1,7-Dibromo-2,8-dimethyl-6H,12H-5,11-methano­dibenzo[b,f][1,5]diazo­cine

In the title compound, C₁₇H₁₆Br₂N₂, the 1,7-dibromo-2,8-dimethyl analogue of Tröger's base, the aryl rings are offset with respect to one another. The dihedral angle between the two benzene rings is 97.47 (5)°; the mol­ecule is C₂-symmetric.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C)= 0.003 Å
• R factor = 0.022
• wR factor = 0.057
• Data-to-parameter ratio = 18.7

checkCIF/PLATON results

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Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT and XPREP (Siemens, 1995); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: TEXSAN for Windows (Molecular Structure Corporation, 1998), Xtal3.6 (Hall et al., 1999), ORTEPII (Johnson, 1976) and WinGX (Farrugia, 1999); software used to prepare material for publication: WinGX.

1,7-dibromo-2,8-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine

Crystal data

C17H16Br2N2	F(000) = 808
Mr = 408.14	Dx = 1.783 Mg m^−3
Monoclinic, C2/c	Melting point: 539.8 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 23.583 (7) Å	Cell parameters from 862 reflections
b = 5.096 (2) Å	θ = 2.8–28.2°
c = 14.907 (4) Å	µ = 5.33 mm^−1
β = 121.921 (4)°	T = 150 K
V = 1520.6 (9) Å^3	Prism, colourless
Z = 4	0.55 × 0.26 × 0.17 mm

Data collection

Bruker SMART 1000 CCD diffractometer	1813 independent reflections
Radiation source: fine-focus sealed tube	1721 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ω scans	θmax = 28.3°, θmin = 2.0°
Absorption correction: gaussian [GAUSSIAN (Coppens et al., 1965) and PLATON (Spek, 2003)]	h = −31→31
Tmin = 0.065, Tmax = 0.472	k = −6→6
7490 measured reflections	l = −19→16

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)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.057	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0337P)^2 + 1.4322P] where P = (Fo^2 + 2Fc^2)/3
1813 reflections	(Δ/σ)max = 0.001
97 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.51 e Å^−3

Special details

Experimental. ¹H NMR (400 MHz, CDCl₃): δ 2.31 (6H, s), 4.20–4.26 (4H, m), 4.50 (2H, d, J = 17.4 Hz), 7.10 (4H, app. s); ¹³C NMR: δ 22.71, 60.39, 65.75, 98.35, 98.37, 120.75, 123.85, 125.12, 129.34; HRMS m/z calculated for C₁₇H₁₆Br₂N₂ + H⁺ [M + H⁺] 406.975300, observed 406.975764. Analysis calculated for C₁₇H₁₆Br₂N₂: C 50.03, H 3.95, N 6.86%; found: 49.90, H 3.93, N 7.07%. Single crystals of (I) were obtained by the slow evaporation of a dichloromethane solution of the compound.

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
Br1	0.392824 (9)	0.15685 (4)	0.400291 (14)	0.02926 (8)
N1	0.46326 (7)	0.6216 (3)	0.15545 (12)	0.0226 (3)
C1	0.42175 (8)	0.4356 (3)	0.16598 (13)	0.0201 (3)
C2	0.37236 (9)	0.3037 (4)	0.07596 (14)	0.0267 (4)
H2	0.3677	0.3347	0.0096	0.032*
C3	0.33045 (9)	0.1291 (4)	0.08334 (15)	0.0297 (4)
H3	0.2981	0.0379	0.0216	0.036*
C4	0.33377 (8)	0.0815 (4)	0.17811 (15)	0.0261 (3)
C5	0.38351 (8)	0.2148 (3)	0.26653 (13)	0.0212 (3)
C6	0.42914 (8)	0.3850 (3)	0.26407 (13)	0.0188 (3)
C7	0.48765 (8)	0.5001 (3)	0.36434 (13)	0.0229 (3)
H7A	0.4710	0.6338	0.3931	0.027*
H7B	0.5097	0.3596	0.4178	0.027*
C8	0.5000	0.7829 (5)	0.2500	0.0255 (5)
H8A	0.4683	0.8971	0.2564	0.031*
C9	0.28627 (10)	−0.1079 (4)	0.18264 (19)	0.0382 (5)
H9A	0.2525	−0.1643	0.1109	0.057*
H9B	0.2643	−0.0215	0.2150	0.057*
H9C	0.3111	−0.2612	0.2250	0.057*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.02811 (11)	0.03705 (12)	0.03109 (11)	−0.00195 (7)	0.02141 (9)	0.00293 (7)
N1	0.0240 (7)	0.0216 (6)	0.0274 (7)	0.0047 (5)	0.0171 (6)	0.0053 (5)
C1	0.0187 (7)	0.0199 (7)	0.0229 (7)	0.0046 (6)	0.0118 (6)	0.0025 (6)
C2	0.0231 (8)	0.0337 (9)	0.0209 (8)	0.0057 (7)	0.0101 (7)	−0.0002 (7)
C3	0.0200 (8)	0.0350 (10)	0.0285 (9)	−0.0014 (7)	0.0091 (7)	−0.0102 (7)
C4	0.0196 (8)	0.0241 (8)	0.0353 (9)	−0.0010 (7)	0.0150 (7)	−0.0055 (7)
C5	0.0204 (7)	0.0215 (7)	0.0256 (8)	0.0018 (6)	0.0147 (7)	−0.0014 (6)
C6	0.0186 (7)	0.0176 (7)	0.0224 (7)	0.0020 (6)	0.0124 (6)	−0.0014 (6)
C7	0.0235 (8)	0.0268 (8)	0.0232 (8)	−0.0056 (6)	0.0155 (7)	−0.0067 (6)
C8	0.0282 (12)	0.0157 (10)	0.0396 (14)	0.000	0.0228 (11)	0.000
C9	0.0292 (9)	0.0354 (10)	0.0535 (13)	−0.0114 (8)	0.0242 (9)	−0.0106 (9)

