Molecules of the title compounds, 3′-methylacetanilide [or
N-(
m-tolyl)acetamide], C
9H
11NO, (I), and
N-benzylthioacetamide, C
9H
11NS, (II), are connected by a framework of intermolecular N—H
O and N—H
S hydrogen bonds, respectively, forming chains with the graph-set description
C(4), which run along the
b axis. Analyses of the crystal structures of (I) and (II) are helpful in the elucidation of a generation mechanism of the IR spectra of hydrogen-bonded molecular crystals. The correlation between the IR spectra of studied compounds and structural data is also discussed.
Supporting information
CCDC references: 710753; 710754
3'-Methylacetanilide, (I), was purchased from Sigma–Aldrich (98% pure). White
plate-shaped crystals suitable for diffraction analysis were obtained by slow
evaporation of an ethanol–acetone solution at 281 K.
N-Benzylthioacetamide, (II), was obtained by the reaction of
N-benzylacetamide with phosphorus pentasulfide. Phosphorus pentasulfide
(0.61 g, 0.1 mol) was added in small portions to a solution of
N-benzylacetamide (2.06 g, 0.5 mol) in toluene (5.50 ml) at 343–353 K
with stirring. The reaction mixture was then brought to reflux for 2 h. After
heating, the hot reaction mixture was decanted and the solution concentrated
to give a yellow precipitate. The precipitate was dissolved in petroleum ether
and the solution left for crystallization at room temperature. Single crystals
of (II) suitable for X-ray diffraction analysis were obtained by a slow
evaporation of a diethyl ether–acetone solution [yield: 1.55 g, 67.83%; m.p.
338–339 K, literature m.p. 338 K (Schlatter, 1942)]. The IR spectra of
polycrystalline samples of (I) and (II) dispersed in KBr were measured by the
transmission method at room temperature using an FT–IR Nicolet Magna 560
spectrometer with a resolution of 2 cm-1.
For (I), some of the H atoms were located in a difference Fourier map and were
refined freely; other H atoms were introduced in geometrically idealized
positions and refined with an appropriate riding model, with C—H = 0.95
(aromatic C) or 0.98Å (methyl C). The isotropic displacement parameters were
constrained with Uiso(H) values of 1.2Ueq(C) for H atoms in
CH groups and 1.5Ueq(C) for the methyl H atoms. For (II), some of the
H atoms were located in a difference Fourier map and were refined freely;
other H atoms were introduced in geometrically idealized positions and refined
with an appropriate riding model, with C—H = 0.95 (aromatic), 0.99
(methylene) or 0.98Å (methyl). The isotropic displacement parameters were
constrained with Uiso(H) values of 1.2Ueq(C) for H atoms in CH and
CH2 groups and 1.5Ueq(C) for the methyl H atoms.
For both compounds, data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2008).
(I) 3'-Methylacetanilide
top
Crystal data top
C9H11NO | F(000) = 320 |
Mr = 149.19 | Dx = 1.188 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4166 reflections |
a = 12.280 (3) Å | θ = 3.4–32.7° |
b = 9.4471 (19) Å | µ = 0.08 mm−1 |
c = 7.3028 (15) Å | T = 100 K |
β = 99.97 (3)° | Plate, colourless |
