Acta Cryst. (2007). E63, m2242-m2243 [ doi:10.1107/S1600536807036513 ]
In the title compound, (C6H10N2)[TlBr4], the asymmetric unit contains one half-cation and one half-anion, where the Tl atom has a distorted tetrahedral environment. The Tl atom and two Br atoms lie on a mirror plane; the cation is centrosymmetric, with the H atom disordered over both N atoms. In the crystal structure, the cations and anions are packed into alternate stacks, with no significant intermolecular Br
Br and/or aryl-aryl interactions within each stack. The anion-anion stacks interact via BrBr interactions [BrBr = 3.6368 (16) Å] to form one-dimensional arrays. The Braryl interactions are arranged in a arylBrarylBr infinite motif [Brcentroid distance 4.07 (1) Å], linking the anions and cations into two-dimensional layers.
For the preparation of (I), TlBr3·4H2O (258 mg, 0.5 mmol) dissolved in absolute ethanol (10 ml) and liquid Br2 (20%, 2 ml), was added dropwise to a stirred hot ethanolic solution of 2,5-dimethylpyrazine (75%, 1 ml) dissolved in ethanol (10 ml) and HBr (60%, 2 ml). After heating for 2 h, the mixture was filtered off and allowed to stand undisturbed at room temperature. The salt crystallized out over 3 d as yellow blocks. Crystals were filtered off, washed with ethanol then diethylether, and dried under vacuum (yield; 200 mg, 62.9%).
H atoms were positioned geometrically, with N—H = 0.86 Å (for NH) and C—H = 0.93 and 0.96 Å for aromatic and methyl H atoms, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C,N), where x = 1.5 for methyl H, and x = 1.2 for all other H atoms.
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 2004); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
![[Figure 1]](./hk2276fig1thm.gif)
| Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry code A: x, 1/2 − y, z]. |
![[Figure 2]](./hk2276fig2thm.gif)
| Fig. 2. A partial packing diagram for (I), viewed down the c axis (a is vertical and b is horizontal). The Br···aryl interaction is shown as Br2 and X1 [centroid of cation generated by x, y, z] and Br···Br interactions are shown as dashed lines [symmetry codes: (A) x, 1/2 − y, z, (i) −x, 1/2 + y, −z, (ii) −x, −y,-z]. |
| (C6H10N2)[TlBr4] | F(000) = 562 |
| Mr = 634.14 | Dx = 3.055 Mg m−3 |
| Monoclinic, P21/m | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -P 2yb | Cell parameters from 1290 reflections |
| a = 6.747 (2) Å | θ = 1.8–25.3° |
| b = 14.6689 (7) Å | µ = 23.27 mm−1 |
| c = 6.9651 (7) Å | T = 298 K |
| β = 90.01 (1)° | Block, yellow |
| V = 689.3 (2) Å3 | 0.15 × 0.10 × 0.07 mm |
| Z = 2 |
| Bruker SMART CCD area-detector diffractometer | 1304 independent reflections |
| Radiation source: fine-focus sealed tube | 1290 reflections with I > 2σ(I) |
| graphite | Rint = 0.045 |
| Detector resolution: 8.3 pixels mm-1 | θmax = 25.2°, θmin = 2.9° |
| ω scans | h = −8→8 |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | k = −17→17 |
| Tmin = 0.074, Tmax = 0.192 | l = −8→8 |
| 4843 measured reflections |
| Refinement on F2 | Primary atom site location: structure-invariant direct methods |
| Least-squares matrix: full | Secondary atom site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.026 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.049 | H-atom parameters constrained |
| S = 0.86 | w = 1/[σ2(Fo2) + (0.0135P)2] where P = (Fo2 + 2Fc2)/3 |
| 1304 reflections | (Δ/σ)max < 0.001 |
| 65 parameters | Δρmax = 0.48 e Å−3 |
| 0 restraints | Δρmin = −0.56 e Å−3 |
| (C6H10N2)[TlBr4] | V = 689.3 (2) Å3 |
| Mr = 634.14 | Z = 2 |
