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In situ cryocrystallization has been employed to grow single crystals of 4-methoxybenzaldehyde (anisaldehyde), C
8H
8O
2, 2-hydroxybenzaldehyde (salicylaldehyde), C
7H
6O
2, and (2
E)-3-phenylprop-2-enal (cinnamaldehyde), C
9H
8O, all of which are liquids at room temperature. Several weak C—H
O interactions of the types C
aryl—H
O, C
formyl—H
O and C
sp3—H
O are present in these related crystal structures.
Supporting information
CCDC references: 851739; 851740; 851741
Crystallization was performed on the diffractometer with a miniature
zone-melting procedure using focused infrared laser radiation, according to
Boese & Nussbaumer (1994). The respective temperatures of
crystallization were
263 K for (I), 253 K for (II) (Fluka) and 248 K for (III) (Fluka, 98%, lot No.
1222882 24005132). The low coverage of the reflection data resulted from the
orientation of the cylindrical crystal and the chosen scan mode, both due to
the in situ crystal-growing technique. Any other mounting of the
crystal or different scan mode would lead to melting of the crystals.
H atoms of the methoxy group were idealized with tetrahedral angles in a
combined rotating and rigid-group refinement, with C—H = 0.97 Å and with
Uiso(H) = 1.5Ueq(C). All other C-bound H atoms were refined
using a riding model starting from idealized geometries, with C—H = 0.96 Å
and with Uiso(H) = 1.2Ueq(C). [Please check added C–H
distances] The hydroxy H-atom position in (II) was taken from a Fourier
map and also refined as a riding atom, with Uiso(H) =
1.5Ueq(O).
For all compounds, data collection: APEX2 (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006); data reduction: APEX2 [or SAINT?] (Bruker, 2006); program(s) used to solve structure: APEX2 (Bruker, 2006); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).
(I) 4-methoxybenzaldehyde
top
Crystal data top
C8H8O2 | F(000) = 288 |
Mr = 136.14 | Dx = 1.296 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 637 reflections |
a = 4.970 (4) Å | θ = 2.6–22.8° |
b = 9.034 (9) Å | µ = 0.09 mm−1 |
c = 15.544 (14) Å | T = 203 K |
V = 697.9 (11) Å3 | Cylinder, colourless |
Z = 4 | 0.30 × 0.30 × 0.30 mm |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 705 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.069 |
Graphite monochromator | θmax = 24.0°, θmin = 2.6° |
Detector resolution: 512 pixels mm-1 | h = −3→3 |
Data collection strategy APEX 2/COSMO with chi = 0 scans | k = −10→3 |
2015 measured reflections | l = −17→17 |
885 independent 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)] = 0.036 | H-atom parameters constrained |
wR(F2) = 0.071 | w = 1/[σ2(Fo2) + (0.0204P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.94 | (Δ/σ)max < 0.001 |
885 reflections | Δρmax = 0.12 e Å−3 |
92 parameters | Δρmin = −0.13 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.012 (3) |
Crystal data top
C8H8O2 | V = 697.9 (11) Å3 |
Mr = 136.14 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 4.970 (4) Å | µ = 0.09 mm−1 |
b = 9.034 (9) Å | T = 203 K |
c = 15.544 (14) Å | 0.30 × 0.30 × 0.30 mm |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 705 reflections with I > 2σ(I) |
2015 measured reflections | Rint = 0.069 |
885 independent reflections | θmax = 24.0° |
Refinement top
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.071 | H-atom parameters constrained |
S = 0.94 | Δρmax = 0.12 e Å−3 |
885 reflections | Δρmin = −0.13 e Å−3 |
92 parameters | |
Special details top
Experimental. The crystallization was performed on the diffractometer at a temperature of 263 K with a miniature zone melting procedure using focused infrared-laser-
radiation according to (Boese, 1994). |
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. Treatment of hydrogen atoms Riding model on idealized geometrics
with the 1.2 fold isotropic displacement parameters of the equivalent
Uij of the corresponding carbon atom. The methyl groups are idealized
with tetrahedral angles in a combined rotating and rigid group refinement with
the 1.5 fold isotropic displacement parameters of the equivalent Uij
of the corresponding carbon atom. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 1.0019 (4) | −0.0164 (2) | 0.53640 (11) | 0.0593 (6) | |
C7 | 0.8823 (5) | −0.0842 (3) | 0.48084 (15) | 0.0464 (8) | |
H7 | 0.9283 | −0.1867 | 0.4739 | 0.056* | |
C1 | 0.6769 (5) | −0.0255 (3) | 0.42348 (13) | 0.0369 (7) | |
C2 | 0.5485 (6) | −0.1195 (3) | 0.36659 (14) | 0.0422 (7) | |
H2 | 0.5988 | −0.2220 | 0.3664 | 0.051* | |
C3 | 0.3539 (6) | −0.0705 (2) | 0.30975 (14) | 0.0391 (8) | |
H3 | 0.2692 | −0.1383 | 0.2707 | 0.047* | |
C4 | 0.2870 (5) | 0.0793 (3) | 0.31038 (14) | 0.0347 (7) | |
C5 | 0.4129 (6) | 0.1759 (3) | 0.36761 (14) | 0.0414 (7) | |
H5 | 0.3631 | 0.2786 | 0.3685 | 0.050* | |
C6 | 0.6059 (6) | 0.1246 (3) | 0.42320 (13) | 0.0419 (7) | |
H6 | 0.6969 | 0.1915 | 0.4614 | 0.050* | |
O2 | 0.1022 (3) | 0.14176 (18) | 0.25731 (9) | 0.0455 (6) | |
C8 | −0.0230 (6) | 0.0499 (3) | 0.19443 (14) | 0.0498 (8) | |
H8A | 0.1129 | 0.0015 | 0.1596 | 0.075* | |
H8B | −0.1371 | 0.1102 | 0.1579 | 0.075* | |
H8C | −0.1315 | −0.0244 | 0.2232 | 0.075* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0564 (15) | 0.0673 (13) | 0.0530 (9) | 0.0061 (12) | −0.0073 (10) | 0.0009 (10) |
C7 | 0.047 (2) | 0.0471 (17) | 0.0448 (14) | 0.0043 (15) | 0.0084 (13) | 0.0037 (13) |
C1 | 0.0349 (19) | 0.0400 (14) | 0.0357 (12) | 0.0009 (13) | 0.0065 (12) | 0.0024 (12) |
C2 | 0.048 (2) | 0.0338 (15) | 0.0450 (13) | 0.0046 (13) | 0.0095 (14) | 0.0012 (12) |
C3 | 0.044 (2) | 0.0339 (14) | 0.0395 (13) | −0.0029 (14) | 0.0022 (13) | −0.0050 (11) |
C4 | 0.032 (2) | 0.0390 (14) | 0.0336 (12) | −0.0008 (12) | 0.0030 (12) | 0.0072 (12) |
C5 | 0.047 (2) | 0.0304 (14) | 0.0466 (14) | 0.0018 (13) | −0.0008 (14) | 0.0006 (12) |
C6 | 0.048 (2) | 0.0380 (15) | 0.0392 (13) | −0.0052 (14) | −0.0028 (14) | −0.0024 (12) |
O2 | 0.0449 (15) | 0.0435 (11) | 0.0481 (10) | 0.0000 (10) | −0.0052 (10) | 0.0025 (8) |
C8 | 0.045 (2) | 0.0576 (16) | 0.0472 (13) | −0.0070 (15) | −0.0094 (12) | −0.0003 (14) |
Geometric parameters (Å, º) top
O1—C7 | 1.214 (3) | C4—O2 | 1.357 (3) |
C7—C1 | 1.455 (3) | C4—C5 | 1.394 (3) |
C7—H7 | 0.9601 | C5—C6 | 1.372 (3) |
C1—C2 | 1.382 (3) | C5—H5 | 0.9600 |
C1—C6 | 1.402 (4) | C6—H6 | 0.9600 |
C2—C3 | 1.383 (3) | O2—C8 | 1.425 (3) |
C2—H2 | 0.9600 | C8—H8A | 0.9700 |
C3—C4 | 1.394 (3) | C8—H8B | 0.9700 |
C3—H3 | 0.9601 | C8—H8C | 0.9699 |
| | | |
O1—C7—C1 | 126.6 (3) | C5—C4—C3 | 120.3 (3) |
O1—C7—H7 | 116.8 | C6—C5—C4 | 120.3 (2) |
C1—C7—H7 | 116.7 | C6—C5—H5 | 119.8 |
C2—C1—C6 | 118.4 (2) | C4—C5—H5 | 119.9 |
C2—C1—C7 | 119.5 (2) | C5—C6—C1 | 120.3 (2) |
C6—C1—C7 | 122.1 (2) | C5—C6—H6 | 120.4 |
C3—C2—C1 | 122.4 (2) | C1—C6—H6 | 119.2 |
C3—C2—H2 | 119.3 | C4—O2—C8 | 118.04 (19) |
C1—C2—H2 | 118.3 | O2—C8—H8A | 110.0 |
C2—C3—C4 | 118.2 (2) | O2—C8—H8B | 109.2 |
C2—C3—H3 | 120.5 | H8A—C8—H8B | 109.5 |
C4—C3—H3 | 121.3 | O2—C8—H8C | 109.2 |
O2—C4—C5 | 115.5 (2) | H8A—C8—H8C | 109.5 |
O2—C4—C3 | 124.1 (2) | H8B—C8—H8C | 109.5 |
| | | |
O1—C7—C1—C2 | −176.4 (2) | O2—C4—C5—C6 | −179.0 (2) |
O1—C7—C1—C6 | 4.3 (4) | C3—C4—C5—C6 | 0.7 (4) |
C6—C1—C2—C3 | 0.1 (4) | C4—C5—C6—C1 | −0.5 (4) |
C7—C1—C2—C3 | −179.3 (2) | C2—C1—C6—C5 | 0.1 (4) |
C1—C2—C3—C4 | 0.1 (4) | C7—C1—C6—C5 | 179.4 (2) |
C2—C3—C4—O2 | 179.19 (19) | C5—C4—O2—C8 | 176.8 (2) |
C2—C3—C4—C5 | −0.5 (4) | C3—C4—O2—C8 | −2.9 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O2i | 0.96 | 2.75 | 3.603 (4) | 149 |
C5—H5···O1ii | 0.96 | 2.70 | 3.447 (4) | 135 |
C8—H8A···O1iii | 0.97 | 2.71 | 3.582 (4) | 150 |
C8—H8B···O1iv | 0.97 | 2.75 | 3.434 (4) | 128 |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) −x+3/2, −y, z−1/2; (iv) −x+1/2, −y, z−1/2. |
(II) 2-hydroxybenzaldehyde
top
Crystal data top
C7H6O2 | F(000) = 256 |
Mr = 122.12 | Dx = 1.356 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1182 reflections |
a = 6.3945 (3) Å | θ = 2.9–24.4° |
b = 13.8939 (9) Å | µ = 0.10 mm−1 |
c = 6.9172 (4) Å | T = 233 K |
β = 103.262 (3)° | Cylinder, colourless |
V = 598.17 (6) Å3 | 0.3 × 0.3 × 0.3 mm |
Z = 4 | |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 1002 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.056 |
Graphite monochromator | θmax = 36.2°, θmin = 2.9° |
Detector resolution: 512 pixels mm-1 | h = −10→10 |
Data collection strategy APEX2/COSMO with chi = 0 scans | k = −15→23 |
8643 measured reflections | l = −5→5 |
1853 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)] = 0.057 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.185 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.1022P)2] where P = (Fo2 + 2Fc2)/3 |
1853 reflections | (Δ/σ)max < 0.001 |
82 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
Crystal data top
C7H6O2 | V = 598.17 (6) Å3 |
Mr = 122.12 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.3945 (3) Å | µ = 0.10 mm−1 |
b = 13.8939 (9) Å | T = 233 K |
c = 6.9172 (4) Å | 0.3 × 0.3 × 0.3 mm |
β = 103.262 (3)° | |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 1002 reflections with I > 2σ(I) |
8643 measured reflections | Rint = 0.056 |
1853 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.057 | 0 restraints |
wR(F2) = 0.185 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.32 e Å−3 |
1853 reflections | Δρmin = −0.18 e Å−3 |
82 parameters | |
Special details top
Experimental. The crystallization was performed on the diffractometer at a temperature of 253 K with a miniature zone melting procedure using focused infrared-laser-
radiation according to (Boese, 1994). |
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. Treatment of hydrogen atom: Riding model on idealized geometries
with the 1.2 fold isotropic displacement parameters of the equivalent
Uij of the corresponding carbon atom. Hydroxy hydrogen atom position
taken from a Fourier-map and also refined as riding group with the 1.5 fold
isotropic displacement parameters of the equivalent Uij of the
corresponding hydroxy atom. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.2556 (2) | 0.54061 (8) | 0.6616 (2) | 0.0596 (5) | |
O2 | 0.55260 (18) | 0.67452 (9) | 0.7310 (2) | 0.0587 (5) | |
H2 | 0.4655 | 0.6080 | 0.7059 | 0.088* | |
C1 | 0.1738 (2) | 0.70760 (10) | 0.6451 (3) | 0.0341 (5) | |
C2 | 0.3892 (2) | 0.73841 (11) | 0.6956 (3) | 0.0389 (5) | |
C3 | 0.4344 (3) | 0.83638 (12) | 0.7087 (3) | 0.0490 (5) | |
H3 | 0.5811 | 0.8581 | 0.7432 | 0.059* | |
C4 | 0.2677 (3) | 0.90140 (12) | 0.6715 (3) | 0.0519 (6) | |
H4 | 0.2993 | 0.9692 | 0.6837 | 0.062* | |
C5 | 0.0553 (3) | 0.87229 (12) | 0.6211 (3) | 0.0491 (5) | |
H5 | −0.0589 | 0.9190 | 0.5933 | 0.059* | |
C6 | 0.0090 (2) | 0.77528 (12) | 0.6079 (3) | 0.0409 (5) | |
H6 | −0.1377 | 0.7535 | 0.5742 | 0.049* | |
C7 | 0.1222 (3) | 0.60588 (11) | 0.6320 (3) | 0.0452 (5) | |
H7 | −0.0271 | 0.5880 | 0.6026 | 0.054* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0661 (8) | 0.0368 (6) | 0.0743 (13) | 0.0031 (6) | 0.0129 (7) | 0.0033 (6) |
O2 | 0.0340 (5) | 0.0593 (8) | 0.0783 (13) | 0.0071 (5) | 0.0041 (6) | 0.0058 (7) |
C1 | 0.0350 (6) | 0.0342 (7) | 0.0327 (13) | −0.0043 (5) | 0.0068 (6) | −0.0015 (6) |
C2 | 0.0334 (6) | 0.0428 (7) | 0.0394 (13) | −0.0023 (6) | 0.0060 (6) | 0.0009 (7) |
C3 | 0.0465 (8) | 0.0491 (9) | 0.0501 (15) | −0.0159 (7) | 0.0084 (8) | −0.0032 (8) |
C4 | 0.0702 (12) | 0.0345 (7) | 0.0515 (16) | −0.0090 (7) | 0.0154 (10) | −0.0020 (8) |
C5 | 0.0559 (10) | 0.0405 (8) | 0.0514 (16) | 0.0080 (7) | 0.0134 (8) | 0.0015 (8) |
C6 | 0.0349 (7) | 0.0446 (8) | 0.0418 (14) | 0.0011 (6) | 0.0062 (6) | −0.0008 (7) |
C7 | 0.0488 (9) | 0.0392 (8) | 0.0474 (16) | −0.0069 (6) | 0.0109 (8) | −0.0003 (7) |
Geometric parameters (Å, º) top
O1—C7 | 1.230 (2) | C3—H3 | 0.9621 |
O2—C2 | 1.3499 (19) | C4—C5 | 1.383 (3) |
O2—H2 | 1.0726 | C4—H4 | 0.9637 |
C1—C6 | 1.392 (2) | C5—C6 | 1.378 (2) |
C1—C2 | 1.4075 (19) | C5—H5 | 0.9628 |
C1—C7 | 1.449 (2) | C6—H6 | 0.9620 |
C2—C3 | 1.390 (2) | C7—H7 | 0.9618 |
C3—C4 | 1.375 (3) | | |
| | | |
C2—O2—H2 | 100.7 | C3—C4—H4 | 119.2 |
C6—C1—C2 | 119.78 (13) | C5—C4—H4 | 118.8 |
C6—C1—C7 | 119.68 (13) | C6—C5—C4 | 119.08 (16) |
C2—C1—C7 | 120.53 (14) | C6—C5—H5 | 120.3 |
O2—C2—C3 | 119.43 (14) | C4—C5—H5 | 120.6 |
O2—C2—C1 | 121.18 (14) | C5—C6—C1 | 120.43 (14) |
C3—C2—C1 | 119.40 (14) | C5—C6—H6 | 120.4 |
C4—C3—C2 | 119.36 (15) | C1—C6—H6 | 119.2 |
C4—C3—H3 | 120.6 | O1—C7—C1 | 124.69 (15) |
C2—C3—H3 | 120.0 | O1—C7—H7 | 117.5 |
C3—C4—C5 | 121.94 (15) | C1—C7—H7 | 117.8 |
| | | |
C6—C1—C2—O2 | −179.50 (17) | C3—C4—C5—C6 | 0.1 (3) |
C7—C1—C2—O2 | 0.6 (3) | C4—C5—C6—C1 | 0.1 (3) |
C6—C1—C2—C3 | 0.4 (3) | C2—C1—C6—C5 | −0.3 (3) |
C7—C1—C2—C3 | −179.50 (19) | C7—C1—C6—C5 | 179.58 (18) |
O2—C2—C3—C4 | 179.66 (19) | C6—C1—C7—O1 | 179.85 (19) |
C1—C2—C3—C4 | −0.2 (3) | C2—C1—C7—O1 | −0.3 (3) |
C2—C3—C4—C5 | 0.0 (3) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1 | 1.07 | 1.61 | 2.6231 (18) | 156 |
C3—H3···O1i | 0.96 | 2.76 | 3.460 (2) | 130 |
C7—H7···O1ii | 0.96 | 2.73 | 3.443 (2) | 132 |
C6—H6···O2iii | 0.96 | 2.70 | 3.513 (2) | 143 |
Symmetry codes: (i) −x+1, y+1/2, −z+3/2; (ii) −x, −y+1, −z+1; (iii) x−1, y, z. |
(III) (2
E)-3-phenylprop-2-enal
top
Crystal data top
C9H8O | F(000) = 280 |
Mr = 132.15 | Dx = 1.228 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3800 reflections |
a = 5.9626 (2) Å | θ = 2.2–31.2° |
b = 12.9977 (3) Å | µ = 0.08 mm−1 |
c = 9.2522 (2) Å | T = 173 K |
β = 94.282 (2)° | Cylinder, colourless |
V = 715.04 (3) Å3 | 0.3 × 0.3 × 0.3 mm |
Z = 4 | |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 1648 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.023 |
Graphite monochromator | θmax = 31.8°, θmin = 2.7° |
Detector resolution: 512 pixels mm-1 | h = −6→6 |
Data collection strategy APEX2/COSMO with chi = 0 scans | k = −15→18 |
7349 measured reflections | l = −13→13 |
1775 independent 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)] = 0.050 | H-atom parameters constrained |
wR(F2) = 0.125 | w = 1/[σ2(Fo2) + (0.0531P)2 + 0.1822P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
1775 reflections | Δρmax = 0.28 e Å−3 |
92 parameters | Δρmin = −0.17 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.014 (9) |
Crystal data top
C9H8O | V = 715.04 (3) Å3 |
Mr = 132.15 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.9626 (2) Å | µ = 0.08 mm−1 |
b = 12.9977 (3) Å | T = 173 K |
c = 9.2522 (2) Å | 0.3 × 0.3 × 0.3 mm |
β = 94.282 (2)° | |
Data collection top
Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | 1648 reflections with I > 2σ(I) |
7349 measured reflections | Rint = 0.023 |
1775 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.125 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.28 e Å−3 |
1775 reflections | Δρmin = −0.17 e Å−3 |
92 parameters | |
Special details top
Experimental. The crystallization was performed on the diffractometer at a temperature of 248 K with a miniature zone melting procedure using focused infrared-laser-
radiation according to (Boese, 1994). |
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. Treatment of hydrogen atoms Riding model on idealized geometrics
with the 1.2 fold isotropic displacement parameters of the equivalent
Uij of the corresponding carbon atom. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | −0.0048 (2) | 0.36499 (9) | −0.40008 (12) | 0.0603 (4) | |
C1 | 0.1694 (3) | 0.35814 (9) | −0.32532 (14) | 0.0415 (4) | |
H1 | 0.3033 | 0.3424 | −0.3726 | 0.050* | |
C2 | 0.1944 (2) | 0.37243 (9) | −0.16888 (13) | 0.0375 (3) | |
H2 | 0.0654 | 0.3899 | −0.1177 | 0.045* | |
C3 | 0.3937 (2) | 0.36146 (8) | −0.09649 (12) | 0.0331 (3) | |
H3 | 0.5154 | 0.3430 | −0.1536 | 0.040* | |
C11 | 0.4498 (2) | 0.37396 (8) | 0.05945 (12) | 0.0315 (3) | |
C12 | 0.2969 (2) | 0.41471 (9) | 0.15176 (13) | 0.0362 (3) | |
H12 | 0.1499 | 0.4351 | 0.1128 | 0.043* | |
C13 | 0.3560 (3) | 0.42581 (10) | 0.29890 (14) | 0.0413 (4) | |
H13 | 0.2496 | 0.4537 | 0.3613 | 0.050* | |
C14 | 0.5676 (3) | 0.39691 (10) | 0.35563 (14) | 0.0404 (4) | |
H14 | 0.6060 | 0.4044 | 0.4577 | 0.048* | |
C15 | 0.7210 (2) | 0.35616 (10) | 0.26582 (14) | 0.0393 (3) | |
H15 | 0.8690 | 0.3370 | 0.3045 | 0.047* | |
C16 | 0.6614 (2) | 0.34481 (9) | 0.11886 (13) | 0.0355 (3) | |
H16 | 0.7666 | 0.3158 | 0.0566 | 0.043* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0558 (9) | 0.0722 (7) | 0.0496 (6) | −0.0015 (5) | −0.0178 (6) | −0.0016 (5) |
C1 | 0.0460 (11) | 0.0380 (6) | 0.0396 (6) | −0.0018 (5) | −0.0021 (6) | −0.0014 (5) |
C2 | 0.0351 (10) | 0.0402 (6) | 0.0370 (6) | −0.0001 (5) | 0.0011 (6) | −0.0008 (4) |
C3 | 0.0333 (9) | 0.0299 (5) | 0.0360 (6) | 0.0008 (4) | 0.0030 (5) | −0.0009 (4) |
C11 | 0.0303 (9) | 0.0282 (5) | 0.0360 (5) | −0.0027 (4) | 0.0024 (5) | 0.0007 (4) |
C12 | 0.0303 (9) | 0.0382 (6) | 0.0400 (6) | 0.0008 (5) | 0.0021 (5) | −0.0017 (4) |
C13 | 0.0397 (10) | 0.0460 (6) | 0.0389 (6) | −0.0034 (5) | 0.0074 (6) | −0.0053 (5) |
C14 | 0.0424 (10) | 0.0433 (6) | 0.0352 (6) | −0.0074 (5) | 0.0005 (6) | 0.0016 (5) |
C15 | 0.0324 (9) | 0.0425 (6) | 0.0420 (6) | −0.0029 (5) | −0.0031 (6) | 0.0059 (5) |
C16 | 0.0298 (9) | 0.0367 (6) | 0.0402 (6) | 0.0005 (5) | 0.0034 (5) | 0.0017 (4) |
Geometric parameters (Å, º) top
O1—C1 | 1.2078 (18) | C12—C13 | 1.3881 (18) |
C1—C2 | 1.4559 (17) | C12—H12 | 0.9600 |
C1—H1 | 0.9600 | C13—C14 | 1.382 (2) |
C2—C3 | 1.3270 (19) | C13—H13 | 0.9600 |
C2—H2 | 0.9600 | C14—C15 | 1.3858 (19) |
C3—C11 | 1.4656 (16) | C14—H14 | 0.9600 |
C3—H3 | 0.9599 | C15—C16 | 1.3872 (17) |
C11—C16 | 1.3907 (19) | C15—H15 | 0.9600 |
C11—C12 | 1.3993 (16) | C16—H16 | 0.9600 |
| | | |
O1—C1—C2 | 125.44 (14) | C11—C12—H12 | 119.6 |
O1—C1—H1 | 117.6 | C14—C13—C12 | 120.13 (12) |
C2—C1—H1 | 116.9 | C14—C13—H13 | 120.0 |
C3—C2—C1 | 120.62 (12) | C12—C13—H13 | 119.9 |
C3—C2—H2 | 119.8 | C13—C14—C15 | 120.05 (12) |
C1—C2—H2 | 119.6 | C13—C14—H14 | 119.3 |
C2—C3—C11 | 127.96 (11) | C15—C14—H14 | 120.6 |
C2—C3—H3 | 115.7 | C16—C15—C14 | 119.75 (13) |
C11—C3—H3 | 116.3 | C16—C15—H15 | 119.9 |
C16—C11—C12 | 118.38 (11) | C14—C15—H15 | 120.4 |
C16—C11—C3 | 119.53 (11) | C15—C16—C11 | 121.11 (11) |
C12—C11—C3 | 122.10 (12) | C15—C16—H16 | 120.0 |
C13—C12—C11 | 120.57 (13) | C11—C16—H16 | 118.9 |
C13—C12—H12 | 119.8 | | |
| | | |
O1—C1—C2—C3 | 178.87 (12) | C11—C12—C13—C14 | 0.23 (19) |
C1—C2—C3—C11 | 179.26 (10) | C12—C13—C14—C15 | −0.40 (19) |
C2—C3—C11—C16 | 170.73 (11) | C13—C14—C15—C16 | 0.20 (19) |
C2—C3—C11—C12 | −9.36 (18) | C14—C15—C16—C11 | 0.18 (18) |
C16—C11—C12—C13 | 0.14 (17) | C12—C11—C16—C15 | −0.35 (17) |
C3—C11—C12—C13 | −179.77 (11) | C3—C11—C16—C15 | 179.57 (10) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13···O1i | 0.96 | 2.81 | 3.5982 (18) | 140 |
C14—H14···O1ii | 0.96 | 2.63 | 3.304 (2) | 128 |
C16—H16···O1iii | 0.96 | 2.73 | 3.3880 (17) | 126 |
Symmetry codes: (i) −x, −y+1, −z; (ii) x+1, y, z+1; (iii) x+1, −y+1/2, z+1/2. |
Experimental details
| (I) | (II) | (III) |
Crystal data |
Chemical formula | C8H8O2 | C7H6O2 | C9H8O |
Mr | 136.14 | 122.12 | 132.15 |
Crystal system, space group | Orthorhombic, P212121 | Monoclinic, P21/c | Monoclinic, P21/c |
Temperature (K) | 203 | 233 | 173 |
a, b, c (Å) | 4.970 (4), 9.034 (9), 15.544 (14) | 6.3945 (3), 13.8939 (9), 6.9172 (4) | 5.9626 (2), 12.9977 (3), 9.2522 (2) |
α, β, γ (°) | 90, 90, 90 | 90, 103.262 (3), 90 | 90, 94.282 (2), 90 |
V (Å3) | 697.9 (11) | 598.17 (6) | 715.04 (3) |
Z | 4 | 4 | 4 |
Radiation type | Mo Kα | Mo Kα | Mo Kα |
µ (mm−1) | 0.09 | 0.10 | 0.08 |
Crystal size (mm) | 0.30 × 0.30 × 0.30 | 0.3 × 0.3 × 0.3 | 0.3 × 0.3 × 0.3 |
|
Data collection |
Diffractometer | Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer | Siemens SMART three-axis goniometer with APEXII area-detector system diffractometer |
Absorption correction | – | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2015, 885, 705 | 8643, 1853, 1002 | 7349, 1775, 1648 |
Rint | 0.069 | 0.056 | 0.023 |
θmax (°) | 24.0 | 36.2 | 31.8 |
(sin θ/λ)max (Å−1) | 0.572 | 0.832 | 0.742 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.071, 0.94 | 0.057, 0.185, 1.00 | 0.050, 0.125, 1.06 |
No. of reflections | 885 | 1853 | 1775 |
No. of parameters | 92 | 82 | 92 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.12, −0.13 | 0.32, −0.18 | 0.28, −0.17 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O2i | 0.96 | 2.75 | 3.603 (4) | 148.9 |
C5—H5···O1ii | 0.96 | 2.70 | 3.447 (4) | 135.3 |
C8—H8A···O1iii | 0.97 | 2.71 | 3.582 (4) | 149.8 |
C8—H8B···O1iv | 0.97 | 2.75 | 3.434 (4) | 127.8 |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) −x+3/2, −y, z−1/2; (iv) −x+1/2, −y, z−1/2. |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1 | 1.07 | 1.61 | 2.6231 (18) | 155.9 |
C3—H3···O1i | 0.96 | 2.76 | 3.460 (2) | 129.9 |
C7—H7···O1ii | 0.96 | 2.73 | 3.443 (2) | 131.6 |
C6—H6···O2iii | 0.96 | 2.70 | 3.513 (2) | 142.6 |
Symmetry codes: (i) −x+1, y+1/2, −z+3/2; (ii) −x, −y+1, −z+1; (iii) x−1, y, z. |
Hydrogen-bond geometry (Å, º) for (III) top
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13···O1i | 0.96 | 2.81 | 3.5982 (18) | 140.0 |
C14—H14···O1ii | 0.96 | 2.63 | 3.304 (2) | 127.5 |
C16—H16···O1iii | 0.96 | 2.73 | 3.3880 (17) | 126.2 |
Symmetry codes: (i) −x, −y+1, −z; (ii) x+1, y, z+1; (iii) x+1, −y+1/2, z+1/2. |
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Experimental sophistication and developments in theoretical methodologies have improved the reliability of studies of weaker and lesser known intermolecular interactions (Desiraju & Steiner, 1999). As a result, weakly bound complexes such as those involving C—H···O interactions are being extensively studied, and the nature and strength of these interactions are being assessed. The formyl C—H···O hydrogen bond in small-molecule aldehydes is one such example. Many simple aldehydes are liquids, so not many structural reports are available for these compounds. Even if solid, there are not many crystal structure determinations for aldehydes. [37 simple aromatic aldehydes in the Cambridge Structural Database (CSD, Version?; Allen, 2002) with refcodes ANTHAL, AYOHAL, BARFOT, DEWLOH, DPEDAL, FATVUS, FAXXEI, FEDSAJ, FIXHIE, FIXHOK, FIYQOT, FOMZUD, FORBZA, HEQXOR, HODMAP, IHEMAJ, IHEMIR, IZALAW, JULZAR, KATKIA, KERKOI, LOSGOQ, MASBUD, NARZUC, OKUHEH, PHBALD10, RAJKOC, RAFJOC, SAZQIT, SOCHAT, SUNDUA, TEBBOR, WASLOS, XAMVUJ, XAMVEN, XAYCIJ and XIGWAM; four α,β-unsaturated aldehydes with refcodes JAZLAX, SIPKEH, WOBJOM and WOBJUS; and nine salicylaldehyde derivatives with refcodes KOYTOH, MAYWEO, NEJJOB, OVANIL, RAPLAW, XEVRUL, YIQYIH, YOMXOO and YOMXUU]. Therefore, we chose to investigate the nature and type of intermolecular interactions in the crystal structures of some very simple aldehydes.
Anisaldehyde (4-methoxybenzaldehyde), (I), salicylaldehyde (2-hydroxybenzaldehyde), (II), and cinnamaldehyde [(2E)-3-phenylprop-2-enal], (III), are liquids with melting points of 272, 266 and 265.5 K, respectively. These compounds are widely used in the chemical industry as intermediates in the preparation of perfumes, flavouring agents, dyes, pharmaceuticals and agrochemicals. The interesting feature of these compounds is that they do not possess any strong hydrogen-bonding functionalities. In salicylaldehyde, the OH group is bound intramolecularly to the aldehyde C═O group. The possible intermolecular interactions in these three compounds are of the types Caryl—H···O, Cformyl—H···O, Csp2—H···O, Csp3—H···O, C—H···π and π···π. The formyl C—H···O interaction is known to be very weak, owing to the poor electropositive character of the formyl H atom (Breneman & Wiberg, 1990; Williams, 1988). Despite this, short Cformyl—H···O contacts are frequently observed in the crystal structures of aliphatic aldehydes (Thakur et al., 2011). The stabilizing nature of these Cformyl—H···O contacts has also been confirmed by computations on formaldehyde clusters; these calculations show a gradual increase in the electropositive nature of the formyl H atom on going from an isolated gas-phase environment to the crystal. X-ray crystallographic studies of aromatic aldehydes by Moorthy and Venugopalan also established that formyl C—H···O interactions are relevant to crystal packing (Moorthy et al., 2003, 2004, 2005; Lo Presti et al., 2006). However, in the case of aromatic aldehydes, the Cformyl—H···O interactions have to compete with Caryl—H···O interactions involving a relatively more acidic H atom. With our ongoing interest in the study of C—H···O hydrogen bonds in aldehydes we report here the crystal structures of (I), (II) and (III) (Fig. 1). Crystals were obtained in each case by means of in situ cryocrystallization.
Compound (I) crystallizes in space group P212121 with Z' = 1. The formyl and methoxy groups lie slightly out of the phenyl-ring plane by 4.3 (4) and -2.9 (3)°, respectively (torsion angles O1—C7—C1—C6 and C3—C4—O2—C8). The Caryl—Cformyl bond [1.455 (3) Å] is slightly shorter than a normal C—C single-bond distance (Standard reference?). This is possibly a result of extended conjugation between the aldehyde group and the aromatic ring. However, the non-coplanarity of the aromatic ring and the formyl group shows that this conjugation is not very pronounced. [This sentence is not consistent with the almost perfect coplanarity of the substituents with the ring, as indicated by the very small torsion angles mentioned a few lines above (4.3 deg. is NOT a very significant deviation from the plane). Please reconsider this statement about the conjugation.] There are several weak C—H···O hydrogen bonds (Table 1). Molecules are arranged in zigzag chains along the c axis and are held together by weak Csp3—H···O hydrogen bonds between atom H8A of the methoxy group and the carbonyl O atom of a neighbouring molecule. The chains are stacked along the a axis via weak Csp3—H···π interactions (Fig. 2a). Molecules in adjacent chains (along the b axis) are held together by weak Caryl—H···O interactions, C3—H3···O2i and C5—H5···O1ii (Fig. 2b; symmetry codes as in Table 1). The formyl H atom is not engaged in a directed intermolecular interaction (Ribeiro-Claro et al., 2002).
Compound (II) crystallizes in space group P21/c with Z' = 1. The hydroxy group is intramolecularly hydrogen-bonded to the formyl O atom (O2—H2···O1), as expected. A shorter Caryl—Cformyl bond [1.449 (2) Å] and a slightly elongated C═O bond [1.230 (2) Å] are observed. Molecules in (II) are linked by weak Caryl—H···O hydrogen bonds (Table 2): C3—H3 and C6—H6 interact with the carbonyl O atom, O1, and hydroxy O atom, O6, respectively, of different neighbouring molecules (Fig. 3a). Additionally, a weak Cformyl—H···O interaction is also observed [C7—H7···O1(-x, 1-y, 1-z), Fig. 3b].
Compound (III) crystallizes in space group P21/c with Z' = 1. The propenal fragment lies out of the phenyl-ring plane by -9.36 (18)° (torsion angle C2—C3—C11—C12), with a Caryl—Csp2 bond length of 1.4656 (16) Å. This indicates poor resonance between the propenal fragment and the aromatic ring. The molecules are arranged in linear chains arranged in a head-to-tail fashion via C14—H14···O1(x + 1, y, z + 1) hydrogen bonds (Table 3, Fig. 4). The carbonyl O atom has weak C—H···O interactions with one Caryl—H group (C13—H13 or C16—H16) from each of two adjacent chains. Despite the high acidity of the Csp2—H group relative to the Caryl—H groups, no Csp2—H···O hydrogen bonds (between the carbonyl O atom and aliphatic fragment) are observed. However, such interactions have been observed frequently in the crystal structures of some substituted cinnamaldehydes (CSD refcodes CUBNUJ, LUJTEQ, CUBJUJ and QODVAH).