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Crystals of the title compound, C10H9NO2, whose structure has already been determined four times by different research groups, were found to be twinned. Satisfactory refinement is only possible if the twinning is taken into account. This kind of twinning in the monoclinic crystal system can, in principle, occur if the following condition is met: a·|cosβ| = c/2, i.e. if the short diagonal of the ac plane is of the same length as a or c itself.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680101532X/cv6058sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S160053680101532X/cv6058Isup2.hkl
Contains datablock I

CCDC reference: 175993

Key indicators

  • Single-crystal X-ray study
  • T = 100 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.029
  • wR factor = 0.074
  • Data-to-parameter ratio = 13.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_420 Alert C D-H Without Acceptor N(1) - H(1) ?
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The structure of the title compound, (I), has already be determined (Karle et al., 1964; Chandrasekhar & Raghunathan, 1982; Pfeiffer et al., 1987; Nigovic et al., 2000), but none of the authors has described any twinning.

Surprisingly, we encountered a twinned crystal and satisfactory refinement was only possible when the correct twin law (101/010/001) was applied. This case of twinning is characterized by the fact that one of the face diagonals is of the same length as one of the axes bordering the face. As a result of that, the face diagonal can be an axis of the twin unit cell, whereas the other axis runs in its opposite direction. The present kind of twinning in the monoclinic crystal system can in principle occur if the following condition is met: a.cos(β) = c/2. The structure determinations of Chandrasekhar & Raghunathan (1982), Pfeiffer et al. (1987) and Nigovic et al. (2000) have led to acceptable results. However, Karle et al. (1964), who had used Equi-inclination Weissenberg photographs and zero-level precession photographs on a thin plate-like crystal to collect the diffracted intensities, ascribed the relatively high R value to the shape of the crystal and to the difficulty to estimate the density of the diffraction spots.

Experimental top

The title compound was purchased from Fluka and recrystallized from diethyl ether.

Refinement top

After having encountered severe problems during structure solution, anisotropic refinement remained stuck at R1 = 0.28. It was therefore assumed that the crystal was twinned and applying the twin law (101/010/001), which is equivalent to (101/010/001) provided the ultimate success (R1 dropped below 0.1). All H atoms could now be located by difference Fourier synthesis. They were refined with fixed individual displacement parameters [U(H) = 1.2Ueq(C)] using a riding model with C—H(aromatic) = 0.95 Å or CH(methylene) = 0.99 Å. H atoms bonded to N and O atoms were refined isotropically. The twin ratio refined to 0.416 (1)/0.584 (1).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990).

Figures top
[Figure 1] Fig. 1. Perspective view of (I) with the atom numbering; displacement ellipsoids are at the 50% probability level.
(I) top
Crystal data top
C10H9NO2F(000) = 368
Mr = 175.18Dx = 1.356 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 17.848 (2) ÅCell parameters from 10779 reflections
b = 5.2214 (7) Åθ = 1.7–26.5°
c = 9.568 (1) ŵ = 0.10 mm1
β = 105.70 (1)°T = 100 K
V = 858.39 (17) Å3Block, colourless
Z = 40.40 × 0.30 × 0.20 mm
Data collection top
Stoe IPDS-II two-circle
diffractometer
1476 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.050
Graphite monochromatorθmax = 26.4°, θmin = 2.2°
ω scansh = 2222
11341 measured reflectionsk = 66
1756 independent reflectionsl = 1111
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.029H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.074 w = 1/[σ2(Fo2) + (0.0454P)2 + 0.0141P]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max < 0.001
1756 reflectionsΔρmax = 0.12 e Å3
128 parametersΔρmin = 0.12 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.046 (5)
Crystal data top
C10H9NO2V = 858.39 (17) Å3
Mr = 175.18Z = 4
Monoclinic, P21/cMo Kα radiation
a = 17.848 (2) ŵ = 0.10 mm1
b = 5.2214 (7) ÅT = 100 K
c = 9.568 (1) Å0.40 × 0.30 × 0.20 mm
β = 105.70 (1)°
Data collection top
Stoe IPDS-II two-circle
diffractometer
1476 reflections with I > 2σ(I)
11341 measured reflectionsRint = 0.050
1756 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0290 restraints
wR(F2) = 0.074H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.12 e Å3
1756 reflectionsΔρmin = 0.12 e Å3
128 parameters
Special details top

Experimental. ;

