Acta Cryst. (2012). E68, o2786 [ doi:10.1107/S1600536812036136 ]
In the title salt, C6H9N2+·Br2I-, the cation is essentially planar (r.m.s. deviation = 0.0062 Å for the non-H atoms) while the anion is almost linear with a Br-I-Br angle of 177.67 (2)°. The crystal packing shows two anions and two cations connected via N-H
Br and (pyridine)N-HBr hydrogen-bonding interactions, forming centrosymmetric tetramers with R44(16) ring motifs. Very weak offset aromatic ![[pi]](/logos/entities/pi_rmgif.gif)
- stacking interactions [centroid-centroid separation = 4.038 (4), slippage = 1.773 Å] also occur.
A solution of CdI2 (0.37 g, 1.0 mmol) dissolved in 95% EtOH (10 ml) and 60% HBr (1 ml) solution was added to a mixture of 2-amino-5-methylpyridine (0.11 g, 1.0 mmol) dissolved in 95% EtOH (10 ml), 60% HBr (1 ml) and molecular bromine (2 ml). The resulting mixture was refluxed for 2.5 hr. On slow evaporation at room temperature yellow plates of the title compound were formed in 4 days (yield 85%).
All H atoms were positioned geometrically and refined using a riding model, with N—H = 0.86 Å and C—H = 0.93 and 0.96 Å, for aryl and methyl H-atoms, respectively. The Uiso(H) were allowed at 1.5Ueq(C methyl) or 1.2Ueq(N/C non-methyl).
Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./pv2581fig1thm.gif)
| Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as small spheres of arbitrary radius. |
![[Figure 2]](./pv2581fig2thm.gif)
| Fig. 2. A view of the pyN–H···Br and H–N–H···Br hydrogen bonds (dotted lines) in the crystal structure of the title compound. H atoms non-participating in hydrogen-bonding were omitted for clarity. |
| C6H9N2+·Br2I− | Z = 2 |
| Mr = 395.85 | F(000) = 364 |
| Triclinic, P1 | Dx = 2.422 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
| a = 8.3648 (13) Å | Cell parameters from 1406 reflections |
| b = 8.4233 (16) Å | θ = 3.2–30.0° |
| c = 9.2321 (16) Å | µ = 10.26 mm−1 |
| α = 105.107 (16)° | T = 293 K |
| β = 115.371 (16)° | Plate, yellow |
| γ = 98.241 (15)° | 0.54 × 0.39 × 0.30 mm |
| V = 542.7 (2) Å3 |
| Agilent Xcalibur Eos diffractometer | 2465 independent reflections |
| Radiation source: Enhance (Mo) X-ray Source | 1777 reflections with I > 2σ(I) |
| Graphite monochromator | Rint = 0.029 |
| Detector resolution: 16.0534 pixels mm-1 | θmax = 29.1°, θmin = 3.2° |
| ω scans | h = −11→10 |
| Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | k = −11→11 |
| Tmin = 0.011, Tmax = 0.045 | l = −10→12 |
| 4283 measured reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
| wR(F2) = 0.096 | w = 1/[σ2(Fo2) + (0.035P)2] where P = (Fo2 + 2Fc2)/3 |
| S = 1.01 | (Δ/σ)max < 0.001 |
| 2465 reflections | Δρmax = 1.17 e Å−3 |
| 102 parameters | Δρmin = −0.85 e Å−3 |
| 0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0292 (12) |
| C6H9N2+·Br2I− | γ = 98.241 (15)° |
| Mr = 395.85 | V = 542.7 (2) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 8.3648 (13) Å | Mo Kα radiation |
| b = 8.4233 (16) Å | µ = 10.26 mm−1 |
| c = 9.2321 (16) Å | T = 293 K |
| α = 105.107 (16)° | 0.54 × 0.39 × 0.30 mm |
| β = 115.371 (16)° |
| Agilent Xcalibur Eos diffractometer | 2465 independent reflections |
| Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | 1777 reflections with I > 2σ(I) |
| Tmin = 0.011, Tmax = 0.045 | Rint = 0.029 |
| 4283 measured reflections | θmax = 29.1° |
| R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
| wR(F2) = 0.096 | Δρmax = 1.17 e Å−3 |
| S = 1.01 | Δρmin = −0.85 e Å−3 |
| 2465 reflections | Absolute structure: ? |
| 102 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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 | ||
| N1 | 1.0416 (7) | 0.3049 (7) | 0.7106 (6) | 0.0606 (15) | |
| H1A | 1.0387 | 0.3331 | 0.8057 | 0.073* | |
| I1 | 0.70649 (5) | −0.04784 (5) | 0.90281 (5) | 0.04214 (17) | |
| Br1 | 0.55742 (10) | −0.38624 (9) | 0.80942 (10) | 0.0661 (2) | |
| N2 | 0.7745 (7) | 0.3836 (7) | 0.5894 (7) | 0.0699 (17) | |
| H2A | 0.7751 | 0.4121 | 0.6862 | 0.084* | |
| H2B | 0.6882 | 0.3947 | 0.5021 | 0.084* | |
| C2 | 0.9069 (8) | 0.3223 (8) | 0.5748 (8) | 0.0509 (16) | |
| Br2 | 0.85761 (10) | 0.29148 (9) | 0.98508 (9) | 0.0589 (2) | |
| C3 | 0.9133 (8) | 0.2686 (8) | 0.4207 (8) | 0.0500 (15) | |
| H3A | 0.8224 | 0.2749 | 0.3211 | 0.060* | |
| C4 | 1.0533 (8) | 0.2076 (9) | 0.4194 (8) | 0.0551 (17) | |
| H4A | 1.0562 | 0.1728 | 0.3166 | 0.066* | |
| C5 | 1.1936 (8) | 0.1936 (8) | 0.5625 (7) | 0.0438 (14) | |
| C6 | 1.1819 (9) | 0.2455 (9) | 0.7061 (9) | 0.0591 (18) | |
| H6A | 1.2732 | 0.2406 | 0.8064 | 0.071* | |
| C7 | 1.3488 (8) | 0.1264 (9) | 0.5598 (9) | 0.0647 (19) | |
| H7A | 1.4329 | 0.1335 | 0.6734 | 0.097* | |
| H7B | 1.4130 | 0.1938 | 0.5211 | 0.097* | |
| H7C | 1.2999 | 0.0087 | 0.4830 | 0.097* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| N1 | 0.077 (4) | 0.061 (4) | 0.032 (3) | 0.007 (3) | 0.025 (3) | 0.008 (3) |
| I1 | 0.0468 (3) | 0.0479 (3) | 0.0301 (2) | 0.01598 (19) | 0.01656 (19) | 0.01427 (19) |
| Br1 | 0.0739 (5) | 0.0464 (4) | 0.0580 (5) | 0.0088 (4) | 0.0210 (4) | 0.0132 (4) |
| N2 | 0.076 (4) | 0.076 (5) | 0.060 (4) | 0.019 (3) | 0.039 (3) | 0.019 (4) |
| C2 | 0.052 (3) | 0.050 (4) | 0.046 (4) | 0.002 (3) | 0.023 (3) | 0.018 (3) |
| Br2 | 0.0794 (5) | 0.0461 (4) | 0.0465 (4) | 0.0117 (4) | 0.0284 (4) | 0.0173 (4) |
| C3 | 0.054 (4) | 0.054 (4) | 0.038 (4) | 0.011 (3) | 0.023 (3) | 0.014 (3) |
| C4 | 0.062 (4) | 0.058 (4) | 0.041 (4) | 0.008 (3) | 0.026 (3) | 0.014 (3) |
| C5 | 0.049 (3) | 0.042 (4) | 0.031 (3) | 0.005 (3) | 0.013 (3) | 0.015 (3) |
| C6 | 0.060 (4) | 0.064 (5) | 0.040 (4) | 0.013 (4) | 0.016 (3) | 0.016 (4) |
| C7 | 0.063 (4) | 0.069 (5) | 0.057 (5) | 0.022 (4) | 0.023 (4) | 0.025 (4) |
| N1—C2 | 1.340 (7) | C3—H3A | 0.9300 |
| N1—C6 | 1.352 (8) | C4—C5 | 1.389 (8) |
| N1—H1A | 0.8600 | C4—H4A | 0.9300 |
| I1—Br1 | 2.6836 (10) | C5—C6 | 1.334 (8) |
| I1—Br2 | 2.7119 (10) | C5—C7 | 1.496 (8) |
| N2—C2 | 1.330 (7) | C6—H6A | 0.9300 |
| N2—H2A | 0.8600 | C7—H7A | 0.9600 |
| N2—H2B | 0.8600 | C7—H7B | 0.9600 |
| C2—C3 | 1.402 (8) | C7—H7C | 0.9600 |
| C3—C4 | 1.348 (8) | ||
| C2—N1—C6 | 123.5 (5) | C3—C4—H4A | 118.0 |
| C2—N1—H1A | 118.3 | C5—C4—H4A | 118.0 |
| C6—N1—H1A | 118.3 | C6—C5—C4 | 115.2 (6) |
| Br1—I1—Br2 | 177.67 (2) | C6—C5—C7 | 121.3 (6) |
| C2—N2—H2A | 120.0 | C4—C5—C7 | 123.5 (5) |
