Acta Cryst. (2008). E64, o862 [ doi:10.1107/S1600536808010131 ]
In the title Schiff base, C15H15NO, the benzene rings form a dihedral angle of 74.91 (1)°. There is a strong intramolecular O-H
N hydrogen bond.
1-Phenylmethanamine (0.02 mol, 2.14 g) and 5-methylsalicylaldehyde (0.02 mol, 2.76 g) were dissolved in ethanol and the solution was refluxed for 3 h. After evaporation, a crude product was recrystallized twice from ethanol to give a pure yellow product. Yield: 87.3%. Calcd. for C15H15NO: C, 79.97; H, 6.71; N, 6.22; Found: C, 79.53; H, 6.78; N, 6.02%.
All H atoms were located from difference Fourier syntheses. H atoms from the C—H groups and O—H group were placed in geometrically idealized positions and constrained to ride on their parent atoms (C—H = 0.93–0.97%A; O—H = 0.82 Å). and Uiso(H) values equal to 1.2 Ueq(C) or 1.5Ueq(O).
Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku/MSC, 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./gk2138fig1thm.gif)
| Fig. 1. The structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. |
| C15H15NO | F000 = 480 |
| Mr = 225.28 | Dx = 1.201 Mg m−3 |
| Monoclinic, P21/c | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2ybc | Cell parameters from 6530 reflections |
| a = 14.248 (3) Å | θ = 1.0–27.5º |
| b = 6.1724 (2) Å | µ = 0.08 mm−1 |
| c = 14.529 (3) Å | T = 295 (2) K |
| β = 102.79 (3)º | Block, yellow |
| V = 1246.0 (4) Å3 | 0.54 × 0.30 × 0.25 mm |
| Z = 4 |
| Rigaku R-AXIS RAPID IP diffractometer | 2826 independent reflections |
| Radiation source: fine-focus sealed tube | 1636 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.036 |
| Detector resolution: 0 pixels mm-1 | θmax = 27.5º |
| T = 295(2) K | θmin = 3.5º |
| ω scans | h = −18→18 |
| Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −7→7 |
| Tmin = 0.970, Tmax = 0.986 | l = −18→18 |
| 11598 measured reflections |
| 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)] = 0.049 | H-atom parameters constrained |
| wR(F2) = 0.146 | w = 1/[σ2(Fo2) + (0.0657P)2 + 0.0924P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.03 | (Δ/σ)max < 0.001 |
| 2826 reflections | Δρmax = 0.15 e Å−3 |
| 155 parameters | Δρmin = −0.14 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C15H15NO | V = 1246.0 (4) Å3 |
| Mr = 225.28 | Z = 4 |
| Monoclinic, P21/c | Mo Kα |
| a = 14.248 (3) Å | µ = 0.08 mm−1 |
| b = 6.1724 (2) Å | T = 295 (2) K |
| c = 14.529 (3) Å | 0.54 × 0.30 × 0.25 mm |
| β = 102.79 (3)º |
| Rigaku R-AXIS RAPID IP diffractometer | 2826 independent reflections |
| Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 1636 reflections with I > 2σ(I) |
| Tmin = 0.970, Tmax = 0.986 | Rint = 0.036 |
| 11598 measured reflections |
| R[F2 > 2σ(F2)] = 0.049 | 155 parameters |
| wR(F2) = 0.146 | H-atom parameters constrained |
| S = 1.03 | Δρmax = 0.15 e Å−3 |
| 2826 reflections | Δρmin = −0.14 e Å−3 |
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. |
| x | y | z | Uiso*/Ueq | ||
| O1 | 0.60971 (8) | −0.30589 (18) | 0.62915 (9) | 0.0799 (4) | |
| H1A | 0.6539 | −0.2326 | 0.6595 | 0.120* | |
| N1 | 0.69322 (11) | 0.0362 (3) | 0.71735 (10) | 0.0756 (4) | |
| C1 | 0.90441 (17) | 0.3943 (4) | 0.58653 (16) | 0.0962 (7) | |
| H1C | 0.9018 | 0.5185 | 0.5498 | 0.115* | |
| C2 | 0.96894 (15) | 0.2373 (4) | 0.58075 (16) | 0.0989 (7) | |
| H2A | 1.0104 | 0.2536 | 0.5400 | 0.119* | |
| C3 | 0.97336 (16) | 0.0579 (4) | 0.63369 (17) | 0.0958 (7) | |
| H3A | 1.0182 | −0.0494 | 0.6299 | 0.115* | |
| C4 | 0.84281 (13) | 0.3717 (3) | 0.64613 (14) | 0.0820 (5) | |
| H4A | 0.7988 | 0.4809 | 0.6495 | 0.098* | |
| C5 | 0.91196 (15) | 0.0324 (3) | 0.69338 (14) | 0.0833 (6) | |
| H5A | 0.9154 | −0.0931 | 0.7294 | 0.100* | |
| C6 | 0.84528 (12) | 0.1892 (3) | 0.70109 (12) | 0.0672 (5) | |
| C7 | 0.77651 (14) | 0.1640 (4) | 0.76503 (14) | 0.0978 (7) | |
| H7A | 0.8085 | 0.0919 | 0.8228 | 0.117* | |
| H7B | 0.7554 | 0.3055 | 0.7813 | 0.117* | |
| C8 | 0.61136 (13) | 0.1263 (3) | 0.70132 (11) | 0.0661 (5) | |
| H8A | 0.6068 | 0.2672 | 0.7225 | 0.079* | |
| C9 | 0.52454 (11) | 0.0188 (2) | 0.65129 (10) | 0.0535 (4) | |
| C10 | 0.43697 (12) | 0.1266 (2) | 0.63498 (11) | 0.0616 (4) | |
| H10A | 0.4351 | 0.2656 | 0.6592 | 0.074* | |
| C11 | 0.25972 (15) | 0.1615 (4) | 0.56557 (16) | 0.1024 (7) | |
| H12A | 0.2726 | 0.3131 | 0.5601 | 0.154* | |
| H12B | 0.2278 | 0.1393 | 0.6165 | 0.154* | |
| H12C | 0.2192 | 0.1109 | 0.5077 | 0.154* | |
| C12 | 0.35323 (12) | 0.0375 (3) | 0.58492 (11) | 0.0657 (4) | |
| C13 | 0.35819 (13) | −0.1710 (3) | 0.55086 (11) | 0.0694 (5) | |
| H14A | 0.3023 | −0.2357 | 0.5167 | 0.083* | |
| C14 | 0.44260 (13) | −0.2846 (3) | 0.56589 (12) | 0.0671 (5) | |
| H15A | 0.4433 | −0.4245 | 0.5423 | 0.081* | |
| C15 | 0.52682 (11) | −0.1926 (2) | 0.61595 (11) | 0.0572 (4) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0798 (8) | 0.0663 (7) | 0.1004 (10) | 0.0110 (6) | 0.0346 (7) | −0.0035 (6) |
| N1 | 0.0683 (10) | 0.0952 (11) | 0.0659 (9) | −0.0153 (8) | 0.0206 (8) | −0.0023 (8) |
| C1 | 0.0927 (15) | 0.0946 (15) | 0.1008 (16) | −0.0124 (12) | 0.0202 (13) | 0.0275 (12) |
| C2 | 0.0763 (14) | 0.135 (2) | 0.0896 (15) | −0.0130 (14) | 0.0268 (12) | 0.0031 (15) |
| C3 | 0.0789 (14) | 0.1082 (17) | 0.0998 (16) | 0.0156 (12) | 0.0189 (12) | −0.0135 (14) |
| C4 | 0.0696 (12) | 0.0780 (12) | 0.0946 (14) | 0.0086 (9) | 0.0096 (10) | 0.0031 (11) |
| C5 | 0.0920 (14) | 0.0717 (11) | 0.0777 (13) | −0.0020 (11) | 0.0007 (11) | 0.0079 (9) |
| C6 | 0.0584 (10) | 0.0795 (11) | 0.0601 (10) | −0.0123 (9) | 0.0053 (8) | −0.0041 (8) |
| C7 | 0.0822 (13) | 0.143 (2) | 0.0699 (12) | −0.0370 (13) | 0.0208 (10) | −0.0184 (12) |
| C8 | 0.0832 (12) | 0.0665 (10) | 0.0539 (9) | −0.0141 (9) | 0.0265 (9) | −0.0049 (8) |
| C9 | 0.0675 (10) | 0.0496 (8) | 0.0470 (8) | −0.0047 (7) | 0.0206 (7) | 0.0014 (6) |
| C10 | 0.0832 (12) | 0.0492 (8) | 0.0563 (9) | 0.0028 (8) | 0.0239 (9) | 0.0022 (7) |
| C11 | 0.0860 (14) | 0.1106 (17) | 0.1066 (17) | 0.0238 (13) | 0.0126 (12) | 0.0172 (13) |
| C12 | 0.0722 (11) | 0.0711 (10) | 0.0555 (9) | 0.0062 (9) | 0.0179 (8) | 0.0090 (8) |
| C13 | 0.0746 (12) | 0.0814 (12) | 0.0543 (10) | −0.0160 (10) | 0.0184 (8) | −0.0064 (8) |
| C14 | 0.0848 (12) | 0.0565 (9) | 0.0675 (10) | −0.0122 (9) | 0.0331 (9) | −0.0132 (8) |
| C15 | 0.0705 (10) | 0.0517 (8) | 0.0566 (9) | 0.0021 (8) | 0.0297 (8) | 0.0034 (7) |
| O1—C15 | 1.3493 (18) | C7—H7B | 0.9700 |
| O1—H1A | 0.8200 | C8—C9 | 1.449 (2) |
| N1—C8 | 1.266 (2) | C8—H8A | 0.9300 |
| N1—C7 | 1.465 (2) | C9—C10 | 1.387 (2) |
| C1—C2 | 1.351 (3) | C9—C15 | 1.405 (2) |
| C1—C4 | 1.370 (3) | C10—C12 | 1.368 (2) |
| C1—H1C | 0.9300 | C10—H10A | 0.9300 |
| C2—C3 | 1.342 (3) | C11—C12 | 1.508 (2) |
| C2—H2A | 0.9300 | C11—H12A | 0.9600 |
| C3—C5 | 1.370 (3) | C11—H12B | 0.9600 |
| C3—H3A | 0.9300 | C11—H12C | 0.9600 |
| C4—C6 | 1.376 (3) | C12—C13 | 1.386 (2) |
| C4—H4A | 0.9300 | C13—C14 | 1.367 (2) |
| C5—C6 | 1.378 (3) | C13—H14A | 0.9300 |
| C5—H5A | 0.9300 | C14—C15 | 1.380 (2) |
| C6—C7 | 1.500 (2) | C14—H15A | 0.9300 |
| C7—H7A | 0.9700 | ||
| C15—O1—H1A | 109.5 | N1—C8—H8A | 118.6 |
| C8—N1—C7 | 117.85 (18) | C9—C8—H8A | 118.6 |
| C2—C1—C4 | 120.4 (2) | C10—C9—C15 | 118.39 (15) |
| C2—C1—H1C | 119.8 | C10—C9—C8 | 120.12 (14) |
| C4—C1—H1C | 119.8 | C15—C9—C8 | 121.47 (15) |
| C3—C2—C1 | 120.2 (2) | C12—C10—C9 | 122.94 (15) |
| C3—C2—H2A | 119.9 | C12—C10—H10A | 118.5 |
| C1—C2—H2A | 119.9 | C9—C10—H10A | 118.5 |
| C2—C3—C5 | 120.1 (2) | C12—C11—H12A | 109.5 |
| C2—C3—H3A | 119.9 | C12—C11—H12B | 109.5 |
| C5—C3—H3A | 119.9 | H12A—C11—H12B | 109.5 |
| C1—C4—C6 | 120.83 (19) | C12—C11—H12C | 109.5 |
| C1—C4—H4A | 119.6 | H12A—C11—H12C | 109.5 |
| C6—C4—H4A | 119.6 | H12B—C11—H12C | 109.5 |
| C3—C5—C6 | 121.27 (19) | C10—C12—C13 | 117.10 (16) |
| C3—C5—H5A | 119.4 | C10—C12—C11 | 121.73 (17) |
| C6—C5—H5A | 119.4 | C13—C12—C11 | 121.15 (18) |
| C4—C6—C5 | 117.19 (17) | C14—C13—C12 | 122.12 (16) |
| C4—C6—C7 | 120.53 (18) | C14—C13—H14A | 118.9 |
| C5—C6—C7 | 122.28 (18) | C12—C13—H14A | 118.9 |
| N1—C7—C6 | 109.57 (15) | C13—C14—C15 | 120.28 (15) |
| N1—C7—H7A | 109.8 | C13—C14—H15A | 119.9 |
| C6—C7—H7A | 109.8 | C15—C14—H15A | 119.9 |
| N1—C7—H7B | 109.8 | O1—C15—C14 | 119.53 (14) |
| C6—C7—H7B | 109.8 | O1—C15—C9 | 121.32 (15) |
| H7A—C7—H7B | 108.2 | C14—C15—C9 | 119.15 (15) |
| N1—C8—C9 | 122.71 (16) |
This project was supported by the Talent Fund of Ningbo University (grant No.2006668).
Cohen, M. D., Schmidt, G. M. J. & Flavian, S. (1964). J. Chem. Soc. pp. 2041–2043.
Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.
Rigaku (1998). RAPID-AUTO. Rigaku Corporation, Tokyo, Japan.
Rigaku/MSC (2002). CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Compounds presenting photochromism, a reversible color change brought about in at least one direction by the action of electromagnetic radiation, attract considerable attention from various fields of chemistry, physics and material science as potential candidates for practical applications. For a long time, the Schiff bases of salicylaldehyde with aromatic amines (anils or N-salicylideneaniline derivatives) are recognized as such compounds, which undergo keto-enol tautomerism and present common features in their structures and reaction mechanisms (Cohen et al., 1964). The tautomerism involves proton transfer from the hydroxylic oxygen to the imino nitrogen atom that occurs intramolecularly via a six-membered ring, with the keto species showing bathochromically shifted spectra. Continuing our studies on the relation between the Schiff base geometry in the crystalline state and photochromism and/or thermochromism, we report here the crystal structure of 2-[(E)-(benzylimino)methyl]-4-methylphenol (I).
The molecular structure of (I) is illustrated in Fig. 1. Compound (I) is a typical Schiff base derived from salicylaldehyde with the C8—N1 bond length (Table 1) indicating double-bond character. The title molecule is not planar. The dihedral angle between the phenyl ring and salicylaldimine group is 74.91 (1)°. There is a strong intramolecular hydrogen bond between the phenolic group and the imine N atom (Table 1).