9,10-Di­cyano­dibenzoisobullvalene

In the title compound, C₂₀H₁₂N₂, the bond lengths in the cyclo­propane ring are 1.526, 1.532 and 1.541 (2) Å. The mol­ecules are linked by two C—H...N contacts.

Key indicators

• Single-crystal X-ray study
• T = 178 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.040
• wR factor = 0.111
• Data-to-parameter ratio = 12.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Prebullvalene, bicyclo[4.2.2]deca-2,4,7,9-tetraene, is a (CH)₁₀ hydrocarbon whose photoisomerization behaviour has been investigated (for a review see Scott & Jones, 1972). Our studies of the addition of cyanoacetylene to aromatic compounds (Hopf & Witulski, 1995) furnished us with the dibenzoprebullvalenedicarbonitrile, (1), and we have investigated its photochemical behaviour in acetone solution with light of wavelength > 300 nm. The photoisomerization yielded the title compound (2), and we here present its crystal structure.

Whereas the parent hydrocarbon prebullvalene isomerizes to bullvalene when irradiated (Scott & Jones, 1972; Jones & Scott, 1967), the photorearrangement of (1) takes a completely different course. To rationalize the formation of (2), we propose that the process is initiated by a [1,3] carbon shift followed by a di-π-methane rearrangement.

The structure of (2) is shown in Fig. 1. Molecular dimensions are normal. Bond lengths in the cyclopropane ring (Table 1) are somewhat greater than the average value of 1.509 Å e stablished by Allen (1980); see also Rozsondai (1995).

The molecules are linked to form columns parallel to the x axis by two C—H···N interactions (Fig. 2 and Table 2).

S2. Experimental

Compound (1) was irradiated for 4 h at room temperature using a 450 W mercury high-pressure lamp, forming (2) in 65% yield (Witulski, 1992). The product was crystallized 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 methine = 1.00 Å); U_sio(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, 1994); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecule of compound (2) in the crystal. Ellipsoids represent 30% probability levels and H-atom radii are arbitrary.
	Fig. 2. The packing of compound (2) in the crystal. Dashed lines indicate hydrogen bonds; only those H atoms participating in hydrogen bonds are included. The view direction is perpendicular to the xy plane.

9,10-Dicyano-dibenzoisobullvalene

Crystal data

C20H12N2	Z = 2
Mr = 280.32	F(000) = 292
Triclinic, P1	Dx = 1.286 Mg m^−3
a = 6.722 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.154 (3) Å	Cell parameters from 50 reflections
c = 12.143 (4) Å	θ = 10–12°
α = 96.85 (3)°	µ = 0.08 mm^−1
β = 90.65 (3)°	T = 178 K
γ = 102.51 (3)°	Prism, colourless
V = 723.7 (5) Å^3	0.7 × 0.4 × 0.2 mm

Data collection

Nicolet R3 diffractometer	Rint = 0.016
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 3.0°
Graphite monochromator	h = −7→2
ω scans	k = −10→10
3368 measured reflections	l = −14→14
2539 independent reflections	3 standard reflections every 147 reflections
1923 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)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.111	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0631P)^2 + 0.0943P] where P = (Fo^2 + 2Fc^2)/3
2539 reflections	(Δ/σ)max < 0.001
199 parameters	Δρmax = 0.14 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

