metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890
Volume 64| Part 3| March 2008| Pages m485-m486

Bis(2,6-di­methyl­pyridinium) tetra­bromido­cobaltate(II)

aDepartment of Chemistry, Al al-Bayt University, Mafraq 25113, Jordan, bFaculty of Information Technology and Science, Al-Balqa'a Applied University, Salt, Jordan, and cDepartment of Chemistry, The University of Jordan, Amman, Jordan
*Correspondence e-mail: rohi@bau.edu.jo

(Received 9 February 2008; accepted 13 February 2008; online 20 February 2008)

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—H⋯Br hydrogen bonds to form two-dimensional cation–anion–cation layers normal to the crystallographic b axis. Inter­actions of the ππ 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.

Related literature

For general background, see: Al-Far & Ali (2007a[Al-Far, R. & Ali, B. F. (2007a). Acta Cryst. C63, m137-m139.],b[Al-Far, R. & Ali, B. F. (2007b). J. Chem. Crystallogr. 37, 333-341.]); Ali & Al-Far (2007[Ali, B. F. & Al-Far, R. (2007). Acta Cryst. C63, m451-m453.]); Allen et al. (1997[Allen, F. H., Hoy, V. J., Howard, J. A. K., Thalladi, V. R., Desiraju, G. R., Wilson, C. C. & McIntyre, G. J. (1997). J. Am. Chem. Soc. 119, 3477-3480.]); Desiraju & Steiner (1999[Desiraju, G. R. & Steiner, T. (1999). The Weak Hydrogen Bond in Structural Chemistry and Biology. Oxford University Press.]); Dolling et al. (2001[Dolling, B., Gillon, A. L., Orpen, A. G., Starbuck, J. & Wang, X.-M. (2001). Chem. Commun. pp. 567-568.]); Hunter (1994[Hunter, C. A. (1994). Chem. Soc. Rev. 2, 101-109.]); Panunto et al. (1987[Panunto, T. W., Urbanczyk-Lipkowska, Z., Johnson, R. & Etter, M. C. (1987). J. Am. Chem. Soc. 109, 7786-7797.]); Robinson et al. (2000[Robinson, J. M. A., Philp, D., Harris, K. D. M. & Kariuki, B. M. (2000). New J. Chem. 10, 799-806.]). For related literature, see: Al-Far & Ali (2008[Al-Far, R. & Ali, B. F. (2008). J. Chem. Crystallogr.]); Ali & Al-Far (2008[Ali, B. F. & Al-Far, R. (2008). J. Chem. Crystallogr.]); Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]); Desiraju (1997[Desiraju, G. R. (1997). Chem. Commun. pp. 1475-1482.]); Zhang et al. (2005[Zhang, H., Fang, L. & Yuan, R. (2005). Acta Cryst. E61, m609-m610.]).

[Scheme 1]

Experimental

Crystal data
  • (C7H10N)2[CoBr4]

  • Mr = 594.89

  • Orthorhombic, P b c n

  • a = 17.234 (2) Å

  • b = 9.0691 (10) Å

  • c = 13.729 (2) Å

  • V = 2145.7 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 8.24 mm−1

  • T = 293 (2) K

  • 0.40 × 0.30 × 0.20 mm

Data collection
  • Bruker P4 diffractometer

  • Absorption correction: ψ scan;(North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.064, Tmax = 0.192

  • 2534 measured reflections

  • 1930 independent reflections

  • 885 reflections with I > 2σ(I)

  • Rint = 0.072

Refinement
  • R[F2 > 2σ(F2)] = 0.055

  • wR(F2) = 0.117

  • S = 0.97

  • 1930 reflections

  • 97 parameters

  • H-atom parameters constrained

  • Δρmax = 0.55 e Å−3

  • Δρmin = −0.40 e Å−3

Table 1
Selected geometric parameters (Å, °)

Br1—Co1 2.4002 (13)
Co1—Br2 2.4044 (15)
Br1—Co1—Br1i 115.28 (9)
Br1—Co1—Br2 108.06 (3)
Br1—Co1—Br2i 108.37 (4)
Br2—Co1—Br2i 108.54 (9)
Symmetry code: (i) [-x+1, y, -z+{\script{1\over 2}}].

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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

Data collection: XSCANS (Siemens, 1996[Siemens (1996). XSCANS. Version 2.20. Siemens Analytical X-ray Instruments Inc, Madison, Wisconsin, USA.]); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

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.

