Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102001464/os1149sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102001464/os1149Isup2.hkl |
CCDC reference: 183031
Good quality single crystals of β-phenazine were formed in a crystallization mixture consisting of phenazine (0.694 mmol; Fluka), 1,3,5-trihydroxybenzene (0.395 mmol; Fluka) and ethanol (10 ml) after slow evaporation of the solution.
Data collection: CRYSALIS (Oxford Diffraction, 2001); cell refinement: CRYSALIS; data reduction: CRYSALIS; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97.
C12H8N2 | Dx = 1.309 Mg m−3 |
Mr = 180.20 | Melting point: 431K K |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 11.6418 (12) Å | Cell parameters from 2800 reflections |
b = 11.5449 (11) Å | θ = 3.7–25.0° |
c = 6.8981 (7) Å | µ = 0.08 mm−1 |
β = 99.476 (10)° | T = 293 K |
V = 914.48 (16) Å3 | Prism, yellow |
Z = 4 | 0.3 × 0.2 × 0.2 mm |
F(000) = 376 |
Kuma KM-4 CCD κ geometry diffractometer | 1272 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 25.0°, θmin = 3.7° |
ω scans | h = −13→13 |
4500 measured reflections | k = −13→8 |
1604 independent reflections | l = −8→8 |
Refinement on F2 | Hydrogen site location: difference Fourier map |
Least-squares matrix: full | All H-atom parameters refined |
R[F2 > 2σ(F2)] = 0.053 | w = 1/[σ2(Fo2) + (0.0716P)2 + 0.0381P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.149 | (Δ/σ)max < 0.001 |
S = 1.23 | Δρmax = 0.14 e Å−3 |
1604 reflections | Δρmin = −0.12 e Å−3 |
160 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.026 (7) |
Primary atom site location: coordinates from J. Phys. Chem. B, 103, 7762 (1999) |
C12H8N2 | V = 914.48 (16) Å3 |
Mr = 180.20 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.6418 (12) Å | µ = 0.08 mm−1 |
b = 11.5449 (11) Å | T = 293 K |
c = 6.8981 (7) Å | 0.3 × 0.2 × 0.2 mm |
β = 99.476 (10)° |
Kuma KM-4 CCD κ geometry diffractometer | 1272 reflections with I > 2σ(I) |
4500 measured reflections | Rint = 0.031 |
1604 independent reflections |
R[F2 > 2σ(F2)] = 0.053 | 0 restraints |
wR(F2) = 0.149 | All H-atom parameters refined |
S = 1.23 | Δρmax = 0.14 e Å−3 |
1604 reflections | Δρmin = −0.12 e Å−3 |
160 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.01654 (15) | 0.15551 (14) | 0.3448 (2) | 0.0414 (5) | |
C2 | 0.06582 (15) | 0.14216 (14) | 0.5480 (2) | 0.0420 (5) | |
