[2.2](2,7)Oxepinopara­cyclo­phane-4,5-dicarbo­nitrile

In the title compound, C₁₈H₁₄N₂O, the O atom of the oxepine ring lies above the six-membered ring [3.008 (4) Å from the plane of the non-bridgehead atoms], but the rest of the oxepine ring is bent away from that plane and thus away from the mol­ecule. Three C—H...N contacts connect the mol­ecules to form layers parallel to the ac plane.

Key indicators

• Single-crystal X-ray study
• T = 178 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.068
• wR factor = 0.219
• Data-to-parameter ratio = 12.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_371  Alert C Long   C(sp2)-C(sp1) Bond  C(4)   -   C(17)  =       1.43 Ang.

PLAT_371  Alert C Long   C(sp2)-C(sp1) Bond  C(5)   -   C(18)  =       1.43 Ang.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check

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S1. Comment

When dicyanoacetylene (2) is added to [2.2](2,5)furanocyclophane, (1), in the presence of BF₃–etherate at room temperature, the [2 + 2]-cycloadduct (3) is formed in low yield (7%) (Witulski, 1992). To confirm its structure, we heated this addition product in toluene solution at 433 K and observed the expected ring opening to oxepinophane (4), accompanied by a colour change to deep red (yield 68%; Witulski, 1992). We report here the structure of (4).

The molecule of (4) is shown in Fig. 1. Except for the carbonitrile substituents, the molecule shows approximate mirror symmetry. The six-membered ring shows the flattened boat form typical of paracyclophanes, whereby atom C11 lies 0.172 (6) Å and C14 0.152 (6) Å out of the plane of the other four atoms. The oxepine ring is non-planar, with absolute torsion angles of ca 31° about the bonds involving the O atom (and of ca 17° about C4—C5 and C6—C7). The net effect is that the O atom lies above the six-membered ring [3.008 (4) Å from the C12/C13/C15/C16 plane], but the rest of the oxepine ring is bent away from the six-membered ring and thus away from the molecule as a whole.

Three non-bonded contacts of the type C—H···N could be interpreted as weak hydrogen bonds (Table 2). The overall effect of these is to produce thick layers of molecules parallel to the ac plane (Fig. 2) in the regions y ≈ 0, 1/2, 1, etc.

S2. Experimental

Compound (4) was prepared as described above, isolated by thick-layer chromatography (Witulski, 1992), and recrystallized from chloroform/pentane.

S3. Refinement

H atoms were included using a riding model with fixed C—H bond lengths (sp² C—H = 0.95 Å and methylene C—H = 0.99 Å); U_iso(H) values were fixed at 1.2U_eq of the parent atom.

Computing details

Data collection: P3 (Nicolet, 1987); cell refinement: P3; data reduction: XDISK (Nicolet, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1996); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecule of compound (4) in the crystal. Ellipsoids are drawn at the 30% probability level and H-atom radii are arbitrary.
	Fig. 2. Packing diagram of compound (4). Hydrogen bonds are shown as thick dashed lines. H atoms not involved in hydrogen bonds have been omitted.

[2.2](2,7)Oxepinoparacyclophane-4,5-dicarbonitrile

Crystal data

C18H14N2O	F(000) = 576
Mr = 274.31	Dx = 1.338 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 6.494 (3) Å	Cell parameters from 49 reflections
b = 23.899 (12) Å	θ = 10–11.5°
c = 8.783 (4) Å	µ = 0.08 mm^−1
β = 92.48 (4)°	T = 178 K
V = 1361.8 (11) Å^3	Column, red
Z = 4	0.65 × 0.20 × 0.20 mm

Data collection

Nicolet R3 diffractometer	Rint = 0.023
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 3.3°
Graphite monochromator	h = −7→7
ω scans	k = −28→0
2567 measured reflections	l = 0→10
2409 independent reflections	3 standard reflections every 147 reflections
1211 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.068	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.219	H-atom parameters constrained
S = 0.93	w = 1/[σ^2(Fo^2) + (0.13P)^2] where P = (Fo^2 + 2Fc^2)/3
2409 reflections	(Δ/σ)max < 0.001
190 parameters	Δρmax = 0.28 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

