2,4-Di-tert-butyl-6-[(2,5-difluorophenyl)iminomethyl]phenol.

In the title Schiff base, C(21)H(25)F(2)NO, the dihedral angle between the aromatic rings is 27.90(5)° and an intramolecular O-H⋯N hydrogen bond occurs. In the crystal, the molecules are linked by C-H⋯O, C-H⋯N and C-H⋯F interactions.

Related literature

For background on the photochromic behavior of salicyli­dene­anilines, see: Brown (1971 ▶); Chemla & Zyss (1987 ▶); MacDonald & Whitesides (1994 ▶); Cohen et al. (1966 ▶). For related compounds, see: Ancın et al. (2007 ▶); Kasumov, Köksal & Köseoĝlu (2004 ▶); Kasumov, Medjidov, Ya­ylı & Zeren (2004 ▶); Çelik et al. (2007 ▶, 2009 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶); Etter (1991 ▶).

Experimental

Crystal data

C21H25F2NO

M = 345.42

Monoclinic,

a = 6.423 (5) Å

b = 17.386 (5) Å

c = 17.337 (5) Å

β = 90.319 (5)°

V = 1936.0 (17) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 293 K

0.20 × 0.20 × 0.20 mm

Data collection

Rigaku Rxdiffractometer

Absorption correction: multi-scan (Blessing, 1995 ▶) T min = 0.983, T max = 0.983

50854 measured reflections

5662 independent reflections

2715 reflections with I > 2σ(I)

R int = 0.099

Refinement

R[F 2 > 2σ(F 2)] = 0.057

wR(F 2) = 0.144

S = 0.96

5662 reflections

238 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.11 e Å−3

Δρmin = −0.13 e Å−3

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶) and local programs.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809041099/jh2098sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809041099/jh2098Isup2.hkl

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

C21H25F2NO	F(000) = 736
Mr = 345.42	Dx = 1.185 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 6.423 (5) Å	Cell parameters from 5929 reflections
b = 17.386 (5) Å	θ = 2.6–30.5°
c = 17.337 (5) Å	µ = 0.09 mm−1
β = 90.319 (5)°	T = 293 K
V = 1936.0 (17) Å3	Needle, pale yellow
Z = 4	0.20 × 0.20 × 0.20 mm

Rigaku Rx diffractometer	5662 independent reflections
Radiation source: fine-focus sealed tube	2715 reflections with I > 2σ(I)
graphite	Rint = 0.099
Detector resolution: 10.0000 pixels mm-1	θmax = 30.5°, θmin = 2.6°
dtprofit.ref scans	h = −9→7
Absorption correction: multi-scan (Blessing, 1995)	k = −24→24
Tmin = 0.983, Tmax = 0.983	l = −24→24
50854 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)] = 0.057	Hydrogen site location: mixed
wR(F2) = 0.144	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ2(Fo2) + (0.0514P)2] where P = (Fo2 + 2Fc2)/3
5662 reflections	(Δ/σ)max < 0.001
238 parameters	Δρmax = 0.11 e Å−3
0 restraints	Δρmin = −0.13 e Å−3
none constraints