C3 | 0.01104 (17) | 0.19765 (17) | 0.6929 (3) | 0.0525 (5) | |
H3 | 0.0463 (17) | 0.1870 (16) | 0.830 (3) | 0.062 (5)* | |
C4 | −0.08431 (18) | 0.26431 (18) | 0.6378 (3) | 0.0593 (6) | |
H4 | −0.1228 (18) | 0.3008 (18) | 0.742 (3) | 0.071 (6)* | |
C5 | −0.13282 (18) | 0.27771 (18) | 0.4371 (3) | 0.0585 (6) | |
H5 | −0.2011 (18) | 0.3274 (17) | 0.398 (3) | 0.060 (6)* | |
C6 | −0.08454 (17) | 0.22539 (16) | 0.2958 (3) | 0.0520 (5) | |
H6 | −0.1175 (17) | 0.2343 (16) | 0.159 (3) | 0.058 (5)* | |
C7 | 0.16029 (15) | 0.04107 (14) | 0.2577 (3) | 0.0426 (5) | |
C8 | 0.21420 (19) | −0.01561 (16) | 0.1137 (3) | 0.0539 (5) | |
H8 | 0.1770 (18) | −0.0068 (18) | −0.028 (3) | 0.077 (7)* | |
C9 | 0.31299 (19) | −0.07804 (18) | 0.1679 (3) | 0.0629 (6) | |
H9 | 0.3507 (18) | −0.1154 (17) | 0.065 (3) | 0.065 (6)* | |
C10 | 0.3638 (2) | −0.08772 (19) | 0.3689 (3) | 0.0649 (6) | |
H10 | 0.4332 (19) | −0.1324 (17) | 0.401 (3) | 0.069 (6)* | |
C11 | 0.31476 (18) | −0.03677 (18) | 0.5098 (3) | 0.0579 (6) | |
H11 | 0.3486 (18) | −0.0399 (17) | 0.649 (3) | 0.071 (6)* | |
C12 | 0.21100 (15) | 0.02927 (14) | 0.4609 (3) | 0.0436 (5) | |
N13 | 0.06430 (13) | 0.10528 (12) | 0.2019 (2) | 0.0467 (5) | |
N14 | 0.16283 (13) | 0.07926 (12) | 0.6036 (2) | 0.0470 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0444 (11) | 0.0378 (9) | 0.0400 (10) | −0.0048 (7) | 0.0011 (8) | 0.0015 (7) |
C2 | 0.0465 (10) | 0.0379 (9) | 0.0396 (10) | −0.0034 (8) | 0.0011 (8) | 0.0022 (7) |
C3 | 0.0609 (12) | 0.0550 (12) | 0.0408 (11) | 0.0038 (10) | 0.0057 (9) | −0.0013 (9) |
C4 | 0.0635 (14) | 0.0583 (12) | 0.0577 (13) | 0.0122 (10) | 0.0139 (11) | −0.0005 (10) |
C5 | 0.0543 (13) | 0.0551 (12) | 0.0639 (13) | 0.0122 (10) | 0.0030 (10) | 0.0056 (10) |
C6 | 0.0533 (12) | 0.0510 (11) | 0.0479 (12) | 0.0022 (9) | −0.0032 (9) | 0.0064 (9) |
C7 | 0.0485 (10) | 0.0378 (9) | 0.0406 (10) | −0.0071 (8) | 0.0052 (8) | 0.0019 (7) |
C8 | 0.0671 (13) | 0.0503 (11) | 0.0452 (12) | −0.0006 (10) | 0.0120 (10) | −0.0018 (9) |
C9 | 0.0723 (15) | 0.0594 (12) | 0.0616 (14) | 0.0065 (11) | 0.0242 (12) | −0.0050 (10) |
C10 | 0.0578 (14) | 0.0677 (14) | 0.0693 (15) | 0.0170 (11) | 0.0109 (12) | 0.0007 (11) |
C11 | 0.0552 (12) | 0.0658 (13) | 0.0497 (12) | 0.0100 (10) | −0.0005 (10) | 0.0027 (10) |
C12 | 0.0471 (10) | 0.0424 (9) | 0.0407 (10) | −0.0017 (8) | 0.0051 (8) | −0.0001 (8) |