Experimental. [2.2](2,7)Oxepinoparacyclophane-4,5-dicarbonitrile

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
O	0.1051 (4)	0.37919 (11)	0.6606 (3)	0.0397 (7)
C1	0.3209 (7)	0.34058 (18)	1.0008 (5)	0.0454 (11)
H1A	0.4077	0.3696	1.0521	0.054*
H1B	0.2872	0.3117	1.0765	0.054*
C2	0.1216 (7)	0.36684 (18)	0.9291 (5)	0.0436 (11)
H2A	0.0276	0.3363	0.8949	0.052*
H2B	0.0524	0.3882	1.0089	0.052*
C3	0.1542 (6)	0.40548 (18)	0.7952 (4)	0.0348 (9)
C4	0.2123 (6)	0.45882 (17)	0.8158 (5)	0.0376 (10)
C5	0.2365 (6)	0.50262 (16)	0.6964 (4)	0.0364 (10)
C6	0.2523 (6)	0.49358 (17)	0.5471 (5)	0.0391 (10)
H6	0.2672	0.5257	0.4850	0.047*
C7	0.2491 (6)	0.44003 (17)	0.4699 (5)	0.0399 (10)
H7	0.3005	0.4405	0.3703	0.048*
C8	0.1856 (6)	0.39029 (17)	0.5166 (4)	0.0355 (10)
C9	0.1729 (6)	0.33921 (16)	0.4174 (5)	0.0390 (10)
H9A	0.1207	0.3504	0.3143	0.047*
H9B	0.0714	0.3131	0.4591	0.047*
C10	0.3826 (7)	0.30732 (18)	0.4024 (5)	0.0418 (11)
H10A	0.3607	0.2716	0.3469	0.050*
H10B	0.4814	0.3304	0.3471	0.050*
C11	0.4612 (6)	0.29679 (17)	0.5614 (5)	0.0382 (10)
C12	0.5843 (6)	0.33691 (17)	0.6360 (5)	0.0386 (10)
H12	0.6805	0.3579	0.5808	0.046*
C13	0.5665 (6)	0.34618 (18)	0.7900 (5)	0.0408 (11)
H13	0.6481	0.3742	0.8400	0.049*
C14	0.4308 (6)	0.31495 (18)	0.8716 (4)	0.0394 (10)
C15	0.3469 (6)	0.26629 (17)	0.8048 (5)	0.0418 (11)
H15	0.2795	0.2396	0.8653	0.050*
C16	0.3630 (6)	0.25747 (17)	0.6507 (5)	0.0410 (11)
H16	0.3070	0.2245	0.6051	0.049*
C17	0.2454 (6)	0.47720 (17)	0.9703 (5)	0.0402 (10)
C18	0.2411 (6)	0.55968 (18)	0.7472 (5)	0.0398 (10)
N1	0.2681 (6)	0.49346 (16)	1.0932 (4)	0.0543 (11)
N2	0.2467 (6)	0.60528 (16)	0.7884 (4)	0.0499 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.0379 (16)	0.0444 (17)	0.0369 (16)	−0.0044 (13)	0.0018 (12)	−0.0045 (13)
C1	0.047 (3)	0.049 (3)	0.039 (2)	−0.001 (2)	−0.001 (2)	0.009 (2)
C2	0.041 (2)	0.050 (3)	0.041 (2)	−0.002 (2)	0.008 (2)	−0.001 (2)
C3	0.028 (2)	0.047 (2)	0.030 (2)	0.0025 (18)	0.0016 (17)	−0.0034 (18)
C4	0.030 (2)	0.041 (2)	0.041 (2)	0.0024 (19)	0.0001 (18)	−0.003 (2)
C5	0.033 (2)	0.035 (2)	0.040 (2)	0.0031 (18)	−0.0005 (18)	−0.0049 (19)
C6	0.035 (2)	0.033 (2)	0.049 (3)	0.0036 (18)	0.001 (2)	0.0050 (19)
C7	0.041 (2)	0.042 (3)	0.036 (2)	0.007 (2)	−0.0008 (19)	0.0031 (19)
C8	0.029 (2)	0.038 (2)	0.039 (2)	0.0043 (18)	0.0002 (18)	−0.0034 (19)
C9	0.044 (2)	0.036 (2)	0.036 (2)	0.0044 (19)	−0.0036 (19)	−0.0013 (19)
C10	0.047 (3)	0.036 (2)	0.043 (2)	0.004 (2)	0.004 (2)	−0.0024 (19)
C11	0.036 (2)	0.037 (2)	0.042 (2)	0.0093 (19)	0.0037 (19)	−0.0006 (19)
C12	0.031 (2)	0.038 (2)	0.047 (3)	0.0046 (18)	0.0065 (19)	0.006 (2)
C13	0.025 (2)	0.049 (3)	0.048 (3)	−0.0006 (19)	−0.0052 (19)	0.006 (2)
C14	0.034 (2)	0.049 (3)	0.034 (2)	0.002 (2)	−0.0031 (19)	0.011 (2)
C15	0.037 (2)	0.038 (2)	0.051 (3)	0.0024 (19)	0.002 (2)	0.015 (2)
C16	0.041 (2)	0.034 (2)	0.048 (3)	0.0055 (19)	0.001 (2)	0.003 (2)
C17	0.032 (2)	0.041 (3)	0.046 (3)	0.0054 (19)	0.000 (2)	0.000 (2)
C18	0.034 (2)	0.040 (3)	0.045 (2)	0.0013 (19)	−0.0007 (19)	−0.001 (2)
N1	0.062 (3)	0.057 (3)	0.044 (2)	0.000 (2)	−0.001 (2)	−0.008 (2)
N2	0.047 (2)	0.037 (2)	0.066 (3)	0.0034 (17)	0.0021 (19)	−0.005 (2)

