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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Volume 61| Part 6| June 2005| Pages o383-o385
doi:10.1107/S0108270105012485

6-Meth­yl-2-pyridone: an elusive structure finally solved

CROSSMARK_Color_square_no_text.svg
Gary S. Nichola and William Clegga*

aSchool of Natural Sciences – Chemistry, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, England
*Correspondence e-mail: w.clegg@ncl.ac.uk

(Received 7 March 2005; accepted 20 April 2005; online 13 May 2005)

The title compound, C6H7NO, crystallizes unsolvated from dry toluene after storage for several months at approximately 263 K. Synchrotron radiation was needed in order to carry out data collection because of the small size of the crystals obtained. There are four crystallographically independent mol­ecules in the asymmetric unit. Packing diagrams show that the mol­ecules are linked into infinite chains by hydrogen bonding; two of the four independent mol­ecules link together to form a chain, while the other two mol­ecules form chains involving only their own symmetry equivalents, giving a total of three crystallographically distinct chains in all. The chains are held together by weak π–π inter­actions. This structure provides conclusive proof that, in the absence of any other co-­crystallized mol­ecule or solvent, the compound exists in the solid state as the pyridone and not the pyridinol tautomer.

Comment

For many years, 2-pyridone and its 6-substituted derivatives have been widely used as ligands in transition metal coordination chemistry (Rawson & Winpenny, 1995[Rawson, J. M. & Winpenny, R. E. P. (1995). Coord. Chem. Rev. 139, 313-374.]), and their use in s-block metal coordination chemistry is increasing. There is also great inter­est in the organic compounds themselves, particularly owing to the presence of a keto–enol tautomeric equilibrium, which is observed in the gas phase and in solution. This property has been investigated comprehensively by IR spectroscopy (Gibson et al., 1955[Gibson, J. A., Kynaston, W. & Lindsey, A. S. (1955). J. Chem. Soc. pp. 4340-4344.]; Katritzky et al., 1967[Katritzky, A. R., Rowe, J. D. & Roy, S. K. (1967). J. Chem. Soc. B, pp. 758-761.]; Mason, 1957[Mason, S. F. (1957). J. Chem. Soc. pp. 4874-4880.]), UV–visible spectroscopy (Beak et al., 1976[Beak, P., Fry, F. S., Lee, J. & Steele, F. (1976). J. Am. Chem. Soc. 98, 171-179.]), nuclear magnetic resonance spectroscopy (Coburn & Dudek, 1968[Coburn, R. A. & Dudek, G. O. (1968). J. Phys. Chem. 72, 1177-1181.]) and theoretical calculations (Beak & Covington, 1978[Beak, P. & Covington, J. B. (1978). J. Am. Chem. Soc. 100, 3961-3963.]; Beak et al., 1980[Beak, P., Covington, J. B. & White, J. M. (1980). J. Org. Chem. 45, 1347-1353.]; Parchment et al., 1991[Parchment, O. G., Hillier, I. H. & Green, D. S. V. (1991). J. Chem. Soc. Perkin Trans. 2, pp. 799-802.]; Wong et al., 1992[Wong, M. W., Wiberg, K. B. & Frisch, M. J. (1992). J. Am. Chem. Soc. 114, 1645-1652.]). Factors influencing this tautomerism include solvent polarity, pH, substituent positions and electronic effects of any substituent. Substituents at the 6-position have the greatest effect; electron-withdrawing substituents are seen to drive the equilibrium towards the pyridinol tautomer, whereas electron-donating substituents favour the pyridone tautomer. For example, 6-chloro-2-hydroxy­pyridine (Kvick & Olovsson, 1969[Kvick, Å. & Olovsson, I. (1969). Ark. Kemi, 30, 71-80.]) and 6-bromo-2-hydroxy­pyridine (Kvick, 1976[Kvick, Å. (1976). Acta Cryst. B32, 220-224.]) have electron-withdrawing substituents and both crystallize in the pyridinol form, as predicted by spectroscopic and theoretical studies. By contrast, the unsubstituted mol­ecule crystallizes in the pyridone form (Penfold, 1953[Penfold, B. R. (1953). Acta Cryst. 6, 591-600.]).

[Scheme 1]

There is, however, little firm crystallographic evidence to support the theory that an electron-donating substituent, in the absence of any other external influence (e.g. a co-crystallized mol­ecule), will drive the equilibrium towards the pyridone tautomer. Recently, we reported the structure of 6-meth­yl-2-pyridone as its penta­hydrate and we noted then that the only known structures of this mol­ecule were either coordination complexes or co-crystals, with the difficulty in each case of being certain that the structure is pyridone and not pyridinol (Clegg & Nichol, 2004[Clegg, W. & Nichol, G. S. (2004). Acta Cryst. E60, o1433-o1436.]).

