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Acta Crystallogr Sect E Struct Rep Online. 2010 April 1; 66(Pt 4): o749.
Published online 2010 March 6. doi:  10.1107/S1600536810007762
PMCID: PMC2983984

4-Phenyl­diazenyl-2-[(R)-(1-phenyl­ethyl)imino­meth­yl]phenol

Abstract

The title chiral photochromic Schiff base compound, C21H19N3O, was synthesized from (R)-1-phenyl­ethyl­amine and the salicylaldehyde of an azobenzene derivative. The mol­ecule corresponds to the phenol–imine tautomer, the C=N and N—C bond distances being 1.279 (3) and 1.477 (3) Å, respectively. An intra­molecular O—H(...)N hydrogen bond occurs. The diazenyl group adopts a trans form with an N=N distance of 1.243 (3) Å.

Related literature

For applications of Schiff base–metal complexes and azobenzene, see: Akitsu & Einaga (2005a [triangle],b [triangle]); Akitsu (2007 [triangle]); Akitsu & Itoh (2010 [triangle]). For Schiff base ligands, see: Akitsu et al. (2004 [triangle], 2006 [triangle]); Miura et al. (2009 [triangle]); Hadjoudis & Mavridis (2004 [triangle]). For Schiff base compounds with an azobenzene group, see: Aslantaş et al. (2007 [triangle]); Khandar & Rezvani (1999 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o749-scheme1.jpg

Experimental

Crystal data

  • C21H19N3O
  • M r = 329.39
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o749-efi1.jpg
  • a = 22.430 (2) Å
  • b = 5.9566 (6) Å
  • c = 13.4670 (13) Å
  • β = 106.396 (1)°
  • V = 1726.1 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 173 K
  • 0.31 × 0.12 × 0.09 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.976, T max = 0.993
  • 4632 measured reflections
  • 1960 independent reflections
  • 1741 reflections with I > 2σ(I)
  • R int = 0.029

Refinement

  • R[F 2 > 2σ(F 2)] = 0.040
  • wR(F 2) = 0.123
  • S = 0.96
  • 1960 reflections
  • 231 parameters
  • 1 restraint
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.26 e Å−3
  • Δρmin = −0.27 e Å−3

Data collection: APEX2 (Bruker, 1998 [triangle]); cell refinement: SAINT (Bruker, 1998 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810007762/zq2030sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810007762/zq2030Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

This work was supported by the Kato Foundation for the Promotion of Science.

supplementary crystallographic information

Comment

In the recent years, we have developed organic-inorganic hybrid materials of photochromic compounds and chiral Schiff base metal complexes. Due to structural flexibility of such complexes, cis-trans photoisomerization of azobenzene could switch conformation of chiral ligands (Akitsu & Einaga, 2005a,b). Moreover, multifunctional (photochemical) development of Schiff base CuII, NiII, or ZnII complexes (Akitsu, 2007) and optical anisotropy in polymer films (Akitsu & Itoh, 2010) have been reported so far. On the other hand, free Schiff base ligands may act as photochromic, thermochromic, and fluorescence materials (Hadjoudis et al., 2004). We have developed chiral Schiff base liagnds to include chiral functions (Akitsu et al., 2004, 2006b; Miura et al., 2009). Herein we prepared the title chiral photochromic Schiff base compound (I), having two photochromic moieties.

The crystal structure of (I) is similar to that of the analogous Schiff base ligands (Akitsu et al., 2006b; Miura et al., 2009). The molecule of (I) (Fig. 1) adopts an E configuration with respect to the imine C=N double bond with C6—C7—N1—C8 torsion angle of 179.21 (16)°. Thus, the π-conjugated system around the imine group is essentially planar. The C1—O1 bond distance of 1.337 (3) Å suggests that it is in the phenol-imine tautomer. The contraction of the C7=N1 bond is also in agreement with the phenol-imine tautomer. As for the azobenzene moiety, the azo N=N double bond adopts an E configuration with the N=N distance of 1.243 (3) Å. Beside them, geometric parameters reported agree with the corresponding values for analogous azobenzene derivatives (Aslantaş et al., 2007; Khandar & Rezvani,1999).