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
F1	1.34032 (17)	−0.06161 (7)	0.45693 (7)	0.0928 (4)
F2	0.7822 (2)	−0.18169 (7)	0.25642 (7)	0.1106 (5)
O	0.43585 (19)	−0.00558 (7)	0.19801 (7)	0.0716 (3)
N	0.7118 (2)	−0.03731 (8)	0.30481 (8)	0.0599 (3)
C1	0.8873 (2)	−0.07788 (9)	0.33323 (9)	0.0579 (4)
C2	1.0326 (3)	−0.04776 (11)	0.38404 (10)	0.0632 (4)
C3	1.2008 (3)	−0.09201 (11)	0.40566 (10)	0.0670 (4)
C4	1.2353 (3)	−0.16381 (13)	0.37793 (11)	0.0817 (6)
C5	1.0919 (3)	−0.19439 (12)	0.32701 (12)	0.0887 (6)
C6	0.9227 (3)	−0.15091 (11)	0.30581 (10)	0.0727 (5)
C7	0.6290 (3)	0.01624 (9)	0.34520 (10)	0.0571 (4)
C8	0.4535 (2)	0.06101 (9)	0.31824 (8)	0.0533 (4)
C9	0.3601 (2)	0.04900 (8)	0.24564 (9)	0.0542 (4)
C10	0.1864 (2)	0.09270 (8)	0.22268 (8)	0.0531 (4)
C11	0.1149 (3)	0.14730 (9)	0.27431 (9)	0.0551 (4)
C12	0.2021 (2)	0.16151 (8)	0.34774 (9)	0.0517 (4)
C13	0.3714 (2)	0.11717 (8)	0.36766 (9)	0.0543 (4)
C14	0.0847 (3)	0.08127 (9)	0.14289 (9)	0.0608 (4)
C15	0.2440 (3)	0.10244 (12)	0.07964 (10)	0.0878 (6)
C16	0.0150 (3)	−0.00280 (10)	0.13124 (10)	0.0745 (5)
C17	−0.1094 (3)	0.13131 (11)	0.13211 (11)	0.0852 (6)
C18	0.1136 (3)	0.22420 (9)	0.40007 (9)	0.0590 (4)
C19	0.2129 (3)	0.22172 (12)	0.48075 (10)	0.0835 (6)
C20	−0.1214 (3)	0.21370 (11)	0.40956 (11)	0.0767 (5)
C21	0.1544 (3)	0.30292 (10)	0.36414 (12)	0.0909 (6)
H0	0.5354	−0.0269	0.2187	0.107*
H2	1.018 (3)	0.0018 (10)	0.4049 (10)	0.072 (5)*
H4	1.3524	−0.1916	0.3929	0.098*
H5	1.1096	−0.2437	0.3073	0.106*
H7	0.681 (2)	0.0293 (9)	0.4007 (10)	0.071 (5)*
H11	0.001 (2)	0.1785 (8)	0.2587 (8)	0.054 (4)*
H13	0.4337	0.1247	0.4156	0.065*
H15A	0.3659	0.0709	0.0853	0.132*
H15B	0.2820	0.1556	0.0846	0.132*
H15C	0.1830	0.0939	0.0297	0.132*
H16A	0.1327	−0.0363	0.1374	0.112*
H16B	−0.0422	−0.0088	0.0803	0.112*
H16C	−0.0888	−0.0156	0.1687	0.112*
H17A	−0.1680	0.1223	0.0819	0.128*
H17B	−0.0719	0.1845	0.1369	0.128*
H17C	−0.2100	0.1184	0.1708	0.128*
H19A	0.1544	0.2617	0.5121	0.125*
H19B	0.3604	0.2292	0.4766	0.125*
H19C	0.1858	0.1727	0.5041	0.125*
H20A	−0.1749	0.2537	0.4421	0.115*
H20B	−0.1487	0.1645	0.4326	0.115*
H20C	−0.1881	0.2163	0.3599	0.115*
H21A	0.0982	0.3423	0.3968	0.136*
H21B	0.0890	0.3055	0.3143	0.136*
H21C	0.3017	0.3105	0.3588	0.136*

	U11	U22	U33	U12	U13	U23
F1	0.0730 (7)	0.1143 (9)	0.0908 (8)	−0.0059 (6)	−0.0254 (6)	0.0194 (6)
F2	0.1241 (10)	0.0941 (9)	0.1131 (10)	0.0261 (7)	−0.0420 (8)	−0.0405 (7)
O	0.0734 (8)	0.0773 (8)	0.0639 (7)	0.0170 (6)	−0.0125 (6)	−0.0166 (6)
N	0.0572 (8)	0.0612 (8)	0.0613 (8)	0.0052 (6)	−0.0076 (6)	−0.0001 (6)
C1	0.0557 (9)	0.0593 (10)	0.0587 (9)	0.0053 (8)	−0.0012 (7)	0.0062 (7)
C2	0.0598 (10)	0.0635 (11)	0.0662 (11)	−0.0011 (8)	−0.0034 (8)	0.0075 (8)
C3	0.0579 (10)	0.0824 (12)	0.0608 (10)	−0.0001 (9)	−0.0042 (8)	0.0134 (9)
C4	0.0724 (12)	0.0961 (15)	0.0766 (13)	0.0274 (11)	0.0037 (10)	0.0123 (11)
C5	0.1007 (16)	0.0829 (13)	0.0825 (13)	0.0350 (12)	−0.0014 (12)	−0.0069 (10)
C6	0.0785 (12)	0.0752 (12)	0.0644 (11)	0.0108 (10)	−0.0086 (9)	−0.0091 (9)
C7	0.0557 (9)	0.0584 (10)	0.0572 (10)	−0.0004 (8)	−0.0077 (8)	0.0019 (7)
C8	0.0518 (9)	0.0542 (9)	0.0538 (9)	−0.0010 (7)	−0.0049 (7)	0.0000 (7)
C9	0.0585 (9)	0.0503 (9)	0.0536 (9)	−0.0021 (7)	−0.0026 (7)	−0.0037 (7)
C10	0.0573 (9)	0.0521 (8)	0.0498 (8)	−0.0045 (7)	−0.0064 (7)	0.0026 (7)
C11	0.0576 (10)	0.0494 (9)	0.0582 (9)	0.0010 (7)	−0.0075 (7)	0.0040 (7)
C12	0.0536 (9)	0.0468 (8)	0.0546 (8)	−0.0063 (7)	−0.0038 (7)	−0.0004 (6)
C13	0.0562 (9)	0.0540 (9)	0.0527 (8)	−0.0049 (7)	−0.0091 (7)	−0.0027 (7)
C14	0.0723 (11)	0.0595 (10)	0.0504 (9)	−0.0034 (8)	−0.0122 (8)	0.0013 (7)
C15	0.1058 (16)	0.0983 (15)	0.0594 (11)	−0.0252 (12)	−0.0046 (11)	0.0053 (10)
C16	0.0868 (13)	0.0699 (11)	0.0667 (11)	−0.0099 (10)	−0.0171 (9)	−0.0068 (8)
C17	0.0960 (15)	0.0814 (13)	0.0779 (13)	0.0107 (11)	−0.0372 (11)	0.0014 (10)
C18	0.0635 (10)	0.0500 (9)	0.0636 (10)	−0.0017 (7)	−0.0001 (8)	−0.0090 (7)
C19	0.0862 (13)	0.0914 (14)	0.0727 (12)	0.0044 (11)	−0.0081 (10)	−0.0281 (10)
C20	0.0649 (11)	0.0869 (13)	0.0784 (12)	0.0017 (9)	0.0046 (9)	−0.0107 (10)
C21	0.1132 (17)	0.0543 (11)	0.1054 (16)	−0.0062 (11)	0.0154 (13)	−0.0068 (10)

