Phenazin-5-ium bromide

In the title compound, C12H9N2 +·Br−, the protonated tricyclic ring system is slightly twisted, with a dihedral angle of 3.9 (1)° between the two outer benzene rings. In the crystal, N—H⋯Br and C—H⋯Br hydrogen bonds link two cations and two bromide anions into centrosymmetric assemblies, which are further packed into stacks along [010] via π–π interactions between the aromatic rings [centroid–centroid distance = 3.725 (4) Å].

In the title compound, C 12 H 9 N 2 + ÁBr À , the protonated tricyclic ring system is slightly twisted, with a dihedral angle of 3.9 (1) between the two outer benzene rings. In the crystal, N-HÁ Á ÁBr and C-HÁ Á ÁBr hydrogen bonds link two cations and two bromide anions into centrosymmetric assemblies, which are further packed into stacks along [010] viainteractions between the aromatic rings [centroid-centroid distance = 3.725 (4) Å ].

Experimental
In (I) (Fig. 1), the bond lengths and angles are normal and correspond to those observed in the related phenazinium chloride (Braga et al., 2010). The asymmetric unit of (I) contains a phenazinium cation and a bromide anion. The phenazinium cations show planar configuration with the largest deviation from the least-square-plane of 0.053 (4) Å for C7. The protonated tricycle is twisted with a dihedral angle of 3.9 (1)° between the two utmost benzene rings.
The cations are packed along the b axis and the tilted angle between the phenazinium plane and b axis of 50.40 (5)°. In the crystal, N-H···Br and C-H···Br hydrogen bonds (Table 1) link two cations and two bromide anions into centrosymmetric clusters, which are further packed into stacks along [010] via π-π interactions between the aromatic rings [centroid-centroid distance = 3.725 (4) Å].

Experimental
Phenazine(10.0 g) and 2-bromopropane (4.2 mL) was placed in the teflon liner of an autoclave, which was sealed and heated to 433 K for 48 h, cooled at speed of 10 K/min, whereupon a few of black block of title crystal were obtained.

Phenazin-5-ium bromide
Crystal data C 12 H 9 N 2 + ·Br − M r = 261.12 Triclinic, P1 Hall symbol: -P 1 a = 5.639 (5) Å b = 7.958 (5) Å c = 12.149 (5) Å α = 73.284 (5) where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.81 e Å −3 Δρ min = −0.65 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.028 (5) 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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq