7,8-Dichloro-1,2,3,4-tetra­hydro­phenazine

In the structure of the title compound, C₁₂H₁₀Cl₂N₂, the cyclo­hexene ring adopts a half-chair conformation.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.032
• wR factor = 0.089
• Data-to-parameter ratio = 10.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.

   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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   0 ALERT type 5 Informative message, check

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S1. Comment

One of the primary interests of our lab is the synthesis and characterization of novel substituted quinoxalines and the closely related phenazines. Quinoxalines and their derivatives have received considerable attention in the past several years due to their electronic properties (Page et al., 1998; Simpson & Gordon, 1995), H-bonding ability (Pascal & Ho, 1993; Wozniak et al., 1993), and their capacity to coordinate to metals (Wu et al., 2002; Willett et al., 2001). During our investigations, we have prepared a number of substituted quinoxalines and phenazines, which readily coordinate to copper iodide forming novel structures. Our current work involves the synthesis of new nitrogen heterocycles (Gibson, et al., 2006) which may lead to novel three-dimensional structures upon coordination to cuprous salts. Here, we report the crystal structure of 7,8-dichloro-1,2,3,4-tetrahydrophenazine (I), (Figure 1).

The structure of (I) exhibits bond distances and angles that are normal, for all fall within ranges established in the literature for similar nitrogen heterocycles (Brown et al., 2004). There are two molecules per unit cell, related to each other by an inversion center. The chloride substituents are almost eclipsed with respect to each other, with a torsion angle Cl1—C10—C9—Cl2 of 0.36 (16)°. Both aromatic rings are essentially planar and almost co-planar with a dihedral angle of 1.20 (18)°, based on least-squares plane calculations on C12—C11—C10—C9—C8—C7 and C7—C12—N1—C1—C6—N2. The H-saturated fragment of the ring system adopts a twisted, cyclohexyl-like conformation as evidenced by the angles depicted by atoms C5 C4 C3 110.68 (12)°, C2 C3 C4 109.92 (12)°, and the C2—C3—C4—C5 torsion angle of 63.62 (17)°, which suggest the presence of some angle and torsional strain.

Related literature

For related literature, see: Brown et al. (2004); Farrugia (1997); Gibson et al. (2006); Page et al. (1998); Pascal & Ho (1993); Simpson & Gordon (1995); Willett et al. (2001); Wozniak et al. (1993); Wu et al. (2002).

S2. Experimental

A 20 ml test tube was charged with 4,5-Dichloro-o-phenylenediamine (177 mg, 1 mmol) and 1,2-Cyclohexanedione (112 mg, 1 mmol). This was heated in a boiling water bath for 1 h, until the reaction mixture was homogeneous. The residue was then dissolved in boiling ethanol (100% EtOH, 15 ml). Upon cooling to 0° C, light yellow crystals of (1) were obtained (215 mg, 85% yield) mp 215–216° C.

S3. Refinement

H atoms were treated as riding, with C—H = 1.00 with U_iso(H) = 1.2 U_eq(C) for all H atoms.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: XSHELL (Bruker, 2004); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. ORTEP drawing of (I) (Farrugia, 1997). Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as spheres.

7,8-dichloro-1,2,3,4-tetrahydrophenazine

Crystal data

C12H10Cl2N2	Z = 2
Mr = 253.12	F(000) = 260
Triclinic, P1	Dx = 1.549 Mg m^−3
Hall symbol: -P 1	Cu Kα radiation, λ = 1.54178 Å
a = 6.3442 (3) Å	Cell parameters from 71 reflections
b = 7.3885 (3) Å	θ = 9.5–41.0°
c = 11.7831 (5) Å	µ = 5.13 mm^−1
α = 85.720 (2)°	T = 200 K
β = 82.122 (2)°	Block, yellow
γ = 83.572 (2)°	0.35 × 0.21 × 0.08 mm
V = 542.68 (4) Å^3

Data collection

Bruker SMART APEX II CCD diffractometer	1868 independent reflections
Radiation source: fine-focus sealed tube	1810 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω and ψ scans	θmax = 67.0°, θmin = 3.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −7→7
Tmin = 0.267, Tmax = 0.685	k = −8→8
9473 measured reflections	l = −14→14