Related literature top

For general background, see: Al-Far & Ali (2007a,b); Ali & Al-Far (2007); Allen et al. (1997); Desiraju & Steiner (1999); Dolling et al. (2001); Hunter (1994); Panunto et al. (1987); Robinson et al. (2000). For related literature, see: Al-Far & Ali (2008); Ali & Al-Far (2008); Allen et al. (1987); Desiraju (1997); Zhang et al. (2005). N.B. the cystal description in the CIF is currently `Shunk'; should this be changed to `chunk' or `block'?

Experimental top

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.

Refinement top

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).

Computing details top

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).

Figures top
[Figure 1] 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] Fig. 2. A packing diagram of (I), shows alternating stacks of anions and cations. Hydrogen atoms have been omitted for clarity.
[Figure 3] 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]
Bis(2,6-dimethylpyridinium) tetrabromidocobaltate(II) top
Crystal data top
(C7H10N)2[CoBr4]F(000) = 1140
Mr = 594.89Dx = 1.842 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 36 reflections
a = 17.234 (2) Åθ = 2.4–16.8°
b = 9.0691 (10) ŵ = 8.24 mm1
c = 13.729 (2) ÅT = 293 K
V = 2145.7 (5) Å3Chunk, blue
Z = 40.40 × 0.30 × 0.20 mm
Data collection top
Bruker P4
diffractometer
1930 independent reflections
Radiation source: fine-focus sealed tube885 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.072
Detector resolution: 3 pixels mm-1θmax = 25.2°, θmin = 2.4°
ω Scans scansh = 120
Absorption correction: ψ scan
(North et al., 1968)
k = 110
Tmin = 0.064, Tmax = 0.192l = 161
2534 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.055H-atom parameters constrained
wR(F2) = 0.117 w = 1/[σ2(Fo2) + (0.0321P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.97(Δ/σ)max < 0.001
1930 reflectionsΔρmax = 0.55 e Å3
97 parametersΔρmin = 0.40 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0060 (4)
Crystal data top
(C7H10N)2[CoBr4]V = 2145.7 (5) Å3
Mr = 594.89Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 17.234 (2) ŵ = 8.24 mm1
b = 9.0691 (10) ÅT = 293 K
c = 13.729 (2) Å0.40 × 0.30 × 0.20 mm
Data collection top
Bruker P4
diffractometer
1930 independent reflections
Absorption correction: ψ scan
(North et al., 1968)
885 reflections with I > 2σ(I)
Tmin = 0.064, Tmax = 0.192Rint = 0.072
2534 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0550 restraints
wR(F2) = 0.117H-atom parameters constrained
S = 0.97Δρmax = 0.55 e Å3
1930 reflectionsΔρmin = 0.40 e Å3
97 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.39353 (5)0.42729 (12)0.18719 (7)0.0680 (4)
Co10.50000.2856 (2)0.25000.0500 (6)
Br20.45145 (6)0.13081 (14)0.37845 (7)0.0845 (5)
N10.6230 (4)0.1559 (9)0.4945 (5)0.056 (2)
H10.58060.14980.46180.067*
C20.6211 (6)0.2366 (13)0.5769 (8)0.071 (3)
C30.6900 (8)0.2499 (13)0.6250 (9)0.097 (4)
H30.69280.30520.68190.116*
C40.7556 (7)0.1811 (15)0.5891 (10)0.099 (4)
H40.80250.19180.62180.119*
C50.7527 (6)0.0991 (13)0.5078 (8)0.085 (4)
H50.79730.05260.48520.102*
C60.6850 (6)0.0840 (11)0.4588 (6)0.061 (3)
C70.5478 (6)0.3092 (14)0.6029 (8)0.116 (5)
H7A0.50830.28130.55720.174*
H7B0.53250.27950.66720.174*
H7C0.55460.41420.60120.174*
C80.6727 (5)0.0072 (13)0.3689 (7)0.106 (4)
H8A0.61970.00110.34830.159*
H8B0.70630.02740.31800.159*
H8C0.68430.10860.38290.159*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0521 (6)0.0757 (8)0.0762 (7)0.0135 (6)0.0140 (6)0.0045 (6)
Co10.0379 (9)0.0594 (14)0.0527 (10)0.0000.0008 (9)0.000
Br20.0537 (6)0.1130 (11)0.0867 (8)0.0146 (7)0.0040 (6)0.0405 (7)
N10.036 (4)0.069 (6)0.063 (5)0.006 (4)0.001 (4)0.005 (5)
C20.056 (7)0.081 (8)0.075 (7)0.007 (6)0.003 (6)0.018 (7)
C30.106 (10)0.080 (10)0.103 (9)0.013 (8)0.024 (9)0.009 (8)
C40.065 (8)0.116 (12)0.117 (11)0.032 (9)0.045 (8)0.020 (9)
C50.055 (7)0.113 (11)0.087 (8)0.006 (7)0.012 (7)0.007 (8)
C60.050 (6)0.068 (7)0.065 (7)0.014 (6)0.005 (5)0.017 (6)
C70.104 (10)0.124 (12)0.120 (9)0.034 (9)0.006 (8)0.055 (9)
C80.085 (8)0.150 (13)0.082 (8)0.045 (9)0.002 (7)0.040 (9)
Geometric parameters (Å, º) top
Br1—Co12.4002 (13)C4—C51.341 (15)
Co1—Br1i2.4002 (13)C4—H40.9300
Co1—Br22.4044 (15)C5—C61.354 (12)
Co1—Br2i2.4044 (15)C5—H50.9300
N1—C21.348 (11)C6—C81.501 (12)
N1—C61.345 (10)C7—H7A0.9600
N1—H10.8600C7—H7B0.9600
C2—C31.363 (13)C7—H7C0.9600
C2—C71.468 (12)C8—H8A0.9600
C3—C41.383 (15)C8—H8B0.9600
C3—H30.9300C8—H8C0.9600
Br1—Co1—Br1i115.28 (9)C4—C5—C6120.1 (12)
Br1—Co1—Br2108.06 (3)C4—C5—H5119.9
Br1i—Co1—Br2108.37 (4)C6—C5—H5119.9
Br1—Co1—Br2i108.37 (4)N1—C6—C5117.0 (10)
Br1i—Co1—Br2i108.06 (3)N1—C6—C8117.1 (9)
Br2—Co1—Br2i108.54 (9)C5—C6—C8125.9 (10)
C2—N1—C6126.0 (8)C2—C7—H7A109.5
C2—N1—H1117.0C2—C7—H7B109.5
C6—N1—H1117.0H7A—C7—H7B109.5
N1—C2—C3115.7 (10)C2—C7—H7C109.5
N1—C2—C7117.9 (9)H7A—C7—H7C109.5
C3—C2—C7126.3 (11)H7B—C7—H7C109.5
C2—C3—C4120.0 (11)C6—C8—H8A109.5
C2—C3—H3120.0C6—C8—H8B109.5
C4—C3—H3120.0H8A—C8—H8B109.5
C5—C4—C3121.1 (11)C6—C8—H8C109.5
C5—C4—H4119.5H8A—C8—H8C109.5
C3—C4—H4119.5H8B—C8—H8C109.5
C6—N1—C2—C32.9 (16)C3—C4—C5—C61 (2)
C6—N1—C2—C7178.9 (10)C2—N1—C6—C53.0 (15)
N1—C2—C3—C40.8 (18)C2—N1—C6—C8176.3 (9)
C7—C2—C3—C4176.5 (12)C4—C5—C6—N11.0 (16)
C2—C3—C4—C51 (2)C4—C5—C6—C8178.2 (11)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Br20.862.513.366 (7)176
C7—H7A···Br20.962.973.856 (10)153

