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The β modification of pyridinium dichloroiodide, C5H6N+·Cl2I−, was obtained as yellow crystals by the reaction of (C5NH5)AuCl3, C5H6N+·Cl− and I2 in a vacuum-sealed ampoule. The dichloroiodide ion is nearly symmetric and linear with I—Cl bond lengths of 2.544 (3) and 2.550 (3) Å and a Cl—I—Cl angle of 179.68 (12)°.
Supporting information
CCDC reference: 144642
The β-piridinium dichloroiodide is formed when (C5NH5)AuCl3,
(C5NH6)+Cl- and I2 in the molar ratio 1:1:4 are heated in sealed
glass ampoule (diameter = 1.2 cm, length = 20 cm). To obtain high quality
crystals it is essential that the temperature is slowly increased between 373
and 523 K. After cooling, β-pyridinium dichloroiodide deposits as yellow
single crystals. Element analysis (calculated/found) C 21.60/23.07 H 2.16/2.34 N 5.03/5.07%
Data collection: CAD-4 Software (Enraf-Nonius, 1994); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.
/b-Pyridinium Dichlroiodide
top
Crystal data top
C5H6N+·Cl2I− | Dx = 2.112 Mg m−3 |
Mr = 277.91 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pnma | Cell parameters from 25 reflections |
a = 8.0390 (5) Å | θ = 5.3–16.3° |
b = 7.6940 (16) Å | µ = 4.20 mm−1 |
c = 14.130 (2) Å | T = 208 K |
V = 874.0 (2) Å3 | Needle, yellow |
Z = 4 | 0.20 × 0.10 × 0.05 mm |
F(000) = 520 | |
Data collection top
CAD4 diffractometer | Rint = 0.075 |
Radiation source: fine-focus sealed tube | θmax = 28.0°, θmin = 3.0° |
Graphite monochromator | h = −1→10 |
ω/2θ scans | k = 0→10 |
Absorption correction: ψ scan (North et al., 1968) | l = −18→1 |
Tmin = 0.660, Tmax = 0.811 | 3 standard reflections every 200 reflections |
1378 measured reflections | intensity decay: 5.3% |
1129 independent reflections | |
Refinement top
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) = 0.141 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Calculated w = 1/[σ2(Fo2) + (0.0715P)2] where P = (Fo2 + 2Fc2)/3 |
1129 reflections | (Δ/σ)max < 0.001 |
46 parameters | Δρmax = 1.92 e Å−3 |
0 restraints | Δρmin = −1.11 e Å−3 |
Crystal data top
C5H6N+·Cl2I− | V = 874.0 (2) Å3 |
Mr = 277.91 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 8.0390 (5) Å | µ = 4.20 mm−1 |
b = 7.6940 (16) Å | T = 208 K |
c = 14.130 (2) Å | 0.20 × 0.10 × 0.05 mm |
Data collection top
CAD4 diffractometer | 1129 independent reflections |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.075 |
Tmin = 0.660, Tmax = 0.811 | 3 standard reflections every 200 reflections |
1378 measured reflections | intensity decay: 5.3% |
Refinement top
R[F2 > 2σ(F2)] = 0.057 | 0 restraints |
wR(F2) = 0.141 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 1.92 e Å−3 |
1129 reflections | Δρmin = −1.11 e Å−3 |
46 parameters | |
Special details top
Experimental. PyAuCl3.H2O + PyHCl + I2 —-> [PyH][ICl2] + ··· |
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 | x | y | z | Uiso*/Ueq | Occ. (<1) |
I1 | 0.01318 (9) | 0.2500 | 0.07469 (5) | 0.0409 (3) | |
Cl1 | 0.3121 (4) | 0.2500 | 0.1339 (3) | 0.0600 (9) | |
Cl2 | −0.2858 (4) | 0.2500 | 0.0144 (2) | 0.0654 (10) | |
C1 | −0.1723 (12) | 0.1601 (11) | −0.2206 (5) | 0.054 (2) | 0.83333 |
H1 | −0.1831 | 0.0989 | −0.1642 | 0.065* | |
C2 | −0.1563 (12) | 0.0739 (13) | −0.3042 (6) | 0.061 (2) | 0.83333 |
H2 | −0.1530 | −0.0469 | −0.3050 | 0.073* | |
C3 | −0.1453 (10) | 0.1648 (12) | −0.3867 (5) | 0.050 (2) | 0.83333 |
H3 | −0.1376 | 0.1051 | −0.4438 | 0.060* | |
N1 | −0.1723 (12) | 0.1601 (11) | −0.2206 (5) | 0.054 (2) | 0.16666 |
N2 | −0.1563 (12) | 0.0739 (13) | −0.3042 (6) | 0.061 (2) | 0.16666 |
N3 | −0.1453 (10) | 0.1648 (12) | −0.3867 (5) | 0.050 (2) | 0.16666 |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
I1 | 0.0529 (5) | 0.0353 (4) | 0.0345 (4) | 0.000 | 0.0026 (4) | 0.000 |
Cl1 | 0.0522 (18) | 0.063 (2) | 0.065 (2) | 0.000 | −0.0063 (17) | 0.000 |
Cl2 | 0.0536 (19) | 0.090 (3) | 0.053 (2) | 0.000 | −0.0056 (15) | 0.000 |
C1 | 0.088 (6) | 0.037 (5) | 0.038 (4) | −0.002 (5) | 0.007 (5) | 0.005 (4) |
C2 | 0.098 (7) | 0.033 (5) | 0.052 (5) | 0.004 (5) | 0.001 (5) | −0.011 (4) |
C3 | 0.060 (5) | 0.055 (6) | 0.034 (4) | 0.005 (4) | 0.010 (4) | −0.010 (4) |
N1 | 0.088 (6) | 0.037 (5) | 0.038 (4) | −0.002 (5) | 0.007 (5) | 0.005 (4) |
