Acta Cryst. (2008). E64, m485-m486 [ doi:10.1107/S160053680800439X ]
In the crystal structure of the title compound, (C7H10N)2[CoBr4], the [CoBr4]2- anion is connected to two cations through N-H
Br and H2C-HBr hydrogen bonds to form two-dimensional cation-anion-cation layers normal to the crystallographic b axis. Interactions of the ![[pi]](/logos/entities/pi_rmgif.gif)
- type are absent between cations in the stacks [centroid-centroid separation = 5.01 (5) Å]. Significant intermolecular Br-aryl interactions are present in the structure, especially an unusually short Br-ring centroid interaction of 3.78 (1) Å. The coordination geometry of the anion is approximately tetrahedral and a twofold rotation axis passes through the Co atom.
Boiling CoCl2(1.0 mmol), dissolved in absolute ethanol (10 ml) was added to a stirred absolute ethanol solution (10 ml) of 2,6-lutidine (1 mmol) and 48% HBr (3 ml). The mixture was then treated with liquid Br2 (2 ml). After refluxing for ca 1 h, the mixture was filtered off and allowed to evaporate undisturbed at room temperature. The salt crystallized out over 1 d as blue crystals.
H atoms bound to carbon and nitrogen were placed at idealized positions [C—H = 0.93 and 0.96 Å and N—H = 0.86 Å] and allowed to ride on their parent atoms with Uiso fixed at 1.2 or 1.5 Ueq(C,N).
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS (Siemens, 1996); data reduction: SHELXTL (Sheldrick, 2008); 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]](./at2543fig1thm.gif)
| Fig. 1. A view of the asymmetric unit of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry operation: (A) -x + 1, y, -z + 1/2]. |
![[Figure 2]](./at2543fig2thm.gif)
| Fig. 2. A packing diagram of (I), shows alternating stacks of anions and cations. Hydrogen atoms have been omitted for clarity. |
![[Figure 3]](./at2543fig3thm.gif)
| Fig. 3. Anion···cation intermolecular interactions. C,N—H···Br—Co intermolecular interactions are shown as dashed lines. Hydrogen atoms not involved in hydrogen bonding omitted for clarity. [Symmetry operation: (i) -x + 1, y, -z + 1/2] |
| (C7H10N)2[CoBr4] | F000 = 1140 |
| Mr = 594.89 | Dx = 1.842 Mg m−3 |
| Orthorhombic, Pbcn | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2n 2ab | Cell parameters from 36 reflections |
| a = 17.234 (2) Å | θ = 2.4–16.8º |
| b = 9.0691 (10) Å | µ = 8.24 mm−1 |
| c = 13.729 (2) Å | T = 293 (2) K |
| V = 2145.7 (5) Å3 | Chunk, blue |
| Z = 4 | 0.40 × 0.30 × 0.20 mm |
| Bruker P4 diffractometer | 1930 independent reflections |
| Radiation source: fine-focus sealed tube | 885 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.072 |
| Detector resolution: 3 pixels mm-1 | θmax = 25.2º |
| T = 293(2) K | θmin = 2.4º |
| ω Scans scans | h = −1→20 |
| Absorption correction: ψ scan (North et al., 1968) | k = −1→10 |
| Tmin = 0.064, Tmax = 0.192 | l = −16→1 |
| 2534 measured reflections |
| Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
| Least-squares matrix: full | H-atom parameters constrained |
| R[F2 > 2σ(F2)] = 0.055 | w = 1/[σ2(Fo2) + (0.0321P)2] where P = (Fo2 + 2Fc2)/3 |
| wR(F2) = 0.117 | (Δ/σ)max < 0.001 |
| S = 0.97 | Δρmax = 0.55 e Å−3 |
| 1930 reflections | Δρmin = −0.40 e Å−3 |
| 97 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0060 (4) |
| Secondary atom site location: difference Fourier map |
| (C7H10N)2[CoBr4] | V = 2145.7 (5) Å3 |
| Mr = 594.89 | Z = 4 |
| Orthorhombic, Pbcn | Mo Kα |
| a = 17.234 (2) Å | µ = 8.24 mm−1 |
| b = 9.0691 (10) Å | T = 293 (2) K |
| c = 13.729 (2) Å | 0.40 × 0.30 × 0.20 mm |
| Bruker P4 diffractometer | 1930 independent reflections |
| Absorption correction: ψ scan (North et al., 1968) | 885 reflections with I > 2σ(I) |
| Tmin = 0.064, Tmax = 0.192 | Rint = 0.072 |
| 2534 measured reflections |
| R[F2 > 2σ(F2)] = 0.055 | 97 parameters |
| wR(F2) = 0.117 | H-atom parameters constrained |
| S = 0.97 | Δρmax = 0.55 e Å−3 |
| 1930 reflections | Δρmin = −0.40 e Å−3 |
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 | ||
| Br1 | 0.39353 (5) | −0.42729 (12) | 0.18719 (7) | 0.0680 (4) | |
| Co1 | 0.5000 | −0.2856 (2) | 0.2500 | 0.0500 (6) | |
| Br2 | 0.45145 (6) | −0.13081 (14) | 0.37845 (7) | 0.0845 (5) | |
| N1 | 0.6230 (4) | −0.1559 (9) | 0.4945 (5) | 0.056 (2) | |
| H1 | 0.5806 | −0.1498 | 0.4618 | 0.067* | |
| C2 | 0.6211 (6) | −0.2366 (13) | 0.5769 (8) | 0.071 (3) | |
| C3 | 0.6900 (8) | −0.2499 (13) | 0.6250 (9) | 0.097 (4) | |
| H3 | 0.6928 | −0.3052 | 0.6819 | 0.116* | |
| C4 | 0.7556 (7) | −0.1811 (15) | 0.5891 (10) | 0.099 (4) | |
| H4 | 0.8025 | −0.1918 | 0.6218 | 0.119* | |
| C5 | 0.7527 (6) | −0.0991 (13) | 0.5078 (8) | 0.085 (4) | |
| H5 | 0.7973 | −0.0526 | 0.4852 | 0.102* | |
| C6 | 0.6850 (6) | −0.0840 (11) | 0.4588 (6) | 0.061 (3) | |
| C7 | 0.5478 (6) | −0.3092 (14) | 0.6029 (8) | 0.116 (5) | |
| H7A | 0.5083 | −0.2813 | 0.5572 | 0.174* | |
| H7B | 0.5325 | −0.2795 | 0.6672 | 0.174* | |
| H7C | 0.5546 | −0.4142 | 0.6012 | 0.174* | |
| C8 | 0.6727 (5) | 0.0072 (13) | 0.3689 (7) | 0.106 (4) | |
| H8A | 0.6197 | −0.0011 | 0.3483 | 0.159* | |
| H8B | 0.7063 | −0.0274 | 0.3180 | 0.159* | |
| H8C | 0.6843 | 0.1086 | 0.3829 | 0.159* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Br1 | 0.0521 (6) | 0.0757 (8) | 0.0762 (7) | −0.0135 (6) | −0.0140 (6) | 0.0045 (6) |
| Co1 | 0.0379 (9) | 0.0594 (14) | 0.0527 (10) | 0.000 | −0.0008 (9) | 0.000 |
| Br2 | 0.0537 (6) | 0.1130 (11) | 0.0867 (8) | 0.0146 (7) | −0.0040 (6) | −0.0405 (7) |
| N1 | 0.036 (4) | 0.069 (6) | 0.063 (5) | −0.006 (4) | 0.001 (4) | −0.005 (5) |