N13 | 0.0520 (10) | 0.0448 (9) | 0.0407 (9) | −0.0020 (7) | −0.0003 (7) | 0.0018 (7) |
N14 | 0.0492 (9) | 0.0493 (9) | 0.0399 (9) | 0.0012 (7) | −0.0003 (7) | 0.0005 (7) |
C1—N13 | 1.341 (2) | C7—N13 | 1.343 (2) |
C1—C6 | 1.421 (2) | C7—C8 | 1.419 (3) |
C1—C2 | 1.433 (2) | C7—C12 | 1.435 (2) |
C2—N14 | 1.344 (2) | C8—C9 | 1.357 (3) |
C2—C3 | 1.423 (2) | C8—H8 | 1.01 (2) |
C3—C4 | 1.353 (3) | C9—C10 | 1.419 (3) |
C3—H3 | 0.98 (2) | C9—H9 | 0.99 (2) |
C4—C5 | 1.415 (3) | C10—C11 | 1.341 (3) |
C4—H4 | 1.00 (2) | C10—H10 | 0.95 (2) |
C5—C6 | 1.346 (3) | C11—C12 | 1.421 (3) |
C5—H5 | 0.98 (2) | C11—H11 | 0.97 (2) |
C6—H6 | 0.97 (2) | C12—N14 | 1.341 (2) |
N13—C1—C6 | 119.88 (16) | N13—C7—C12 | 121.42 (16) |
N13—C1—C2 | 121.68 (16) | C8—C7—C12 | 118.81 (17) |
C6—C1—C2 | 118.43 (17) | C9—C8—C7 | 120.29 (19) |
N14—C2—C3 | 119.68 (15) | C9—C8—H8 | 122.1 (13) |
N14—C2—C1 | 121.30 (16) | C7—C8—H8 | 117.6 (13) |
C3—C2—C1 | 119.02 (17) | C8—C9—C10 | 120.6 (2) |
C4—C3—C2 | 120.04 (18) | C8—C9—H9 | 119.2 (12) |
C4—C3—H3 | 122.6 (12) | C10—C9—H9 | 120.2 (12) |
C2—C3—H3 | 117.3 (12) | C11—C10—C9 | 121.0 (2) |
C3—C4—C5 | 120.9 (2) | C11—C10—H10 | 120.8 (13) |
C3—C4—H4 | 118.9 (12) | C9—C10—H10 | 118.1 (13) |
C5—C4—H4 | 120.1 (12) | C10—C11—C12 | 120.62 (19) |
C6—C5—C4 | 120.83 (19) | C10—C11—H11 | 123.0 (13) |
C6—C5—H5 | 118.6 (11) | C12—C11—H11 | 116.4 (13) |
C4—C5—H5 | 120.6 (11) | N14—C12—C11 | 119.89 (16) |
C5—C6—C1 | 120.73 (18) | N14—C12—C7 | 121.45 (16) |
C5—C6—H6 | 121.1 (12) | C11—C12—C7 | 118.66 (17) |
C1—C6—H6 | 118.2 (12) | C1—N13—C7 | 116.99 (14) |
N13—C7—C8 | 119.77 (16) | C12—N14—C2 | 117.14 (14) |
Experimental details
Crystal data | |
Chemical formula | C12H8N2 |
Mr | 180.20 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 11.6418 (12), 11.5449 (11), 6.8981 (7) |
β (°) | 99.476 (10) |
V (Å3) | 914.48 (16) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.3 × 0.2 × 0.2 |
Data collection | |
Diffractometer | Kuma KM-4 CCD κ geometry diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4500, 1604, 1272 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.053, 0.149, 1.23 |
No. of reflections | 1604 |
No. of parameters | 160 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.14, −0.12 |
Computer programs: CRYSALIS (Oxford Diffraction, 2001), CRYSALIS, SHELXL97 (Sheldrick, 1997), Stereochemical Workstation Operation Manual (Siemens, 1989), SHELXL97.
