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Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): m728.
Published online 2010 June 5. doi:  10.1107/S1600536810020192
PMCID: PMC3007045

Dimethyl­ammonium tetra­chloridoferrate(III) 18-crown-6 clathrate

Abstract

The reaction of dimethyl­amine hydro­chloride, 18-crown-6 and ferric chloride in ethanol yields the title compound, (C2H8N)[FeCl4]·C12H24O6, which exhibits an unusual supramolecular structure. The protonated dimethyl­amine contains one NH2 + group, resulting in a 1:1 supra­molecular rotator–stator structure (CH3—NH2 +—CH3)(18-crown-6), through N—H(...)O hydrogen-bonding inter­actions between the ammonium group of the cation and the O atoms of the crown ether. In the crystal, all three components lie on a common crystallographic mirror plane normal to [010].

Related literature

For similar 18-crown-6 clathrates, see: Akutagawa et al. (2002 [triangle]); Fender et al. (2002 [triangle]). For the ferroelectric properties of these materials, see: Zhang et al. (2009 [triangle]); Ye et al. (2009 [triangle]).

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Object name is e-66-0m728-scheme1.jpg

Experimental

Crystal data

  • (C2H8N)[FeCl4]·C12H24O6
  • M r = 508.06
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-66-0m728-efi1.jpg
  • a = 9.3035 (19) Å
  • b = 11.328 (2) Å
  • c = 23.230 (5) Å
  • V = 2448.1 (9) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 1.08 mm−1
  • T = 293 K
  • 0.40 × 0.30 × 0.20 mm

Data collection

  • Rigaku SCXmini diffractometer
  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 [triangle]) T min = 0.685, T max = 0.806
  • 23771 measured reflections
  • 2940 independent reflections
  • 1799 reflections with I > 2σ(I)
  • R int = 0.073

Refinement

  • R[F 2 > 2σ(F 2)] = 0.052
  • wR(F 2) = 0.128
  • S = 0.99
  • 2940 reflections
  • 130 parameters
  • H-atom parameters constrained
  • Δρmax = 0.33 e Å−3
  • Δρmin = −0.23 e Å−3

Data collection: CrystalClear (Rigaku, 2005 [triangle]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: PRPKAPPA (Ferguson, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810020192/bh2286sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810020192/bh2286Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors are grateful to the starter fund of Southeast University for financial support to buy the X-ray diffractometer.

supplementary crystallographic information

Comment

There is currently a great deal of interest in crown ethers because of their ability to form non-covalent, H-bonding complexes with ammonium cations, both in solid and in solution (Akutagawa et al., 2002; Fender et al., 2002). Not only the size of the crown ether, but also the nature of the ammonium cation (NH4+, RNH3+, R2NH2+, etc.) can influence on the stoichiometry and stability of these host–guest complexes. The host molecules combine with the guest species by intermolecular interactions, and, if the host molecule contains some specific sites, it is easy to realise high selectivity in ion or molecular recognition. 18-Crown-6 has the highest affinity for ammonium cations RNH3+. While most studies of 18-crown-6 and its derivatives invariably showed a 1:1 stoichiometry with RNH3+ cations, some structurally characterized complexes of crown ethers include R2NH2+ cations.

The present study is a part of systematic investigation of ferroelectric, phase transitions materials (Ye et al., 2009; Zhang et al., 2009) that include metal-organic coordination compounds with organic ligands, or are related to the structures with both organic and inorganic building fragments. In the measured temperature range from 80 to 420 K (m.p. > 430 K), the temperature dependence of the relative permittivity at 1 MHz varied smoothly from 4.6 to 7.2 in the title compound. No dielectric anomaly has been observed. This suggests that this compound is not an actual ferroelectric, or that no distinct phase transition occurred within the probed temperature range.

The title compound is composed of cationic [C2H8N (18-Crown-6)]+ and one single anionic [FeCl4]- complex (Fig. 1). Supramolecular rotators are assembled between protonated dimethylamine (CH3—NH2—CH3)+ and 18-crown-6 by hydrogen-bonding. The ammonium moieties of (NH2+) cations interact with two O atoms of the crown ether through two simple N—H···O hydrogen bonds, forming a 1:1 supramolecular rotator-stator structure.

Supramolecular cation structure, [C2H8N (18-Crown-6)]+, were introduced as counter cations to [FeCl4]- anions. The crown adopts a conformation in which the ring shows some distortion from the mean plane, with the torsion angles: C3—O2—C2—C1 = 178.2 (3)°; C2—O2—C3—C4 = 72.6 (4)°; C5—O3—C4—C3=178.9 (3)°; C4—O3—C5—C6 = 179.5 (3)°; O3—C4—C3—O2=61.0 (5)°. Fe(III) has a flattened tetrahedral coordination by four Cl- ions [range of cis-bond angles: 108.14 (4)–111.67 (9)°; dav (Fe—Cl) = 2.1728 (15)–2.1889 (12) Å].

Fig. 2 shows a view of the crystal structure down the a axis. An alternate arrangement of cations and anions layers is elongated along the b axis. The title compound is stabilized by intramolecular N—H···O hydrogen bonds, but no significant intermolecular hydrogen bonds are observed.

