Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807025585/wn2141sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807025585/wn2141Isup2.hkl |
CCDC reference: 624131
The salt was synthesized from the reaction of ethane-1,2-dipyridinium dibromide (0.035 g, 0.1 mmol) in methanol (5 ml) and cadmium dichloride (0.037 g, 0.2 mmol) in DMF (10 ml). The mixture was set aside for the formation of colourless block-shaped crystals in 40% yield after several days. CH&N elemental analysis: Calc. C 27.22, H 2.67, N 5.29%. Found C 27.89, H 2.49, N 5.36%.
Of the three halogens in the asymmetric unit, one lies in a general position and the other two on a mirror plane. Initial attempts to refine the structure with either three chlorines or three bromines gave unacceptably high R-indices (and large peaks/holes). The three halogen atoms were then refined as three (Br+Cl) mixtures; in one attempt the components had only the same displacement parameters. A second attempt allowed the mixtures to have the same displacement parameters as well as sharing the same site. The second led to a formulation consisting of approximately two Br and two Cl atoms. The use of a special restraint command that fixed the number of Br and Cl atoms as both being exactly two led to the occupancy of Br1 as nearly 0.25 and that of Br2 and Br3 as both nearly 0.75. In the best disorder model, the halogen in the general position was set to (0.25Br + 0.75Cl); those in the special position were both set to (0.75Br + 0.25Cl)·The anion is [CdBr2Cl2]2-, a formulation that is supported by CH&N elemental analysis. Other formulations led to much larger peaks/holes.
Disorder also affected the cation; the pyridyl ring was refined as a rigid hexagon of 1.39 Å sides. The C—C distance was restrained to 1.50±0.01 Å, and the N···C distance to 2.45±0.01 Å. The displacement parameters of atoms of the cation were restrained to be nearly isotropic. Carbon-bound H atoms were positioned geometrically (C–H 0.93 and 0.97 Å), and were included in the refinement in the riding model approximation, with Uiso(H) = 1.2Ueq(C).
In the final difference Fourier map the largest peak was 0.9 Å from C6 and the deepest hole at 0.6 Å from Cl3.
The discrete tetrahedral tetrahalidocadmate(II) dianion has been characterized in a number of salts (Cambridge Structural Database, Version 5.28; Allen, 2002); examples of the ammonium salts include, for example, bis(tetramethylammonium) tetrachloridocadmate, bis(tetramethylammonium) tetrabromidomercurate (Sato et al., 1986) and bis(tetramethylammonium) tetraiodidocadmate (Kallel et al., 1981). In the 1,2-ethanedipyridinium salt of the mixed-halogen cadmate, the metal atom is coordinated by four halogen atoms in a tetrahedral geometry; the halogen atoms are disordered (Fig. 1). The cations and anions do not have signification interactions with each other.
For related literature, see: Allen (2002); Kallel et al. (1981); Sato et al. (1986).
Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2007).
(C12H14N2)[CdBr2Cl2] | F(000) = 1008 |
Mr = 529.37 | Dx = 2.056 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 4134 reflections |
a = 17.955 (2) Å | θ = 2.3–27.4° |
b = 14.338 (1) Å | µ = 6.25 mm−1 |
c = 6.6437 (6) Å | T = 295 K |
V = 1710.4 (3) Å3 | Block, colourless |
Z = 4 | 0.20 × 0.20 × 0.10 mm |
