2,2′-{(Z)-Ethane-1,2-diyl­bis­[(Z)-o-phenyl­ene­nitrilo­methyl­idyne]}diphenol (EIEP)

The salicyl­idene­aniline moiety in the centrosymmetric title compound, C₂₈H₂₄N₂O₂, is a phenol–imine tautomer which is non-planar and photochromic. A strong intramolecular hydrogen-bonding interaction, which is a common feature in related imine–phenol compounds, stabilizes the molecular structure. The π system in the salicyl­idene­aniline moiety interacts with symmetry-related π systems through face-to-face π–π interactions and C—H...π interactions, to stabilize the mol­ecules in the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.057
• wR factor = 0.199
• Data-to-parameter ratio = 21.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         47 Perc.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C9     -   C10     ..       5.38 su

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990) and ORTEP-3 (Farrugia, 1997).

2,2'-{(Z)-Ethane-1,2-diylbis[(Z)-o-phenylenenitrilomethylidyne]}diphenol

Crystal data

C28H24N2O2	F(000) = 444
Mr = 420.49	Dx = 1.273 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 11.817 (3) Å	θ = 8–15°
b = 13.762 (6) Å	µ = 0.08 mm^−1
c = 6.873 (2) Å	T = 293 K
β = 101.15 (3)°	Block, yellow
V = 1096.6 (6) Å^3	0.25 × 0.22 × 0.20 mm
Z = 2

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.042
Radiation source: fine-focus sealed tube	θmax = 30.0°, θmin = 1.8°
Graphite monochromator	h = −16→16
non–profiled ω/2θ scans	k = 0→19
3425 measured reflections	l = 0→9
3179 independent reflections	3 standard reflections every 120 min
1504 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.057	H-atom parameters constrained
wR(F^2) = 0.199	w = 1/[σ^2(Fo^2) + (0.0961P)^2 + 0.0403P] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max = 0.005
3179 reflections	Δρmax = 0.19 e Å^−3
147 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (7)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.95547 (17)	0.12126 (14)	0.3165 (3)	0.0384 (5)
C2	1.03434 (17)	0.05488 (14)	0.2642 (3)	0.0392 (5)
C3	1.14800 (19)	0.06032 (17)	0.3620 (3)	0.0477 (5)
H3	1.2014	0.0171	0.3280	0.057*
C4	1.1842 (2)	0.1278 (2)	0.5082 (3)	0.0552 (6)
H4	1.2609	0.1291	0.5732	0.066*
C5	1.1068 (2)	0.19376 (18)	0.5584 (3)	0.0536 (6)
H5	1.1313	0.2402	0.6558	0.064*
C6	0.99255 (19)	0.19053 (17)	0.4633 (3)	0.0473 (5)
H6	0.9401	0.2347	0.4973	0.057*
C7	0.99653 (18)	−0.01933 (15)	0.1034 (3)	0.0429 (5)
H7A	0.9177	−0.0386	0.1048	0.051*
H7B	1.0449	−0.0766	0.1309	0.051*
N8	0.84017 (14)	0.11922 (12)	0.2103 (3)	0.0425 (4)
C9	0.75664 (19)	0.13183 (16)	0.3012 (3)	0.0475 (5)
H9	0.7732	0.1416	0.4376	0.057*
C10	0.63706 (18)	0.13139 (16)	0.1995 (3)	0.0481 (5)
C11	0.60639 (19)	0.12047 (17)	−0.0074 (4)	0.0523 (6)
C12	0.4916 (2)	0.1182 (2)	−0.0978 (4)	0.0694 (8)
H12	0.4712	0.1104	−0.2345	0.083*
C13	0.4078 (2)	0.1272 (2)	0.0120 (5)	0.0766 (8)
H13	0.3307	0.1251	−0.0509	0.092*
C14	0.4352 (2)	0.1392 (2)	0.2140 (5)	0.0805 (9)
H14	0.3772	0.1462	0.2870	0.097*
C15	0.5490 (2)	0.1408 (2)	0.3073 (4)	0.0697 (8)
H15	0.5677	0.1483	0.4442	0.084*
O16	0.68777 (14)	0.11178 (16)	−0.1208 (2)	0.0698 (6)
H16	0.7513	0.1049	−0.0490	0.105*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0443 (11)	0.0406 (11)	0.0315 (9)	−0.0013 (9)	0.0105 (8)	0.0024 (9)
C2	0.0497 (12)	0.0380 (11)	0.0322 (10)	0.0014 (9)	0.0136 (9)	0.0031 (9)
C3	0.0490 (12)	0.0553 (14)	0.0401 (11)	0.0086 (10)	0.0118 (9)	0.0024 (10)
C4	0.0483 (13)	0.0761 (17)	0.0397 (11)	0.0018 (12)	0.0041 (10)	0.0006 (12)
C5	0.0591 (15)	0.0656 (16)	0.0365 (11)	−0.0103 (12)	0.0104 (10)	−0.0101 (11)
C6	0.0576 (13)	0.0467 (13)	0.0409 (11)	−0.0005 (10)	0.0181 (10)	−0.0060 (10)
C7	0.0527 (12)	0.0385 (11)	0.0396 (11)	0.0021 (9)	0.0145 (9)	−0.0009 (9)
N8	0.0424 (9)	0.0422 (10)	0.0444 (10)	0.0006 (7)	0.0119 (8)	−0.0025 (8)
C9	0.0564 (14)	0.0455 (13)	0.0434 (12)	−0.0015 (10)	0.0167 (10)	−0.0028 (10)
C10	0.0432 (11)	0.0464 (13)	0.0571 (14)	−0.0002 (9)	0.0162 (10)	−0.0033 (11)
C11	0.0471 (12)	0.0529 (14)	0.0575 (14)	0.0014 (10)	0.0112 (11)	0.0021 (11)
C12	0.0500 (15)	0.083 (2)	0.0719 (17)	0.0012 (13)	0.0032 (13)	0.0050 (16)
C13	0.0468 (14)	0.084 (2)	0.098 (2)	−0.0002 (14)	0.0098 (15)	−0.0024 (18)
C14	0.0496 (16)	0.098 (2)	0.101 (2)	−0.0068 (14)	0.0332 (16)	−0.0195 (19)
C15	0.0556 (15)	0.089 (2)	0.0704 (17)	−0.0088 (14)	0.0279 (13)	−0.0167 (15)
O16	0.0537 (10)	0.1074 (16)	0.0493 (10)	0.0072 (11)	0.0127 (8)	0.0000 (10)