Experimental

CH3—NH—CH3.HCl (2 mmol, 0.163 g) and 18-crown-6 (2 mmol, 0.528 g) were dissolved in ethanol. Then, trivalent ferric chloride (2 mmol, 0.54 g) was added to the mixture in concentrated hydrochloric acid medium, the precipitate was filtered and washed with a small amount of ethanol. Five days later, single crystals suitable for X-ray diffraction analysis were obtained from slow evaporation of ethanol and DMF solution at room temperature.

Refinement

All C-bonded H atoms were calculated geometrically with C—H distances fixed to 0.96 Å, and were allowed to ride on the C atoms to which they are bonded, with Uiso(H) = 1.2Ueq(C) or Uiso(H) = 1.5Ueq(C) (methyl groups). The ammonium H atom (H1C) was calculated geometrically and refined using a riding model with N—H = 0.90 Å and Uiso(H) = 1.2Ueq(N).

Figures

Fig. 1.
The title compound, with the atomic numbering scheme. The displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
A view of the structure along the a axis. The dashed lines depict the hydrogen bonds.

Crystal data

(C2H8N)[FeCl4]·C12H24O6F(000) = 1060
Mr = 508.06Dx = 1.378 Mg m3
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 17071 reflections
a = 9.3035 (19) Åθ = 3.2–27.8°
b = 11.328 (2) ŵ = 1.08 mm1
c = 23.230 (5) ÅT = 293 K
V = 2448.1 (9) Å3Prism, yellow
Z = 40.40 × 0.30 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer2940 independent reflections
Radiation source: fine-focus sealed tube1799 reflections with I > 2σ(I)
graphiteRint = 0.073
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 3.2°
CCD_Profile_fitting scansh = −12→12
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)k = −14→14
Tmin = 0.685, Tmax = 0.806l = −30→30
23771 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.052Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128H-atom parameters constrained
S = 0.99w = 1/[σ2(Fo2) + (0.04P)2 + 1.99P] where P = (Fo2 + 2Fc2)/3
2940 reflections(Δ/σ)max < 0.001
130 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = −0.23 e Å3
0 constraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
Fe10.47623 (7)0.25000.38202 (3)0.0633 (2)
Cl20.25400 (14)0.25000.35240 (7)0.0926 (5)
Cl10.61871 (16)0.25000.30791 (6)0.0890 (4)
Cl30.51101 (12)0.09011 (13)0.43307 (5)0.1218 (5)
O1−0.1251 (4)0.25000.57334 (13)0.0776 (10)
O20.0327 (3)0.0373 (2)0.58570 (10)0.0804 (7)
O40.0916 (4)0.25000.76754 (13)0.0731 (9)
O30.1171 (3)0.0390 (2)0.70458 (11)0.0814 (7)
C2−0.1174 (4)0.0408 (4)0.5777 (2)0.0991 (14)
H2A−0.16460.04420.61440.119*
H2B−0.1483−0.02980.55840.119*
C40.0511 (5)−0.0599 (3)0.67999 (18)0.0899 (12)
H4A−0.0510−0.05560.68560.108*
H4B0.0856−0.13050.69820.108*
C60.1585 (5)0.1474 (4)0.78905 (16)0.0929 (12)
H6A0.15030.14540.83020.111*
H6B0.25870.14800.77930.111*
C30.0837 (5)−0.0633 (3)0.61760 (18)0.0901 (12)
H3A0.1859−0.06890.61280.108*
H3B0.0418−0.13340.60140.108*
C1−0.1581 (5)0.1448 (4)0.54302 (18)0.1033 (15)
H1A−0.10710.14380.50710.124*
H1B−0.25920.14240.53480.124*
C50.0908 (5)0.0448 (4)0.76473 (16)0.0910 (12)
H5A0.1280−0.02490.78300.109*
H5B−0.01080.04780.77170.109*
N10.1943 (4)0.25000.60266 (16)0.0631 (10)
H1C0.13950.31420.60880.076*
C80.3114 (6)0.25000.6442 (2)0.0885 (16)
H8A0.27460.25000.68280.133*
H8B0.36920.18080.63830.133*
C70.2423 (7)0.25000.5428 (2)0.107 (2)
H7A0.16060.25000.51750.161*
H7B0.29920.31920.53580.161*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Fe10.0520 (4)0.0775 (5)0.0602 (4)0.000−0.0032 (3)0.000
Cl20.0602 (7)0.0757 (9)0.1419 (13)0.000−0.0276 (8)0.000
Cl10.0893 (10)0.1058 (11)0.0719 (8)0.0000.0172 (7)0.000
Cl30.0934 (8)0.1508 (12)0.1212 (9)0.0227 (7)0.0078 (6)0.0725 (9)
O10.076 (2)0.098 (3)0.0589 (19)0.000−0.0134 (17)0.000
O20.0754 (16)0.0766 (17)0.0892 (17)−0.0121 (13)0.0188 (13)−0.0222 (14)
O40.080 (2)0.076 (2)0.064 (2)0.000−0.0125 (17)0.000
O30.0913 (18)0.0591 (15)0.0937 (18)0.0036 (13)0.0070 (14)−0.0007 (13)
C20.080 (3)0.098 (3)0.120 (4)−0.019 (2)0.008 (2)−0.045 (3)
C40.097 (3)0.058 (2)0.115 (3)0.007 (2)0.017 (2)−0.001 (2)
C60.092 (3)0.113 (3)0.074 (2)0.018 (3)−0.015 (2)0.019 (2)
C30.103 (3)0.050 (2)0.117 (3)0.003 (2)0.031 (3)−0.013 (2)
C10.082 (3)0.145 (4)0.083 (3)−0.005 (3)−0.020 (2)−0.034 (3)
C50.106 (3)0.082 (3)0.085 (3)0.012 (2)−0.007 (2)0.022 (2)
N10.050 (2)0.060 (2)0.080 (3)0.0000.0050 (19)0.000
C80.066 (3)0.114 (5)0.086 (4)0.000−0.009 (3)0.000
C70.113 (5)0.141 (6)0.069 (4)0.0000.010 (3)0.000

Geometric parameters (Å, °)

Fe1—Cl12.1728 (15)C4—H4B0.9599
Fe1—Cl22.1791 (14)C6—C51.437 (5)
Fe1—Cl3i2.1889 (12)C6—H6A0.9601
Fe1—Cl32.1889 (12)C6—H6B0.9600
O1—C11.418 (4)C3—H3A0.9600
O1—C1i1.418 (4)C3—H3B0.9601
O2—C21.410 (4)C1—H1A0.9599
O2—C31.440 (4)C1—H1B0.9600
O4—C6i1.410 (4)C5—H5A0.9600
O4—C61.410 (4)C5—H5B0.9600
O3—C41.399 (4)N1—C81.455 (6)
O3—C51.420 (4)N1—C71.461 (6)
C2—C11.476 (6)N1—H1C0.9000
C2—H2A0.9601C8—H8A0.9599
C2—H2B0.9600C8—H8B0.9601
C4—C31.481 (5)C7—H7A0.9600
C4—H4A0.9600C7—H7B0.9600
Cl1—Fe1—Cl2109.19 (7)O2—C3—C4114.5 (3)
Cl1—Fe1—Cl3i109.82 (4)O2—C3—H3A108.6
Cl2—Fe1—Cl3i108.14 (4)C4—C3—H3A108.6
Cl1—Fe1—Cl3109.82 (4)O2—C3—H3B108.6
Cl2—Fe1—Cl3108.14 (4)C4—C3—H3B108.7
Cl3i—Fe1—Cl3111.67 (9)H3A—C3—H3B107.6
C1—O1—C1i114.3 (4)O1—C1—C2110.1 (3)
C2—O2—C3114.6 (3)O1—C1—H1A109.6
C6i—O4—C6111.1 (4)C2—C1—H1A109.7
C4—O3—C5111.3 (3)O1—C1—H1B109.6
O2—C2—C1110.4 (4)C2—C1—H1B109.6
O2—C2—H2A109.7H1A—C1—H1B108.2
C1—C2—H2A109.5O3—C5—C6110.4 (3)
O2—C2—H2B109.6O3—C5—H5A109.6
C1—C2—H2B109.5C6—C5—H5A109.4
H2A—C2—H2B108.1O3—C5—H5B109.6
O3—C4—C3109.3 (3)C6—C5—H5B109.6
O3—C4—H4A109.8H5A—C5—H5B108.1
C3—C4—H4A109.7C8—N1—C7113.7 (4)
O3—C4—H4B109.9C8—N1—H1C108.6
C3—C4—H4B109.9C7—N1—H1C109.0
H4A—C4—H4B108.3N1—C8—H8A110.6
O4—C6—C5109.5 (3)N1—C8—H8B108.9
O4—C6—H6A109.7H8A—C8—H8B109.5
C5—C6—H6A109.8N1—C7—H7A109.9
O4—C6—H6B109.8N1—C7—H7B109.3
C5—C6—H6B109.8H7A—C7—H7B109.5
H6A—C6—H6B108.2

Symmetry codes: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H1C···O2i0.902.032.867 (3)155

Symmetry codes: (i) x, −y+1/2, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BH2286).

References

  • Akutagawa, T., Hashimoto, A., Nishihara, S., Hasegawa, T. & Nakamura, T. (2002). J. Supramol. Chem.2, 175–186.
  • Fender, N. S., Kahwa, I. A. & Fronczek, F. R. (2002). J. Solid State Chem.163, 286–293.
  • Ferguson, G. (1999). PRPKAPPA University of Guelph, Canada.
  • Rigaku (2005). CrystalClear Rigaku Corporation, Tokyo, Japan.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Ye, H.-Y., Fu, D.-W., Zhang, Y., Zhang, W., Xiong, R.-G. & Huang, S. D. (2009). J. Am. Chem. Soc.131, 42–43. [PubMed]
  • Zhang, W., Cheng, L.-Z., Xiong, R.-G., Nakamura, T. & Huang, S. D. (2009). J. Am. Chem. Soc.131, 12544–12545. [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography