Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801004536/bt6024sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801004536/bt6024Isup2.hkl |
CCDC reference: 162822
An equimolar solution of NMe4I and SnI2 in water was maintained at 368 K for 2 h with stirring. The initial orange-coloured solution initially produced a near-black coloured precipitate which slowly redissolved to be replaced by a pale-yellow precipitate. The reaction mixture was filtered and green–black crystals of the title compound were deposited from the filtrate on standing. M.p. 398–400 K: literature value 399–400 K (Gama & Filguieras, 1989). Analysis: C 6.68, H 1.99, N 1.83%; calculated for C4H12I5N: C 6.78, H 1.71, N 1.98%.
The maximum residual electron density was 1.48 e Å-3 at 0.89 Å from I3; all residuals >0.8 e Å-3 were within 1 Å of I atoms.
Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 1999) and ORTEP-3 (Farrugia, 1999); software used to prepare material for publication: CIFTAB (Sheldrick, 1997).
C4H12N+·I5− | F(000) = 1232 |
Mr = 708.64 | Dx = 3.092 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 13.311 (1) Å | Cell parameters from 2244 reflections |
b = 13.5395 (11) Å | θ = 2.4–29.4° |
c = 8.8727 (7) Å | µ = 10.17 mm−1 |
β = 107.801 (2)° | T = 296 K |
V = 1522.5 (2) Å3 | Prism, dark purple |
Z = 4 | 0.60 × 0.50 × 0.50 mm |
Bruker SMART 1000 Area CCD diffractometer | 2182 independent reflections |
Radiation source: fine-focus sealed tube | 1622 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.032 |
ϕ–ω scans | θmax = 30.9°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −10→18 |
Tmin = 0.742, Tmax = 0.906 | k = −18→18 |
4712 measured reflections | l = −12→11 |
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)] = 0.052 | H-atom parameters constrained |
wR(F2) = 0.143 | w = 1/[σ2(Fo2) + (0.074P)2 + 6.1215P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
2182 reflections | Δρmax = 1.48 e Å−3 |
48 parameters | Δρmin = −1.47 e Å−3 |
0 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: heavy-atom method | Extinction coefficient: 0.00143 (18) |
C4H12N+·I5− | V = 1522.5 (2) Å3 |
Mr = 708.64 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 13.311 (1) Å | µ = 10.17 mm−1 |
b = 13.5395 (11) Å | T = 296 K |
c = 8.8727 (7) Å | 0.60 × 0.50 × 0.50 mm |
β = 107.801 (2)° |
Bruker SMART 1000 Area CCD diffractometer | 2182 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 1622 reflections with I > 2σ(I) |
Tmin = 0.742, Tmax = 0.906 | Rint = 0.032 |
4712 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.143 | H-atom parameters constrained |
S = 1.05 | Δρmax = 1.48 e Å−3 |
2182 reflections | Δρmin = −1.47 e Å−3 |
48 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. Also note that for data up to theta max, the completeness is only 90%. Usually ACTA n would have been used to check the >99% completeness, but in this case with the C-centred cell, ACTA 50 gives meaningless (<50%) completeness values (commented out at the bottom of this file). In addition, several frames of data (approx. 10 in 1500) were lost. However a check with PLATON showed that the data are >99% complete at 27.5 °. |
x | y | z | Uiso*/Ueq | ||
I1 | 0.0000 | 0.17657 (6) | 0.2500 | 0.0682 (3) | |
I2 | 0.16060 (4) | 0.01915 (4) | 0.19877 (6) | 0.0605 (2) | |
I3 | 0.30588 (5) | −0.12546 (5) | 0.18005 (8) | 0.0750 (3) | |
N1 | 0.0000 | 0.6882 (8) | 0.2500 | 0.075 (3) | |
C1 | 0.032 (2) | 0.6330 (18) | 0.135 (2) | 0.210 (14) | |
H1A | −0.0277 | 0.5980 | 0.0673 | 0.316* | |
H1B | 0.0859 | 0.5868 | 0.1872 | 0.316* | |
H1C | 0.0589 | 0.6774 | 0.0718 | 0.316* | |
C2 | 0.084 (3) | 0.748 (3) | 0.333 (4) | 0.33 (3) | |
H2A | 0.1427 | 0.7387 | 0.2930 | 0.494* | |
H2B | 0.1050 | 0.7316 | 0.4436 | 0.494* | |
H2C | 0.0626 | 0.8164 | 0.3201 | 0.494* |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.0614 (5) | 0.0515 (4) | 0.1039 (7) | 0.000 | 0.0432 (4) | 0.000 |
I2 | 0.0564 (3) | 0.0629 (4) | 0.0645 (4) | −0.0039 (2) | 0.0222 (2) | −0.0007 (2) |
I3 | 0.0687 (4) | 0.0790 (5) | 0.0831 (5) | 0.0114 (3) | 0.0316 (3) | −0.0031 (3) |
N1 | 0.088 (8) | 0.059 (6) | 0.091 (8) | 0.000 | 0.045 (6) | 0.000 |
C1 | 0.31 (3) | 0.20 (2) | 0.152 (17) | 0.15 (2) | 0.12 (2) | 0.017 (16) |
C2 | 0.38 (5) | 0.35 (5) | 0.33 (5) | −0.26 (5) | 0.21 (4) | −0.11 (4) |
I1—I2 | 3.1485 (8) | C1—H1A | 0.9600 |
I1—I2i | 3.1486 (8) | C1—H1B | 0.9600 |
I2—I3 | 2.7923 (8) | C1—H1C | 0.9600 |
N1—C2i | 1.40 (3) | C2—H2A | 0.9600 |
N1—C2 | 1.40 (3) | C2—H2B | 0.9600 |
N1—C1 | 1.433 (17) | C2—H2C | 0.9600 |
N1—C1i | 1.433 (17) | ||
I2—I1—I2i | 94.79 (3) | H1A—C1—H1B | 109.5 |
I3—I2—I1 | 175.11 (2) | N1—C1—H1C | 109.5 |
C2i—N1—C2 | 109 (3) | H1A—C1—H1C | 109.5 |
C2i—N1—C1 | 106.9 (16) | H1B—C1—H1C | 109.5 |
C2—N1—C1 | 108.5 (16) | N1—C2—H2A | 109.5 |
C2i—N1—C1i | 108.5 (16) | N1—C2—H2B | 109.5 |
C2—N1—C1i | 106.9 (16) | H2A—C2—H2B | 109.5 |