Geometric parameters (Å, º)

Br1—C5	1.9102 (17)	C4—C5	1.393 (2)
N1—C1	1.429 (2)	C4—C9	1.507 (3)
N1—C8	1.457 (2)	C5—C6	1.397 (2)
N1—C7^i	1.474 (2)	C6—C7	1.517 (2)
C1—C2	1.399 (2)	C7—H7A	0.9900
C1—C6	1.402 (2)	C7—H7B	0.9900
C2—C3	1.377 (3)	C8—H8A	0.9900
C2—H2	0.9500	C9—H9A	0.9800
C3—C4	1.394 (3)	C9—H9B	0.9800
C3—H3	0.9500	C9—H9C	0.9800
C1—N1—C8	111.07 (12)	C5—C6—C1	117.95 (15)
C1—N1—C7^i	113.55 (13)	C5—C6—C7	121.74 (15)
C8—N1—C7^i	107.60 (12)	C1—C6—C7	120.21 (14)
C2—C1—C6	119.56 (16)	N1^i—C7—C6	111.52 (13)
C2—C1—N1	118.98 (15)	N1^i—C7—H7A	109.3
C6—C1—N1	121.45 (15)	C6—C7—H7A	109.3
C3—C2—C1	120.19 (17)	N1^i—C7—H7B	109.3
C3—C2—H2	119.9	C6—C7—H7B	109.3
C1—C2—H2	119.9	H7A—C7—H7B	108.0
C2—C3—C4	122.37 (17)	N1—C8—N1^i	111.26 (19)
C2—C3—H3	118.8	N1—C8—H8A	109.4
C4—C3—H3	118.8	N1^i—C8—H8A	109.4
C5—C4—C3	116.22 (16)	C4—C9—H9A	109.5
C5—C4—C9	122.97 (18)	C4—C9—H9B	109.5
C3—C4—C9	120.80 (17)	H9A—C9—H9B	109.5
C4—C5—C6	123.57 (16)	C4—C9—H9C	109.5
C4—C5—Br1	119.13 (13)	H9A—C9—H9C	109.5
C6—C5—Br1	117.27 (12)	H9B—C9—H9C	109.5
C8—N1—C1—C2	166.25 (14)	C4—C5—C6—C1	3.9 (2)
C7^i—N1—C1—C2	−72.32 (19)	Br1—C5—C6—C1	−178.15 (11)
C8—N1—C1—C6	−13.1 (2)	C4—C5—C6—C7	−172.39 (16)
C7^i—N1—C1—C6	108.29 (17)	Br1—C5—C6—C7	5.5 (2)
C6—C1—C2—C3	1.3 (2)	C2—C1—C6—C5	−4.0 (2)
N1—C1—C2—C3	−178.15 (15)	N1—C1—C6—C5	175.43 (14)
C1—C2—C3—C4	1.8 (3)	C2—C1—C6—C7	172.42 (15)
C2—C3—C4—C5	−1.9 (3)	N1—C1—C6—C7	−8.2 (2)
C2—C3—C4—C9	179.02 (18)	C5—C6—C7—N1^i	166.79 (14)
C3—C4—C5—C6	−1.0 (3)	C1—C6—C7—N1^i	−9.4 (2)
C9—C4—C5—C6	178.03 (17)	C1—N1—C8—N1^i	53.33 (10)
C3—C4—C5—Br1	−178.89 (13)	C7^i—N1—C8—N1^i	−71.53 (10)
C9—C4—C5—Br1	0.1 (2)

Symmetry code: (i) −x+1, y, −z+1/2.