Geometric parameters (Å, º)

O—C3	1.364 (5)	C9—C10	1.571 (6)
O—C8	1.415 (5)	C9—H9A	0.9900
C1—C14	1.498 (6)	C9—H9B	0.9900
C1—C2	1.547 (6)	C10—C11	1.487 (6)
C1—H1A	0.9900	C10—H10A	0.9900
C1—H1B	0.9900	C10—H10B	0.9900
C2—C3	1.518 (6)	C11—C12	1.394 (6)
C2—H2A	0.9900	C11—C16	1.396 (6)
C2—H2B	0.9900	C12—C13	1.380 (6)
C3—C4	1.340 (6)	C12—H12	0.9500
C4—C17	1.434 (6)	C13—C14	1.379 (6)
C4—C5	1.495 (6)	C13—H13	0.9500
C5—C6	1.337 (5)	C14—C15	1.402 (6)
C5—C18	1.435 (6)	C15—C16	1.378 (6)
C6—C7	1.448 (6)	C15—H15	0.9500
C6—H6	0.9500	C16—H16	0.9500
C7—C8	1.329 (5)	C17—N1	1.151 (5)
C7—H7	0.9500	C18—N2	1.148 (5)
C8—C9	1.500 (5)
C3—O—C8	127.4 (3)	C8—C9—H9A	108.6
C14—C1—C2	106.0 (3)	C10—C9—H9A	108.6
C14—C1—H1A	110.5	C8—C9—H9B	108.6
C2—C1—H1A	110.5	C10—C9—H9B	108.6
C14—C1—H1B	110.5	H9A—C9—H9B	107.6
C2—C1—H1B	110.5	C11—C10—C9	105.5 (3)
H1A—C1—H1B	108.7	C11—C10—H10A	110.6
C3—C2—C1	114.8 (3)	C9—C10—H10A	110.6
C3—C2—H2A	108.6	C11—C10—H10B	110.6
C1—C2—H2A	108.6	C9—C10—H10B	110.6
C3—C2—H2B	108.6	H10A—C10—H10B	108.8
C1—C2—H2B	108.6	C12—C11—C16	117.7 (4)
H2A—C2—H2B	107.5	C12—C11—C10	119.4 (4)
C4—C3—O	127.6 (4)	C16—C11—C10	119.7 (4)
C4—C3—C2	121.5 (4)	C13—C12—C11	120.0 (4)
O—C3—C2	110.9 (3)	C13—C12—H12	120.0
C3—C4—C17	116.7 (4)	C11—C12—H12	120.0
C3—C4—C5	127.5 (4)	C14—C13—C12	120.3 (4)
C17—C4—C5	115.7 (4)	C14—C13—H13	119.8
C6—C5—C18	117.2 (4)	C12—C13—H13	119.8
C6—C5—C4	126.1 (4)	C13—C14—C15	118.5 (4)
C18—C5—C4	116.7 (3)	C13—C14—C1	120.6 (4)
