ = 0.08 mm^−1
β = 90.078 (1)°	T = 133 K
V = 1289.82 (6) Å^3	Block, colourless
Z = 4	0.50 × 0.30 × 0.20 mm

Data collection

Siemens CCD three-circle diffractometer	2629 independent reflections
Radiation source: fine-focus sealed tube	2240 reflections with I > 2σ(I)
Highly oriented graphite crystal monochromator	Rint = 0.028
ω scans	θmax = 26.3°, θmin = 2.2°
Absorption correction: empirical (using intensity measurements) 'SADABS (Sheldrick, 1996)'	h = −8→8
Tmin = 0.960, Tmax = 0.984	k = −13→13
23905 measured reflections	l = −20→20

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.095	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0446P)^2 + 0.3616P] where P = (Fo^2 + 2Fc^2)/3
2629 reflections	(Δ/σ)max = 0.001
173 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.23 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
N1	0.21514 (14)	0.59679 (9)	0.49618 (6)	0.0237 (2)
H1	0.103 (2)	0.5843 (14)	0.5224 (9)	0.040 (4)*
C2	0.24808 (15)	0.51472 (10)	0.43411 (7)	0.0212 (2)
O2	0.13024 (11)	0.43464 (8)	0.41927 (5)	0.0268 (2)
N3	0.41201 (14)	0.52965 (9)	0.39267 (6)	0.0217 (2)
H3	0.487 (2)	0.5872 (14)	0.4103 (9)	0.034 (4)*
C11	0.32076 (16)	0.69639 (10)	0.52357 (7)	0.0212 (2)
N12	0.48814 (13)	0.71846 (9)	0.48957 (6)	0.0221 (2)
C13	0.58920 (17)	0.81542 (11)	0.51587 (7)	0.0244 (3)
C13'	0.77567 (17)	0.83441 (12)	0.47475 (8)	0.0321 (3)
H13A	0.8506	0.7600	0.4788	0.048*
H13B	0.8428	0.9013	0.5013	0.048*
H13C	0.7550	0.8544	0.4174	0.048*
C14	0.52281 (18)	0.89154 (11)	0.57654 (8)	0.0291 (3)
H14	0.5947	0.9596	0.5937	0.035*
C15	0.34913 (18)	0.86673 (12)	0.61205 (8)	0.0295 (3)
H15	0.3026	0.9174	0.6541	0.035*
C16	0.24496 (17)	0.76839 (11)	0.58593 (7)	0.0253 (3)
H16	0.1263	0.7501	0.6093	0.030*
C31	0.48264 (15)	0.46026 (10)	0.32803 (7)	0.0205 (2)
N32	0.65170 (13)	0.50075 (9)	0.30376 (6)	0.0225 (2)
C33	0.73843 (17)	0.44228 (11)	0.24248 (7)	0.0258 (3)
C33'	0.92571 (18)	0.49386 (14)	0.21721 (8)	0.0362 (3)
H33A	1.0077	0.5008	0.2649	0.054*
H33B	0.9071	0.5744	0.1931	0.054*
H33C	0.9842	0.4400	0.1772	0.054*
C34	0.65752 (18)	0.34201 (12)	0.20396 (7)	0.0291 (3)
H34	0.7217	0.3016	0.1612	0.035*
C35	0.48189 (18)	0.30239 (11)	0.22920 (7)	0.0284 (3)
H35	0.4244	0.2348	0.2033	0.034*
C36	0.39009 (17)	0.36147 (11)	0.29223 (7)	0.0242 (3)
H36	0.2696	0.3360	0.3103	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0198 (5)	0.0254 (5)	0.0260 (5)	−0.0033 (4)	0.0062 (4)	−0.0035 (4)
C2	0.0199 (5)	0.0207 (6)	0.0230 (6)	0.0010 (4)	0.0008 (4)	0.0014 (4)
O2	0.0218 (4)	0.0273 (5)	0.0313 (5)	−0.0053 (3)	0.0051 (3)	−0.0050 (4)
N3	0.0209 (5)	0.0194 (5)	0.0249 (5)	−0.0028 (4)	0.0046 (4)	−0.0027 (4)
C11	0.0222 (6)	0.0203 (6)	0.0212 (6)	0.0013 (4)	−0.0007 (4)	0.0018 (4)
N12	0.0219 (5)	0.0212 (5)	0.0232 (5)	−0.0010 (4)	0.0006 (4)	0.0018 (4)
C13	0.0266 (6)	0.0212 (6)	0.0254 (6)	−0.0021 (5)	−0.0047 (5)	0.0047 (5)
C13'	0.0278 (6)	0.0292 (7)	0.0392 (7)	−0.0079 (5)	−0.0014 (5)	0.0031 (6)
C14	0.0354 (7)	0.0217 (6)	0.0300 (6)	−0.0025 (5)	−0.0075 (5)	−0.0006 (5)
C15	0.0373 (7)	0.0255 (6)	0.0256 (6)	0.0061 (5)	−0.0020 (5)	−0.0042 (5)
C16	0.0249 (6)	0.0263 (6)	0.0249 (6)	0.0040 (5)	0.0016 (5)	0.0003 (5)
C31	0.0220 (6)	0.0187 (6)	0.0209 (5)	0.0035 (4)	0.0019 (4)	0.0030 (4)
N32	0.0221 (5)	0.0224 (5)	0.0229 (5)	0.0023 (4)	0.0031 (4)	0.0034 (4)
C33	0.0264 (6)	0.0289 (6)	0.0222 (6)	0.0064 (5)	0.0037 (5)	0.0044 (5)
C33'	0.0281 (7)	0.0479 (9)	0.0326 (7)	0.0021 (6)	0.0107 (5)	−0.0005 (6)
C34	0.0377 (7)	0.0277 (6)	0.0220 (6)	0.0084 (5)	0.0053 (5)	−0.0008 (5)
C35	0.0386 (7)	0.0208 (6)	0.0258 (6)	0.0024 (5)	−0.0008 (5)	−0.0010 (5)
C36	0.0262 (6)	0.0206 (6)	0.0259 (6)	−0.0003 (5)	0.0015 (5)	0.0016 (5)