Geometric parameters (Å, º)

C1—C6	1.396 (3)	N8—C9	1.278 (3)
C1—C2	1.401 (3)	C9—C10	1.450 (3)
C1—N8	1.416 (3)	C9—H9	0.93
C2—C3	1.383 (3)	C10—C15	1.395 (3)
C2—C7	1.508 (3)	C10—C11	1.405 (3)
C3—C4	1.375 (3)	C11—O16	1.355 (3)
C3—H3	0.93	C11—C12	1.379 (3)
C4—C5	1.379 (3)	C12—C13	1.361 (4)
C4—H4	0.93	C12—H12	0.93
C5—C6	1.382 (3)	C13—C14	1.373 (4)
C5—H5	0.93	C13—H13	0.93
C6—H6	0.93	C14—C15	1.374 (3)
C7—C7^i	1.534 (4)	C14—H14	0.93
C7—H7A	0.97	C15—H15	0.93
C7—H7B	0.97	O16—H16	0.82
C6—C1—C2	119.98 (19)	C9—N8—C1	120.15 (18)
C6—C1—N8	121.50 (18)	N8—C9—C10	122.4 (2)
C2—C1—N8	118.43 (18)	N8—C9—H9	118.8
C3—C2—C1	118.13 (19)	C10—C9—H9	118.8
C3—C2—C7	121.03 (18)	C15—C10—C11	118.3 (2)
C1—C2—C7	120.83 (18)	C15—C10—C9	120.0 (2)
C4—C3—C2	121.9 (2)	C11—C10—C9	121.6 (2)
C4—C3—H3	119.1	O16—C11—C12	119.0 (2)
C2—C3—H3	119.1	O16—C11—C10	121.2 (2)
C3—C4—C5	120.0 (2)	C12—C11—C10	119.8 (2)
C3—C4—H4	120.0	C13—C12—C11	120.4 (3)
C5—C4—H4	120.0	C13—C12—H12	119.8
C4—C5—C6	119.7 (2)	C11—C12—H12	119.8
C4—C5—H5	120.2	C12—C13—C14	121.1 (3)
C6—C5—H5	120.2	C12—C13—H13	119.4
C5—C6—C1	120.3 (2)	C14—C13—H13	119.4
C5—C6—H6	119.8	C13—C14—C15	119.5 (3)
C1—C6—H6	119.8	C13—C14—H14	120.3
C2—C7—C7^i	112.5 (2)	C15—C14—H14	120.3
C2—C7—H7A	109.1	C14—C15—C10	120.9 (3)
C7^i—C7—H7A	109.1	C14—C15—H15	119.5
C2—C7—H7B	109.1	C10—C15—H15	119.5
C7^i—C7—H7B	109.1	C11—O16—H16	109.5
H7A—C7—H7B	107.8
C6—C1—C2—C3	0.2 (3)	C1—N8—C9—C10	179.39 (18)
N8—C1—C2—C3	176.95 (18)	N8—C9—C10—C15	176.9 (2)
C6—C1—C2—C7	−178.86 (18)	N8—C9—C10—C11	−2.3 (4)
N8—C1—C2—C7	−2.1 (3)	C15—C10—C11—O16	179.4 (2)
C1—C2—C3—C4	0.5 (3)	C9—C10—C11—O16	−1.3 (3)
C7—C2—C3—C4	179.62 (19)	C15—C10—C11—C12	−0.8 (3)
C2—C3—C4—C5	−1.2 (3)	C9—C10—C11—C12	178.5 (2)
C3—C4—C5—C6	1.0 (3)	O16—C11—C12—C13	−179.7 (3)
C4—C5—C6—C1	−0.3 (3)	C10—C11—C12—C13	0.5 (4)
C2—C1—C6—C5	−0.4 (3)	C11—C12—C13—C14	0.4 (5)
N8—C1—C6—C5	−176.99 (19)	C12—C13—C14—C15	−0.9 (5)
C3—C2—C7—C7^i	−91.0 (3)	C13—C14—C15—C10	0.7 (5)
C1—C2—C7—C7^i	88.1 (3)	C11—C10—C15—C14	0.2 (4)
C6—C1—N8—C9	−42.4 (3)	C9—C10—C15—C14	−179.1 (3)
C2—C1—N8—C9	140.9 (2)

Symmetry code: (i) −x+2, −y, −z.