metal-organic compounds
Redetermination of catena-poly[[sodium(I)-tri-μ-dimethylformamide-κ6O:O] iodide] at 140 K
aSchool of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, England
*Correspondence e-mail: joseph.wright@uea.ac.uk
The structure of the title compound, {[Na(C3H7NO)3]I}n, has been redetermined at 140 (2) K. The Na+ cations lie on sites of 32 and are linked into one-dimensional chains via bridging DMF molecules lying on mirror planes. The coordination geometry of Na+ is intermediate between octahedral and trigonal prismatic. The I− anions lie on sites of between the chains.
Comment
The structure of the title compound, (I), has been determined previously at room temperature (Gobillon et al., 1962; Batsanov & Struchkov, 1994). In the first case, all atoms were refined using only isotropic displacement parameters. The second determination gave unsatisfactory R values (R = 0.140). Compound (I) has been obtained as a by-product of a Heck reaction involving an aryl iodide in DMF, using Na2CO3 as base. We have taken this opportunity to redetermine the structure of (I) at 140 (2) K, leading to significantly improved precision.
The Na+ cation in (I) is coordinated by six DMF molecules lying on mirror planes (Fig. 1). The bond distances (Table 1) and coplanar nature of O1, C1 and N1 suggests a degree of double-bond character between C1 and N1 in addition to that between C1 and O1. This suggests the presence of a partial positive charge on N1 and a partial negative charge on O1, as suggested by Gobillon et al. (1962), which may lead to enhanced electrostatic interaction between the DMF molecules and the Na+ cation.
The geometry at Na1 is intermediate between octahedral and trigonal prismatic; when viewed along the c axis (Fig. 2), the angle between O atoms in successive layers is 29.0°. The bridging DMF molecules generate one-dimensional chains along c. The positions of the DMF molecules alternate along the c axis, leading to an ABAB pattern of DMF sites.
Gobillon et al. (1962) have described the structure of (I) as containing C—H⋯I hydrogen bonds, involving C1 and C3. The C⋯I distances determined in the current study [C1⋯I1 = 4.261 (3) and C3⋯I1 4.349 (4) Å] are outside the normal range for such an interaction, based on the van der Waals radii of the elements involved (Pauling, 1960). The interaction of the cationic polymer with the anions is, therefore, best described as largely electrostatic.
Experimental
Crystals of (I) were obtained by crystallization from a hexane–chloroform (1:1) mixture of the solid residues from a Heck reaction. A mixture of 1-butyl-3-methylimidazolium hexafluorophosphate (0.188 ml, 1.0 mmol), Pd(OAc)2 (112 mg, 0.50 mmol) and triphenylphosphane (256 mg, 1.0 mmol) was suspended in dry tetrahydrofuran (15 ml) and stirred overnight under nitrogen. The resulting brown suspension was evaporated in vacuo and washed with CH2Cl2. The dried residue was then used as a catalyst for a Mizoroki–Heck reaction, according to the following typical procedure. Iodobenzene (1.0 mmol), sodium acetate (1.5 mmol), and tert-butyl acrylate (1.4 mmol) were placed in a Schlenk tube under N2, and the reagents were suspended in dimethylformamide (DMF, 3 ml), before injection of the catalyst (0.05 mmol) in DMF (3 ml). The reaction mixture was stirred for 8 h at 353 K, before cooling and extraction of the organic components with several portions of hexane. Extraction of the residue with chloroform followed by layering with hexane yielded crystals of (I).
Crystal data
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H atoms were included in calculated positions and refined using a riding model, with C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C) for H1, and C—H = 0.98 Å and Uiso(H) = 1.5Ueq(C) for the methyl groups. The methyl groups were allowed to rotate about their local threefold axes.
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97, PLATON (Spek, 2003), WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).
Supporting information
https://doi.org/10.1107/S1600536807007052/bi2152sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807007052/bi2152Isup2.hkl
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell
CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97, PLATON (Spek, 2003), WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).[Na(C3H7NO)3]I | Dx = 1.591 Mg m−3 |