The planarity of (I) is stabilized by an intramolecular O—H···N hydrogen bond (Table 1). However, there is no intermolecular hydrogen bonds in the crystal structure.

Experimental

Treatment of aniline (6.24 g, 67.0 mmol) in 30 ml of 6M HCl and NaNO2 (4.69 g, 68.0 mmol) in 30 ml of H2O for 30 min at 278 K gave rise to the yellow precursor. Treatment of the precursor and salicylaldehyde (8.18 g, 67.0 mmol) in 30 ml of 10 % NaOH aqueous solution for 1 hour at 278 K, and the resulting brown precipitates were filtrated and washed with water and ethanol, and dried in a desiccator for several days. Treatment of the brown precipitates (0.226 g, 1.00 mmol) and (R)-1-phenylethylamine (0.121 g, 1.00 mmol) for 2 hours at 313 K gave rise to redish violet crystals after evaporation (yield 0.21 g, 64 %).

Refinement

All H atoms were placed at the calculated positions (C-H = 0.95-1.00 Å) and were included in the refinement in the riding mode with Uiso(H) = 1.2-1.5Ueq(C). The OH hydrogen atom was located in a difference Fourier map, and was freely refined. Friedel pairs were merged.

Figures

Fig. 1.
The molecular structure of (I), showing the atom labeling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Crystal data

C21H19N3OF(000) = 696
Mr = 329.39Dx = 1.268 Mg m3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2yCell parameters from 1707 reflections
a = 22.430 (2) Åθ = 2.8–25.6°
b = 5.9566 (6) ŵ = 0.08 mm1
c = 13.4670 (13) ÅT = 173 K
β = 106.396 (1)°Prism, red violet
V = 1726.1 (3) Å30.31 × 0.12 × 0.09 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer1960 independent reflections
Radiation source: fine-focus sealed tube1741 reflections with I > 2σ(I)
graphiteRint = 0.029
Detector resolution: 8.333 pixels mm-1θmax = 26.6°, θmin = 1.6°
[var phi] and ω scansh = −16→28
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)k = −6→7
Tmin = 0.976, Tmax = 0.993l = −16→16
4632 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123H atoms treated by a mixture of independent and constrained refinement
S = 0.96w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3
1960 reflections(Δ/σ)max = 0.001
231 parametersΔρmax = 0.26 e Å3
1 restraintΔρmin = −0.27 e Å3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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)