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.089	All H-atom parameters refined
S = 1.05	w = 1/[σ^2(Fo^2) + (0.067P)^2 + 0.0594P] where P = (Fo^2 + 2Fc^2)/3
1868 reflections	(Δ/σ)max = 0.001
185 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.29 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
Cl1	0.93385 (5)	0.65523 (4)	0.28885 (3)	0.04023 (16)
Cl2	0.50704 (6)	0.83977 (5)	0.20124 (3)	0.04102 (16)
N1	0.54783 (19)	0.67203 (16)	0.69452 (11)	0.0335 (3)
N2	0.16607 (18)	0.84040 (15)	0.61792 (10)	0.0314 (3)
C1	0.3736 (2)	0.71175 (17)	0.76619 (11)	0.0313 (3)
C2	0.3837 (3)	0.6595 (2)	0.89145 (13)	0.0402 (3)
C3	0.2006 (2)	0.7516 (2)	0.97160 (12)	0.0395 (3)
C4	−0.0116 (2)	0.7388 (2)	0.92727 (12)	0.0390 (3)
C5	−0.0180 (2)	0.8423 (2)	0.81112 (13)	0.0382 (3)
C6	0.1794 (2)	0.79711 (17)	0.72703 (11)	0.0307 (3)
C7	0.3461 (2)	0.79900 (16)	0.54201 (11)	0.0294 (3)
C8	0.3393 (2)	0.83969 (17)	0.42346 (12)	0.0322 (3)
C9	0.5173 (2)	0.79438 (17)	0.34757 (11)	0.0322 (3)
C10	0.7083 (2)	0.71125 (16)	0.38628 (11)	0.0316 (3)
C11	0.7188 (2)	0.67350 (18)	0.50048 (12)	0.0340 (3)
C12	0.5361 (2)	0.71473 (17)	0.58085 (11)	0.0298 (3)
H8	0.202 (3)	0.896 (2)	0.3985 (14)	0.039 (4)*
H11	0.855 (3)	0.616 (2)	0.5315 (13)	0.037 (4)*
H2A	0.376 (3)	0.524 (3)	0.9028 (15)	0.047 (4)*
H3A	0.205 (3)	0.698 (2)	1.0494 (15)	0.037 (4)*
H4A	−0.025 (3)	0.613 (2)	0.9204 (13)	0.036 (4)*
H5A	−0.142 (3)	0.818 (3)	0.7777 (16)	0.050 (5)*
H2B	0.523 (3)	0.682 (3)	0.9123 (17)	0.057 (5)*
H3B	0.218 (3)	0.880 (2)	0.9745 (14)	0.043 (4)*
H4B	−0.127 (3)	0.781 (2)	0.9851 (15)	0.043 (4)*
H5B	−0.032 (3)	0.976 (2)	0.8240 (15)	0.046 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0375 (2)	0.0407 (2)	0.0404 (2)	−0.00292 (16)	0.00363 (15)	−0.00642 (15)
Cl2	0.0478 (2)	0.0431 (2)	0.0313 (2)	−0.00231 (17)	−0.00522 (15)	0.00027 (15)
N1	0.0326 (6)	0.0321 (6)	0.0357 (6)	−0.0007 (5)	−0.0071 (5)	−0.0007 (5)
N2	0.0302 (6)	0.0283 (6)	0.0354 (6)	−0.0037 (5)	−0.0041 (5)	0.0023 (4)
C1	0.0332 (7)	0.0272 (6)	0.0337 (7)	−0.0040 (5)	−0.0056 (5)	0.0001 (5)
C2	0.0387 (8)	0.0460 (8)	0.0348 (7)	−0.0002 (7)	−0.0069 (6)	0.0016 (6)
C3	0.0451 (8)	0.0406 (8)	0.0329 (7)	−0.0077 (6)	−0.0032 (6)	−0.0014 (6)
C4	0.0387 (7)	0.0392 (8)	0.0373 (7)	−0.0057 (6)	0.0011 (6)	0.0008 (6)
C5	0.0336 (7)	0.0381 (8)	0.0402 (8)	−0.0006 (6)	−0.0004 (6)	0.0025 (6)
C6	0.0325 (6)	0.0242 (6)	0.0354 (7)	−0.0051 (5)	−0.0048 (5)	0.0013 (5)
C7	0.0297 (6)	0.0231 (6)	0.0358 (7)	−0.0046 (5)	−0.0051 (5)	0.0001 (5)
C8	0.0337 (7)	0.0274 (6)	0.0363 (7)	−0.0043 (6)	−0.0077 (5)	0.0009 (5)
C9	0.0398 (7)	0.0261 (6)	0.0318 (6)	−0.0078 (5)	−0.0059 (5)	0.0003 (5)
C10	0.0328 (6)	0.0246 (6)	0.0372 (7)	−0.0044 (5)	−0.0013 (5)	−0.0041 (5)
C11	0.0318 (7)	0.0301 (6)	0.0399 (7)	−0.0012 (6)	−0.0059 (6)	−0.0024 (5)
C12	0.0320 (6)	0.0249 (6)	0.0331 (6)	−0.0039 (5)	−0.0066 (5)	−0.0002 (5)

Geometric parameters (Å, º)

