4-Phenyl-diazenyl-2-[(R)-(1-phenyl-ethyl)imino-meth-yl]phenol.

The title chiral photochromic Schiff base compound, C(21)H(19)N(3)O, was synthesized from (R)-1-phenyl-ethyl-amine and the salicylaldehyde of an azobenzene derivative. The mol-ecule 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 intra-molecular 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 ▶,b ▶); Akitsu (2007 ▶); Akitsu & Itoh (2010 ▶). For Schiff base ligands, see: Akitsu et al. (2004 ▶, 2006 ▶); Miura et al. (2009 ▶); Hadjoudis & Mavridis (2004 ▶). For Schiff base compounds with an azobenzene group, see: Aslantaş et al. (2007 ▶); Khandar & Rezvani (1999 ▶).

Experimental

Crystal data

C21H19N3O

M = 329.39

Monoclinic,

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

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

C21H19N3O	F(000) = 696
Mr = 329.39	Dx = 1.268 Mg m−3
Monoclinic, C2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2y	Cell parameters from 1707 reflections
a = 22.430 (2) Å	θ = 2.8–25.6°
b = 5.9566 (6) Å	µ = 0.08 mm−1
c = 13.4670 (13) Å	T = 173 K
β = 106.396 (1)°	Prism, red violet
V = 1726.1 (3) Å3	0.31 × 0.12 × 0.09 mm
Z = 4

Bruker APEXII CCD diffractometer	1960 independent reflections
Radiation source: fine-focus sealed tube	1741 reflections with I > 2σ(I)
graphite	Rint = 0.029
Detector resolution: 8.333 pixels mm-1	θmax = 26.6°, θmin = 1.6°
φ and ω scans	h = −16→28
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −6→7
Tmin = 0.976, Tmax = 0.993	l = −16→16
4632 measured reflections

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)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3
1960 reflections	(Δ/σ)max = 0.001
231 parameters	Δρmax = 0.26 e Å−3
1 restraint	Δρmin = −0.27 e Å−3

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.

	x	y	z	Uiso*/Ueq
O1	0.99357 (8)	−0.0345 (3)	0.86831 (13)	0.0407 (4)
C5	1.01961 (10)	0.3842 (4)	0.68547 (16)	0.0311 (5)
H5	1.0052	0.5273	0.6577	0.037*
C2	1.06244 (11)	−0.0381 (4)	0.76572 (17)	0.0358 (5)
H2	1.0775	−0.1809	0.7930	0.043*
C6	0.99411 (9)	0.2834 (4)	0.75769 (15)	0.0286 (5)
C4	1.06632 (10)	0.2751 (4)	0.65393 (16)	0.0328 (5)
C3	1.08666 (11)	0.0649 (4)	0.69370 (18)	0.0364 (5)
H3	1.1179	−0.0097	0.6710	0.044*
C17	1.10112 (11)	0.8454 (4)	0.44134 (19)	0.0386 (6)
H17	1.0665	0.9222	0.4526	0.046*
C7	0.94575 (9)	0.3980 (4)	0.79195 (15)	0.0286 (5)
H7	0.9314	0.5415	0.7646	0.034*
C16	1.11935 (10)	0.6407 (4)	0.48836 (16)	0.0326 (5)
C1	1.01590 (10)	0.0684 (4)	0.79815 (16)	0.0301 (5)
C21	1.17050 (11)	0.5300 (4)	0.47323 (18)	0.0382 (6)
H21	1.1831	0.3894	0.5057	0.046*
C18	1.13343 (12)	0.9384 (5)	0.37779 (18)	0.0439 (6)
H18	1.1205	1.0778	0.3444	0.053*
C13	0.72251 (11)	−0.0416 (5)	0.85593 (19)	0.0414 (6)
H13	0.6892	−0.1453	0.8464	0.050*
C10	0.82061 (9)	0.2628 (4)	0.88270 (16)	0.0297 (5)
C8	0.87446 (9)	0.4249 (4)	0.89349 (16)	0.0311 (5)
H8	0.8598	0.5583	0.8481	0.037*
C20	1.20294 (11)	0.6245 (5)	0.41107 (19)	0.0449 (7)
H20	1.2382	0.5495	0.4010	0.054*
C19	1.18438 (11)	0.8291 (5)	0.36290 (18)	0.0451 (7)
H19	1.2068	0.8937	0.3197	0.054*
C11	0.76386 (10)	0.3026 (5)	0.81026 (17)	0.0371 (5)
H11	0.7580	0.4359	0.7699	0.045*
C15	0.82718 (10)	0.0696 (4)	0.94228 (19)	0.0380 (6)
H15	0.8656	0.0397	0.9923	0.046*
C14	0.77806 (11)	−0.0812 (5)	0.9297 (2)	0.0441 (6)
H14	0.7829	−0.2114	0.9720	0.053*
C12	0.71552 (11)	0.1493 (5)	0.79616 (19)	0.0429 (6)
H12	0.6773	0.1764	0.7449	0.051*
C9	0.90390 (11)	0.5033 (5)	1.00386 (17)	0.0393 (6)
H9A	0.9363	0.6144	1.0046	0.059*
H9B	0.9224	0.3746	1.0469	0.059*
H9C	0.8720	0.5714	1.0312	0.059*
N3	1.08366 (9)	0.5577 (3)	0.55470 (14)	0.0347 (5)
N1	0.92269 (8)	0.3059 (3)	0.85861 (14)	0.0320 (4)
N2	1.09774 (9)	0.3622 (3)	0.58460 (15)	0.0375 (5)
H1	0.9594 (15)	0.061 (7)	0.882 (2)	0.075 (10)*