| C2 | 0.056 (7) | 0.081 (8) | 0.075 (7) | −0.007 (6) | −0.003 (6) | 0.018 (7) |
| C3 | 0.106 (10) | 0.080 (10) | 0.103 (9) | 0.013 (8) | −0.024 (9) | 0.009 (8) |
| C4 | 0.065 (8) | 0.116 (12) | 0.117 (11) | 0.032 (9) | −0.045 (8) | −0.020 (9) |
| C5 | 0.055 (7) | 0.113 (11) | 0.087 (8) | 0.006 (7) | −0.012 (7) | −0.007 (8) |
| C6 | 0.050 (6) | 0.068 (7) | 0.065 (7) | −0.014 (6) | 0.005 (5) | −0.017 (6) |
| C7 | 0.104 (10) | 0.124 (12) | 0.120 (9) | −0.034 (9) | 0.006 (8) | 0.055 (9) |
| C8 | 0.085 (8) | 0.150 (13) | 0.082 (8) | −0.045 (9) | 0.002 (7) | 0.040 (9) |
| Br1—Co1 | 2.4002 (13) | C4—C5 | 1.341 (15) |
| Co1—Br1i | 2.4002 (13) | C4—H4 | 0.9300 |
| Co1—Br2 | 2.4044 (15) | C5—C6 | 1.354 (12) |
| Co1—Br2i | 2.4044 (15) | C5—H5 | 0.9300 |
| N1—C2 | 1.348 (11) | C6—C8 | 1.501 (12) |
| N1—C6 | 1.345 (10) | C7—H7A | 0.9600 |
| N1—H1 | 0.8600 | C7—H7B | 0.9600 |
| C2—C3 | 1.363 (13) | C7—H7C | 0.9600 |
| C2—C7 | 1.468 (12) | C8—H8A | 0.9600 |
| C3—C4 | 1.383 (15) | C8—H8B | 0.9600 |
| C3—H3 | 0.9300 | C8—H8C | 0.9600 |
| Br1—Co1—Br1i | 115.28 (9) | C4—C5—C6 | 120.1 (12) |
| Br1—Co1—Br2 | 108.06 (3) | C4—C5—H5 | 119.9 |
| Br1i—Co1—Br2 | 108.37 (4) | C6—C5—H5 | 119.9 |
| Br1—Co1—Br2i | 108.37 (4) | N1—C6—C5 | 117.0 (10) |
| Br1i—Co1—Br2i | 108.06 (3) | N1—C6—C8 | 117.1 (9) |
| Br2—Co1—Br2i | 108.54 (9) | C5—C6—C8 | 125.9 (10) |
| C2—N1—C6 | 126.0 (8) | C2—C7—H7A | 109.5 |
| C2—N1—H1 | 117.0 | C2—C7—H7B | 109.5 |
| C6—N1—H1 | 117.0 | H7A—C7—H7B | 109.5 |
| N1—C2—C3 | 115.7 (10) | C2—C7—H7C | 109.5 |
| N1—C2—C7 | 117.9 (9) | H7A—C7—H7C | 109.5 |
| C3—C2—C7 | 126.3 (11) | H7B—C7—H7C | 109.5 |
| C2—C3—C4 | 120.0 (11) | C6—C8—H8A | 109.5 |
| C2—C3—H3 | 120.0 | C6—C8—H8B | 109.5 |
| C4—C3—H3 | 120.0 | H8A—C8—H8B | 109.5 |
| C5—C4—C3 | 121.1 (11) | C6—C8—H8C | 109.5 |
| C5—C4—H4 | 119.5 | H8A—C8—H8C | 109.5 |
| C3—C4—H4 | 119.5 | H8B—C8—H8C | 109.5 |
| C6—N1—C2—C3 | −2.9 (16) | C3—C4—C5—C6 | −1(2) |
| C6—N1—C2—C7 | −178.9 (10) | C2—N1—C6—C5 | 3.0 (15) |
| N1—C2—C3—C4 | 0.8 (18) | C2—N1—C6—C8 | −176.3 (9) |
| C7—C2—C3—C4 | 176.5 (12) | C4—C5—C6—N1 | −1.0 (16) |
| C2—C3—C4—C5 | 1(2) | C4—C5—C6—C8 | 178.2 (11) |
| Symmetry codes: (i) −x+1, y, −z+1/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1···Br2 | 0.86 | 2.51 | 3.366 (7) | 176 |
| C7—H7A···Br2 | 0.96 | 2.97 | 3.856 (10) | 153 |
| Br1—Co1 | 2.4002 (13) | Co1—Br2 | 2.4044 (15) |
| Br1—Co1—Br1i | 115.28 (9) | Br1—Co1—Br2i | 108.37 (4) |
| Br1—Co1—Br2 | 108.06 (3) | Br2—Co1—Br2i | 108.54 (9) |
| Symmetry codes: (i) −x+1, y, −z+1/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1···Br2 | 0.86 | 2.51 | 3.366 (7) | 176 |
| C7—H7A···Br2 | 0.96 | 2.97 | 3.856 (10) | 153 |
Financial support from Al al-Bayt University and Al-Balqa'a Applied University is greatly appreciated.