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
N10.78667 (9)0.2286 (3)0.31213 (17)0.0508 (4)
H10.8077 (14)0.099 (5)0.276 (3)0.087 (8)*
C10.71228 (10)0.3206 (3)0.2555 (2)0.0492 (4)
H1A0.67520.25300.17300.059*
C20.70028 (9)0.5233 (3)0.33589 (18)0.0421 (4)
C30.77160 (8)0.5603 (3)0.44932 (16)0.0356 (3)
C40.79686 (9)0.7378 (3)0.56268 (19)0.0428 (4)
H40.76250.86760.57750.051*
C50.87205 (10)0.7234 (3)0.6530 (2)0.0496 (4)
H50.88890.84390.72940.060*
C60.92328 (9)0.5336 (3)0.6329 (2)0.0522 (4)
H60.97450.52640.69610.063*
C70.90057 (9)0.3563 (3)0.5222 (2)0.0491 (4)
H70.93550.22760.50840.059*
C80.82467 (9)0.3714 (3)0.43107 (19)0.0405 (4)
C90.62743 (9)0.6794 (3)0.3094 (2)0.0500 (4)
H9B0.59930.66810.20510.060*
H9A0.64200.86100.33110.060*
C100.57321 (8)0.6008 (3)0.39668 (18)0.0395 (3)
O10.58057 (7)0.4048 (2)0.46829 (14)0.0512 (3)
O20.51619 (7)0.7638 (2)0.38738 (15)0.0548 (3)
H20.4854 (14)0.697 (5)0.444 (3)0.084 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0638 (9)0.0389 (7)0.0580 (9)0.0064 (7)0.0308 (8)0.0095 (6)
C10.0536 (9)0.0515 (9)0.0460 (10)0.0176 (7)0.0192 (9)0.0014 (8)
C20.0411 (8)0.0452 (8)0.0453 (9)0.0084 (6)0.0207 (7)0.0063 (7)
C30.0362 (7)0.0326 (7)0.0442 (8)0.0049 (5)0.0213 (7)0.0033 (6)
C40.0470 (8)0.0353 (7)0.0546 (10)0.0013 (7)0.0281 (8)0.0027 (7)
C50.0511 (9)0.0454 (9)0.0553 (11)0.0147 (8)0.0197 (8)0.0075 (7)
C60.0379 (8)0.0556 (10)0.0629 (11)0.0063 (7)0.0134 (8)0.0063 (9)
C70.0423 (8)0.0414 (8)0.0700 (12)0.0062 (7)0.0263 (9)0.0061 (8)
C80.0461 (8)0.0303 (7)0.0525 (10)0.0047 (6)0.0259 (7)0.0012 (7)
C90.0401 (8)0.0579 (10)0.0551 (11)0.0036 (7)0.0181 (8)0.0168 (8)
C100.0331 (7)0.0454 (8)0.0397 (8)0.0040 (6)0.0093 (7)0.0057 (7)
O10.0438 (6)0.0571 (7)0.0582 (7)0.0055 (5)0.0233 (6)0.0199 (6)
O20.0484 (6)0.0542 (6)0.0688 (9)0.0067 (5)0.0278 (6)0.0212 (6)
Geometric parameters (Å, º) top
N1—C81.376 (2)C5—H50.9500
N1—C11.378 (2)C6—C71.382 (3)
N1—H10.89 (3)C6—H60.9500
C1—C21.359 (2)C7—C81.401 (2)
C1—H1A0.9500C7—H70.9500
C2—C31.445 (2)C9—C101.497 (2)
C2—C91.497 (2)C9—H9B0.9900
C3—C41.405 (2)C9—H9A0.9900
C3—C81.410 (2)C10—O11.2187 (18)
C4—C51.388 (2)C10—O21.3110 (19)
C4—H40.9500O2—H20.94 (3)
C5—C61.396 (2)
C8—N1—C1110.06 (14)C7—C6—H6119.5
C8—N1—H1124.9 (17)C5—C6—H6119.5
C1—N1—H1125.0 (17)C6—C7—C8118.21 (14)
C2—C1—N1109.37 (16)C6—C7—H7120.9
C2—C1—H1A125.3C8—C7—H7120.9
N1—C1—H1A125.3N1—C8—C7131.40 (14)
C1—C2—C3106.70 (14)N1—C8—C3106.51 (14)
C1—C2—C9126.21 (16)C7—C8—C3122.07 (15)
C3—C2—C9127.09 (15)C2—C9—C10114.78 (13)
C4—C3—C8118.09 (14)C2—C9—H9B108.6
C4—C3—C2134.52 (14)C10—C9—H9B108.6
C8—C3—C2107.36 (14)C2—C9—H9A108.6
C5—C4—C3119.93 (14)C10—C9—H9A108.6
C5—C4—H4120.0H9B—C9—H9A107.5
C3—C4—H4120.0O1—C10—O2123.14 (14)
C4—C5—C6120.77 (16)O1—C10—C9123.81 (14)
C4—C5—H5119.6O2—C10—C9113.04 (13)
C6—C5—H5119.6C10—O2—H2106.4 (14)
C7—C6—C5120.92 (16)
C8—N1—C1—C20.17 (18)C1—N1—C8—C7178.52 (16)
N1—C1—C2—C30.17 (17)C1—N1—C8—C30.09 (17)
N1—C1—C2—C9179.20 (14)C6—C7—C8—N1178.32 (16)
C1—C2—C3—C4177.99 (15)C6—C7—C8—C30.1 (2)
C9—C2—C3—C41.0 (3)C4—C3—C8—N1178.45 (12)
C1—C2—C3—C80.11 (15)C2—C3—C8—N10.01 (15)
C9—C2—C3—C8179.13 (14)C4—C3—C8—C70.3 (2)
C8—C3—C4—C50.2 (2)C2—C3—C8—C7178.78 (14)
C2—C3—C4—C5178.18 (16)C1—C2—C9—C1096.2 (2)
C3—C4—C5—C60.1 (2)C3—C2—C9—C1084.92 (19)
C4—C5—C6—C70.3 (3)C2—C9—C10—O110.3 (2)
C5—C6—C7—C80.2 (2)C2—C9—C10—O2170.32 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.94 (3)1.70 (3)2.6372 (16)172 (2)
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC10H9NO2
Mr175.18
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)17.848 (2), 5.2214 (7), 9.568 (1)
β (°) 105.70 (1)
V3)858.39 (17)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.40 × 0.30 × 0.20
Data collection
DiffractometerStoe IPDS-II two-circle
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
11341, 1756, 1476
Rint0.050
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.074, 1.01
No. of reflections1756
No. of parameters128
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.12, 0.12

Computer programs: X-AREA (Stoe & Cie, 2001), X-AREA, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1990).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.94 (3)1.70 (3)2.6372 (16)172 (2)
Symmetry code: (i) x+1, y+1, z+1.
 

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