C1—N1—C1i | 117 (2) | N1—C2—H2C | 109.5 |
N1—C1—H1A | 109.5 | H2A—C2—H2C | 109.5 |
N1—C1—H1B | 109.5 | H2B—C2—H2C | 109.5 |
Symmetry code: (i) −x, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C4H12N+·I5− |
Mr | 708.64 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 296 |
a, b, c (Å) | 13.311 (1), 13.5395 (11), 8.8727 (7) |
β (°) | 107.801 (2) |
V (Å3) | 1522.5 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 10.17 |
Crystal size (mm) | 0.60 × 0.50 × 0.50 |
Data collection | |
Diffractometer | Bruker SMART 1000 Area CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.742, 0.906 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4712, 2182, 1622 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.722 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.052, 0.143, 1.05 |
No. of reflections | 2182 |
No. of parameters | 48 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.48, −1.47 |
Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 1999), SAINT, SHELXS86 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ATOMS (Dowty, 1999) and ORTEP-3 (Farrugia, 1999), CIFTAB (Sheldrick, 1997).
Various polyiodide ions are known, with the most frequently reported being I3- and I5- (Kloo et al., 2000; Blake et al., 1998). The structures of a number of tetraorganoammonium salts of I5- are in the Cambridge Structural Database (CSD; Allen & Kennard, 1993) at the Chemical database service of the EPSRC (Fletcher et al., 1996), including those of [EtMePh2N]I5 (213550, refcode FIQLAS; Tebbe & Loukili, 1999), {2[Me2Ph2N][I5]2.I2} (161933, ZIVXOR; Tebbe & Gilles, 1996a) [EtMe3N]I5 (Loukili & Tebbe, 1999), [PriMe2PhN]I5.I2 (195990, PAZQEM; Tebbe & Loukili, 1998), [Pr4N]I5 (Tebbe & Gilles, 1996b) and [Me4N]I5 (130287, DULZOZ; Tsvetkov et al., 1986). However, only the data for cell dimensions and space group are provided for [Me4N]I5 in the CSD. The structure of [Me4N]I5 had also featured in earlier studies (Broekema et al., 1959; Hach & Rundle, 1951), while a listing of cell dimensions and the space group for [Me4N]I5, with a reference to a dissertation (Loukili, 1998), were provided by Loukili & Tebbe (1999).
Tetraorganoammonium polyiodides are generally prepared from [R4N]I and the requisite number of molar equivalents of iodine in solvents such as methanol. Tetramethylammonium pentaiodide was isolated in this study from aqueous solutions of [Me4N]I and SnI2 (equimolar) in water, the co-product being yellow–brown hydrated tin(IV) oxide. Similar reactions between [Me4N]X and SnX2 (X = Cl or Br) in contrast simply led to [Me4N][SnX3].
The refinement of the carbon displacement parameters for the tetramethylammonium ion gave very high values, suggesting disorder. This was modelled using two superimposed orientations of the molecule via the SHELX PART instruction. The C atoms could not be refined anisotropically, but the final ratio of the two orientations was 85:15. However, the R value was not improved (5.75% compared to 5.14% for the ordered model) and thus the ordered model has been retained for this report.
The structure of the title compound (Fig. 1) consists of isolated tetramethylammonium ions and I5- ions. The I5 units are linked via longer I—I bonds to form a square mesh normal to (001) (Fig. 2), with I1 coordinated to two I2 atoms at 3.1514 (8) Å and two I3 at 3.6453 (9) Å [symmetry codes: (i) 0.5 - x, y + 0.5, 0.5 - z; (ii) x - 0.5, y + 0.5, z], which are within the van der Waals radius sum of 3.96 Å. The tetramethylammonium ions are located at the centre of each square.
This square mesh is similar to that found in (EtMe3N)I5 (Loukili & Tebbe, 1999); however, in this case, the mesh is flat and parallel to [010], whereas in (EtMe3N)I5 there is significant puckering, likely caused by the relative location of the cation. These are the only such square-mesh formations to be reported to date; other pentaiodide networks form herring-bone, F-shaped and linear conformations, and in a few cases isolated I5- anions.
Many pentaiodides are reported in the literature. In addition, pentaiodide ions may form as part of a more complex polyiodide framework. This is clearly seen in the work of Tebbe and co-workers, in which the V angle varies from 83.51° in (EtMe3N)I5 (Loukili & Tebbe, 1999) to 119.60° in bipyridinium heptaiodide, (C10H9N2)I7 (Tebbe & Bittner, 1995), whereas the `straight limb' angle varies from 172.09° in (Me2Ph2N)3I13 (Tebbe & Gilles, 1996a) to 179.57° in (UrEt)2I8 (Grafe-Kavoosian et al., 1998). Bond lengths in the V motif can be divided into the outer (shorter) and inner (longer). The outer bond lengths range from 2.739 to 2.873 Å, wheras the inner range from 2.975 to 3.460 Å. There is, evidently, a significant (0.1 Å) gap between these values which supports the alternative description of the pentaiodide unit as [2(I2).I]-.