Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807023070/hk2247sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807023070/hk2247Isup2.hkl |
CCDC reference: 650695
Key indicators
- Single-crystal X-ray study
- T = 294 K
- Mean (C-C) = 0.014 Å
- R factor = 0.043
- wR factor = 0.113
- Data-to-parameter ratio = 18.4
checkCIF/PLATON results
No syntax errors found
Alert level B PLAT230_ALERT_2_B Hirshfeld Test Diff for N4 - C3 .. 11.16 su PLAT413_ALERT_2_B Short Inter XH3 .. XHn H1B .. H1B .. 2.09 Ang.
Alert level C PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C3 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for Fe1 PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ... 15 PLAT420_ALERT_2_C D-H Without Acceptor N4 - H4A ... ? PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.29 Ratio
Alert level G PLAT794_ALERT_5_G Check Predicted Bond Valency for Fe1 (2) 2.84
0 ALERT level A = In general: serious problem 2 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 5 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check
For general background, see: Cui et al. (2000); Lacroix et al. (1994); Chakravarthy & Guloy (1997); Huang & Wang (2007); Al-Far & Ali (2007). For related literature, see: Garagorri-Benito et al. (2006); Kruszynski & Wyrzykowski (2006); Hao & Liu (2007); Churakov et al. (2006); Yang et al. (2004).
For the preparation of (I), FeCl2 (127 mg, 1 mmol) dissolved in absolute ethanol (10 ml) and liquid Br2 (20%, 1 ml), was added dropwise to a stirred hot ethanolic solution of dimethylpyrazine (77%, 1 ml) dissolved in ethanol (10 ml) and HBr (60%, 2 ml). After heating for 3 h, the mixture was filtered off and allowed to stand undisturbed at room temperature. The salt crystallized out over 3 d as black blocks. Crystals were filtered off, washed with ethanol then diethylether, and dried under vacuum (yield; 300 mg, 61.8%).
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, respectively, 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.
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; Lacroix et al., 1994; Chakravarthy & Guloy, 1997). 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 [pyzH2]2+ 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 [pyzH2]2+ cation and [FeBr3]1- unit of the anion, where the Fe atom has a distorted tetrahedral environment (Fig. 1, Table 1). The Fe—Br bonds and Br—Fe—Br angles are in the range of 2.3182 (17)–2.3348 (11) Å [mean value is 2.3305 (14) Å] and 108.72 (4)–110.63 (7) °, respectively, in which they are in accordance with the corresponding values (Benito-Garagorri et al., 2006; Kruszynski & Wyrzykowski, 2006). The bond lengths and angles in the brominated cation are also in accordance with the corresponding ones (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 Fe···Fe distance of 6.8583 (14) 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···Br3A = 3.8773 (15) Å (symmetry code A: 2 - x, 1 - y, 1 - 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 ···Br···aryl···Br···aryl··· infinite motif (Al-Far & Ali, 2007), in which the bromide ions of the anion lie between the two cationic species with centroid···Br···centroid (symmetry code: 2 - x, 1/2 + y, 1 - z) repeat distance of 3.928 (1) Å. Beside these interactions along with inter anion-stacks, the Br···Br interactions also link the anions and cations together into 2-D layers approximately normal to the a axis (Fig 2).
For general background, see: Cui et al. (2000); Lacroix et al. (1994); Chakravarthy & Guloy (1997); Huang & Wang (2007); Al-Far & Ali (2007). For related literature, see: Garagorri-Benito et al. (2006); Kruszynski & Wyrzykowski (2006); Hao & Liu (2007); Churakov et al. (2006); Yang et al. (2004).
Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999); software used to prepare material for publication: SHELXTL.