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	0.0414 (3)	0.41201 (17)	0.29653 (13)	0.0338 (4)
H1	−0.0858	0.4411	0.2940	0.041*
C2	0.0870 (3)	0.36070 (18)	0.38951 (13)	0.0364 (4)
H2	−0.0104	0.3631	0.4454	0.044*
C3	0.2631 (3)	0.30107 (18)	0.41978 (13)	0.0346 (4)
C4	0.3735 (2)	0.22503 (17)	0.34350 (13)	0.0312 (4)
C5	0.3123 (2)	0.19330 (16)	0.22141 (12)	0.0282 (4)
H5	0.4095	0.1365	0.1841	0.034*
C6	0.0981 (2)	0.10131 (16)	0.19116 (12)	0.0277 (4)
C7	0.0002 (2)	0.16378 (16)	0.11276 (12)	0.0282 (4)
C8	0.1255 (2)	0.31159 (16)	0.09186 (12)	0.0287 (4)
H8	0.1293	0.3436	0.0159	0.034*
C9	0.1645 (2)	0.42951 (16)	0.19593 (12)	0.0288 (4)
C10	0.3209 (2)	0.33435 (16)	0.16302 (12)	0.0277 (4)
C11	0.3204 (3)	0.3167 (2)	0.53256 (14)	0.0497 (5)
H11	0.2454	0.3656	0.5854	0.060*
C12	0.4832 (3)	0.2630 (2)	0.56888 (16)	0.0579 (6)
H12	0.5193	0.2752	0.6458	0.070*
C13	0.5929 (3)	0.1917 (2)	0.49344 (16)	0.0532 (5)
H13	0.7062	0.1559	0.5180	0.064*
C14	0.5374 (3)	0.1721 (2)	0.38130 (14)	0.0410 (4)
H14	0.6127	0.1218	0.3296	0.049*
C15	0.0033 (3)	−0.03372 (17)	0.22732 (13)	0.0337 (4)
H15	0.0681	−0.0756	0.2819	0.040*
C16	−0.1880 (3)	−0.10647 (18)	0.18220 (14)	0.0385 (4)
H16	−0.2543	−0.1995	0.2057	0.046*
C17	−0.2840 (3)	−0.04492 (18)	0.10301 (14)	0.0380 (4)
H17	−0.4147	−0.0967	0.0727	0.046*
C18	−0.1908 (2)	0.09185 (17)	0.06762 (13)	0.0333 (4)
H18	−0.2565	0.1346	0.0139	0.040*
C19	0.2195 (2)	0.58454 (18)	0.17152 (13)	0.0332 (4)
C20	0.5186 (3)	0.41121 (17)	0.13149 (12)	0.0309 (4)
N1	0.2657 (2)	0.70710 (16)	0.15399 (12)	0.0446 (4)
N2	0.6789 (2)	0.47187 (17)	0.11101 (12)	0.0433 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0304 (9)	0.0312 (8)	0.0382 (9)	0.0059 (7)	0.0046 (7)	−0.0010 (7)
C2	0.0378 (10)	0.0349 (9)	0.0324 (9)	0.0015 (7)	0.0099 (7)	−0.0015 (7)
C3	0.0370 (10)	0.0337 (9)	0.0288 (8)	−0.0030 (7)	0.0015 (7)	0.0066 (6)
C4	0.0305 (9)	0.0298 (8)	0.0310 (8)	−0.0018 (7)	0.0000 (7)	0.0102 (6)
C5	0.0297 (8)	0.0279 (8)	0.0285 (8)	0.0083 (6)	0.0048 (6)	0.0065 (6)
C6	0.0311 (9)	0.0257 (7)	0.0259 (7)	0.0066 (6)	0.0039 (6)	0.0010 (6)
C7	0.0308 (9)	0.0270 (8)	0.0260 (7)	0.0059 (7)	0.0036 (6)	0.0008 (6)
C8	0.0292 (9)	0.0294 (8)	0.0271 (7)	0.0054 (7)	−0.0001 (6)	0.0045 (6)
C9	0.0297 (9)	0.0260 (8)	0.0306 (8)	0.0059 (6)	0.0001 (7)	0.0035 (6)
C10	0.0278 (8)	0.0292 (8)	0.0262 (7)	0.0050 (6)	0.0028 (6)	0.0052 (6)
C11	0.0585 (13)	0.0556 (11)	0.0282 (9)	−0.0022 (10)	0.0025 (9)	0.0049 (8)
C12	0.0580 (13)	0.0729 (14)	0.0339 (10)	−0.0121 (11)	−0.0128 (10)	0.0206 (9)
C13	0.0402 (11)	0.0667 (13)	0.0515 (12)	−0.0032 (10)	−0.0104 (9)	0.0314 (10)
C14	0.0337 (10)	0.0465 (10)	0.0437 (10)	0.0032 (8)	−0.0014 (8)	0.0202 (8)
C15	0.0433 (10)	0.0284 (8)	0.0298 (8)	0.0085 (7)	0.0047 (7)	0.0045 (6)
C16	0.0444 (10)	0.0264 (8)	0.0406 (9)	−0.0010 (7)	0.0088 (8)	0.0032 (7)
C17	0.0336 (9)	0.0349 (9)	0.0397 (9)	−0.0005 (7)	0.0010 (8)	−0.0034 (7)
C18	0.0330 (9)	0.0332 (8)	0.0324 (8)	0.0064 (7)	−0.0014 (7)	0.0003 (7)
C19	0.0338 (9)	0.0328 (9)	0.0328 (8)	0.0074 (7)	−0.0027 (7)	0.0038 (7)
C20	0.0322 (9)	0.0334 (8)	0.0282 (8)	0.0070 (7)	0.0006 (7)	0.0090 (6)
N1	0.0494 (10)	0.0327 (8)	0.0518 (9)	0.0073 (7)	−0.0016 (7)	0.0090 (7)
N2	0.0345 (9)	0.0474 (9)	0.0488 (9)	0.0047 (7)	0.0053 (7)	0.0175 (7)