Mr = 369.18 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, P62c | Cell parameters from 4526 reflections |
Hall symbol: P -6c -2c | θ = 3.8–27.5° |
a = 11.8038 (14) Å | µ = 2.11 mm−1 |
c = 6.3881 (7) Å | T = 140 K |
V = 770.81 (15) Å3 | Needle, colourless |
Z = 2 | 0.25 × 0.04 × 0.01 mm |
F(000) = 368 |
Oxford Diffraction Xcalibur3 CCD diffractometer | 657 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 607 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.054 |
Thin–slice φ and ω scans | θmax = 27.6°, θmin = 3.8° |
Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006) | h = −15→15 |
Tmin = 0.621, Tmax = 0.979 | k = −15→15 |
10001 measured reflections | l = −8→8 |
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)] = 0.021 | H-atom parameters constrained |
wR(F2) = 0.032 | w = 1/[σ2(Fo2) + (0.0162P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max < 0.001 |
657 reflections | Δρmax = 0.41 e Å−3 |
37 parameters | Δρmin = −0.35 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 281 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.00 (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 | Occ. (<1) | |
C1 | 0.2666 (3) | 0.2349 (3) | 0.2500 | 0.0182 (6) | |
H1 | 0.3494 | 0.2396 | 0.2500 | 0.022* | |
C2 | 0.1453 (3) | 0.3513 (4) | 0.2500 | 0.0249 (9) | |
H2A | 0.0717 | 0.2648 | 0.2152 | 0.037* | 0.50 |
H2B | 0.1515 | 0.4151 | 0.1458 | 0.037* | 0.50 |
H2C | 0.1315 | 0.3775 | 0.3890 | 0.037* | 0.50 |
C3 | 0.3875 (3) | 0.4718 (3) | 0.2500 | 0.0261 (8) | |
H3A | 0.3957 | 0.5170 | 0.3826 | 0.039* | 0.50 |
H3B | 0.3864 | 0.5254 | 0.1337 | 0.039* | 0.50 |
H3C | 0.4620 | 0.4575 | 0.2336 | 0.039* | 0.50 |
I1 | 0.6667 | 0.3333 | 0.2500 | 0.02405 (9) | |
N1 | 0.2663 (3) | 0.3463 (3) | 0.2500 | 0.0197 (6) | |
Na1 | 0.0000 | 0.0000 | 0.0000 | 0.0191 (3) | |
O1 | 0.1683 (2) | 0.12459 (19) | 0.2500 | 0.0206 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0183 (16) | 0.0198 (16) | 0.0173 (15) | 0.0100 (14) | 0.000 | 0.000 |
C2 | 0.021 (2) | 0.0151 (17) | 0.0412 (19) | 0.0106 (15) | 0.000 | 0.000 |
C3 | 0.0259 (18) | 0.0160 (16) | 0.0264 (18) | 0.0029 (15) | 0.000 | 0.000 |
I1 | 0.02509 (11) | 0.02509 (11) | 0.02196 (14) | 0.01255 (6) | 0.000 | 0.000 |
N1 | 0.0200 (16) | 0.0160 (15) | 0.0238 (14) | 0.0095 (14) | 0.000 | 0.000 |
Na1 | 0.0177 (5) | 0.0177 (5) | 0.0219 (8) | 0.0088 (2) | 0.000 | 0.000 |
O1 | 0.0156 (11) | 0.0141 (10) | 0.0298 (12) | 0.0057 (9) | 0.000 | 0.000 |
C1—O1 | 1.238 (3) | C3—H3A | 0.980 |
C1—N1 | 1.316 (4) | C3—H3B | 0.980 |
C1—H1 | 0.950 | C3—H3C | 0.980 |
C2—N1 | 1.460 (5) | Na1—O1 | 2.3954 (15) |
C2—H2A | 0.980 | Na1—O1i | 2.3954 (15) |
C2—H2B | 0.980 | Na1—O1ii | 2.3954 (15) |
C2—H2C | 0.980 | Na1—Na1iii | 3.1941 (4) |
C3—N1 | 1.457 (4) | O1—Na1iii | 2.3954 (15) |
O1—C1—N1 | 125.5 (3) | O1—Na1—O1i | 117.02 (8) |
O1—C1—H1 | 117.2 | O1iii—Na1—O1i | 87.62 (7) |
N1—C1—H1 | 117.2 | O1v—Na1—O1i | 80.40 (5) |
N1—C2—H2A | 109.5 | O1iv—Na1—O1ii | 87.62 (7) |
N1—C2—H2B | 109.5 | O1—Na1—O1ii | 80.40 (5) |
H2A—C2—H2B | 109.5 | O1iii—Na1—O1ii | 80.40 (5) |
N1—C2—H2C | 109.5 | O1v—Na1—O1ii | 117.02 (8) |
H2A—C2—H2C | 109.5 | O1i—Na1—O1ii | 157.01 (9) |
H2B—C2—H2C | 109.5 | O1iv—Na1—Na1vi | 48.19 (3) |
N1—C3—H3A | 109.5 | O1—Na1—Na1vi | 131.81 (3) |
N1—C3—H3B | 109.5 | O1iii—Na1—Na1vi | 131.81 (3) |
H3A—C3—H3B | 109.5 | O1v—Na1—Na1vi | 48.19 (3) |
N1—C3—H3C | 109.5 | O1i—Na1—Na1vi | 48.19 (3) |
H3A—C3—H3C | 109.5 | O1ii—Na1—Na1vi | 131.81 (3) |
H3B—C3—H3C | 109.5 | O1iv—Na1—Na1iii | 131.81 (3) |
C1—N1—C3 | 121.6 (3) | O1—Na1—Na1iii | 48.19 (3) |
C1—N1—C2 | 122.2 (3) | O1iii—Na1—Na1iii | 48.19 (3) |
C3—N1—C2 | 116.2 (3) | O1v—Na1—Na1iii | 131.81 (3) |
O1iv—Na1—O1 | 157.01 (9) | O1i—Na1—Na1iii | 131.81 (3) |
O1iv—Na1—O1iii | 117.02 (8) | O1ii—Na1—Na1iii | 48.19 (3) |
O1—Na1—O1iii | 80.40 (5) | Na1vi—Na1—Na1iii | 180.0 |
O1iv—Na1—O1v | 80.40 (5) | C1—O1—Na1 | 134.40 (8) |
O1—Na1—O1v | 87.62 (7) | C1—O1—Na1iii | 134.40 (8) |
O1iii—Na1—O1v | 157.01 (9) | Na1—O1—Na1iii | 83.62 (6) |
O1iv—Na1—O1i | 80.40 (5) |
Symmetry codes: (i) x−y, −y, −z; (ii) −y, x−y, z; (iii) −x+y, −x, −z+1/2; (iv) −x, −x+y, z−1/2; (v) y, x, z−1/2; (vi) −x+y, −x, −z−1/2. |
Acknowledgements
The authors thank the EPSRC for funding and Dr David Hughes for the provision of X-ray facilities.
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