(C6H10N2)[FeBr4] | F(000) = 452 |
Mr = 485.61 | Dx = 2.461 Mg m−3 |
Monoclinic, P21/m | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yb | Cell parameters from 1974 reflections |
a = 6.6591 (13) Å | θ = 3.0–27.9° |
b = 14.352 (3) Å | µ = 13.31 mm−1 |
c = 6.8583 (14) Å | T = 294 K |
β = 90.92 (3)° | Block, black |
V = 655.4 (2) Å3 | 0.20 × 0.15 × 0.10 mm |
Z = 2 |
Rigaku Mercury CCD diffractometer | 1213 independent reflections |
Radiation source: fine-focus sealed tube | 856 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.084 |
Detector resolution: 14.6306 pixels mm-1 | θmax = 25.2°, θmin = 3.0° |
dtintegrate.ref scans | h = −6→7 |
Absorption correction: numerical (Shape Tracing Software; REFERENCE?) | k = −15→17 |
Tmin = 0.103, Tmax = 0.262 | l = −8→8 |
5269 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)] = 0.044 | H-atom parameters constrained |
wR(F2) = 0.113 | w = 1/[σ2(Fo2) + (0.0601P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.97 | (Δ/σ)max = 0.043 |
1213 reflections | Δρmax = 0.66 e Å−3 |
66 parameters | Δρmin = −0.92 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.032 (3) |
(C6H10N2)[FeBr4] | V = 655.4 (2) Å3 |
Mr = 485.61 | Z = 2 |
Monoclinic, P21/m | Mo Kα radiation |
a = 6.6591 (13) Å | µ = 13.31 mm−1 |
b = 14.352 (3) Å | T = 294 K |
c = 6.8583 (14) Å | 0.20 × 0.15 × 0.10 mm |
β = 90.92 (3)° |
Rigaku Mercury CCD diffractometer | 1213 independent reflections |
Absorption correction: numerical (Shape Tracing Software; REFERENCE?) | 856 reflections with I > 2σ(I) |
Tmin = 0.103, Tmax = 0.262 | Rint = 0.084 |
5269 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.113 | H-atom parameters constrained |
S = 0.97 | Δρmax = 0.66 e Å−3 |
1213 reflections | Δρmin = −0.92 e Å−3 |
66 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 | ||
Fe1 | 0.81018 (19) | 0.7500 | 0.77976 (18) | 0.0431 (4) | |
Br2 | 0.92375 (18) | 0.7500 | 1.10355 (15) | 0.0725 (4) | |
Br1 | 0.46205 (15) | 0.7500 | 0.76938 (16) | 0.0627 (4) | |
Br3 | 0.92512 (11) | 0.61623 (5) | 0.62320 (11) | 0.0649 (4) | |
C3 | 0.3172 (15) | 0.5452 (7) | 1.0157 (16) | 0.084 (3) | |
H3A | 0.1937 | 0.5752 | 1.0225 | 0.100* | |
N4 | 0.3605 (14) | 0.4879 (7) | 0.8654 (18) | 0.123 (4) | |
H4A | 0.2698 | 0.4790 | 0.7766 | 0.148* | |
C2 | 0.4576 (15) | 0.5570 (7) | 1.1530 (15) | 0.085 (3) | |
C1 | 0.4033 (16) | 0.6165 (7) | 1.3151 (13) | 0.095 (3) | |
H1A | 0.2912 | 0.5898 | 1.3814 | 0.143* | |
H1B | 0.3673 | 0.6772 | 1.2669 | 0.143* | |
H1C | 0.5154 | 0.6219 | 1.4042 | 0.143* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Fe1 | 0.0450 (8) | 0.0465 (8) | 0.0377 (7) | 0.000 | −0.0013 (6) | 0.000 |
Br2 | 0.0831 (9) | 0.0942 (10) | 0.0398 (6) | 0.000 | −0.0103 (6) | 0.000 |
Br1 | 0.0458 (6) | 0.0744 (8) | 0.0681 (8) | 0.000 | 0.0037 (5) | 0.000 |
Br3 | 0.0702 (6) | 0.0626 (6) | 0.0617 (6) | 0.0158 (4) | −0.0042 (4) | −0.0125 (4) |
C3 | 0.077 (7) | 0.080 (6) | 0.092 (7) | −0.006 (5) | −0.027 (6) | 0.015 (6) |
N4 | 0.082 (6) | 0.125 (8) | 0.160 (10) | −0.036 (6) | −0.062 (6) | 0.057 (7) |
C2 | 0.083 (7) | 0.081 (7) | 0.090 (7) | −0.028 (5) | −0.026 (6) | 0.037 (5) |
C1 | 0.110 (8) | 0.096 (8) | 0.080 (7) | −0.024 (6) | −0.010 (6) | −0.011 (6) |
Fe1—Br1 | 2.3182 (17) | N4—C2ii | 1.380 (13) |
Fe1—Br2 | 2.3343 (17) | N4—H4A | 0.8600 |
Fe1—Br3i | 2.3348 (11) | C2—N4ii | 1.380 (13) |
Fe1—Br3 | 2.3348 (11) | C2—C1 | 1.452 (13) |
C3—C2 | 1.328 (12) | C1—H1A | 0.9600 |