Geometric parameters (Å, º)

C1—C2	1.331 (2)	C9—C19	1.454 (2)
C1—C9	1.488 (2)	C9—C10	1.532 (2)
C1—H1	0.9500	C10—C20	1.442 (2)
C2—C3	1.467 (3)	C11—C12	1.381 (3)
C2—H2	0.9500	C11—H11	0.9500
C3—C11	1.401 (2)	C12—C13	1.375 (3)
C3—C4	1.407 (2)	C12—H12	0.9500
C4—C14	1.390 (2)	C13—C14	1.388 (3)
C4—C5	1.511 (2)	C13—H13	0.9500
C5—C6	1.519 (2)	C14—H14	0.9500
C5—C10	1.536 (2)	C15—C16	1.387 (2)
C5—H5	1.0000	C15—H15	0.9500
C6—C15	1.386 (2)	C16—C17	1.390 (2)
C6—C7	1.395 (2)	C16—H16	0.9500
C7—C18	1.383 (2)	C17—C18	1.393 (2)
C7—C8	1.482 (2)	C17—H17	0.9500
C8—C10	1.526 (2)	C18—H18	0.9500
C8—C9	1.541 (2)	C19—N1	1.144 (2)
C8—H8	1.0000	C20—N2	1.145 (2)
C2—C1—C9	128.14 (16)	C1—C9—C8	122.47 (13)
C2—C1—H1	115.9	C10—C9—C8	59.54 (10)
C9—C1—H1	115.9	C20—C10—C8	124.02 (13)
C1—C2—C3	130.54 (16)	C20—C10—C9	117.86 (13)
C1—C2—H2	114.7	C8—C10—C9	60.54 (10)
C3—C2—H2	114.7	C20—C10—C5	116.99 (13)
C11—C3—C4	118.02 (17)	C8—C10—C5	108.49 (13)
C11—C3—C2	117.62 (16)	C9—C10—C5	116.98 (12)
C4—C3—C2	124.32 (15)	C12—C11—C3	121.67 (19)
C14—C4—C3	119.60 (15)	C12—C11—H11	119.2
C14—C4—C5	118.91 (15)	C3—C11—H11	119.2
C3—C4—C5	121.43 (15)	C13—C12—C11	119.87 (17)
C4—C5—C6	116.61 (13)	C13—C12—H12	120.1
C4—C5—C10	114.76 (12)	C11—C12—H12	120.1
C6—C5—C10	102.94 (12)	C12—C13—C14	119.74 (19)
C4—C5—H5	107.3	C12—C13—H13	120.1
C6—C5—H5	107.3	C14—C13—H13	120.1
C10—C5—H5	107.3	C13—C14—C4	121.07 (19)
C15—C6—C7	120.35 (15)	C13—C14—H14	119.5
C15—C6—C5	127.79 (14)	C4—C14—H14	119.5
C7—C6—C5	111.76 (13)	C6—C15—C16	118.67 (15)
C18—C7—C6	121.22 (14)	C6—C15—H15	120.7
C18—C7—C8	128.14 (14)	C16—C15—H15	120.7
C6—C7—C8	110.61 (14)	C15—C16—C17	120.83 (15)
C7—C8—C10	105.60 (12)	C15—C16—H16	119.6
C7—C8—C9	113.32 (12)	C17—C16—H16	119.6
C10—C8—C9	59.92 (10)	C16—C17—C18	120.73 (16)
C7—C8—H8	120.8	C16—C17—H17	119.6
C10—C8—H8	120.8	C18—C17—H17	119.6
C9—C8—H8	120.8	C7—C18—C17	118.19 (15)
C19—C9—C1	113.08 (13)	C7—C18—H18	120.9