	U11	U22	U33	U12	U13	U23
O1	0.0506 (10)	0.0315 (9)	0.0472 (9)	0.0084 (8)	0.0254 (8)	0.0107 (8)
C5	0.0337 (11)	0.0279 (11)	0.0295 (10)	−0.0018 (10)	0.0053 (8)	0.0015 (10)
C2	0.0434 (12)	0.0261 (12)	0.0387 (11)	0.0061 (10)	0.0127 (10)	0.0024 (10)
C6	0.0303 (10)	0.0268 (11)	0.0271 (9)	−0.0028 (10)	0.0053 (8)	−0.0019 (9)
C4	0.0353 (11)	0.0351 (12)	0.0275 (10)	−0.0048 (11)	0.0082 (8)	0.0000 (10)
C3	0.0405 (12)	0.0336 (13)	0.0382 (12)	0.0049 (11)	0.0163 (10)	−0.0010 (10)
C17	0.0388 (12)	0.0350 (14)	0.0396 (11)	−0.0016 (11)	0.0071 (10)	−0.0017 (10)
C7	0.0272 (10)	0.0272 (11)	0.0296 (10)	0.0010 (9)	0.0052 (8)	0.0010 (9)
C16	0.0344 (11)	0.0363 (13)	0.0247 (10)	−0.0067 (10)	0.0045 (8)	−0.0021 (9)
C1	0.0347 (11)	0.0273 (12)	0.0288 (10)	−0.0020 (10)	0.0096 (9)	−0.0010 (9)
C21	0.0404 (12)	0.0343 (13)	0.0381 (11)	0.0001 (10)	0.0081 (10)	0.0027 (11)
C18	0.0491 (14)	0.0378 (14)	0.0388 (12)	−0.0066 (12)	0.0028 (11)	0.0108 (11)
C13	0.0331 (12)	0.0411 (14)	0.0537 (14)	−0.0038 (11)	0.0183 (10)	−0.0094 (12)
C10	0.0293 (10)	0.0315 (12)	0.0289 (10)	0.0045 (9)	0.0091 (8)	−0.0001 (9)
C8	0.0310 (11)	0.0288 (12)	0.0342 (10)	0.0047 (9)	0.0101 (9)	0.0027 (9)
C20	0.0381 (13)	0.0555 (18)	0.0429 (13)	−0.0007 (13)	0.0141 (11)	−0.0023 (13)
C19	0.0448 (14)	0.0546 (17)	0.0343 (11)	−0.0163 (13)	0.0082 (10)	0.0037 (12)
C11	0.0385 (12)	0.0374 (13)	0.0329 (10)	0.0042 (11)	0.0061 (9)	0.0021 (11)
C15	0.0313 (11)	0.0360 (13)	0.0440 (12)	0.0043 (11)	0.0061 (10)	0.0078 (11)
C14	0.0469 (14)	0.0335 (14)	0.0539 (14)	0.0034 (11)	0.0178 (11)	0.0072 (12)
C12	0.0332 (12)	0.0501 (16)	0.0417 (12)	0.0046 (12)	0.0046 (10)	−0.0059 (12)
C9	0.0361 (12)	0.0402 (14)	0.0402 (12)	0.0025 (11)	0.0083 (10)	−0.0053 (11)
N3	0.0364 (10)	0.0347 (11)	0.0315 (9)	0.0028 (9)	0.0069 (8)	0.0002 (9)
N1	0.0299 (9)	0.0304 (10)	0.0353 (9)	0.0037 (9)	0.0087 (7)	0.0002 (8)
N2	0.0441 (11)	0.0332 (11)	0.0362 (10)	0.0017 (9)	0.0128 (9)	0.0005 (9)