Geometric parameters (Å, º)

N1—C2	1.3843 (15)	C15—C16	1.3806 (18)
N1—C11	1.4036 (15)	C15—H15	0.9500
N1—H1	0.920 (17)	C16—H16	0.9500
C2—O2	1.2409 (14)	C31—N32	1.3440 (15)
C2—N3	1.3618 (15)	C31—C36	1.4012 (16)
N3—C31	1.4036 (15)	N32—C33	1.3471 (15)
N3—H3	0.879 (16)	C33—C34	1.3972 (18)
C11—N12	1.3387 (15)	C33—C33'	1.5075 (18)
C11—C16	1.4054 (16)	C33'—H33A	0.9800
N12—C13	1.3578 (15)	C33'—H33B	0.9800
C13—C14	1.3873 (18)	C33'—H33C	0.9800
C13—C13'	1.5048 (17)	C34—C35	1.3877 (18)
C13'—H13A	0.9800	C34—H34	0.9500
C13'—H13B	0.9800	C35—C36	1.3887 (17)
C13'—H13C	0.9800	C35—H35	0.9500
C14—C15	1.3946 (19)	C36—H36	0.9500
C14—H14	0.9500
C2—N1—C11	131.01 (10)	C14—C15—H15	120.0
C2—N1—H1	113.4 (10)	C15—C16—C11	117.63 (11)
C11—N1—H1	115.6 (10)	C15—C16—H16	121.2
O2—C2—N3	124.47 (11)	C11—C16—H16	121.2
O2—C2—N1	119.62 (10)	N32—C31—C36	123.55 (10)
N3—C2—N1	115.91 (10)	N32—C31—N3	111.48 (10)
C2—N3—C31	128.45 (10)	C36—C31—N3	124.97 (10)
C2—N3—H3	116.3 (10)	C31—N32—C33	118.36 (10)
C31—N3—H3	115.1 (10)	N32—C33—C34	121.93 (11)
N12—C11—N1	118.93 (10)	N32—C33—C33'	115.63 (11)
N12—C11—C16	123.05 (11)	C34—C33—C33'	122.43 (11)
N1—C11—C16	118.02 (10)	C33—C33'—H33A	109.5
C11—N12—C13	118.70 (10)	C33—C33'—H33B	109.5
N12—C13—C14	121.61 (11)	H33A—C33'—H33B	109.5
N12—C13—C13'	115.63 (11)	C33—C33'—H33C	109.5
C14—C13—C13'	122.76 (11)	H33A—C33'—H33C	109.5
C13—C13'—H13A	109.5	H33B—C33'—H33C	109.5
C13—C13'—H13B	109.5	C35—C34—C33	118.89 (11)
H13A—C13'—H13B	109.5	C35—C34—H34	120.6
C13—C13'—H13C	109.5	C33—C34—H34	120.6
H13A—C13'—H13C	109.5	C34—C35—C36	120.06 (12)
H13B—C13'—H13C	109.5	C34—C35—H35	120.0
C13—C14—C15	119.08 (11)	C36—C35—H35	120.0
C13—C14—H14	120.5	C35—C36—C31	117.19 (11)
C15—C14—H14	120.5	C35—C36—H36	121.4
C16—C15—C14	119.91 (12)	C31—C36—H36	121.4
C16—C15—H15	120.0
C11—N1—C2—O2	−177.96 (11)	N12—C11—C16—C15	0.62 (17)
C11—N1—C2—N3	1.58 (18)	N1—C11—C16—C15	−179.50 (10)
O2—C2—N3—C31	−1.10 (19)	C2—N3—C31—N32	−178.54 (10)
N1—C2—N3—C31	179.39 (10)	C2—N3—C31—C36	1.83 (19)
C2—N1—C11—N12	−3.77 (18)	C36—C31—N32—C33	−0.99 (16)
C2—N1—C11—C16	176.34 (11)	N3—C31—N32—C33	179.37 (10)
N1—C11—N12—C13	179.54 (10)	C31—N32—C33—C34	0.15 (17)
C16—C11—N12—C13	−0.58 (16)	C31—N32—C33—C33'	178.84 (10)
C11—N12—C13—C14	−0.19 (16)	N32—C33—C34—C35	0.60 (18)
C11—N12—C13—C13'	−179.94 (10)	C33'—C33—C34—C35	−178.00 (12)
N12—C13—C14—C15	0.88 (18)	C33—C34—C35—C36	−0.55 (18)
C13'—C13—C14—C15	−179.38 (11)	C34—C35—C36—C31	−0.21 (17)
C13—C14—C15—C16	−0.82 (18)	N32—C31—C36—C35	1.02 (17)
C14—C15—C16—C11	0.11 (17)	N3—C31—C36—C35	−179.39 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2^i	0.920 (17)	1.928 (17)	2.8468 (13)	177.0 (15)
N3—H3···N12	0.879 (16)	1.948 (16)	2.6757 (14)	139.3 (13)

Symmetry code: (i) −x, −y+1, −z+1.