xyzUiso*/Ueq
O10.99357 (8)−0.0345 (3)0.86831 (13)0.0407 (4)
C51.01961 (10)0.3842 (4)0.68547 (16)0.0311 (5)
H51.00520.52730.65770.037*
C21.06244 (11)−0.0381 (4)0.76572 (17)0.0358 (5)
H21.0775−0.18090.79300.043*
C60.99411 (9)0.2834 (4)0.75769 (15)0.0286 (5)
C41.06632 (10)0.2751 (4)0.65393 (16)0.0328 (5)
C31.08666 (11)0.0649 (4)0.69370 (18)0.0364 (5)
H31.1179−0.00970.67100.044*
C171.10112 (11)0.8454 (4)0.44134 (19)0.0386 (6)
H171.06650.92220.45260.046*
C70.94575 (9)0.3980 (4)0.79195 (15)0.0286 (5)
H70.93140.54150.76460.034*
C161.11935 (10)0.6407 (4)0.48836 (16)0.0326 (5)
C11.01590 (10)0.0684 (4)0.79815 (16)0.0301 (5)
C211.17050 (11)0.5300 (4)0.47323 (18)0.0382 (6)
H211.18310.38940.50570.046*
C181.13343 (12)0.9384 (5)0.37779 (18)0.0439 (6)
H181.12051.07780.34440.053*
C130.72251 (11)−0.0416 (5)0.85593 (19)0.0414 (6)
H130.6892−0.14530.84640.050*
C100.82061 (9)0.2628 (4)0.88270 (16)0.0297 (5)
C80.87446 (9)0.4249 (4)0.89349 (16)0.0311 (5)
H80.85980.55830.84810.037*
C201.20294 (11)0.6245 (5)0.41107 (19)0.0449 (7)
H201.23820.54950.40100.054*
C191.18438 (11)0.8291 (5)0.36290 (18)0.0451 (7)
H191.20680.89370.31970.054*
C110.76386 (10)0.3026 (5)0.81026 (17)0.0371 (5)
H110.75800.43590.76990.045*
C150.82718 (10)0.0696 (4)0.94228 (19)0.0380 (6)
H150.86560.03970.99230.046*
C140.77806 (11)−0.0812 (5)0.9297 (2)0.0441 (6)
H140.7829−0.21140.97200.053*
C120.71552 (11)0.1493 (5)0.79616 (19)0.0429 (6)
H120.67730.17640.74490.051*
C90.90390 (11)0.5033 (5)1.00386 (17)0.0393 (6)
H9A0.93630.61441.00460.059*
H9B0.92240.37461.04690.059*
H9C0.87200.57141.03120.059*
N31.08366 (9)0.5577 (3)0.55470 (14)0.0347 (5)
N10.92269 (8)0.3059 (3)0.85861 (14)0.0320 (4)
N21.09774 (9)0.3622 (3)0.58460 (15)0.0375 (5)
H10.9594 (15)0.061 (7)0.882 (2)0.075 (10)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0506 (10)0.0315 (9)0.0472 (9)0.0084 (8)0.0254 (8)0.0107 (8)
C50.0337 (11)0.0279 (11)0.0295 (10)−0.0018 (10)0.0053 (8)0.0015 (10)
C20.0434 (12)0.0261 (12)0.0387 (11)0.0061 (10)0.0127 (10)0.0024 (10)
C60.0303 (10)0.0268 (11)0.0271 (9)−0.0028 (10)0.0053 (8)−0.0019 (9)
C40.0353 (11)0.0351 (12)0.0275 (10)−0.0048 (11)0.0082 (8)0.0000 (10)
C30.0405 (12)0.0336 (13)0.0382 (12)0.0049 (11)0.0163 (10)−0.0010 (10)
C170.0388 (12)0.0350 (14)0.0396 (11)−0.0016 (11)0.0071 (10)−0.0017 (10)
C70.0272 (10)0.0272 (11)0.0296 (10)0.0010 (9)0.0052 (8)0.0010 (9)
C160.0344 (11)0.0363 (13)0.0247 (10)−0.0067 (10)0.0045 (8)−0.0021 (9)
C10.0347 (11)0.0273 (12)0.0288 (10)−0.0020 (10)0.0096 (9)−0.0010 (9)
C210.0404 (12)0.0343 (13)0.0381 (11)0.0001 (10)0.0081 (10)0.0027 (11)
C180.0491 (14)0.0378 (14)0.0388 (12)−0.0066 (12)0.0028 (11)0.0108 (11)
C130.0331 (12)0.0411 (14)0.0537 (14)−0.0038 (11)0.0183 (10)−0.0094 (12)
C100.0293 (10)0.0315 (12)0.0289 (10)0.0045 (9)0.0091 (8)−0.0001 (9)
C80.0310 (11)0.0288 (12)0.0342 (10)0.0047 (9)0.0101 (9)0.0027 (9)
C200.0381 (13)0.0555 (18)0.0429 (13)−0.0007 (13)0.0141 (11)−0.0023 (13)
C190.0448 (14)0.0546 (17)0.0343 (11)−0.0163 (13)0.0082 (10)0.0037 (12)
C110.0385 (12)0.0374 (13)0.0329 (10)0.0042 (11)0.0061 (9)0.0021 (11)
C150.0313 (11)0.0360 (13)0.0440 (12)0.0043 (11)0.0061 (10)0.0078 (11)
C140.0469 (14)0.0335 (14)0.0539 (14)0.0034 (11)0.0178 (11)0.0072 (12)
C120.0332 (12)0.0501 (16)0.0417 (12)0.0046 (12)0.0046 (10)−0.0059 (12)
C90.0361 (12)0.0402 (14)0.0402 (12)0.0025 (11)0.0083 (10)−0.0053 (11)
N30.0364 (10)0.0347 (11)0.0315 (9)0.0028 (9)0.0069 (8)0.0002 (9)
N10.0299 (9)0.0304 (10)0.0353 (9)0.0037 (9)0.0087 (7)0.0002 (8)
N20.0441 (11)0.0332 (11)0.0362 (10)0.0017 (9)0.0128 (9)0.0005 (9)

Geometric parameters (Å, °)

O1—C11.337 (3)C18—H180.9500
O1—H11.01 (4)C13—C121.376 (4)
C5—C41.397 (3)C13—C141.377 (4)
C5—C61.396 (3)C13—H130.9500
C5—H50.9500C10—C151.386 (3)
C2—C31.382 (3)C10—C111.388 (3)
C2—C11.393 (3)C10—C81.521 (3)
C2—H20.9500C8—N11.477 (3)
C6—C11.423 (3)C8—C91.520 (3)
C6—C71.462 (3)C8—H81.0000
C4—C31.387 (3)C20—C191.388 (4)
C4—N21.418 (3)C20—H200.9500
C3—H30.9500C19—H190.9500
C17—C161.382 (3)C11—C121.389 (3)
C17—C181.384 (3)C11—H110.9500
C17—H170.9500C15—C141.394 (4)
C7—N11.279 (3)C15—H150.9500
C7—H70.9500C14—H140.9500
C16—C211.387 (3)C12—H120.9500
C16—N31.445 (3)C9—H9A0.9800
C21—C201.375 (3)C9—H9B0.9800
C21—H210.9500C9—H9C0.9800
C18—C191.378 (4)N3—N21.243 (3)
C1—O1—H1109 (2)C15—C10—C11118.4 (2)
C4—C5—C6120.1 (2)C15—C10—C8121.32 (19)
C4—C5—H5119.9C11—C10—C8120.3 (2)
C6—C5—H5119.9N1—C8—C9107.67 (17)
C3—C2—C1119.7 (2)N1—C8—C10107.34 (18)
C3—C2—H2120.1C9—C8—C10113.74 (18)
C1—C2—H2120.1N1—C8—H8109.3
C5—C6—C1119.3 (2)C9—C8—H8109.3
C5—C6—C7120.3 (2)C10—C8—H8109.3
C1—C6—C7120.3 (2)C21—C20—C19120.2 (2)
C3—C4—C5119.7 (2)C21—C20—H20119.9
C3—C4—N2114.5 (2)C19—C20—H20119.9
C5—C4—N2125.8 (2)C18—C19—C20119.9 (2)
C2—C3—C4121.3 (2)C18—C19—H19120.1
C2—C3—H3119.3C20—C19—H19120.1
C4—C3—H3119.3C10—C11—C12120.6 (2)
C16—C17—C18119.9 (2)C10—C11—H11119.7
C16—C17—H17120.1C12—C11—H11119.7
C18—C17—H17120.1C10—C15—C14120.9 (2)
N1—C7—C6120.3 (2)C10—C15—H15119.6
N1—C7—H7119.9C14—C15—H15119.6
C6—C7—H7119.9C13—C14—C15120.0 (2)
C17—C16—C21120.2 (2)C13—C14—H14120.0
C17—C16—N3116.2 (2)C15—C14—H14120.0
C21—C16—N3123.6 (2)C13—C12—C11120.5 (2)
O1—C1—C2118.4 (2)C13—C12—H12119.8
O1—C1—C6121.8 (2)C11—C12—H12119.8
C2—C1—C6119.8 (2)C8—C9—H9A109.5
C20—C21—C16119.8 (2)C8—C9—H9B109.5
C20—C21—H21120.1H9A—C9—H9B109.5
C16—C21—H21120.1C8—C9—H9C109.5
C19—C18—C17120.1 (3)H9A—C9—H9C109.5
C19—C18—H18119.9H9B—C9—H9C109.5
C17—C18—H18119.9N2—N3—C16112.7 (2)
C12—C13—C14119.6 (2)C7—N1—C8119.7 (2)
C12—C13—H13120.2N3—N2—C4115.3 (2)
C14—C13—H13120.2
C4—C5—C6—C1−0.4 (3)C15—C10—C8—C9−53.4 (3)