| Monoclinic, P21/m | Mo Kα radiation |
| a = 6.747 (2) Å | µ = 23.27 mm−1 |
| b = 14.6689 (7) Å | T = 298 K |
| c = 6.9651 (7) Å | 0.15 × 0.10 × 0.07 mm |
| β = 90.01 (1)° |
| Bruker SMART CCD area-detector diffractometer | 1304 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | 1290 reflections with I > 2σ(I) |
| Tmin = 0.074, Tmax = 0.192 | Rint = 0.045 |
| 4843 measured reflections | θmax = 25.2° |
| R[F2 > 2σ(F2)] = 0.026 | H-atom parameters constrained |
| wR(F2) = 0.049 | Δρmax = 0.48 e Å−3 |
| S = 0.86 | Δρmin = −0.56 e Å−3 |
| 1304 reflections | Absolute structure: ? |
| 65 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 | ||
| Tl1 | 0.19905 (6) | 0.2500 | 0.28087 (6) | 0.05200 (14) | |
| Br1 | 0.0840 (2) | 0.2500 | 0.62919 (18) | 0.0897 (4) | |
| Br2 | 0.57533 (16) | 0.2500 | 0.2570 (2) | 0.0760 (4) | |
| Br3 | 0.07269 (13) | 0.10561 (5) | 0.11722 (13) | 0.0700 (2) | |
| C1 | 0.6282 (15) | −0.0176 (8) | 0.3530 (18) | 0.096 (3) | |
| H1A | 0.7202 | −0.0285 | 0.2562 | 0.115* | |
| N2 | 0.6727 (13) | 0.0396 (8) | 0.5027 (19) | 0.125 (4) | |
| H2A | 0.7861 | 0.0663 | 0.5041 | 0.150* | |
| C3 | 0.5420 (17) | 0.0558 (7) | 0.6508 (17) | 0.093 (3) | |
| C4 | 0.5876 (19) | 0.1147 (8) | 0.8054 (18) | 0.120 (4) | |
| H4A | 0.5889 | 0.0805 | 0.9230 | 0.180* | |
| H4B | 0.4892 | 0.1618 | 0.8133 | 0.180* | |
| H4C | 0.7155 | 0.1416 | 0.7848 | 0.180* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Tl1 | 0.0567 (2) | 0.0512 (2) | 0.0481 (2) | 0.000 | 0.00006 (17) | 0.000 |
| Br1 | 0.0977 (9) | 0.1257 (11) | 0.0456 (7) | 0.000 | 0.0098 (7) | 0.000 |
| Br2 | 0.0536 (6) | 0.0877 (8) | 0.0869 (9) | 0.000 | −0.0051 (6) | 0.000 |
| Br3 | 0.0787 (5) | 0.0604 (5) | 0.0710 (6) | −0.0134 (3) | 0.0036 (5) | −0.0109 (4) |
| C1 | 0.087 (7) | 0.100 (7) | 0.101 (9) | 0.019 (6) | 0.047 (7) | 0.017 (7) |
| N2 | 0.091 (6) | 0.120 (8) | 0.164 (11) | 0.016 (5) | 0.027 (8) | 0.047 (8) |
| C3 | 0.091 (7) | 0.097 (7) | 0.093 (8) | 0.039 (6) | 0.017 (7) | 0.021 (6) |
| C4 | 0.126 (9) | 0.120 (9) | 0.114 (10) | 0.039 (7) | −0.020 (9) | −0.028 (8) |
| Tl1—Br1 | 2.5473 (13) | N2—C3 | 1.378 (12) |
| Tl1—Br2 | 2.544 (3) | N2—H2A | 0.8600 |
| Tl1—Br3 | 2.5519 (8) | C3—C1ii | 1.278 (14) |
| Tl1—Br3i | 2.5519 (8) | C3—C4 | 1.414 (15) |
| C1—C3ii | 1.278 (14) | C4—H4A | 0.9600 |
| C1—H1A | 0.9300 | C4—H4B | 0.9600 |
| N2—C1 | 1.372 (14) | C4—H4C | 0.9600 |
| Br2—Tl1—Br1 | 111.48 (5) | C3—N2—H2A | 118.8 |
| Br2—Tl1—Br3 | 107.71 (3) | C1ii—C3—N2 | 118.9 (12) |
| Br1—Tl1—Br3 | 108.88 (3) | C1ii—C3—C4 | 118.6 (12) |
| Br2—Tl1—Br3i | 107.71 (3) | N2—C3—C4 | 122.4 (12) |
| Br1—Tl1—Br3i | 108.88 (3) | C3—C4—H4A | 109.5 |
| Br3—Tl1—Br3i | 112.19 (5) | C3—C4—H4B | 109.5 |
| C3ii—C1—N2 | 118.7 (11) | H4A—C4—H4B | 109.5 |
| C3ii—C1—H1A | 120.6 | C3—C4—H4C | 109.5 |
| N2—C1—H1A | 120.6 | H4A—C4—H4C | 109.5 |
| C1—N2—C3 | 122.3 (10) | H4B—C4—H4C | 109.5 |
| C1—N2—H2A | 118.8 | ||
| C3—N2—C1—C3ii | 1.4 (18) | C1—N2—C3—C4 | 179.9 (10) |
| C1—N2—C3—C1ii | −1.4 (18) |
| Symmetry codes: (i) x, −y+1/2, z; (ii) −x+1, −y, −z+1. |
| Tl1—Br1 | 2.5473 (13) | Tl1—Br3 | 2.5519 (8) |
| Tl1—Br2 | 2.544 (3) | Tl1—Br3i | 2.5519 (8) |
| Br2—Tl1—Br1 | 111.48 (5) | Br1—Tl1—Br3 | 108.88 (3) |
| Br2—Tl1—Br3 | 107.71 (3) | Br3—Tl1—Br3i | 112.19 (5) |
| Symmetry codes: (i) x, −y+1/2, z. |
This research was supported by Al al-Bayt University and Al-Balqa'a Applied University. The authors are grateful to the University of Idaho for assistance under the NSF-EPSCoR program and the M. J. Murdock Charitable Trust, Vancouver, WA, USA, for the diffraction facilities.
Abdi, M., Zouari, F. & Ben Salah, A. (2004). J. Chem. Crystallogr. C34, 673–677.
Abdi, M., Zouari, F., Chniba-Boudjada, N., Bordet, P. & Salah, A. B. (2005). Acta Cryst. E61, m240–m241.
Al-Far, R. & Ali, B. F. (2007a). Acta Cryst. E63, m1701–?.
Al-Far, R. & Ali, B. F. (2007b). J. Chem. Crystallogr. 37, 333–341.
Bruker (2001). SMART. Version 5.630. Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2004). SHELXTL (Version 6.14) and SADABS (Version 2004/1). Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2006). SAINT. Version 7.23a. Bruker AXS Inc, Madison, Wisconsin, USA.
Castiñeiras, A., Bermejo, M. R., Garcia-Deibe, A. & Hiller, W. (1991). Acta Cryst. C47, m1738–m1740.
Chakravarthy, V. & Guloy, A. M. (1997). Chem. Commun. pp. 697–698.
Churakov, A. V., Kuz'mina, L. G., Prikhodchenko, P. V. & Howard, J. A. K. (2006). Acta Cryst. E62, o2265–o2267.
Cui, Y., Ren, J., Chen, G., Yu, W.-C. & Qian, Y. (2000). Acta Cryst. C56, e552–e553.
Hao, L.-J. & Liu, T.-T. (2007). Acta Cryst. E63, m169–m171.
He, Z., Zhu, M. & Ma, G. (2002). Acta Cryst. E58, m647–m649.
Huang, P.-Y. & Wang, J.-G. (2007). Acta Cryst. E63, m645–m646.
Lacroix, P. G., Clement, R., Nakatani, K., Zyss, J. & Ledoux, I. (1994). Science, 263, 658–660.
Linden, A., Petridis, A. & James, B. D. (2002). Acta Cryst. C58, m53–m55.
Yang, M., Ni, C., Zheng, Y. & Gu, W. (2004). Acta Cryst. E60, m833–m835.
A large number of Tl(III)-organic complexes are known and their main crystallographic details have also been surveyed and reported (Abdi et al., 2004 and references therein). However, Tl(III) complexes containing Tl(III) anionic species-organic cations are relatively small (Abdi et al., 2004; Castineiras et al., 1991). On the other hand, the research in the field of inorganic-organic hybrids is of great interest due to their magnetic, electronic and optoelectric properties (Cui et al., 2000; Chakravarthy & Guloy, 1997; Lacroix et al., 1994). The packing interactions that govern the crystal organization is expected to affect the packing and then the specific properties of such solids. For example, pyrazine (pyz) and similar ligands have been used through their two nitrogen atoms as neutral linkers to generate and stabilize many open 1-, 2- and 3-D coordination polymers and forming supramolecular coordination assemblies (Hao & Liu, 2007; Huang & Wang, 2007). We herein report the crystal structure of the title complex, (I), wherein, the protonated dimethylpyrazinium ligand [pyzH]+ is not involved in coordination, but in extensive infinite aryl···Br···aryl···Br intermolecular interactions, affording a 2-D network structure by the aid of Br···Br interactions.
The asymmetric unit of the title compound, (I), contains one half [pyzH]+ cation and [TlBr3]− unit of the anion, where the Tl atom has a distorted tetrahedral environment (Fig. 1, Table 1). The Tl—Br bonds and Br—Tl—Br angles are in the range of 2.5452 (13)–2.5518 (9) Å [mean value is 2.5481 (12) Å] and 107.70 (4)–112.20 (5)°, respectively, in which they are in accordance with the corresponding values (Abdi et al., 2005; He et al., 2002; Linden et al., 2002). On the other hand, in the cation the bond lengths and angles are the same as those reported (Al-Far & Ali, 2007a; Hao & Liu, 2007; Churakov et al., 2006; Yang et al., 2004).
The molecules of discrete anions, packed into stacks, are separated by stacks of cations. The anion stacks along the c axis are parallel to the cation stacks with Tl···Tl distance of 6.9651 (7) Å, with no significant interactions between anions and cations within a stack. Inter anion-stacks are linked only through one Br···Br interaction parallel to b axis [Br3···Br3ii = 3.6368 (16) Å (symmetry code (ii): −x, −y, −z)]. The anions and cations are not involved in any of Br···H interactions, but only through Br···aryl interactions, that are represented in the ···aryl···Br···aryl···Br··· infinite motif (Al-Far & Ali, 2007a,b), in which the bromide ions of the anion lie between the two cationic species with centroid···Br···centroid (symmetry code: x, y, z) repeat distance of 4.07 (1) Å. Beside these interactions along with inter anion-stacks, the Br···Br interactions link the anions and cations together into 2-D layers approximately normal to the a axis (Fig 2).