Cl1—C10	1.7394 (13)	C4—C5	1.520 (2)
Cl2—C9	1.7405 (13)	C4—H4A	0.955 (17)
N1—C1	1.3151 (19)	C4—H4B	0.970 (18)
N1—C12	1.3632 (19)	C5—C6	1.5090 (19)
N2—C6	1.3132 (18)	C5—H5A	0.97 (2)
N2—C7	1.3716 (18)	C5—H5B	1.001 (18)
C1—C6	1.4378 (19)	C7—C12	1.4104 (19)
C1—C2	1.506 (2)	C7—C8	1.412 (2)
C2—C3	1.524 (2)	C8—C9	1.368 (2)
C2—H2A	1.006 (19)	C8—H8	0.995 (18)
C2—H2B	0.99 (2)	C9—C10	1.413 (2)
C3—C4	1.524 (2)	C10—C11	1.363 (2)
C3—H3A	0.974 (18)	C11—C12	1.4133 (19)
C3—H3B	0.969 (18)	C11—H11	1.019 (17)
C1—N1—C12	116.95 (11)	C4—C5—H5A	110.3 (11)
C6—N2—C7	116.96 (12)	C6—C5—H5B	108.7 (10)
N1—C1—C6	121.78 (13)	C4—C5—H5B	107.7 (10)
N1—C1—C2	117.16 (12)	H5A—C5—H5B	108.0 (16)
C6—C1—C2	121.04 (13)	N2—C6—C1	121.97 (13)
C1—C2—C3	113.99 (13)	N2—C6—C5	117.29 (12)
C1—C2—H2A	107.4 (10)	C1—C6—C5	120.73 (13)
C3—C2—H2A	107.6 (10)	N2—C7—C12	120.84 (12)
C1—C2—H2B	110.1 (12)	N2—C7—C8	119.23 (12)
C3—C2—H2B	111.0 (12)	C12—C7—C8	119.92 (12)
H2A—C2—H2B	106.4 (16)	C9—C8—C7	119.21 (12)
C4—C3—C2	109.92 (12)	C9—C8—H8	122.7 (9)
C4—C3—H3A	112.9 (10)	C7—C8—H8	118.0 (9)
C2—C3—H3A	109.4 (10)	C8—C9—C10	120.99 (12)
C4—C3—H3B	107.7 (10)	C8—C9—Cl2	119.22 (10)
C2—C3—H3B	110.3 (10)	C10—C9—Cl2	119.79 (10)
H3A—C3—H3B	106.5 (14)	C11—C10—C9	120.61 (12)
C5—C4—C3	110.68 (12)	C11—C10—Cl1	118.89 (11)
C5—C4—H4A	109.9 (9)	C9—C10—Cl1	120.50 (10)
C3—C4—H4A	107.9 (10)	C10—C11—C12	119.75 (13)
C5—C4—H4B	113.5 (11)	C10—C11—H11	122.7 (9)
C3—C4—H4B	108.5 (10)	C12—C11—H11	117.6 (9)
H4A—C4—H4B	106.2 (14)	N1—C12—C7	121.50 (12)
C6—C5—C4	113.28 (12)	N1—C12—C11	119.01 (12)
C6—C5—H5A	108.7 (11)	C7—C12—C11	119.49 (12)
C12—N1—C1—C6	−0.29 (19)	C12—C7—C8—C9	0.80 (19)
C12—N1—C1—C2	178.13 (12)	C7—C8—C9—C10	−1.3 (2)
N1—C1—C2—C3	164.89 (13)	C7—C8—C9—Cl2	178.55 (9)
C6—C1—C2—C3	−16.7 (2)	C8—C9—C10—C11	0.3 (2)
C1—C2—C3—C4	46.64 (17)	Cl2—C9—C10—C11	−179.53 (10)
C2—C3—C4—C5	−63.51 (17)	C8—C9—C10—Cl1	−179.73 (9)
C3—C4—C5—C6	48.59 (17)	Cl2—C9—C10—Cl1	0.43 (15)
C7—N2—C6—C1	0.57 (19)	C9—C10—C11—C12	1.2 (2)
C7—N2—C6—C5	179.97 (11)	Cl1—C10—C11—C12	−178.78 (9)
N1—C1—C6—N2	−0.3 (2)	C1—N1—C12—C7	0.49 (19)
C2—C1—C6—N2	−178.61 (11)	C1—N1—C12—C11	−179.57 (12)
N1—C1—C6—C5	−179.63 (11)	N2—C7—C12—N1	−0.18 (19)
C2—C1—C6—C5	2.0 (2)	C8—C7—C12—N1	−179.40 (11)
C4—C5—C6—N2	162.46 (13)	N2—C7—C12—C11	179.88 (11)
C4—C5—C6—C1	−18.14 (19)	C8—C7—C12—C11	0.66 (19)
C6—N2—C7—C12	−0.36 (18)	C10—C11—C12—N1	178.41 (12)
C6—N2—C7—C8	178.87 (11)	C10—C11—C12—C7	−1.6 (2)
N2—C7—C8—C9	−178.43 (11)