| C2—N2—H2B | 120.0 | C5—C6—N1 | 122.1 (6) |
| H2A—N2—H2B | 120.0 | C5—C6—H6A | 118.9 |
| N2—C2—N1 | 120.1 (6) | N1—C6—H6A | 118.9 |
| N2—C2—C3 | 123.6 (6) | C5—C7—H7A | 109.5 |
| N1—C2—C3 | 116.3 (6) | C5—C7—H7B | 109.5 |
| C4—C3—C2 | 118.9 (6) | H7A—C7—H7B | 109.5 |
| C4—C3—H3A | 120.5 | C5—C7—H7C | 109.5 |
| C2—C3—H3A | 120.5 | H7A—C7—H7C | 109.5 |
| C3—C4—C5 | 123.9 (6) | H7B—C7—H7C | 109.5 |
| C6—N1—C2—N2 | −179.2 (6) | C3—C4—C5—C6 | 0.0 (10) |
| C6—N1—C2—C3 | 2.4 (9) | C3—C4—C5—C7 | −179.7 (6) |
| N2—C2—C3—C4 | −179.7 (6) | C4—C5—C6—N1 | 1.0 (10) |
| N1—C2—C3—C4 | −1.4 (9) | C7—C5—C6—N1 | −179.3 (6) |
| C2—C3—C4—C5 | 0.3 (10) | C2—N1—C6—C5 | −2.3 (10) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···Br2 | 0.86 | 2.73 | 3.499 (5) | 150 |
| N2—H2B···Br1i | 0.86 | 2.70 | 3.545 (6) | 168 |
| Symmetry code: (i) −x+1, −y, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···Br2 | 0.86 | 2.73 | 3.499 (5) | 149.5 |
| N2—H2B···Br1i | 0.86 | 2.70 | 3.545 (6) | 168.0 |
| Symmetry code: (i) −x+1, −y, −z+1. |
The structure was determined at the Hamdi Mango Center for Scientific Research at the University of Jordan.
Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.
Al-Far, W., Ali, B. F. & Haddad, S. F. (2012). Acta Cryst. E68, o2743.
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Gardberg, A. S., Yang, S., Hoffman, B. M. & Ibers, J. A. (2002). Inorg. Chem. 41, 1778–1781.
Hemamalini, M. & Fun, H.-K. (2010). Acta Cryst. E66, o2192–o2193.
Kochel, A. (2006). Acta Cryst. E62, o5605–o5606.
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Polyhalides display a variety of structures. Various compounds with interesting structures were found when protonated aromatic nitrogen bases were combined with polyhalides (Kochel, 2006). Continuing our research in this area (Al-Far et al., 2012), we now report the crystal structure of the title compound in this article. The cystals of the title compound were found as an unexpected product from a reaction mixture of CdI2, HBr, 2-amino-5-methylpyridine and Br2 upon attempting to synthesize [(C7H10N)]2 [CdBr4] complex of 2-amino-5-methylpyrinium.
In the title compound (Fig. 1), the cation, 2-amino-5-methylpyridinium, is essentially planar (r.m.s.d = 0.0062 Å). The IBr2- anion is symmetrical and almost linear, Br1—I—Br2 angle of 177.67 (2) °, with I—Br distances 2.6836 (10) and 2.7119 (10) Å. These values are in agreement with the values reported in the literature (Gardberg et al., 2002). The molecular dimensions of the cation are also as expected (Hemamalini & Fun, 2010).
The crystal structure (Fig. 2), shows stacks of anions separated by layers of cations. The anions and cations are connected via H–N–H···Br and pyN–H···Br hydrogen bonding (Table 1), forming centrosymmetric tetramers (two cation and two anions). These tetramers form sixteen membered rings in graph set motif R44(16) (Bernstein et al., 1995). The rings are further connected via π···π interactions between the cations with separation betweeen the ring centroids [Cg···Cg (2 - x, -y, 1 - z)] being 4.038 (4) Å. Both hydrogen bonding and π···π interactions consolidate a three dimensional network.