C5—C6—C7	127.0 (4)	C15—C14—C1	117.8 (4)
C5—C6—H6	116.5	C16—C15—C14	119.6 (4)
C7—C6—H6	116.5	C16—C15—H15	120.2
C8—C7—C6	130.1 (4)	C14—C15—H15	120.2
C8—C7—H7	114.9	C15—C16—C11	120.3 (4)
C6—C7—H7	114.9	C15—C16—H16	119.8
C7—C8—O	125.1 (4)	C11—C16—H16	119.8
C7—C8—C9	124.0 (4)	N1—C17—C4	177.8 (5)
O—C8—C9	110.7 (3)	N2—C18—C5	179.3 (5)
C8—C9—C10	114.7 (3)
C14—C1—C2—C3	−51.7 (5)	C3—O—C8—C9	154.0 (3)
C8—O—C3—C4	30.9 (6)	C7—C8—C9—C10	81.8 (5)
C8—O—C3—C2	−152.8 (3)	O—C8—C9—C10	−103.0 (4)
C1—C2—C3—C4	−81.5 (5)	C8—C9—C10—C11	53.0 (5)
C1—C2—C3—O	102.0 (4)	C9—C10—C11—C12	−88.4 (4)
O—C3—C4—C17	176.9 (4)	C9—C10—C11—C16	71.1 (5)
C2—C3—C4—C17	1.0 (6)	C16—C11—C12—C13	−16.3 (6)
O—C3—C4—C5	0.4 (7)	C10—C11—C12—C13	143.6 (4)
C2—C3—C4—C5	−175.5 (4)	C11—C12—C13—C14	1.6 (6)
C3—C4—C5—C6	−17.1 (7)	C12—C13—C14—C15	13.9 (6)
C17—C4—C5—C6	166.4 (4)	C12—C13—C14—C1	−145.7 (4)
C3—C4—C5—C18	162.3 (4)	C2—C1—C14—C13	88.0 (4)
C17—C4—C5—C18	−14.3 (5)	C2—C1—C14—C15	−71.8 (5)
C18—C5—C6—C7	−179.3 (4)	C13—C14—C15—C16	−14.6 (6)
C4—C5—C6—C7	0.1 (7)	C1—C14—C15—C16	145.7 (4)
C5—C6—C7—C8	17.1 (7)	C14—C15—C16—C11	−0.3 (6)
C6—C7—C8—O	−0.6 (7)	C12—C11—C16—C15	15.6 (6)
C6—C7—C8—C9	173.9 (4)	C10—C11—C16—C15	−144.2 (4)
C3—O—C8—C7	−30.8 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···N2^i	0.99	2.66	3.541 (6)	148
C2—H2B···N2^ii	0.99	2.70	3.582 (6)	149
C10—H10B···N2^iii	0.99	2.66	3.649 (6)	177

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x, −y+1, −z+2; (iii) −x+1, −y+1, −z+1.