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Al-Far, R. & Ali, B. F. (2007b). J. Chem. Crystallogr. 37, 333–341.
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Ali, B. F. & Al-Far, R. (2008). J. Chem. Crystallogr. Submitted. Any update?
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Noncovalent interactions play an important role in organizing structural units in both natural and artificial systems (Desiraju, 1997). They exercise important effects on the organization and properties of many materials in areas such as biology (Hunter 1994; Desiraju & Steiner 1999), crystal engineering (see for example: Allen et al.,1997; Dolling et al., 2001) and material science (Panunto et al., 1987; Robinson et al., 2000). The interactions governing the crystal organization are expected to affect the packing and then the specific properties of solids. In connection with ongoing studies (Ali & Al-Far, 2008; Al-Far & Ali, 2008; Ali & Al-Far, 2007; Al-Far & Ali, 2007a,b) of the structural aspects of halo-metal anion salts, we herein report the crystal structure of the title compound (I) along with its crystal supramolecularity.
The asymmetric unit in (I), contains half an anion and one cation (Fig. 1). The geometry of CoBr42- anions is nearly tetrahedral (Td) about Co metal (Table 1). Co—Br distances are similar, but Co—Br that are engaged in Co—Br···H—N,C hydrogen bonding, Co—Br2 and Co—Br2 [1 - x, y, 1/2 - z], are slightly longer than the others (Table 1). The bond distances and angles fall in the range of those reported previously for compounds containing Co—Br anions (Ali & Al-Far 2008; Al-Far & Ali 2008; Zhang et al., 2005). In the cation, the bond lengths and angles are within normal range (Allen et al., 1987).
The packing of the structure (Fig. 2) can be regarded as alternating stacks of anions and stacks of cations. The anion stacks are parallel to the cation stacks, with Co···Co distance of 9.0691 (10) Å (b axis), with no significant inter- and intra-stack halogen···halogen interactions (shortest Br···Br interactions being 4.4236 (20) Å). The anions and cations are interacting significantly through extensive N—H···Br and C—H···Br hydrogen bonding involving Br- anions and N—H and CH3 groups (Table 2; Fig. 3). These interactions link anions and cations into two-dimensional cation···anion···cation layers approximately normal to the crystallographic b axis (Fig. 3).
There is no π···π stacking of cations, the inter-stack centroid separations X1A···X1A [1 - x, y, 1/2 - z] and X1A···X1A [3/2 - x, 1/2 + y, z] being 5.01 (5) Å. This correlates well with the significant intermolecular Br···aryl interactions present in the structure. These are represented by the unusually short Br2···X1A [1 - x, -y, 1 - z] contact (3.78 (1) Å) and Br1···X1A [1 - x, y, 1/2 - z] (4.17 (3) Å) interaction.