C1—N13 | 1.341 (2) | C7—N13 | 1.343 (2) |
C1—C6 | 1.421 (2) | C7—C8 | 1.419 (3) |
C1—C2 | 1.433 (2) | C7—C12 | 1.435 (2) |
C2—N14 | 1.344 (2) | C8—C9 | 1.357 (3) |
C2—C3 | 1.423 (2) | C9—C10 | 1.419 (3) |
C3—C4 | 1.353 (3) | C10—C11 | 1.341 (3) |
C4—C5 | 1.415 (3) | C11—C12 | 1.421 (3) |
C5—C6 | 1.346 (3) | C12—N14 | 1.341 (2) |
N13—C1—C6 | 119.88 (16) | N13—C7—C12 | 121.42 (16) |
N13—C1—C2 | 121.68 (16) | C8—C7—C12 | 118.81 (17) |
C6—C1—C2 | 118.43 (17) | C9—C8—C7 | 120.29 (19) |
N14—C2—C3 | 119.68 (15) | C8—C9—C10 | 120.6 (2) |
N14—C2—C1 | 121.30 (16) | C11—C10—C9 | 121.0 (2) |
C3—C2—C1 | 119.02 (17) | C10—C11—C12 | 120.62 (19) |
C4—C3—C2 | 120.04 (18) | N14—C12—C11 | 119.89 (16) |
C3—C4—C5 | 120.9 (2) | N14—C12—C7 | 121.45 (16) |
C6—C5—C4 | 120.83 (19) | C11—C12—C7 | 118.66 (17) |
C5—C6—C1 | 120.73 (18) | C1—N13—C7 | 116.99 (14) |
N13—C7—C8 | 119.77 (16) | C12—N14—C2 | 117.14 (14) |
It is well known that phenazine crystallizes in two polymorphic forms. The structure of the stable phase (α-phenazine, m.p. 449.5 K) was first determined by Herbstein & Schmidt (1955) and later redetermined by Woźniak et al. (1991). The existence of a second polymorph was also first recognized by Herbstein & Schmidt (1955), who reported the space group and unit-cell parameters, and described the morphology of the β phase. To our knowledge, no other experimental data have been reported on the less stable polymorph to date, and β-phenazine seems to exemplify a disappearing polymorph case (Dunitz & Bernstein, 1995). Nevertheless, Hammond et al. (1999), using the systematic search method of potential packing arrangements, predicted the crystal structure of the β polymorph.
Recently, by chance, we have obtained good quality single crystals of β-phenazine, (I), from a crystallization mixture consisting of phenazine, 1,3,5-trihydroxybenzene and ethanol, by slow evaporation of the solution. In the first crop, we isolated several block-like crystals of α-phenazine and two rod-like crystals of dimensions 1 × 0.2 × 0.2 mm which, after measuring the unit-cell parameters, turned out to be the β-form. The melting point of these crystals (431 K) is 18 K lower than that of the α phase (449 K). The crystal structure of β-phenazine, (I), is presented here. \sch
The bond lengths and angles of the phenazine molecule in both polymorphic forms are very similar. In contrast with α-phenazine, for which a γ-arrangement (Desiraju & Gavezzoti, 1989) of the heteroaromatic rings has been observed, β-phenazine shows a sandwich herringbone type of packing.
The common structural motif for the two polymorphs is a chain of molecules connected via pairs of C—H···N interactions. For the α-form, H···N 2.89 Å and C—H···N 146°. For the β-form, H3···N13i 2.71 (2) Å and C3—H3···N13i 156.5 (16)°, and H8···N14ii 2.71 (2) Å and C8—H8···N14ii 153.9 (16)° [symmetry codes: (i) x, y, 1 + z; (ii) x, y, z - 1]. The interplanar distance between adjacent phenazine molecules along the chain is 1.26 Å in the α polymorph and 1.088 (3) Å in the β form. In the β-polymorph, there is an additional short C—H···N contact between molecules related by an n glide [H5···N14iii 2.60 (2) Å and C5—H5···N14iii 145.1 (16)°; symmetry code: (iii) x - 1/2, 1/2 - y, z - 1/2].
The structure determined from the single-crystal of (I) is very close to that predicted by Hammond et al. (1999), as can be seen from Fig. 2, which shows the superposition of the postulated and experimentally determined crystal structures. The π–π stack distance in the β-phenazine structure is 3.498 (3) Å (predicted distance 3.53 Å), the centroid-centroid distance within the stack is 3.80 Å (predicted 3.81 Å) and the herringbone angle is 71.4 (3)° (predicted 72.9°).