Phenazinium methyl sulfate

The title salt, C12H9N2 +·CH3O4S−, contains an almost planar phenazinium cation [largest deviation from the least-squares plane = 0.040 (3) Å] and a methyl sulfate anion. The sulfate moiety of the latter is disordered over two sets of sites in a 0.853 (5):0.147 (5) ratio. In the crystal, the cations and anions are arranged alternately in layers parallel to (010). The cations pack along [100] with a tilt angle of 28.96 (4)° between this axis and the mean plane and are linked through interplanar π–π interactions [shortest interplanar distance = 3.421 (4) Å]. N—H⋯O hydrogen-bonding between the cations and anions is also observed.

The title salt, C 12 H 9 N 2 + ÁCH 3 O 4 S À , contains an almost planar phenazinium cation [largest deviation from the least-squares plane = 0.040 (3) Å ] and a methyl sulfate anion. The sulfate moiety of the latter is disordered over two sets of sites in a 0.853 (5):0.147 (5) ratio. In the crystal, the cations and anions are arranged alternately in layers parallel to (010). The cations pack along [100] with a tilt angle of 28.96 (4) between this axis and the mean plane and are linked through interplanarinteractions [shortest interplanar distance = 3.421 (4) Å ]. N-HÁ Á ÁO hydrogen-bonding between the cations and anions is also observed.

Related literature
For background to the use of phenazine in crystal engineering, see: Laursen & Nielsen (2004). For a related structure, see: Meszko et al. (2002).  Table 1 Hydrogen-bond geometry (Å , ). In the past decade, phenazines have been widely used as a template in crystal engineering for its two equivalent strong proton acceptors (sp 2 N atoms) and potential weak C-H donor functions, where the aromatic system can act as a good πdonor. Accordingly, phenazine has been employed in the design of charge-transfer complexes and hydrogen bonded assemblies (Laursen et al., 2004). Here, we report the crystal structure of an 1:1 complex of phenazine with methyl sulfate.

D-HÁ
The asymmetric unit of the title salt, [C 12 H 9 N 2 ] + [CH 3 O 4 S] -, contains a phenazinium cation and a methyl sulfate anion The cations pack along [100] with a tilt angle between the phenazinium plane and the a axis being 28.96 (4)°. The shortest plane-to-plane π-π interactions are 3.421 (4) Å. The phenazinium cations and the methyl sulfate anions are alternately arranged parallel to (010) (Fig. 2). Except for Coulombic interactions, there are classical hydrogen bonding interactions between the phenazinium cations and methyl sulfate anions (Table 1), which also play an important role in the stabilisation of the title structure.

Experimental
To a solution containing phenzine (1.0 g, 0.0056 mmol) in n-butyl acetate (20 mL) was added dimethyl sulfate (5.4 mL, 0.057 mmol). The resulting mixture was continuously stired at 373 K for 1 h, then the orange reaction solution was cooled to 283 K. The precipitated yellow solid were collected and recrystallized in ethanol.

Refinement
All H atoms were geometrically fixed and allowed to ride on their attached atoms, whit C-H = 0.93 Å and U iso (H)= 1.2U eq (C) for all phenzine H atoms, and C-H = 0.96 Å and U iso (H)= 1.5U eq (C) for the methyl group. The proton attached to the phenazine N atom was also geometrically fixed, with N-H = 0.86Å and U iso (H)= 1.2U eq (N). The sulfate part of the anion was modelled as disordered over two sets of sites in a 0.853 (5):0.147 (5) ratio; O atoms of the minor component were refined with isotropic displacement parameters.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.54 e Å −3 Δρ min = −0.72 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 Occ. (