V = 834.4 (3) Å3 | 0.4 × 0.4 × 0.07 mm |
Z = 4 | |
Data collection top
Oxford Diffraction KM-4-CCD Sapphire3 diffractometer | 1965 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.029 |
Graphite monochromator | θmax = 32.8°, θmin = 3.4° |
Detector resolution: 16.0328 pixels mm-1 | h = −18→18 |
ω scans | k = −10→14 |
7872 measured reflections | l = −9→10 |
2807 independent reflections | |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.135 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0879P)2 + 0.0298P] where P = (Fo2 + 2Fc2)/3 |
2807 reflections | (Δ/σ)max = 0.001 |
105 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
Crystal data top
C9H11NO | V = 834.4 (3) Å3 |
Mr = 149.19 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.280 (3) Å | µ = 0.08 mm−1 |
b = 9.4471 (19) Å | T = 100 K |
c = 7.3028 (15) Å | 0.4 × 0.4 × 0.07 mm |
β = 99.97 (3)° | |
Data collection top
Oxford Diffraction KM-4-CCD Sapphire3 diffractometer | 1965 reflections with I > 2σ(I) |
7872 measured reflections | Rint = 0.029 |
2807 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.135 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | Δρmax = 0.34 e Å−3 |
2807 reflections | Δρmin = −0.24 e Å−3 |
105 parameters | |
Special details top
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 | x | y | z | Uiso*/Ueq | |
O1 | −0.02585 (6) | 0.73920 (8) | 0.14590 (10) | 0.02283 (19) | |
N1 | 0.05229 (7) | 0.95381 (9) | 0.22691 (12) | 0.01784 (19) | |
H1 | 0.0399 (10) | 1.0377 (14) | 0.2722 (18) | 0.021* | |
C1 | 0.15971 (8) | 0.93353 (10) | 0.18758 (13) | 0.0171 (2) | |
C2 | 0.23887 (9) | 1.03419 (11) | 0.26142 (14) | 0.0198 (2) | |
H2 | 0.2186 | 1.1085 | 0.3366 | 0.024* | |
C3 | 0.34665 (9) | 1.02751 (11) | 0.22684 (15) | 0.0218 (2) | |
C4 | 0.37505 (9) | 0.91664 (12) | 0.11781 (15) | 0.0223 (2) | |
H4 | 0.4484 | 0.9100 | 0.0933 | 0.027* | |
C5 | 0.29710 (9) | 0.81616 (11) | 0.04498 (14) | 0.0216 (2) | |
H5 | 0.3179 | 0.7413 | −0.0287 | 0.026* | |
C6 | 0.18906 (9) | 0.82308 (11) | 0.07795 (14) | 0.0194 (2) | |
H6 | 0.1361 | 0.7541 | 0.0270 | 0.023* | |
C7 | 0.42999 (10) | 1.13762 (14) | 0.30661 (19) | 0.0320 (3) | |
H7A | 0.3971 | 1.2320 | 0.2850 | 0.048* | |
H7B | 0.4951 | 1.1307 | 0.2463 | 0.048* | |
H7C | 0.4520 | 1.1219 | 0.4406 | 0.048* | |
C8 | −0.03272 (8) | 0.86013 (11) | 0.20571 (13) | 0.0176 (2) | |
C9 | −0.13768 (9) | 0.91364 (12) | 0.26136 (14) | 0.0216 (2) | |
H9A | −0.1970 | 0.9140 | 0.1526 | 0.032* | |
H9B | −0.1261 | 1.0101 | 0.3103 | 0.032* | |
H9C | −0.1584 | 0.8517 | 0.3574 | 0.032* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0271 (4) | 0.0175 (4) | 0.0245 (4) | −0.0038 (3) | 0.0063 (3) | −0.0021 (3) |
N1 | 0.0199 (4) | 0.0150 (4) | 0.0191 (4) | −0.0002 (3) | 0.0049 (3) | −0.0019 (3) |
C1 | 0.0195 (5) | 0.0167 (4) | 0.0152 (4) | 0.0003 (3) | 0.0036 (3) | 0.0024 (3) |
C2 | 0.0235 (5) | 0.0179 (5) | 0.0181 (5) | −0.0013 (4) | 0.0044 (4) | −0.0015 (4) |
C3 | 0.0220 (5) | 0.0208 (5) | 0.0224 (5) | −0.0028 (4) | 0.0031 (4) | 0.0021 (4) |
C4 | 0.0206 (5) | 0.0246 (5) | 0.0227 (5) | 0.0018 (4) | 0.0060 (4) | 0.0026 (4) |
C5 | 0.0242 (5) | 0.0210 (5) | 0.0202 (5) | 0.0039 (4) | 0.0056 (4) | 0.0001 (4) |
C6 | 0.0224 (5) | 0.0172 (5) | 0.0183 (4) | −0.0002 (4) | 0.0027 (4) | −0.0006 (3) |
C7 | 0.0256 (6) | 0.0312 (6) | 0.0389 (7) | −0.0088 (5) | 0.0045 (5) | −0.0052 (5) |
C8 | 0.0211 (5) | 0.0178 (5) | 0.0137 (4) | 0.0000 (4) | 0.0024 (3) | 0.0027 (3) |
C9 | 0.0217 (5) | 0.0219 (5) | 0.0213 (5) | −0.0006 (4) | 0.0039 (4) | 0.0025 (4) |
Geometric parameters (Å, º) top
O1—C8 | 1.2312 (13) | C4—H4 | 0.9500 |
N1—C8 | 1.3568 (13) | C5—C6 | 1.3904 (15) |
N1—C1 | 1.4109 (14) | C5—H5 | 0.9500 |
N1—H1 | 0.882 (13) | C6—H6 | 0.9500 |
C1—C2 | 1.3995 (14) | C7—H7A | 0.9800 |
C1—C6 | 1.3999 (14) | C7—H7B | 0.9800 |
C2—C3 | 1.3912 (15) | C7—H7C | 0.9800 |
C2—H2 | 0.9500 | C8—C9 | 1.5046 (15) |
C3—C4 | 1.3960 (15) | C9—H9A | 0.9800 |
C3—C7 | 1.5041 (16) | C9—H9B | 0.9800 |
C4—C5 | 1.3870 (16) | C9—H9C | 0.9800 |
| | | |
C8—N1—C1 | 128.04 (9) | C5—C6—C1 | 118.82 (9) |
C8—N1—H1 | 116.8 (8) | C5—C6—H6 | 120.6 |
C1—N1—H1 | 115.2 (8) | C1—C6—H6 | 120.6 |
C2—C1—C6 | 119.76 (9) | C3—C7—H7A | 109.5 |
C2—C1—N1 | 116.16 (9) | C3—C7—H7B | 109.5 |
C6—C1—N1 | 124.06 (9) | H7A—C7—H7B | 109.5 |
C3—C2—C1 | 121.23 (9) | C3—C7—H7C | 109.5 |
C3—C2—H2 | 119.4 | H7A—C7—H7C | 109.5 |
C1—C2—H2 | 119.4 | H7B—C7—H7C | 109.5 |
C2—C3—C4 | 118.50 (10) | O1—C8—N1 | 123.17 (9) |
C2—C3—C7 | 120.21 (10) | O1—C8—C9 | 121.48 (9) |
C4—C3—C7 | 121.29 (10) | N1—C8—C9 | 115.35 (9) |
C5—C4—C3 | 120.54 (10) | C8—C9—H9A | 109.5 |
C5—C4—H4 | 119.7 | C8—C9—H9B | 109.5 |
C3—C4—H4 | 119.7 | H9A—C9—H9B | 109.5 |
C4—C5—C6 | 121.15 (10) | C8—C9—H9C | 109.5 |
C4—C5—H5 | 119.4 | H9A—C9—H9C | 109.5 |
C6—C5—H5 | 119.4 | H9B—C9—H9C | 109.5 |
| | | |
C8—N1—C1—C2 | −165.66 (9) | C7—C3—C4—C5 | −179.86 (10) |
C8—N1—C1—C6 | 15.95 (16) | C3—C4—C5—C6 | 0.13 (16) |
C6—C1—C2—C3 | 0.51 (15) | C4—C5—C6—C1 | −0.33 (15) |
N1—C1—C2—C3 | −177.95 (9) | C2—C1—C6—C5 | 0.02 (15) |
C1—C2—C3—C4 | −0.71 (15) | N1—C1—C6—C5 | 178.35 (9) |
C1—C2—C3—C7 | 179.54 (10) | C1—N1—C8—O1 | −0.09 (16) |
C2—C3—C4—C5 | 0.39 (15) | C1—N1—C8—C9 | 179.68 (9) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.882 (13) | 2.011 (14) | 2.8882 (12) | 172.3 (12) |
Symmetry code: (i) −x, y+1/2, −z+1/2. |
(II) N-benzylthioacetamide
top
Crystal data top
C9H11NS | F(000) = 352 |
Mr = 165.25 | Dx = 1.238 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 6508 reflections |
a = 5.5957 (11) Å | θ = 3.3–25.0° |
b = 8.2201 (16) Å | µ = 0.30 mm−1 |
c = 19.278 (4) Å | T = 95 K |
V = 886.7 (3) Å3 | Needle, colourless |
Z = 4 | 0.6 × 0.15 × 0.14 mm |
Data collection top
Oxford Diffraction KM-4-CCD Sapphire3 diffractometer | 1557 independent reflections |
Radiation source: fine-focus sealed tube | 1496 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.061 |
Detector resolution: 16.0328 pixels mm-1 | θmax = 25.0°, θmin = 3.3° |
ω scans | h = −6→3 |
Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2006); nalytical numeric absorption
correction using a multifaceted crystal model based on expressions derived
by Clark & Reid (1995)] | k = −9→9 |
Tmin = 0.974, Tmax = 0.990 | l = −22→22 |
5596 measured reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.021 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.066 | w = 1/[σ2(Fo2) + (0.0483P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.00 | (Δ/σ)max = 0.001 |
1557 reflections | Δρmax = 0.13 e Å−3 |
104 parameters | Δρmin = −0.19 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 618 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.01 (6) |
Crystal data top
C9H11NS | V = 886.7 (3) Å3 |
Mr = 165.25 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.5957 (11) Å | µ = 0.30 mm−1 |
b = 8.2201 (16) Å | T = 95 K |
c = 19.278 (4) Å | 0.6 × 0.15 × 0.14 mm |
Data collection top
Oxford Diffraction KM-4-CCD Sapphire3 diffractometer | 1557 independent reflections |
Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2006); nalytical numeric absorption
correction using a multifaceted crystal model based on expressions derived
by Clark & Reid (1995)] | 1496 reflections with I > 2σ(I) |
Tmin = 0.974, Tmax = 0.990 | Rint = 0.061 |
5596 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.021 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.066 | Δρmax = 0.13 e Å−3 |
S = 1.00 | Δρmin = −0.19 e Å−3 |
1557 reflections | Absolute structure: Flack (1983), 618 Friedel pairs |
104 parameters | Absolute structure parameter: −0.01 (6) |
0 restraints | |
Special details top
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 | x | y | z | Uiso*/Ueq | |
S1 | 0.63434 (6) | 0.96207 (4) | 0.223279 (17) | 0.02212 (13) | |
N1 | 1.0166 (2) | 0.76854 (14) | 0.21454 (5) | 0.0180 (3) | |
H1 | 1.109 (3) | 0.698 (2) | 0.2337 (8) | 0.022* | |
C1 | 0.9766 (2) | 0.66430 (16) | 0.09427 (7) | 0.0165 (3) | |
C2 | 1.1098 (2) | 0.62576 (16) | 0.03507 (7) | 0.0190 (3) | |
H2 | 1.2537 | 0.6829 | 0.0256 | 0.023* | |
C3 | 1.0327 (2) | 0.50387 (17) | −0.01021 (7) | 0.0217 (3) | |
H3 | 1.1237 | 0.4790 | −0.0504 | 0.026* | |
C4 | 0.8234 (2) | 0.41908 (17) | 0.00346 (7) | 0.0221 (3) | |
H4 | 0.7706 | 0.3363 | −0.0273 | 0.027* | |
C5 | 0.6914 (2) | 0.45616 (17) | 0.06246 (7) | 0.0216 (3) | |
H5 | 0.5488 | 0.3977 | 0.0721 | 0.026* | |
C6 | 0.7667 (2) | 0.57863 (16) | 0.10773 (7) | 0.0193 (3) | |
H6 | 0.6747 | 0.6035 | 0.1478 | 0.023* | |
C7 | 1.0591 (2) | 0.80248 (17) | 0.14085 (6) | 0.0196 (3) | |
H7A | 1.2320 | 0.8212 | 0.1334 | 0.024* | |
H7B | 0.9733 | 0.9033 | 0.1278 | 0.024* | |
C8 | 0.8409 (2) | 0.82857 (15) | 0.25267 (7) | 0.0182 (3) | |
C9 | 0.8330 (3) | 0.76823 (17) | 0.32645 (7) | 0.0229 (3) | |
H9A | 0.9716 | 0.6983 | 0.3353 | 0.034* | |
H9B | 0.6859 | 0.7059 | 0.3338 | 0.034* | |
H9C | 0.8363 | 0.8612 | 0.3583 | 0.034* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
S1 | 0.01793 (19) | 0.0210 (2) | 0.0274 (2) | 0.00247 (13) | −0.00427 (14) | −0.00280 (14) |
N1 | 0.0183 (6) | 0.0178 (6) | 0.0180 (6) | 0.0019 (5) | −0.0041 (5) | 0.0012 (4) |
C1 | 0.0158 (6) | 0.0165 (7) | 0.0171 (7) | 0.0031 (5) | −0.0020 (6) | 0.0040 (5) |
C2 | 0.0165 (6) | 0.0198 (6) | 0.0208 (7) | 0.0021 (6) | 0.0033 (6) | 0.0056 (5) |
C3 | 0.0252 (6) | 0.0227 (7) | 0.0171 (7) | 0.0053 (6) | 0.0043 (5) | 0.0011 (5) |
C4 | 0.0251 (7) | 0.0205 (7) | 0.0208 (7) | 0.0023 (5) | −0.0032 (6) | −0.0039 (5) |
C5 | 0.0171 (7) | 0.0234 (7) | 0.0245 (7) | −0.0019 (6) | 0.0007 (5) | −0.0012 (6) |
C6 | 0.0154 (6) | 0.0228 (7) | 0.0198 (7) | 0.0021 (5) | 0.0036 (5) | 0.0003 (6) |
C7 | 0.0181 (6) | 0.0229 (7) | 0.0178 (7) | −0.0021 (6) | 0.0015 (5) | 0.0010 (6) |
C8 | 0.0191 (6) | 0.0136 (6) | 0.0219 (7) | −0.0051 (6) | −0.0037 (6) | −0.0040 (5) |
C9 | 0.0292 (8) | 0.0207 (7) | 0.0189 (7) | −0.0021 (6) | 0.0007 (6) | −0.0017 (5) |
Geometric parameters (Å, º) top
S1—C8 | 1.6917 (14) | C4—C5 | 1.390 (2) |
N1—C8 | 1.3230 (17) | C4—H4 | 0.9500 |
N1—C7 | 1.4669 (17) | C5—C6 | 1.3974 (19) |
N1—H1 | 0.858 (16) | C5—H5 | 0.9500 |
C1—C6 | 1.3938 (19) | C6—H6 | 0.9500 |
C1—C2 | 1.3994 (19) | C7—H7A | 0.9900 |
C1—C7 | 1.5197 (19) | C7—H7B | 0.9900 |
C2—C3 | 1.397 (2) | C8—C9 | 1.507 (2) |
C2—H2 | 0.9500 | C9—H9A | 0.9800 |
C3—C4 | 1.3883 (19) | C9—H9B | 0.9800 |
C3—H3 | 0.9500 | C9—H9C | 0.9800 |
| | | |
C8—N1—C7 | 125.98 (12) | C1—C6—C5 | 120.12 (12) |
C8—N1—H1 | 117.4 (10) | C1—C6—H6 | 119.9 |
C7—N1—H1 | 116.5 (11) | C5—C6—H6 | 119.9 |
C6—C1—C2 | 119.09 (13) | N1—C7—C1 | 112.39 (11) |
C6—C1—C7 | 121.56 (12) | N1—C7—H7A | 109.1 |
C2—C1—C7 | 119.30 (12) | C1—C7—H7A | 109.1 |
C3—C2—C1 | 120.49 (13) | N1—C7—H7B | 109.1 |
C3—C2—H2 | 119.8 | C1—C7—H7B | 109.1 |
C1—C2—H2 | 119.8 | H7A—C7—H7B | 107.9 |
C4—C3—C2 | 120.14 (13) | N1—C8—C9 | 115.07 (12) |
C4—C3—H3 | 119.9 | N1—C8—S1 | 124.30 (11) |
C2—C3—H3 | 119.9 | C9—C8—S1 | 120.63 (10) |
C3—C4—C5 | 119.56 (13) | C8—C9—H9A | 109.5 |
C3—C4—H4 | 120.2 | C8—C9—H9B | 109.5 |
C5—C4—H4 | 120.2 | H9A—C9—H9B | 109.5 |
C4—C5—C6 | 120.59 (12) | C8—C9—H9C | 109.5 |
C4—C5—H5 | 119.7 | H9A—C9—H9C | 109.5 |
C6—C5—H5 | 119.7 | H9B—C9—H9C | 109.5 |
| | | |
C6—C1—C2—C3 | 0.45 (19) | C4—C5—C6—C1 | −0.4 (2) |
C7—C1—C2—C3 | −177.31 (12) | C8—N1—C7—C1 | −102.17 (15) |
C1—C2—C3—C4 | −0.4 (2) | C6—C1—C7—N1 | 39.01 (17) |
C2—C3—C4—C5 | −0.1 (2) | C2—C1—C7—N1 | −143.30 (12) |
C3—C4—C5—C6 | 0.5 (2) | C7—N1—C8—C9 | 177.61 (11) |
C2—C1—C6—C5 | −0.04 (19) | C7—N1—C8—S1 | −1.87 (19) |
C7—C1—C6—C5 | 177.66 (12) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···S1i | 0.858 (16) | 2.554 (17) | 3.4056 (13) | 171.8 (15) |
Symmetry code: (i) −x+2, y−1/2, −z+1/2. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C9H11NO | C9H11NS |
Mr | 149.19 | 165.25 |
Crystal system, space group | Monoclinic, P21/c | Orthorhombic, P212121 |
Temperature (K) | 100 | 95 |
a, b, c (Å) | 12.280 (3), 9.4471 (19), 7.3028 (15) | 5.5957 (11), 8.2201 (16), 19.278 (4) |
α, β, γ (°) | 90, 99.97 (3), 90 | 90, 90, 90 |
V (Å3) | 834.4 (3) | 886.7 (3) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.08 | 0.30 |
Crystal size (mm) | 0.4 × 0.4 × 0.07 | 0.6 × 0.15 × 0.14 |
|
Data collection |
Diffractometer | Oxford Diffraction KM-4-CCD Sapphire3 diffractometer | Oxford Diffraction KM-4-CCD Sapphire3 diffractometer |
Absorption correction | – | Analytical [CrysAlis RED (Oxford Diffraction, 2006); nalytical numeric absorption
correction using a multifaceted crystal model based on expressions derived
by Clark & Reid (1995)] |
Tmin, Tmax | – | 0.974, 0.990 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7872, 2807, 1965 | 5596, 1557, 1496 |
Rint | 0.029 | 0.061 |
(sin θ/λ)max (Å−1) | 0.762 | 0.596 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.135, 1.00 | 0.021, 0.066, 1.00 |
No. of reflections | 2807 | 1557 |
No. of parameters | 105 | 104 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.34, −0.24 | 0.13, −0.19 |
Absolute structure | ? | Flack (1983), 618 Friedel pairs |
Absolute structure parameter | ? | −0.01 (6) |
Selected geometric parameters (Å, º) for (I) topO1—C8 | 1.2312 (13) | C2—C3 | 1.3912 (15) |
N1—C8 | 1.3568 (13) | C3—C4 | 1.3960 (15) |
N1—C1 | 1.4109 (14) | C4—C5 | 1.3870 (16) |
N1—H1 | 0.882 (13) | C5—C6 | 1.3904 (15) |
C1—C2 | 1.3995 (14) | C8—C9 | 1.5046 (15) |
C1—C6 | 1.3999 (14) | | |
| | | |
C8—N1—C1—C2 | −165.66 (9) | C8—N1—C1—C6 | 15.95 (16) |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.882 (13) | 2.011 (14) | 2.8882 (12) | 172.3 (12) |
Symmetry code: (i) −x, y+1/2, −z+1/2. |
Selected geometric parameters (Å, º) for (II) topS1—C8 | 1.6917 (14) | C2—C3 | 1.397 (2) |
N1—C8 | 1.3230 (17) | C3—C4 | 1.3883 (19) |
N1—C7 | 1.4669 (17) | C4—C5 | 1.390 (2) |
C1—C6 | 1.3938 (19) | C5—C6 | 1.3974 (19) |
C1—C2 | 1.3994 (19) | C8—C9 | 1.507 (2) |
C1—C7 | 1.5197 (19) | | |
| | | |
C6—C1—C7—N1 | 39.01 (17) | C2—C1—C7—N1 | −143.30 (12) |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···S1i | 0.858 (16) | 2.554 (17) | 3.4056 (13) | 171.8 (15) |
Symmetry code: (i) −x+2, y−1/2, −z+1/2. |
3'-Methylacetanilide, (I), and the sulfur analogue N-(m-tolyl)thioacetamide, as well as N-benzylthioacetamide, (II), and the oxygen analogue N-benzylacetamide, have been the subject of our studies for a generation mechanism of the IR spectra of hydrogen-bonded molecular crystals [please clarify]. The theoretical analysis of (I) and (II) and of their analogues N-(m-tolyl)thioacetamide and N-benzylacetamide, respectively, preceded by measurement of the IR spectra of polycrystalline and monocrystalline samples, concerned characteristic isotopic and spectroscopic effects, e.g. linear dichroic effects, self-organization and temperature effects. These effects were observed in the solid-state IR spectra of hydrogen and deuterium bonds at the frequency ranges of the νN—H and νN—D bands, respectively. Some spectacular effects are especially visible for those systems where the proton acceptor is sulfur or oxygen (Flakus et al., 2003, 2004, 2005, 2006, 2007). Accordingly, for a reliable interpretation of the isotopic and spectroscopic effects, determination of the crystal structure (I) and (II) is indispensable. In the case of N-(m-tolyl)thioacetamide (Śmiszek-Lindert et al., 2007a) and N-benzylacetamide (Śmiszek-Lindert et al., 2007b), crystallographic studies have been reported previously.
Compound (I) crystallizes with one molecule in the asymmetric unit cell (Fig. 1). In each molecule, the six-membered ring (C1–C6) form a planar skeleton, with r.m.s. deviations from the mean plane of 0.0023Å; atoms O1, C8, C9 are significantly out of the benzene ring plane by 0.5411 (13), 0.2385 (13) and 0.1325 (16)Å, respectively. The benzene ring is not coplanar with the CO–NH plane [torsion angles: C8—N1—C1—C2 = -165.66 (9)° and C8—N1—C1—C6 = 15.95 (16)°]. The dihedral angle between the plane of the benzene ring and the plane of the –CO–NH– group is 14.89 (10)°. Moreover, in the molecule of (I), the –CO–NH– group adopts a trans conformation. By comparison, in the molecule N-(m-tolyl)thioacetamide, the –CS–NH– group also adopts a trans conformation. However, different from (I), the –CS–NH– group is twisted out of the benzene ring plane [torsion angles: C8—N1—C1—C2 = 135.02 (15)° and C8—N1—C1—C6 = -47.40 (2)°]. The dihedral angle between the plane of the benzene ring and the plane of the –CS–NH– group is 48.35(0.12)° (Śmiszek-Lindert et al., 2007a). This is very surprising because in the literature the trans acetanilides and thioacetanilides have planar main skeletons with the amide and thioamide groups lying in the plane of the aromatic ring. The deviations from planarity are smaller than 3° (Galabov et al., 2003). The length of the C8═O1 bond [1.2312 (13)Å] is very similar to that of the corresponding bond [1.230 (9)Å] in the analogous compound 4'-methylacetanilide (Haisa et al., 1977) and these values are both different for bonds of this type [average value 1.224 (1)Å; Allen et al., 1997]. The elongation of the C═O bond lengths is connected with electron shift accompanying formation of an intermolecular N—H···O hydrogen bond. The length of the C8—N1 single bond [1.3568 (13)Å] is typical for bonds of this type [average value 1.351 (1)Å; Allen et al., 1997]. The C—N bond length differs slightly from the values found in similar structures, for example, p-aminoacetanilide [1.344 (4)Å; Haisa et al., 1977], 4'-methylacetanilide [1.349 (3)Å; Haisa et al., 1977], p-hydroxyacetanilide [1.341 (6)Å; Haisa et al., 1974], and other amide derivatives, such as acetanilide (1.330Å; Brown & Corbridge, 1954) or trans-N-phenylformamide [1.3359 (18)Å; Omondi et al., 2008]. The C1—N1 single bond is shortened [Table 1; average value 1.4260Å; Allen et al. (1987)], but this shortening always occurs when an N atom is attached to a benzene ring; a summary of corresponding lengths in other compounds has already been reported (Brown, 1949). The sum of the angles around the amide N atom is 360°, which indicates that the geometry around this atom is trigonal planar (sp2-hybridization). An almost identical angle sum [359.87°] around the thioamide N atom is observed in the case of N-(m-tolyl)thioacetamide (Śmiszek-Lindert et al., 2007a).
The crystal structure of (I) is stabilized by intermolecular N—H···O hydrogen bonds (Fig. 2). Atom N1 of the NH group in the molecule at (x, y, z) acts as a hydrogen-bond donor via atom H1 to carbonyl atom O1 of the molecule at (-x, y+1/2, 1/2-z) (Fig. 3). These interactions form a zigzag chain running parallel to the [010] direction with graph-set motif C11(4) (Bernstein et al., 1995; Etter et al., 1990). The same graph-set motif is found in N-(m-tolyl)thioacetamide (Śmiszek-Lindert et al., 2007a).
The IR spectrum of a polycrystalline sample of (I) is shown in Fig. 4. The values of the H···O and N···O distances, as well the N—H···O angle (Table 2), characterize this as a medium-strength hydrogen bond (Desiraju & Steiner, 1999; Steiner, 2002). The strength of the hydrogen bond in (I) is supported by spectroscopic measurements. Analysis of the IR spectrum of (I) shows that the band of the isolated N—H stretching vibration, νN—H, is located in the frequency range 3380–2900 cm-1, with the centre of gravity at ca 3198 cm-1. In not associated compounds [please clarify], this band lies at 3400 cm-1, e.g. the νN—H band in 3'-methylacetanilide is shifted towards the lower frequencies by about ca 202 cm-1, or 6%. This relative shift is larger than 5% and is characteristic of a medium-strength hydrogen bond (Desiraju & Steiner, 1999). The N—H···O hydrogen bond has an N···O distance of 2.8882 (12)Å, shorter than the values of 2.935 (3), 3.088 (4) and 2.904 (8)Å found in acetanilide (Johnson et al., 1995), p-aminoacetanilide (Haisa et al., 1977) and 4'-methylacetanilide (Haisa et al., 1977), respectively. The N—H···O angle of (I) is almost linear, as is also the case in acetanilide [172.3 (4)°; Johnson et al., 1995].
The molecule of (II) with the atom-labelling scheme is shown in Fig. 5. As revealed by X-ray structure analysis, the molecule of (II) is not planar. The –CS—NH– group is twisted out of the benzene ring plane [torsion angles: C2—C1—C7—N1 = -143.30 (12)° and C6—C1—C7—N1 = 39.01 (17)°]. The dihedral angle between the plane of the benzene ring and the plane of the –CS—NH– group is 86.30 (7)°. Nevertheless, the –CH2– group directly attached to the benzene ring is almost coplanar with it, as shown by the relevant torsion angles [C7–C1–C2–C3 = -177.31 (12)° and C7–C1–C6–C5 = 177.66 (12)°]. The C8═S1 bond (Table 3) is approximately 0.04Å longer than the average C═S double-bond length of 1.654 (2)Å (Allen et al., 1997) and also longer than in thioamide compounds studied previously by us, for example N-(m-tolyl)thioacetamide [1.6565 (15)Å; Śmiszek-Lindert et al., 2007a], N-(p-tolyl)thioacetamide [1.6723 (12)Å; Śmiszek-Lindert et al., 2007c], N-benzylthioformamide [1.6652 (11)Å; Śmiszek-Lindert et al., 2007d], N-methylthiobenzamide [1.6630 (2)Å; Śmiszek-Lindert et al., 2007e]. The lengthening of the C═S double bond is probably connected withan electron shift accompanying the formation of the N—H···S hydrogen bond. The C8—N1 single-bond length in N-benzylthioacetamide is consistent with the average value found in the fragment X2C═S (X = C, N, O or S) of 1.322 (2)Å (Allen et al.,1997). The average value is very close to the values found in similar structures, i.e. thioacetanilide (Michta et al., 2008), N-methylthioacetamide (Flakus et al., 2007), N-(2-hydroxyethyl)-2-thiofuramide (Galešić et al., 1987) or N-(m-tolyl)thioacetamide (Śmiszek-Lindertet et al., 2007a). The value of the C═S bond distance of 1.61Å is cited in the literature as representing 100% double-bond character, e.g. thioformaldehyde, in the gas phase (Johnson et al., 1971). Moreover, C═S bond lengths of ca 1.74Å are cited as representing ca 50% double-bond character, as in the case of dithiolate anions (Johnson et al., 1971; Fausto et al., 1989).
In the crystal structure, molecules of (II) are linked by a single N—H···S hydrogen bond into infinite zigzag chains which run parallel to the [010] direction. An intermolecular N—H···S hydrogen bond between donor atom N1 and acceptor atom S1 can be described by the graph-set motif C11(4) (Bernstein et al., 1995; Etter et al., 1990) (Fig. 6). Atom N1 in the molecule at (x, y, z) acts as an intermolecular hydrogen-bond donor via atom H1 to atom S1 at (2-x, y-1/2, 1/2-z). The values of the H···S, N···S distances and the N—H···S angle (Table 4) characterize this as a weak hydrogen bond (Desiraju & Steiner, 1999; Steiner, 2002). The strength of the hydrogen bonds in this compound was also investigated by IR spectroscopy. The νN—H proton-stretching band covers the range 3300–2990 cm-1 (Fig. 7), with the centre of gravity at ca 3140 cm-1. This band is shifted towards the lower frequencies by ca 260 cm-1, or 8%. This relative shift is larger than 5% and is characteristic for a medium-strength hydrogen bond (Desiraju & Steiner, 1999).
Knowledge of the hydrogen-bond geometry in the molecular crystals of amides and thioamides enables us to interpret and understand isotopic and spectroscopic effects in IR spectra. Further studies on the polarized IR spectra of the title compounds and their isotopic derivatives will be carried out in the future.