We succeeded, after many attempts, in obtaining crystals of unsolvated 6-meth­yl-2-pyridone, (I)[link], from a dry toluene solution layered with dry dieth­yl ether. The crystals resulted as a by-product of a reaction mixture and were grown by storage at approximately 263 K over a period of several months. The product consisted of large agglomerations of very small single crystals, too weakly diffracting for analysis with standard laboratory X-ray equipment, even with a rotating-anode source, so we used Station 9.8 of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, Cheshire, England, to carry out data collection.

The asymmetric unit of (I)[link] is presented in Fig. 1[link]. There are four crystallographically independent mol­ecules in the asymmetric unit; overall Z = 16. Each mol­ecule is in the pyridone form and has a planar non-H-atom skeleton; the mol­ecular dimensions are unexceptional, apart from the C=O bond lengths (Table 1[link]), which are rather long for a carbon­yl group of this type but are in general agreement with published lengths (Clegg & Nichol, 2004[Clegg, W. & Nichol, G. S. (2004). Acta Cryst. E60, o1433-o1436.]). Table 1[link] also gives geometric data for the atoms of one of the four mol­ecules, and this is representative of the other three. There are differences in the C—C bond lengths within the ring, showing that there are distinctly separate localized C—N, C—C and C=C bonds as opposed to a delocalized aromatic ring.

Fig. 2[link] gives a representation of the hydrogen bonding (Table 2[link]) observed in this structure. The mol­ecules link together to form infinite chains, a motif also observed in the parent 2-pyridone structure but not in the 6-bromo- or 6-chloro-2-hydroxy­pyridine structures, where instead the mol­ecules dimerize. There are three separate hydrogen-bonded chains (formed by different mol­ecules) in this structure (Fig. 3[link]), and these can be seen most easily by colouring each symmetry-independent mol­ecule differently (as shown in the online version of the journal). The `yellow' and `red' mol­ecules form separate chains (top and middle) involving only their own symmetry equivalents (i.e. other `yellow' or `red' mol­ecules, respectively), whereas the `blue' and `green' mol­ecules are linked together alternately to form the third chain (the lowest in Fig. 3[link]). The positions of these three chains relative to one another are clearly seen by viewing along the a axis (Fig. 4[link]).

There is no π–π stacking between the red chains, as they are displaced from each other by half a unit cell along the a axis, and there is also no π–π stacking between the blue/green chains; at around 7 Å they are too far apart. There is a small amount of overlap observed between the red mol­ecule and the blue mol­ecule, and edge–face inter­actions exist between the red mol­ecule and the yellow mol­ecule. The inter­molecular distances are shown in Fig. 5[link]. Given that these weak inter­actions are the only ones observed of any significance that hold the chains together, it is perhaps not surprising that this compound does not crystallize easily without solvent or another different mol­ecule to encourage hydrogen bonding.

[Figure 1]
Figure 1
The asymmetric unit of (I)[link], with displacement ellipsoids drawn at the 50% probability level. H atoms not involved in hydrogen bonding have been omitted for clarity.
[Figure 2]
Figure 2
The hydrogen-bonding pattern in (I)[link], forming infinite chains.
[Figure 3]
Figure 3
The three different hydrogen-bonded chains. The mol­ecules are coloured in the online version in order to show clearly which mol­ecules form chains with their symmetry equivalents (the yellow top chain and the red middle chain) and which link together (blue and green) to form another chain (the bottom one).
[Figure 4]
Figure 4
A packing diagram, viewed along the a axis, showing the relative orientation of the three different chains. There are no inter­chain hydrogen bonds.
[Figure 5]
Figure 5
Selected inter­molecular distances in Å.

Experimental

Commercially available 6-meth­yl-2-pyridone was refluxed with an excess of CaH2 in dry toluene in an attempt to form a calcium complex. After two days, the mixture was filtered and the colourless filtrate was stored at approximately 263 K for one month. No crystals had formed, so the solution was then layered with diethyl ether and the flask was stored again at approximately 263 K for a period of around six months, when large clusters of very small crystals were observed. Data were collected at SRS Daresbury via the EPSRC National X-ray Crystallography Service. The crystals redissolved when the flask was stored at room temperature and so no other experimental data (analytical or spectroscopic) could be obtained.