C4—C5—C6—C7179.25 (17)C11—C10—C8—C9128.4 (2)
C6—C5—C4—C30.8 (3)C16—C21—C20—C19−0.5 (4)
C6—C5—C4—N2−177.3 (2)C17—C18—C19—C200.6 (4)
C1—C2—C3—C41.1 (4)C21—C20—C19—C180.3 (4)
C5—C4—C3—C2−1.2 (3)C15—C10—C11—C12−1.7 (3)
N2—C4—C3—C2177.2 (2)C8—C10—C11—C12176.6 (2)
C5—C6—C7—N1−179.60 (19)C11—C10—C15—C140.1 (3)
C1—C6—C7—N10.0 (3)C8—C10—C15—C14−178.1 (2)
C18—C17—C16—C211.0 (3)C12—C13—C14—C15−1.1 (4)
C18—C17—C16—N3179.1 (2)C10—C15—C14—C131.3 (4)
C3—C2—C1—O1−179.6 (2)C14—C13—C12—C11−0.5 (4)
C3—C2—C1—C6−0.6 (3)C10—C11—C12—C131.9 (4)
C5—C6—C1—O1179.2 (2)C17—C16—N3—N2172.05 (19)
C7—C6—C1—O1−0.4 (3)C21—C16—N3—N2−9.9 (3)
C5—C6—C1—C20.3 (3)C6—C7—N1—C8179.21 (16)
C7—C6—C1—C2−179.3 (2)C9—C8—N1—C7−107.9 (2)
C17—C16—C21—C20−0.1 (3)C10—C8—N1—C7129.3 (2)
N3—C16—C21—C20−178.1 (2)C16—N3—N2—C4177.16 (18)
C16—C17—C18—C19−1.2 (4)C3—C4—N2—N3−174.4 (2)
C15—C10—C8—N165.6 (2)C5—C4—N2—N33.8 (3)
C11—C10—C8—N1−112.6 (2)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1···N1i1.01 (4)1.66 (4)2.557 (3)145 (3)

Symmetry codes: i.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: ZQ2030).

References

  • Akitsu, T. (2007). Polyhedron, 26, 2527–2535.
  • Akitsu, T. & Einaga, Y. (2005a). Polyhedron, 24, 1869–1877.
  • Akitsu, T. & Einaga, Y. (2005b). Polyhedron, 24, 2933–2943.
  • Akitsu, T. & Einaga, Y. (2006). Acta Cryst. E62, o4315–o4317.
  • Akitsu, T. & Itoh, T. (2010). Polyhedron, 29, 477–487.
  • Akitsu, T., Takeuchi, Y. & Einaga, Y. (2004). Acta Cryst. C60, o801–o802. [PubMed]
  • Aslantaş, M., Kurtoğlu, N., Şahin, E. & Kurtoğlu, M. (2007). Acta Cryst. E63, o3637.
  • Bruker (1998). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Hadjoudis, E. & Mavridis, I. M. (2004). Chem. Soc. Rev.33, 579–588. [PubMed]
  • Khandar, A. A. & Rezvani, Z. (1999). Polyhedron, 18, 129–133.
  • Miura, Y., Aritake, Y. & Akitsu, T. (2009). Acta Cryst. E65, o2381. [PMC free article] [PubMed]
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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