F1—C3	1.365 (2)	C2—H2	0.940 (17)
F2—C6	1.351 (2)	C16—H16A	0.9600
O—C9	1.3503 (18)	C16—H16B	0.9600
N—C7	1.282 (2)	C16—H16C	0.9600
N—C1	1.416 (2)	C19—H19A	0.9600
C1—C2	1.383 (2)	C19—H19B	0.9600
C1—C6	1.375 (2)	C19—H19C	0.9600
C3—C4	1.356 (3)	C17—H17A	0.9600
C3—C2	1.376 (2)	C17—H17B	0.9600
C4—C5	1.379 (3)	C17—H17C	0.9600
C6—C5	1.372 (3)	C20—H20A	0.9600
C8—C13	1.404 (2)	C20—H20B	0.9600
C8—C9	1.407 (2)	C20—H20C	0.9600
C8—C7	1.445 (2)	C4—H4	0.9300
C10—C11	1.385 (2)	C15—H15A	0.9600
C10—C9	1.405 (2)	C15—H15B	0.9600
C10—C14	1.540 (2)	C15—H15C	0.9600
C11—C12	1.410 (2)	C5—H5	0.9300
C12—C13	1.375 (2)	C21—H21A	0.9600
C12—C18	1.530 (2)	C21—H21B	0.9600
C14—C17	1.531 (2)	C21—H21C	0.9600
C14—C16	1.542 (2)	C11—H11	0.948 (14)
C14—C15	1.548 (3)	C13—H13	0.9300
C18—C21	1.527 (2)	C7—H7	1.042 (17)
C18—C20	1.530 (3)	O—H0	0.8200
C18—C19	1.535 (2)
C7—N—C1	120.24 (14)	C14—C16—H16C	109.5
C11—C10—C9	116.96 (14)	H16A—C16—H16C	109.5
C11—C10—C14	121.90 (14)	H16B—C16—H16C	109.5
C9—C10—C14	121.13 (14)	C18—C19—H19A	109.5
C10—C11—C12	124.88 (15)	C18—C19—H19B	109.5
C13—C8—C9	119.32 (14)	H19A—C19—H19B	109.5
C13—C8—C7	118.16 (14)	C18—C19—H19C	109.5
C9—C8—C7	122.50 (14)	H19A—C19—H19C	109.5
C13—C12—C11	116.00 (14)	H19B—C19—H19C	109.5
C13—C12—C18	123.12 (14)	C14—C17—H17A	109.5
C11—C12—C18	120.87 (14)	C14—C17—H17B	109.5
C12—C13—C8	122.39 (14)	H17A—C17—H17B	109.5
C6—C1—C2	117.22 (16)	C14—C17—H17C	109.5
C6—C1—N	118.20 (15)	H17A—C17—H17C	109.5
C2—C1—N	124.49 (16)	H17B—C17—H17C	109.5
O—C9—C10	119.66 (14)	C18—C20—H20A	109.5
O—C9—C8	119.88 (14)	C18—C20—H20B	109.5
C10—C9—C8	120.45 (14)	H20A—C20—H20B	109.5
C21—C18—C12	109.36 (14)	C18—C20—H20C	109.5
C21—C18—C20	108.81 (15)	H20A—C20—H20C	109.5
C12—C18—C20	110.42 (13)	H20B—C20—H20C	109.5
C21—C18—C19	109.01 (15)	C3—C4—H4	120.9
C12—C18—C19	111.50 (14)	C5—C4—H4	120.9
C20—C18—C19	107.68 (14)	C14—C15—H15A	109.5
N—C7—C8	122.66 (15)	C14—C15—H15B	109.5
C17—C14—C10	112.19 (14)	H15A—C15—H15B	109.5
C17—C14—C16	106.69 (15)	C14—C15—H15C	109.5
C10—C14—C16	111.20 (13)	H15A—C15—H15C	109.5
C17—C14—C15	108.64 (15)	H15B—C15—H15C	109.5
C10—C14—C15	109.07 (14)	C6—C5—H5	120.5
C16—C14—C15	108.97 (15)	C4—C5—H5	120.5
C4—C3—F1	118.63 (17)	C18—C21—H21A	109.5
C4—C3—C2	123.19 (18)	C18—C21—H21B	109.5
F1—C3—C2	118.17 (18)	H21A—C21—H21B	109.5
C3—C2—C1	119.19 (18)	C18—C21—H21C	109.5
F2—C6—C5	118.48 (17)	H21A—C21—H21C	109.5
F2—C6—C1	118.27 (16)	H21B—C21—H21C	109.5
C5—C6—C1	123.24 (18)	C10—C11—H11	117.7 (9)
C3—C4—C5	118.17 (18)	C12—C11—H11	117.4 (9)
C6—C5—C4	118.96 (19)	C12—C13—H13	118.8
C3—C2—H2	119.2 (11)	C8—C13—H13	118.8
C1—C2—H2	121.6 (11)	N—C7—H7	122.0 (9)
C14—C16—H16A	109.5	C8—C7—H7	115.3 (9)
C14—C16—H16B	109.5	C9—O—H0	109.5
H16A—C16—H16B	109.5
C9—C10—C11—C12	−0.5 (2)	C11—C12—C18—C19	172.11 (15)
C14—C10—C11—C12	−179.12 (14)	C1—N—C7—C8	178.23 (14)
C10—C11—C12—C13	0.3 (2)	C13—C8—C7—N	178.59 (15)
C10—C11—C12—C18	178.97 (15)	C9—C8—C7—N	0.1 (2)
C11—C12—C13—C8	0.0 (2)	C11—C10—C14—C17	−4.9 (2)
C18—C12—C13—C8	−178.57 (14)	C9—C10—C14—C17	176.53 (15)
C9—C8—C13—C12	−0.2 (2)	C11—C10—C14—C16	−124.32 (17)
C7—C8—C13—C12	−178.68 (14)	C9—C10—C14—C16	57.1 (2)
C7—N—C1—C6	155.18 (17)	C11—C10—C14—C15	115.49 (18)
C7—N—C1—C2	−28.3 (2)	C9—C10—C14—C15	−63.06 (19)
C11—C10—C9—O	179.42 (14)	C4—C3—C2—C1	1.8 (3)
C14—C10—C9—O	−2.0 (2)	F1—C3—C2—C1	−178.84 (14)
C11—C10—C9—C8	0.3 (2)	C6—C1—C2—C3	−1.3 (2)
C14—C10—C9—C8	178.94 (14)	N—C1—C2—C3	−177.87 (15)
C13—C8—C9—O	−179.09 (14)	C2—C1—C6—F2	179.66 (16)
C7—C8—C9—O	−0.7 (2)	N—C1—C6—F2	−3.5 (3)
C13—C8—C9—C10	0.0 (2)	C2—C1—C6—C5	0.6 (3)
C7—C8—C9—C10	178.43 (14)	N—C1—C6—C5	177.43 (17)
C13—C12—C18—C21	111.27 (18)	F1—C3—C4—C5	179.11 (17)
C11—C12—C18—C21	−67.3 (2)	C2—C3—C4—C5	−1.6 (3)
C13—C12—C18—C20	−129.03 (17)	F2—C6—C5—C4	−179.41 (17)
C11—C12—C18—C20	52.4 (2)	C1—C6—C5—C4	−0.4 (3)
C13—C12—C18—C19	−9.4 (2)	C3—C4—C5—C6	0.8 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O—H0···N	0.82	1.88	2.615 (2)	149
C16—H16A···O	0.96	2.27	2.935 (3)	126
C15—H15A···O	0.96	2.40	3.038 (2)	123
C7—H7···F1i	1.042	2.875	3.010 (2)	87
C16—H16C···Ni	0.96	2.72	3.643 (3)	162
C21—H21B···F2ii	0.96	2.68	3.498 (3)	143

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O—H0⋯N	0.82	1.88	2.615 (2)	149
C16—H16A⋯O	0.96	2.27	2.935 (3)	126
C15—H15A⋯O	0.96	2.40	3.038 (2)	123
C16—H16C⋯Ni	0.96	2.72	3.643 (3)	162
C21—H21B⋯F2ii	0.96	2.68	3.498 (3)	143

Symmetry codes: (i) ; (ii) .