Bruker APEX area-detector diffractometer | 1564 independent reflections |
Radiation source: fine-focus sealed tube | 1415 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
φ and ω scans | θmax = 25.0°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −17→21 |
Tmin = 0.147, Tmax = 0.574 | k = −15→17 |
8939 measured reflections | l = −7→7 |
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)] = 0.057 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.179 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.1162P)2 + 9.0378P] where P = (Fo2 + 2Fc2)/3 |
1564 reflections | (Δ/σ)max = 0.001 |
79 parameters | Δρmax = 1.77 e Å−3 |
44 restraints | Δρmin = −1.30 e Å−3 |
(C12H14N2)[CdBr2Cl2] | V = 1710.4 (3) Å3 |
Mr = 529.37 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 17.955 (2) Å | µ = 6.25 mm−1 |
b = 14.338 (1) Å | T = 295 K |
c = 6.6437 (6) Å | 0.20 × 0.20 × 0.10 mm |
Bruker APEX area-detector diffractometer | 1564 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1415 reflections with I > 2σ(I) |
Tmin = 0.147, Tmax = 0.574 | Rint = 0.025 |
8939 measured reflections |
R[F2 > 2σ(F2)] = 0.057 | 44 restraints |
wR(F2) = 0.179 | H-atom parameters constrained |
S = 1.06 | Δρmax = 1.77 e Å−3 |
1564 reflections | Δρmin = −1.30 e Å−3 |
79 parameters |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Cd1 | 0.92879 (4) | 0.7500 | 0.64150 (12) | 0.0371 (3) | |
Br1 | 0.91363 (10) | 0.60359 (14) | 0.4500 (3) | 0.0702 (6) | 0.25 |
Br2 | 0.82923 (11) | 0.7500 | 0.9121 (3) | 0.0760 (6) | 0.75 |
Br3 | 1.06428 (9) | 0.7500 | 0.7605 (3) | 0.0720 (6) | 0.75 |
Cl1 | 0.91363 (10) | 0.60359 (14) | 0.4500 (3) | 0.0702 (6) | 0.75 |
Cl2 | 0.82923 (11) | 0.7500 | 0.9121 (3) | 0.0760 (6) | 0.25 |
Cl3 | 1.06428 (9) | 0.7500 | 0.7605 (3) | 0.0720 (6) | 0.25 |
N1 | 0.5912 (2) | 0.5361 (5) | 0.4128 (9) | 0.069 (2) | |
C1 | 0.6503 (3) | 0.5331 (5) | 0.5477 (8) | 0.075 (3) | |
C2 | 0.7163 (2) | 0.5795 (5) | 0.5034 (8) | 0.056 (2) | |
C3 | 0.7231 (2) | 0.6288 (4) | 0.3243 (8) | 0.055 (2) | |
C4 | 0.6640 (3) | 0.6318 (4) | 0.1894 (7) | 0.053 (2) | |
C5 | 0.5980 (2) | 0.5854 (4) | 0.2336 (7) | 0.055 (2) | |
C6 | 0.5283 (5) | 0.4733 (7) | 0.4383 (15) | 0.080 (3) | |
H1 | 0.6457 | 0.5001 | 0.6675 | 0.090* | |
H2 | 0.7558 | 0.5775 | 0.5937 | 0.067* | |
H3 | 0.7673 | 0.6599 | 0.2947 | 0.067* | |
H4 | 0.6686 | 0.6648 | 0.0695 | 0.064* | |
H5 | 0.5585 | 0.5874 | 0.1434 | 0.066* | |
H6a | 0.5436 | 0.4170 | 0.5081 | 0.096* | |
H6b | 0.5076 | 0.4561 | 0.3087 | 0.096* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd1 | 0.0328 (5) | 0.0379 (5) | 0.0406 (5) | 0.000 | 0.0018 (3) | 0.000 |
Br1 | 0.0544 (10) | 0.0715 (12) | 0.0846 (13) | −0.0025 (8) | −0.0020 (9) | −0.0256 (10) |
Br2 | 0.0685 (11) | 0.1012 (14) | 0.0584 (10) | 0.000 | 0.0344 (8) | 0.000 |
Br3 | 0.0437 (9) | 0.0825 (12) | 0.0897 (14) | 0.000 | −0.0088 (8) | 0.000 |
Cl1 | 0.0544 (10) | 0.0715 (12) | 0.0846 (13) | −0.0025 (8) | −0.0020 (9) | −0.0256 (10) |
Cl2 | 0.0685 (11) | 0.1012 (14) | 0.0584 (10) | 0.000 | 0.0344 (8) | 0.000 |
Cl3 | 0.0437 (9) | 0.0825 (12) | 0.0897 (14) | 0.000 | −0.0088 (8) | 0.000 |
N1 | 0.033 (3) | 0.105 (6) | 0.069 (4) | −0.018 (4) | −0.009 (3) | 0.033 (4) |
C1 | 0.057 (5) | 0.100 (7) | 0.069 (5) | −0.008 (5) | −0.006 (4) | 0.034 (5) |
C2 | 0.025 (3) | 0.070 (5) | 0.072 (5) | −0.002 (3) | −0.008 (3) | 0.018 (4) |
C3 | 0.032 (4) | 0.061 (5) | 0.073 (5) | −0.010 (4) | 0.005 (4) | 0.011 (4) |
C4 | 0.050 (4) | 0.054 (4) | 0.055 (4) | −0.010 (4) | 0.006 (4) | 0.009 (4) |
C5 | 0.036 (4) | 0.069 (5) | 0.059 (5) | −0.011 (4) | −0.002 (4) | 0.013 (4) |
C6 | 0.100 (7) | 0.066 (5) | 0.074 (6) | 0.021 (5) | −0.016 (5) | −0.011 (5) |
Cd1—Br1 | 2.470 (2) | C2—H2 | 0.9300 |
Cd1—Br1i | 2.470 (2) | C3—C4 | 1.3900 |
Cd1—Br2 | 2.535 (2) | C3—H3 | 0.9300 |
Cd1—Br3 | 2.558 (2) | C4—C5 | 1.3900 |
N1—C1 | 1.3900 | C4—H4 | 0.9300 |
N1—C5 | 1.3900 | C5—H5 | 0.9300 |
N1—C6 | 1.453 (12) | C6—C6ii | 1.514 (9) |
C1—C2 | 1.3900 | C6—H6A | 0.9700 |
C1—H1 | 0.9300 | C6—H6B | 0.9700 |
C2—C3 | 1.3900 | ||
Br1—Cd1—Br1i | 116.4 (1) | C4—C3—C2 | 120.0 |
Br1—Cd1—Br2 | 106.7 (1) | C4—C3—H3 | 120.0 |
Br1—Cd1—Br3 | 105.3 (1) | C2—C3—H3 | 120.0 |
Br1i—Cd1—Br2 | 106.7 (1) | C3—C4—C5 | 120.0 |
Br1i—Cd1—Br3 | 105.3 (1) | C3—C4—H4 | 120.0 |
Br2—Cd1—Br3 | 116.8 (1) | C5—C4—H4 | 120.0 |
C1—N1—C5 | 120.0 | C4—C5—N1 | 120.0 |
C1—N1—C6 | 119.9 (6) | C4—C5—H5 | 120.0 |
C5—N1—C6 | 118.9 (6) | N1—C5—H5 | 120.0 |
N1—C1—C2 | 120.0 | N1—C6—C6ii | 105.8 (10) |
N1—C1—H1 | 120.0 | N1—C6—H6A | 110.6 |
C2—C1—H1 | 120.0 | C6ii—C6—H6A | 110.6 |
C1—C2—C3 | 120.0 | N1—C6—H6B | 110.6 |
C1—C2—H2 | 120.0 | C6ii—C6—H6B | 110.6 |
C3—C2—H2 | 120.0 | H6A—C6—H6B | 108.7 |
C5—N1—C1—C2 | 0.0 | C3—C4—C5—N1 | 0.0 |
C6—N1—C1—C2 | 167.7 (7) | C1—N1—C5—C4 | 0.0 |
N1—C1—C2—C3 | 0.0 | C6—N1—C5—C4 | −167.8 (6) |
C1—C2—C3—C4 | 0.0 | C1—N1—C6—C6ii | 93.0 (11) |
C2—C3—C4—C5 | 0.0 | C5—N1—C6—C6ii | −99.2 (11) |
Symmetry codes: (i) x, −y+3/2, z; (ii) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | (C12H14N2)[CdBr2Cl2] |
Mr | 529.37 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 295 |
a, b, c (Å) | 17.955 (2), 14.338 (1), 6.6437 (6) |
V (Å3) | 1710.4 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 6.25 |
Crystal size (mm) | 0.20 × 0.20 × 0.10 |
Data collection | |
Diffractometer | Bruker APEX area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.147, 0.574 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8939, 1564, 1415 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.057, 0.179, 1.06 |
No. of reflections | 1564 |
No. of parameters | 79 |
No. of restraints | 44 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.77, −1.30 |
Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), X-SEED (Barbour, 2001), publCIF (Westrip, 2007).
Cd1—Br1 | 2.470 (2) | Cd1—Br3 | 2.558 (2) |
Cd1—Br2 | 2.535 (2) | ||
Br1—Cd1—Br1i | 116.4 (1) | Br1—Cd1—Br3 | 105.3 (1) |
Br1—Cd1—Br2 | 106.7 (1) | Br2—Cd1—Br3 | 116.8 (1) |
Symmetry code: (i) x, −y+3/2, z. |
The discrete tetrahedral tetrahalidocadmate(II) dianion has been characterized in a number of salts (Cambridge Structural Database, Version 5.28; Allen, 2002); examples of the ammonium salts include, for example, bis(tetramethylammonium) tetrachloridocadmate, bis(tetramethylammonium) tetrabromidomercurate (Sato et al., 1986) and bis(tetramethylammonium) tetraiodidocadmate (Kallel et al., 1981). In the 1,2-ethanedipyridinium salt of the mixed-halogen cadmate, the metal atom is coordinated by four halogen atoms in a tetrahedral geometry; the halogen atoms are disordered (Fig. 1). The cations and anions do not have signification interactions with each other.