Experimental details

Crystal data
Chemical formula(C7H10N)2[CoBr4]
Mr594.89
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)293
a, b, c (Å)17.234 (2), 9.0691 (10), 13.729 (2)
V3)2145.7 (5)
Z4
Radiation typeMo Kα
µ (mm1)8.24
Crystal size (mm)0.40 × 0.30 × 0.20
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.064, 0.192
No. of measured, independent and
observed [I > 2σ(I)] reflections
2534, 1930, 885
Rint0.072
(sin θ/λ)max1)0.600
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.055, 0.117, 0.97
No. of reflections1930
No. of parameters97
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.55, 0.40

Computer programs: XSCANS (Siemens, 1996), SHELXTL (Sheldrick, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008).

Selected geometric parameters (Å, º) top
Br1—Co12.4002 (13)Co1—Br22.4044 (15)
Br1—Co1—Br1i115.28 (9)Br1—Co1—Br2i108.37 (4)
Br1—Co1—Br2108.06 (3)Br2—Co1—Br2i108.54 (9)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Br20.862.513.366 (7)175.6
C7—H7A···Br20.962.973.856 (10)153.4
 

Acknowledgements

Financial support from Al al-Bayt University and Al-Balqa'a Applied University is greatly appreciated.

References

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Volume 64| Part 3| March 2008| Pages m485-m486
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