Crystal data

  • C6H7NO

  • Mr = 109.13

  • Orthorhombic, P 21 21 21

  • a = 7.5229 (17) Å

  • b = 13.083 (3) Å

  • c = 22.149 (5) Å

  • V = 2180.0 (9) Å3

  • Z = 16

  • Dx = 1.330 Mg m−3

  • Synchrotron radiation

  • λ= 0.6768 Å

  • Cell parameters from 1153 reflections

  • θ = 3.0–19.4°

  • μ = 0.09 mm−1

  • T = 120 (2) K

  • Needle, colourless

  • 0.20 × 0.02 × 0.01 mm
Data collection

  • Bruker APEX-2 CCD diffractometer

  • Thin-slice ω scans

  • Absorption correction: multi-scan(SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.])Tmin = 0.982, Tmax = 0.999

  • 16 261 measured reflections

  • 2202 independent reflections

  • 1474 reflections with I > 2σ(I)

  • Rint = 0.128

  • θmax = 23.7°

  • h = −8 → 8

  • k = −15 → 15

  • l = −26 → 26
Refinement

  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.050

  • wR(F2) = 0.128

  • S = 1.05

  • 2202 reflections

  • 306 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • w = 1/[σ2(Fo2) + (0.0679P)2] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.24 e Å−3

  • Δρmin = −0.23 e Å−3

  • Extinction correction: SHELXTL

  • Extinction coefficient: 0.037 (4)

Table 1
Selected interatomic distances (Å)[link]

O1—C1 1.270 (5)
O2—C7 1.263 (5)
O3—C13 1.268 (6)
O4—C19 1.247 (6)
N1—C1 1.372 (6)
N1—C5 1.371 (6)
C1—C2 1.430 (7)
C2—C3 1.368 (7)
C3—C4 1.400 (7)
C4—C5 1.342 (7)
C5—C6 1.512 (7)

Table 2
Hydrogen-bond geometry (Å, °)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N1—H1N⋯O2i 0.93 (2) 1.90 (2) 2.816 (5) 167 (4)
N2—H2N⋯O1 0.91 (2) 1.90 (2) 2.795 (5) 168 (4)
N3—H3N⋯O3ii 0.89 (2) 1.95 (3) 2.806 (5) 161 (4)
N4—H4N⋯O4iii 0.90 (2) 1.89 (2) 2.783 (5) 174 (5)
Symmetry codes: (i) x-1, y, z; (ii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (iii) [x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1].

SADABS (Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.]) was used to correct for the synchrotron beam decay through frame scaling. Methyl H atoms were positioned geometrically (C—H = 0.98 Å) and refined as riding, with free rotation about the C—C bond, and with Uiso(H) values of 1.5Ueq(C). Ring-attached H atoms were also positioned geometrically (C—H = 0.95 Å) and refined as riding, with Uiso(H) values of 1.2Ueq(C). Amide H atoms were found in a difference map and refined with Uiso(H) values of 1.2Ueq(N); N—H bond lengths were restrained to 0.90 (2) Å. In the absence of significant anomalous scattering effects, Friedel pairs were merged in the final refinement cycles.

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2001[Sheldrick, G. M. (2001). SHELXTL. Version 6. Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and MERCURY (Version 1.3; Bruno et al., 2002[Bruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389-397.]); software used to prepare material for publication: SHELXTL and local programs.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S0108270105012485/hj1052sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270105012485/hj1052Isup2.hkl


Comment top

For many years, the molecule 2-pyridone and its 6-substituted derivatives have been widely used as ligands in transition metal coordination chemisty (Rawson & Winpenny, 1995), and their use in s-block metal coordination chemistry is increasing. There is also great interest in the organic compounds themselves, particularly owing to the presence of a keto–enol tautomeric equilibrium, which is observed in the gas phase and in solution. This property has been investigated comprehensively by IR spectroscopy (Gibson et al., 1955; Katritzky et al., 1967; Mason, 1957), UV/visible spectroscopy (Beak et al., 1976), nuclear magnetic resonance spectroscopy (Coburn & Dudek, 1968) and theoretical calculations (Beak & Covington, 1978; Beak et al., 1980; Parchment et al., 1991; Wong et al., 1992). Factors influencing this tautormerism include solvent polarity, pH, substituent positions and electronic effects of any substituent. Substituents at position 6 have the greatest effect; electron-withdrawing substituents are seen to drive the equilibrium towards the pyridinol tautomer, whereas electron-donating substituents favour the pyridone tautomer. For example, 6-chloro-2-hydroxypyridine (Kvick & Olovsson, 1969) and 6-bromo-2-hydroxypyridine (Kvick, 1976) have electron-withdrawing substituents and both crystallize in the pyridinol form, as predicted by spectroscopic and theoretical studies. By contrast, the unsubstituted molecule crystallizes in the pyridone form (Penfold, 1953).

There is, however, little firm crystallographic evidence to support the theory that an electron-donating substituent, in the absence of any other external influence (e.g. a cocrystallized molecule), will drive the equilibrium towards the pyridone tautomer. Recently, we reported the structure of 6-methyl-2-pyridone as its pentahydrate, and we noted then that the only known structures of this molecule were either coordination complexes or cocrystals, with the difficulty in each case of being certain that the structure is pyridone and not pyridinol (Clegg & Nichol, 2004).