C3—N4 | 1.353 (13) | C1—H1B | 0.9600 |
C3—H3A | 0.9300 | C1—H1C | 0.9600 |
Br1—Fe1—Br2 | 109.74 (7) | C2ii—N4—H4A | 118.3 |
Br1—Fe1—Br3i | 108.72 (4) | C3—C2—N4ii | 119.0 (10) |
Br2—Fe1—Br3i | 109.51 (4) | C3—C2—C1 | 115.9 (11) |
Br1—Fe1—Br3 | 108.72 (4) | N4ii—C2—C1 | 125.1 (10) |
Br2—Fe1—Br3 | 109.51 (4) | C2—C1—H1A | 109.5 |
Br3i—Fe1—Br3 | 110.63 (7) | C2—C1—H1B | 109.5 |
C2—C3—N4 | 117.5 (10) | H1A—C1—H1B | 109.5 |
C2—C3—H3A | 121.2 | C2—C1—H1C | 109.5 |
N4—C3—H3A | 121.2 | H1A—C1—H1C | 109.5 |
C3—N4—C2ii | 123.5 (9) | H1B—C1—H1C | 109.5 |
C3—N4—H4A | 118.3 | ||
C2—C3—N4—C2ii | −1.0 (16) | N4—C3—C2—C1 | −178.0 (9) |
N4—C3—C2—N4ii | 1.0 (16) |
Symmetry codes: (i) x, −y+3/2, z; (ii) −x+1, −y+1, −z+2. |
Experimental details
Crystal data | |
Chemical formula | (C6H10N2)[FeBr4] |
Mr | 485.61 |
Crystal system, space group | Monoclinic, P21/m |
Temperature (K) | 294 |
a, b, c (Å) | 6.6591 (13), 14.352 (3), 6.8583 (14) |
β (°) | 90.92 (3) |
V (Å3) | 655.4 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 13.31 |
Crystal size (mm) | 0.20 × 0.15 × 0.10 |
Data collection | |
Diffractometer | Rigaku Mercury CCD |
Absorption correction | Numerical (Shape Tracing Software; REFERENCE?) |
Tmin, Tmax | 0.103, 0.262 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5269, 1213, 856 |
Rint | 0.084 |
(sin θ/λ)max (Å−1) | 0.600 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.113, 0.97 |
No. of reflections | 1213 |
No. of parameters | 66 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.66, −0.92 |
Computer programs: CrystalClear (Rigaku, 2000), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1999), SHELXTL.
Fe1—Br1 | 2.3182 (17) | Fe1—Br3i | 2.3348 (11) |
Fe1—Br2 | 2.3343 (17) | Fe1—Br3 | 2.3348 (11) |
Br1—Fe1—Br2 | 109.74 (7) | Br1—Fe1—Br3 | 108.72 (4) |
Br1—Fe1—Br3i | 108.72 (4) | Br2—Fe1—Br3 | 109.51 (4) |
Br2—Fe1—Br3i | 109.51 (4) | Br3i—Fe1—Br3 | 110.63 (7) |
Symmetry code: (i) x, −y+3/2, z. |
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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; Lacroix et al., 1994; Chakravarthy & Guloy, 1997). 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 [pyzH2]2+ 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 [pyzH2]2+ cation and [FeBr3]1- unit of the anion, where the Fe atom has a distorted tetrahedral environment (Fig. 1, Table 1). The Fe—Br bonds and Br—Fe—Br angles are in the range of 2.3182 (17)–2.3348 (11) Å [mean value is 2.3305 (14) Å] and 108.72 (4)–110.63 (7) °, respectively, in which they are in accordance with the corresponding values (Benito-Garagorri et al., 2006; Kruszynski & Wyrzykowski, 2006). The bond lengths and angles in the brominated cation are also in accordance with the corresponding ones (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 Fe···Fe distance of 6.8583 (14) 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···Br3A = 3.8773 (15) Å (symmetry code A: 2 - x, 1 - y, 1 - 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 ···Br···aryl···Br···aryl··· infinite motif (Al-Far & Ali, 2007), in which the bromide ions of the anion lie between the two cationic species with centroid···Br···centroid (symmetry code: 2 - x, 1/2 + y, 1 - z) repeat distance of 3.928 (1) Å. Beside these interactions along with inter anion-stacks, the Br···Br interactions also link the anions and cations together into 2-D layers approximately normal to the a axis (Fig 2).