C19—C9—C10	114.98 (13)	C17—C18—H18	120.9
C1—C9—C10	122.88 (13)	N1—C19—C9	178.63 (17)
C19—C9—C8	113.88 (13)	N2—C20—C10	176.98 (16)
C9—C1—C2—C3	−2.8 (3)	C9—C8—C10—C20	−105.44 (16)
C1—C2—C3—C11	152.47 (18)	C7—C8—C10—C9	−108.25 (13)
C1—C2—C3—C4	−29.7 (3)	C7—C8—C10—C5	2.87 (15)
C11—C3—C4—C14	−1.8 (2)	C9—C8—C10—C5	111.13 (13)
C2—C3—C4—C14	−179.55 (15)	C19—C9—C10—C20	11.23 (19)
C11—C3—C4—C5	175.52 (14)	C1—C9—C10—C20	−133.46 (15)
C2—C3—C4—C5	−2.3 (2)	C8—C9—C10—C20	115.36 (15)
C14—C4—C5—C6	119.09 (16)	C19—C9—C10—C8	−104.13 (15)
C3—C4—C5—C6	−58.22 (19)	C1—C9—C10—C8	111.19 (16)
C14—C4—C5—C10	−120.45 (16)	C19—C9—C10—C5	158.91 (13)
C3—C4—C5—C10	62.23 (19)	C1—C9—C10—C5	14.2 (2)
C4—C5—C6—C15	−49.2 (2)	C8—C9—C10—C5	−96.96 (15)
C10—C5—C6—C15	−175.76 (14)	C4—C5—C10—C20	79.58 (17)
C4—C5—C6—C7	134.56 (14)	C6—C5—C10—C20	−152.68 (13)
C10—C5—C6—C7	7.99 (16)	C4—C5—C10—C8	−134.07 (14)
C15—C6—C7—C18	−1.3 (2)	C6—C5—C10—C8	−6.33 (15)
C5—C6—C7—C18	175.23 (13)	C4—C5—C10—C9	−68.39 (18)
C15—C6—C7—C8	176.80 (13)	C6—C5—C10—C9	59.35 (16)
C5—C6—C7—C8	−6.64 (17)	C4—C3—C11—C12	1.6 (3)
C18—C7—C8—C10	−179.81 (14)	C2—C3—C11—C12	179.48 (16)
C6—C7—C8—C10	2.22 (16)	C3—C11—C12—C13	−0.2 (3)
C18—C7—C8—C9	116.69 (17)	C11—C12—C13—C14	−1.0 (3)
C6—C7—C8—C9	−61.28 (17)	C12—C13—C14—C4	0.7 (3)
C2—C1—C9—C19	−119.42 (18)	C3—C4—C14—C13	0.7 (2)
C2—C1—C9—C10	25.9 (2)	C5—C4—C14—C13	−176.68 (15)
C2—C1—C9—C8	98.1 (2)	C7—C6—C15—C16	1.4 (2)
C7—C8—C9—C19	−158.92 (13)	C5—C6—C15—C16	−174.56 (14)
C10—C8—C9—C19	105.99 (15)	C6—C15—C16—C17	−0.5 (2)
C7—C8—C9—C1	−16.8 (2)	C15—C16—C17—C18	−0.4 (2)
C10—C8—C9—C1	−111.85 (16)	C6—C7—C18—C17	0.4 (2)
C7—C8—C9—C10	95.09 (14)	C8—C7—C18—C17	−177.42 (14)
C7—C8—C10—C20	146.31 (14)	C16—C17—C18—C7	0.5 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C18—H18···N1^i	0.95	2.65	3.526 (2)	154
C8—H8···N2^ii	1.00	2.57	3.440 (2)	145

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