We succeeded, after many attempts, in obtaining crystals of unsolvated 6-methyl-2-pyridone, (I), from a dry toluene solution layered with dry diethyl ether. The crystals resulted as a by-product of a reaction mixture and were grown by storage at approximately 263 K over a period of several months. The product consisted of large agglomerations of very small single crystals, too weakly diffracting for analysis with standard laboratory X-ray equipment, even with a rotating-anode source, so we used Station 9.8 of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, Cheshire, England to carry out data collection.

The asymmetric unit of (I) is presented in Fig. 1. There are four crystallographically independent molecules in the asymmetric unit; overall Z = 16. Each molecule is in the pyridone form and has a planar non-H skeleton; molecular dimensions are unexceptional, apart from the C═O bond lengths (Table 1), which are rather long for a carbonyl group of this type but are in general agreement with published lengths (Clegg & Nichol, 2004). Table 1 also gives geometric data for the atoms of one of the four molecules and this is representative of the other three. There are differences in the C—C bond lengths within the ring, showing that there are distinctly separate localized C—N, C—C and C═C bonds as opposed to a delocalized aromatic ring.

Fig. 2 gives a representation of the hydrogen bonding observed in this structure. The molecules link together to form infinite chains, a motif also observed in the parent 2-pyridone structure but not in the 6-bromo- or 6-chloro-2-hydroxypyridine structures, where instead the molecules dimerize. There are three separate hydrogen-bonded chains (formed by different molecules) in this structure (Fig. 3) and this can be seen most easily by colouring each symmetry-independent molecule differently (in the on-line version of the journal). The yellow and red molecules form separate chains involving only their own symmetry equivalents (i.e. other yellow or red molecules, respectively), whereas the blue and green molecules are linked together alternately to form the third chain (the lowest one in Fig. 3). The positions of these three chains relative to one another are clearly seen by viewing along the a axis (Fig. 4).

There is no π–π stacking between the red chains, as they are displaced from each other by half a unit cell along the a axis, and there is also no π–π stacking between the blue/green chains; at around 7 Å they are too far apart. There is a small amount of overlap observed between the red molecule and the blue molecule, and edge–face interactions between the red molecule and the yellow molecule. The intermolecular distances are shown in Fig. 5. Given that these weak interactions are the only ones observed of any significance that hold the chains together, it is perhaps not surprising that this compound does not crystallize easily without solvent or another different molecule to encourage hydrogen bonding.

Experimental top

Commercially available 6-methyl-2-pyridone was refluxed with an excess of CaH2 in dry toluene in an attempt to form a calcium complex. After two days, the mixture was filtered and the colourless filtrate was stored at approximately 263 K for one month. No crystals had formed, so the solution was then layered with diethyl ether and the flask was stored again at approximately 263 K for a period of around six months, when large clusters of very small crystals were observed. Data were collected at SRS Daresbury via the EPSRC National X-ray Crystallography Service. The crystals redissolved when the flask was stored at room temperature and so no other experimental data (analytical or spectroscopic) could be obtained.

Refinement top

SADABS (Sheldrick, 2003) was used to correct for the synchrotron beam decay through frame scaling. Methyl H atoms were positioned geometrically (C—H = 0.98 Å) and refined as riding, with free rotation about the C—C bond, and with Uiso(H) values of 1.5Ueq(C). Ring-attached H atoms were also positioned geometrically (C—H = 0.95 Å) and refined as riding, with Uiso(H) values of 1.2Ueq(C). Amide H atoms were found in a difference map and refined with Uiso(H) values of 1.2Ueq(N); N—H bond lengths were restrained to 0.90 (2) Å. In the absence of significant anomalous scattering effects, Friedel pairs were merged in the final refinement cycles.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Version 1.3; Bruno et al., 2002); software used to prepare material for publication: SHELXTL and local programs.