N2 | 0.098 (7) | 0.033 (5) | 0.052 (5) | 0.004 (5) | 0.001 (5) | −0.011 (4) |
N3 | 0.060 (5) | 0.055 (6) | 0.034 (4) | 0.005 (4) | 0.010 (4) | −0.010 (4) |
Geometric parameters (Å, º) top
I1—Cl1 | 2.544 (3) | C1—C2 | 1.361 (11) |
I1—Cl2 | 2.550 (3) | C1—C1i | 1.384 (17) |
I1—Cl2 | 2.550 (3) | C2—C3 | 1.363 (11) |
Cl2—Cl2 | 0.000 (9) | C3—C3i | 1.312 (18) |
| | | |
Cl1—I1—Cl2 | 179.68 (12) | C2—C1—C1i | 119.2 (5) |
Cl1—I1—Cl2 | 179.68 (12) | C1—C2—C3 | 120.0 (8) |
Cl2—I1—Cl2 | 0.00 (15) | C3i—C3—C2 | 120.9 (5) |
Cl2—Cl2—I1 | 0 (10) | | |
Symmetry code: (i) x, −y+1/2, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1···Cl1ii | 0.93 | 2.91 | 3.566 (9) | 129 |
C1—H1···Cl2 | 0.93 | 2.90 | 3.512 (8) | 125 |
C3—H3···Cl1iii | 0.93 | 2.94 | 3.570 (9) | 127 |
C3—H3···Cl2iv | 0.93 | 2.86 | 3.527 (9) | 130 |
Symmetry codes: (ii) −x, −y, −z; (iii) x−1/2, y, −z−1/2; (iv) −x−1/2, −y, z−1/2. |
Experimental details
Crystal data |
Chemical formula | C5H6N+·Cl2I− |
Mr | 277.91 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 208 |
a, b, c (Å) | 8.0390 (5), 7.6940 (16), 14.130 (2) |
V (Å3) | 874.0 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 4.20 |
Crystal size (mm) | 0.20 × 0.10 × 0.05 |
|
Data collection |
Diffractometer | CAD4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.660, 0.811 |
No. of measured, independent and observed (?) reflections | 1378, 1129, ? |
Rint | 0.075 |
(sin θ/λ)max (Å−1) | 0.660 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.057, 0.141, 1.05 |
No. of reflections | 1129 |
No. of parameters | 46 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.92, −1.11 |
Selected geometric parameters (Å, º) topI1—Cl1 | 2.544 (3) | C1—C1i | 1.384 (17) |
I1—Cl2 | 2.550 (3) | C2—C3 | 1.363 (11) |
C1—C2 | 1.361 (11) | C3—C3i | 1.312 (18) |
| | | |
Cl1—I1—Cl2 | 179.68 (12) | C1—C2—C3 | 120.0 (8) |
C2—C1—C1i | 119.2 (5) | C3i—C3—C2 | 120.9 (5) |
Symmetry code: (i) x, −y+1/2, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1···Cl1ii | 0.93 | 2.91 | 3.566 (9) | 128.8 |
C1—H1···Cl2 | 0.93 | 2.90 | 3.512 (8) | 124.7 |
C3—H3···Cl1iii | 0.93 | 2.94 | 3.570 (9) | 126.6 |
C3—H3···Cl2iv | 0.93 | 2.86 | 3.527 (9) | 129.5 |
Symmetry codes: (ii) −x, −y, −z; (iii) x−1/2, y, −z−1/2; (iv) −x−1/2, −y, z−1/2. |
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The dichloroiodide ion has been characterized in many compounds, showing different forms (Brandoli et al., 1978; Grebe et al., 1995). Tucker reported the α modification of pyridinium dichloroiodide as trigonal, space group R3 m, with a = 6.165 (4) Å, α = 82.45 (6)° and Z = 1 (Tucker & Kroon, 1973). We present (I), the β modification of this compound that crystallizes in the orthorhombic space group Pnma with a = 8.0390 (5), b = 7.694 (16), c = 14.130 (2) Å and Z = 4. \sch
The title compound is formed during the reaction of (C5NH5)AuCl3, (C5NH6)+Cl- and I2 in a sealed glass ampoule. We also observed the formation of elemental gold. Crystals of good quality were obtained by subsequent sublimation. The asymmetric unit contains a half dichloroiodide anion located on a mirror plane and a half pyridium cation off a mirror plane.
The packing diagram (Fig. 1) shows the pyridium cation packed in stacks along the a axis. The dichloroiodide anion packs with the Cl–I–Cl units parallel in a zigzag pattern along the b axis between the pyridium stacks with a spacing of 4.3931 (10) Å between the anions. The cation-anion (H—Cl) distance of 2.86–2.94 Å (Table 2) is rather shorter than the sum of the van der Waals radii (Pauling, 1960), suggesting that the cation-anion interactions control the packing.
In the β-modification, the deviation of the Cl—I—Cl bond angle [179.68 (12)°] from linearity is not significant. The bond lengths of I—Cl1 = 2.544 (3) Å and I—Cl2 = 2.550 (3) Å can be considered symmetric and have values similar to that already found in similar anions (2.54–2.69 Å) (Bandoli et al., 1978; Grebe et al., 1995). In agreement with another similar structure we are assuming that the cation is sixfold disordered; we have been unable to distingish an ordered (C5NH6)+ ion (Tucker & Kroon, 1973). The pyridinium ion is treated as six symmetry-related C—H groups (occupancy = 5/6) and six related N—H groups (occupancy = 1/6). Selected bond distances and angles are given in Table 1.