O1—C1	1.337 (3)	C18—H18	0.9500
O1—H1	1.01 (4)	C13—C12	1.376 (4)
C5—C4	1.397 (3)	C13—C14	1.377 (4)
C5—C6	1.396 (3)	C13—H13	0.9500
C5—H5	0.9500	C10—C15	1.386 (3)
C2—C3	1.382 (3)	C10—C11	1.388 (3)
C2—C1	1.393 (3)	C10—C8	1.521 (3)
C2—H2	0.9500	C8—N1	1.477 (3)
C6—C1	1.423 (3)	C8—C9	1.520 (3)
C6—C7	1.462 (3)	C8—H8	1.0000
C4—C3	1.387 (3)	C20—C19	1.388 (4)
C4—N2	1.418 (3)	C20—H20	0.9500
C3—H3	0.9500	C19—H19	0.9500
C17—C16	1.382 (3)	C11—C12	1.389 (3)
C17—C18	1.384 (3)	C11—H11	0.9500
C17—H17	0.9500	C15—C14	1.394 (4)
C7—N1	1.279 (3)	C15—H15	0.9500
C7—H7	0.9500	C14—H14	0.9500
C16—C21	1.387 (3)	C12—H12	0.9500
C16—N3	1.445 (3)	C9—H9A	0.9800
C21—C20	1.375 (3)	C9—H9B	0.9800
C21—H21	0.9500	C9—H9C	0.9800
C18—C19	1.378 (4)	N3—N2	1.243 (3)
C1—O1—H1	109 (2)	C15—C10—C11	118.4 (2)
C4—C5—C6	120.1 (2)	C15—C10—C8	121.32 (19)
C4—C5—H5	119.9	C11—C10—C8	120.3 (2)
C6—C5—H5	119.9	N1—C8—C9	107.67 (17)
C3—C2—C1	119.7 (2)	N1—C8—C10	107.34 (18)
C3—C2—H2	120.1	C9—C8—C10	113.74 (18)
C1—C2—H2	120.1	N1—C8—H8	109.3
C5—C6—C1	119.3 (2)	C9—C8—H8	109.3
C5—C6—C7	120.3 (2)	C10—C8—H8	109.3
C1—C6—C7	120.3 (2)	C21—C20—C19	120.2 (2)
C3—C4—C5	119.7 (2)	C21—C20—H20	119.9
C3—C4—N2	114.5 (2)	C19—C20—H20	119.9
C5—C4—N2	125.8 (2)	C18—C19—C20	119.9 (2)
C2—C3—C4	121.3 (2)	C18—C19—H19	120.1
C2—C3—H3	119.3	C20—C19—H19	120.1
C4—C3—H3	119.3	C10—C11—C12	120.6 (2)
C16—C17—C18	119.9 (2)	C10—C11—H11	119.7
C16—C17—H17	120.1	C12—C11—H11	119.7
C18—C17—H17	120.1	C10—C15—C14	120.9 (2)
N1—C7—C6	120.3 (2)	C10—C15—H15	119.6
N1—C7—H7	119.9	C14—C15—H15	119.6
C6—C7—H7	119.9	C13—C14—C15	120.0 (2)
C17—C16—C21	120.2 (2)	C13—C14—H14	120.0
C17—C16—N3	116.2 (2)	C15—C14—H14	120.0
C21—C16—N3	123.6 (2)	C13—C12—C11	120.5 (2)
O1—C1—C2	118.4 (2)	C13—C12—H12	119.8
O1—C1—C6	121.8 (2)	C11—C12—H12	119.8
C2—C1—C6	119.8 (2)	C8—C9—H9A	109.5
C20—C21—C16	119.8 (2)	C8—C9—H9B	109.5
C20—C21—H21	120.1	H9A—C9—H9B	109.5
C16—C21—H21	120.1	C8—C9—H9C	109.5
C19—C18—C17	120.1 (3)	H9A—C9—H9C	109.5
C19—C18—H18	119.9	H9B—C9—H9C	109.5
C17—C18—H18	119.9	N2—N3—C16	112.7 (2)
C12—C13—C14	119.6 (2)	C7—N1—C8	119.7 (2)
C12—C13—H13	120.2	N3—N2—C4	115.3 (2)
C14—C13—H13	120.2
C4—C5—C6—C1	−0.4 (3)	C15—C10—C8—C9	−53.4 (3)
C4—C5—C6—C7	179.25 (17)	C11—C10—C8—C9	128.4 (2)
C6—C5—C4—C3	0.8 (3)	C16—C21—C20—C19	−0.5 (4)
C6—C5—C4—N2	−177.3 (2)	C17—C18—C19—C20	0.6 (4)
C1—C2—C3—C4	1.1 (4)	C21—C20—C19—C18	0.3 (4)
C5—C4—C3—C2	−1.2 (3)	C15—C10—C11—C12	−1.7 (3)
N2—C4—C3—C2	177.2 (2)	C8—C10—C11—C12	176.6 (2)
C5—C6—C7—N1	−179.60 (19)	C11—C10—C15—C14	0.1 (3)
C1—C6—C7—N1	0.0 (3)	C8—C10—C15—C14	−178.1 (2)
C18—C17—C16—C21	1.0 (3)	C12—C13—C14—C15	−1.1 (4)
C18—C17—C16—N3	179.1 (2)	C10—C15—C14—C13	1.3 (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—C13	1.9 (4)
C5—C6—C1—O1	179.2 (2)	C17—C16—N3—N2	172.05 (19)
C7—C6—C1—O1	−0.4 (3)	C21—C16—N3—N2	−9.9 (3)
C5—C6—C1—C2	0.3 (3)	C6—C7—N1—C8	179.21 (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—C7	129.3 (2)
N3—C16—C21—C20	−178.1 (2)	C16—N3—N2—C4	177.16 (18)
C16—C17—C18—C19	−1.2 (4)	C3—C4—N2—N3	−174.4 (2)
C15—C10—C8—N1	65.6 (2)	C5—C4—N2—N3	3.8 (3)
C11—C10—C8—N1	−112.6 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1i	1.01 (4)	1.66 (4)	2.557 (3)	145 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	1.01 (4)	1.66 (4)	2.557 (3)	145 (3)