Figures top
[Figure 1] Fig. 1. The asymmetric unit of (I), with displacement ellipsoids drawn at the 50% probability level. H atoms not involved in hydrogen bonding have been omitted for clarity.
[Figure 2] Fig. 2. The hydrogen-bonding pattern, forming infinite chains.
[Figure 3] Fig. 3. The three different hydrogen-bonded chains. The molecules are coloured in the online version, in order to show clearly which molecules form chains with their symmetry equivalents (the yellow top chain and the red middle chain) and which link together (blue and green) to form another chain (the bottom one).
[Figure 4] Fig. 4. A packing diagram viewed along the a axis, showing the relative orientation of the three different chains. There are no interchain hydrogen bonds.
[Figure 5] Fig. 5. Selected intermolecular distances in Å.
6-Methyl-2-pyridone top
Crystal data top
C6H7NOF(000) = 928
Mr = 109.13Dx = 1.330 Mg m−3
Orthorhombic, P212121Synchrotron radiation, λ = 0.6768 Å
Hall symbol: P 2ac 2abCell parameters from 1153 reflections
a = 7.5229 (17) Åθ = 3.0–19.4°
b = 13.083 (3) ŵ = 0.09 mm−1
c = 22.149 (5) ÅT = 120 K
V = 2180.0 (9) Å3Needle, colourless
Z = 160.20 × 0.02 × 0.01 mm
Data collection top
Bruker APEX2 CCD
diffractometer		2202 independent reflections
Radiation source: Daresbury SRS station 9.81474 reflections with I > 2σ(I)
Silicon 111 monochromatorRint = 0.128
thin–slice ω scansθmax = 23.7°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		h = −8→8
Tmin = 0.982, Tmax = 0.999k = −15→15
16261 measured reflectionsl = −26→26
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.050H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.128 w = 1/[σ2(Fo2) + (0.0679P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
2202 reflectionsΔρmax = 0.24 e Å−3
306 parametersΔρmin = −0.23 e Å−3
4 restraintsExtinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.037 (4)
Crystal data top
C6H7NOV = 2180.0 (9) Å3
Mr = 109.13Z = 16
Orthorhombic, P212121Synchrotron radiation, λ = 0.6768 Å
a = 7.5229 (17) ŵ = 0.09 mm−1
b = 13.083 (3) ÅT = 120 K
c = 22.149 (5) Å0.20 × 0.02 × 0.01 mm
Data collection top
Bruker APEX2 CCD
diffractometer		2202 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		1474 reflections with I > 2σ(I)
Tmin = 0.982, Tmax = 0.999Rint = 0.128
16261 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0504 restraints
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 1.05Δρmax = 0.24 e Å−3
2202 reflectionsΔρmin = −0.23 e Å−3
306 parameters
Special details top

Experimental. Flack absolute structure parameter is −3(2). Meaningless, so MERG 4 was used during refinement to merge Friedel opposites.

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 (Å2) top
xyzUiso*/Ueq
O10.0030 (5)0.3128 (2)0.68262 (14)0.0387 (9)
O20.5073 (5)0.2875 (2)0.68216 (14)0.0397 (9)
O30.3860 (4)0.2342 (2)0.50465 (16)0.0401 (9)
O40.7244 (4)0.7449 (3)0.50887 (16)0.0405 (9)
N1−0.1785 (6)0.1909 (3)0.64326 (18)0.0337 (10)
H1N−0.275 (4)0.232 (3)0.654 (2)0.040*
N20.3198 (6)0.4185 (3)0.70381 (17)0.0325 (10)
H2N0.227 (5)0.376 (3)0.697 (2)0.039*
N30.5713 (6)0.3625 (3)0.53228 (18)0.0328 (11)
H3N0.655 (5)0.324 (3)0.5148 (19)0.039*
N40.5403 (6)0.7298 (3)0.42750 (18)0.0355 (11)
H4N0.440 (4)0.743 (4)0.4478 (19)0.043*
C1−0.0116 (6)0.2278 (4)0.6553 (2)0.0328 (11)
C20.1350 (7)0.1656 (4)0.6370 (2)0.0347 (12)
H20.25360.18770.64360.042*
C30.1018 (7)0.0737 (4)0.6097 (2)0.0371 (13)
H30.19870.03140.59830.044*
C4−0.0722 (7)0.0409 (4)0.5985 (2)0.0349 (12)
H4−0.0925−0.02290.57920.042*
C5−0.2103 (7)0.0996 (4)0.6148 (2)0.0345 (12)
C6−0.4036 (6)0.0738 (4)0.6041 (2)0.0371 (13)
H6A−0.41190.00930.58180.056*
H6B−0.45950.12850.58050.056*
H6C−0.46470.06700.64300.056*
C70.4881 (7)0.3800 (4)0.6972 (2)0.0320 (12)
C80.6304 (6)0.4482 (4)0.7101 (2)0.0353 (13)
H80.75000.42570.70680.042*
C90.5940 (7)0.5471 (4)0.7275 (2)0.0356 (12)
H90.68900.59220.73700.043*
C100.4186 (7)0.5819 (4)0.7313 (2)0.0367 (13)
H100.39530.65090.74190.044*
C110.2822 (7)0.5175 (4)0.7200 (2)0.0342 (12)
C120.0883 (6)0.5453 (4)0.7236 (2)0.0382 (13)
H12A0.07660.61840.73250.057*
H12B0.03140.50560.75580.057*
H12C0.03060.53010.68500.057*
C130.4036 (6)0.3237 (4)0.5258 (2)0.0350 (12)
C140.2623 (7)0.3895 (4)0.5430 (2)0.0362 (13)
H140.14340.36510.54220.043*
C150.2960 (7)0.4869 (4)0.5604 (2)0.0379 (13)
H150.19990.53110.57000.045*
C160.4736 (7)0.5236 (4)0.5646 (2)0.0369 (13)
H160.49590.59200.57690.044*
C170.6110 (7)0.4607 (4)0.5508 (2)0.0351 (12)
C180.8028 (7)0.4875 (4)0.5551 (3)0.0423 (14)
H18A0.81510.56090.56300.063*
H18B0.86230.47050.51700.063*
H18C0.85750.44880.58810.063*
C190.7078 (7)0.7263 (4)0.4539 (2)0.0366 (12)
C200.8514 (7)0.7012 (4)0.4142 (2)0.0382 (13)
H200.96910.69650.42960.046*
C210.8199 (8)0.6841 (4)0.3548 (2)0.0404 (13)
H210.91630.66700.32900.048*
C220.6471 (7)0.6911 (4)0.3305 (2)0.0379 (13)
H220.62790.68050.28860.046*
C230.5087 (7)0.7133 (3)0.3675 (2)0.0319 (11)
C240.3192 (7)0.7201 (4)0.3474 (2)0.0439 (13)
H24A0.31350.71340.30330.066*
H24B0.26980.78630.35940.066*
H24C0.25030.66510.36610.066*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.036 (2)0.0301 (19)0.050 (2)−0.0042 (17)0.0029 (18)−0.0083 (16)
O20.0340 (19)0.0264 (19)0.059 (2)0.0028 (16)−0.0009 (18)−0.0017 (16)
O30.036 (2)0.0293 (19)0.055 (2)−0.0035 (16)−0.0008 (18)−0.0032 (17)
O40.039 (2)0.0404 (19)0.042 (2)0.0020 (17)−0.0014 (17)−0.0073 (17)
N10.031 (2)0.029 (2)0.041 (2)−0.0010 (19)0.003 (2)0.0007 (19)
N20.032 (3)0.029 (2)0.037 (2)−0.001 (2)0.004 (2)0.0021 (19)
N30.033 (3)0.032 (2)0.034 (3)0.001 (2)0.002 (2)−0.0002 (18)
N40.033 (3)0.029 (2)0.044 (3)0.001 (2)0.002 (2)−0.0023 (19)
C10.027 (3)0.034 (3)0.037 (3)−0.003 (2)0.003 (2)0.005 (2)
C20.032 (3)0.030 (3)0.042 (3)0.004 (2)0.008 (2)0.001 (2)
C30.038 (3)0.034 (3)0.039 (3)0.007 (2)0.004 (3)0.005 (2)
C40.038 (3)0.029 (3)0.038 (3)0.005 (2)0.000 (2)0.001 (2)
C50.042 (3)0.027 (3)0.034 (3)−0.006 (3)−0.005 (3)0.003 (2)
C60.031 (3)0.031 (3)0.049 (3)−0.002 (2)−0.001 (3)0.002 (2)
C70.027 (3)0.033 (3)0.036 (3)0.002 (2)0.000 (2)0.007 (2)
C80.025 (3)0.041 (3)0.040 (3)−0.003 (2)0.002 (2)0.007 (2)
C90.027 (3)0.037 (3)0.043 (3)−0.007 (3)−0.004 (2)0.001 (2)
C100.040 (3)0.030 (3)0.040 (3)−0.002 (3)0.000 (3)0.000 (2)
C110.042 (3)0.029 (3)0.032 (3)0.002 (2)0.001 (2)0.004 (2)
C120.029 (3)0.035 (3)0.051 (3)0.003 (3)0.000 (3)−0.003 (3)
C130.029 (3)0.033 (3)0.043 (3)−0.001 (2)0.000 (2)0.006 (2)
C140.029 (3)0.037 (3)0.043 (3)0.001 (2)0.001 (3)0.001 (2)
C150.039 (3)0.028 (3)0.047 (3)0.007 (3)−0.002 (3)−0.001 (2)
C160.038 (3)0.034 (3)0.039 (3)−0.004 (3)0.003 (3)−0.003 (2)
C170.040 (3)0.029 (3)0.036 (3)0.001 (3)0.005 (3)0.001 (2)
C180.041 (3)0.032 (3)0.054 (3)0.002 (3)−0.001 (3)−0.004 (2)
C190.037 (3)0.030 (3)0.043 (3)−0.002 (2)0.003 (3)0.002 (2)
C200.033 (3)0.035 (3)0.046 (3)−0.004 (2)0.006 (3)−0.001 (2)
C210.046 (3)0.035 (3)0.041 (3)0.000 (3)0.005 (3)−0.004 (2)
C220.042 (3)0.035 (3)0.037 (3)0.001 (2)0.000 (3)−0.003 (2)
C230.034 (3)0.028 (3)0.034 (3)−0.001 (2)−0.004 (2)0.003 (2)
C240.048 (3)0.039 (3)0.045 (3)0.004 (3)−0.006 (3)−0.001 (3)
Geometric parameters (Å, º) top
O1—C11.270 (5)C9—H90.950
O2—C71.263 (5)C9—C101.398 (7)
O3—C131.268 (6)C10—H100.950
O4—C191.247 (6)C10—C111.351 (7)
N1—H1N0.93 (2)C11—C121.506 (7)
N1—C11.372 (6)C12—H12A0.980
N1—C51.371 (6)C12—H12B0.980
N2—H2N0.91 (2)C12—H12C0.980
N2—C71.371 (6)C13—C141.419 (7)
N2—C111.374 (6)C14—H140.950
N3—H3N0.89 (2)C14—C151.356 (7)
N3—C131.367 (6)C15—H150.950
N3—C171.382 (6)C15—C161.423 (7)
N4—H4N0.90 (2)C16—H160.950
N4—C191.391 (6)C16—C171.356 (7)
N4—C231.368 (6)C17—C181.488 (7)
C1—C21.430 (7)C18—H18A0.980
C2—H20.950C18—H18B0.980
C2—C31.368 (7)C18—H18C0.980
C3—H30.950C19—C201.431 (7)
C3—C41.400 (7)C20—H200.950
C4—H40.950C20—C211.356 (7)
C4—C51.342 (7)C21—H210.950
C5—C61.512 (7)C21—C221.410 (7)
C6—H6A0.980C22—H220.950
C6—H6B0.980C22—C231.356 (7)
C6—H6C0.980C23—C241.496 (7)
C7—C81.423 (7)C24—H24A0.980
C8—H80.950C24—H24B0.980
C8—C91.378 (7)C24—H24C0.980
H1N—N1—C1118 (3)C11—C12—H12A109.5
H1N—N1—C5119 (3)C11—C12—H12B109.5
C1—N1—C5123.8 (4)C11—C12—H12C109.5
H2N—N2—C7118 (3)H12A—C12—H12B109.5
H2N—N2—C11118 (3)H12A—C12—H12C109.5
C7—N2—C11124.4 (4)H12B—C12—H12C109.5
H3N—N3—C13113 (3)O3—C13—N3118.6 (4)
H3N—N3—C17120 (3)O3—C13—C14125.5 (5)
C13—N3—C17125.2 (4)N3—C13—C14116.0 (4)
H4N—N4—C19124 (3)C13—C14—H14119.8
H4N—N4—C23112 (3)C13—C14—C15120.4 (5)
C19—N4—C23124.2 (4)H14—C14—C15119.8
O1—C1—N1118.7 (4)C14—C15—H15119.6
O1—C1—C2124.5 (5)C14—C15—C16120.8 (5)
N1—C1—C2116.8 (4)H15—C15—C16119.6
C1—C2—H2120.5C15—C16—H16120.1
C1—C2—C3119.0 (5)C15—C16—C17119.7 (5)
H2—C2—C3120.5H16—C16—C17120.1
C2—C3—H3119.4N3—C17—C16117.8 (5)
C2—C3—C4121.2 (5)N3—C17—C18116.6 (5)
H3—C3—C4119.4C16—C17—C18125.6 (5)
C3—C4—H4120.0C17—C18—H18A109.5
C3—C4—C5120.0 (5)C17—C18—H18B109.5
H4—C4—C5120.0C17—C18—H18C109.5
N1—C5—C4119.2 (5)H18A—C18—H18B109.5
N1—C5—C6115.8 (5)H18A—C18—H18C109.5
C4—C5—C6125.0 (5)H18B—C18—H18C109.5
C5—C6—H6A109.5O4—C19—N4119.7 (5)
C5—C6—H6B109.5O4—C19—C20124.7 (5)
C5—C6—H6C109.5N4—C19—C20115.6 (4)
H6A—C6—H6B109.5C19—C20—H20119.9
H6A—C6—H6C109.5C19—C20—C21120.2 (5)
H6B—C6—H6C109.5H20—C20—C21119.9
O2—C7—N2119.0 (4)C20—C21—H21119.3
O2—C7—C8124.6 (5)C20—C21—C22121.4 (5)
N2—C7—C8116.3 (4)H21—C21—C22119.3
C7—C8—H8120.1C21—C22—H22120.3
C7—C8—C9119.7 (5)C21—C22—C23119.4 (4)
H8—C8—C9120.1H22—C22—C23120.3
C8—C9—H9119.7N4—C23—C22119.2 (5)
C8—C9—C10120.7 (5)N4—C23—C24116.5 (4)
H9—C9—C10119.7C22—C23—C24124.4 (4)
C9—C10—H10119.9C23—C24—H24A109.5
C9—C10—C11120.2 (5)C23—C24—H24B109.5
H10—C10—C11119.9C23—C24—H24C109.5
N2—C11—C10118.7 (5)H24A—C24—H24B109.5
N2—C11—C12116.2 (4)H24A—C24—H24C109.5
C10—C11—C12125.1 (4)H24B—C24—H24C109.5
C5—N1—C1—O1−179.1 (4)C17—N3—C13—O3175.4 (4)
C5—N1—C1—C2−0.4 (6)C17—N3—C13—C14−3.6 (7)
O1—C1—C2—C3177.7 (4)O3—C13—C14—C15−174.5 (5)
N1—C1—C2—C3−0.9 (6)N3—C13—C14—C154.5 (7)
C1—C2—C3—C41.3 (7)C13—C14—C15—C16−2.9 (8)
C2—C3—C4—C5−0.5 (8)C14—C15—C16—C170.2 (8)
C3—C4—C5—N1−0.9 (7)C15—C16—C17—N30.8 (7)
C3—C4—C5—C6178.7 (5)C15—C16—C17—C18−177.7 (5)
C1—N1—C5—C41.3 (7)C13—N3—C17—C161.1 (7)
C1—N1—C5—C6−178.3 (4)C13—N3—C17—C18179.7 (5)
C11—N2—C7—O2180.0 (4)C23—N4—C19—O4178.2 (4)
C11—N2—C7—C82.1 (7)C23—N4—C19—C20−1.5 (7)
O2—C7—C8—C9−178.5 (5)O4—C19—C20—C21−178.7 (5)
N2—C7—C8—C9−0.7 (7)N4—C19—C20—C210.9 (7)
C7—C8—C9—C10−1.4 (8)C19—C20—C21—C220.5 (7)
C8—C9—C10—C112.4 (8)C20—C21—C22—C23−1.5 (8)
C9—C10—C11—N2−1.1 (7)C21—C22—C23—N41.0 (7)
C9—C10—C11—C12178.9 (5)C21—C22—C23—C24−178.4 (5)
C7—N2—C11—C10−1.2 (7)C19—N4—C23—C220.5 (7)
C7—N2—C11—C12178.8 (4)C19—N4—C23—C24179.9 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N···O2i0.93 (2)1.90 (2)2.816 (5)167 (4)
N2—H2N···O10.91 (2)1.90 (2)2.795 (5)168 (4)
N3—H3N···O3ii0.89 (2)1.95 (3)2.806 (5)161 (4)
N4—H4N···O4iii0.90 (2)1.89 (2)2.783 (5)174 (5)
Symmetry codes: (i) x−1, y, z; (ii) x+1/2, −y+1/2, −z+1; (iii) x−1/2, −y+3/2, −z+1.

Experimental details

Crystal data
Chemical formulaC6H7NO
Mr109.13
Crystal system, space groupOrthorhombic, P212121
Temperature (K)120
a, b, c (Å)7.5229 (17), 13.083 (3), 22.149 (5)
V (Å3)2180.0 (9)
Z16
Radiation typeSynchrotron, λ = 0.6768 Å
µ (mm−1)0.09
Crystal size (mm)0.20 × 0.02 × 0.01
Data collection
DiffractometerBruker APEX2 CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.982, 0.999
No. of measured, independent and
observed [I > 2σ(I)] reflections		16261, 2202, 1474
Rint0.128
(sin θ/λ)max (Å−1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.128, 1.05
No. of reflections2202
No. of parameters306
No. of restraints4
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.24, −0.23

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SAINT, SHELXTL (Sheldrick, 2001), SHELXTL and Mercury (Version 1.3; Bruno et al., 2002), SHELXTL and local programs.

Selected bond lengths (Å) top
O1—C11.270 (5)C1—C21.430 (7)
O2—C71.263 (5)C2—C31.368 (7)
O3—C131.268 (6)C3—C41.400 (7)
O4—C191.247 (6)C4—C51.342 (7)
N1—C11.372 (6)C5—C61.512 (7)
N1—C51.371 (6)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N···O2i0.93 (2)1.90 (2)2.816 (5)167 (4)
N2—H2N···O10.91 (2)1.90 (2)2.795 (5)168 (4)
N3—H3N···O3ii0.89 (2)1.95 (3)2.806 (5)161 (4)
N4—H4N···O4iii0.90 (2)1.89 (2)2.783 (5)174 (5)
Symmetry codes: (i) x−1, y, z; (ii) x+1/2, −y+1/2, −z+1; (iii) x−1/2, −y+3/2, −z+1.
 

Acknowledgements

The authors thank Dr R. W. Harrington, Mr L. Russo and Mr Z. Yuan for assistance with data collection and processing as part of the EPSRC National X-ray Crystallography Service at Station 9.8, SRS, Daresbury, England. The authors also thank the EPSRC for funding and the CCLRC for synchrotron beam-time allocation.

References

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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Volume 61| Part 6| June 2005| Pages o383-o385
doi:10.1107/S0108270105012485
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