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Acta Cryst. (2010). E66, o1478    [ doi:10.1107/S1600536810019033 ]

4-Methylanilinium tetrafluoroborate 18-crown-6 clathrate

J.-Z. Ge and M.-M. Zhao

Abstract top

In the title compound, C7H10N+·BF4-·C12H24O6, the protonated 4-methylanilinium cation interacts with 18-crown-6 forming a rotator-stator structure, (C6H4CH3NH3+)(18-crown-6), through three bifurcated N-H...(O,O) hydrogen bonds between the ammonium groups of the cations (-NH3) and the O atoms of the crown ether molecule. The BF4- anions, the methyl group and the protonated -NH3 groups of the 4-methylanilinium lie on a dual axis of rotation. The 18-crown-6 unit is perpendicular to the dual axis of rotation and the mirror plane which contains the dual axis of rotation. The benzene ring of 4-methylanilinium is perpendicular to the mirror plane and parallel to the dual axis.

Comment top

The crown ethers were of a great interest since their discovery had been reported by Pedersen (Pedersen et al. 1967). The ability of these macrocycles to form non-covalent,H-bonding complexes with ammonium cations has been actively investigated. Both the size of the crown ether and the nature of the ammonium cation (-NH4+, RNH3+, etc) can influence on the stoichiometry and stability of these host-guest complexes. The host molecules combine with the guest species by intermolecular interaction, and if the host molecule possess some specific sites, it is easy to realise high selectivity in ion or molecular recognitions.18-crown-6 have the highest affinity for ammonium cation RNH3+, while most studies of 18-crown-6 and its derivatives invariably showed a 1:1 stoichiometry with RNH3+ cations.

The title compound dielectric permittivity is tested to systematically investigate the ferroelectric phase transitions materials (Fu et al. 2007; Ye et al. 2009; Zhang et al. 2009). The title compound have no dielectric anomalies with the value of 4-5 and 6-8 under 1M Hz in the temperature from 80 to 300 K and 300 to 473 K (the compound m.p.> 473 K), respectively, suggesting that the compound should be no distinct phase transition occurred within the measured temperature range.

The the title compound is composed of cationic [(C6H4CH3NH3) (18-Crown-6)]+ and one isolated anionic [BF4]- (Fig 1). The protonated 4-methylaniline [C6H4CH3NH3]+ and 18-crown-6 form superamolecular rotator-stator structure by forming hydrogen-bond (N—H···O) between the ammonium moieties of (-NH3+) cations and each of the six oxygen atoms of crown ethers. The intramolecular N—H···O hydrogen bonding length are within the usual range: 2.887 (4) and 2.960 (2) Å. The crown ring show slight distortion. The six oxygen atoms of the crown ether lie approximately in a plane. The C—N bonds of [C6H4CH3NH3]+ were almost perpendicular to the mean oxygen plane.

The typical B—F bond lengths in the tetrahedral coordinate anion [BF4]- are within 1.374 (4)-1.393 (5) Å. The F—B—F bond angles indicate little distortion from a regular tetrahedron [spread of values 107.3 (4)-111.6 (4)°].

Fig. 2 shows a view down the b axis. The couples of head-to-head rotator-stator cations almost paralleling and plumbing the (1 0 1) direction are alternating arranged. The anions [BF4]- inhabit the cave formed by the couples of head-to-head rotator-stator cations. The title compound was stabilized by intramolecular N—H···O hydrogen bonds, but no intermolecular hydrogen bond was observed.

Related literature top

For a similar 18-crown-6 clathrate, see: Pedersen et al. (1967). For ferroelectric properties, see: Fu et al. (2007); Ye et al. (2009).; Zhang et al. (2009).

Experimental top

4-methylaniline(2 mmol, 0.214 g) and excessive tetrafluoroborate (4 mmol, 0.348 g) were dissolved in methanol solution. Then 18-crown-6 (2 mmol, 0.528 g) was added to the mixture. The precipitate was filtered and washed with a small amount of methanol. Single crystals suitable for X-ray diffraction analysis were obtained from slow evaporation of methanol solution at room temperature after two days.

Refinement top

All the C—H hydrogen atoms were calculated geometrically and with C—H distances ranging from 0.93 to 0.97 Å and were allowed to ride on the C and O atoms to which they are bonded. With which Uiso(H) = 1.2Ueq(C).

Computing details top

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

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. A view of the packing of the title compound, stacking along the b axis. Dashed lines indicate hydrogen bonds.
4-Methylanilinium tetrafluoroborate–1,4,7,10,13,16-hexaoxacyclooctadecane (1/1) top
Crystal data top
C7H10N+·BF4−·C12H24O6F(000) = 976
Mr = 459.28Dx = 1.301 Mg m−3
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 2816 reflections
a = 15.439 (3) Åθ = 3.1–27.5°
b = 11.616 (2) ŵ = 0.11 mm−1
c = 13.071 (3) ÅT = 293 K
V = 2344.2 (8) Å3Block, pale yellow
Z = 40.20 × 0.20 × 0.20 mm
Data collection top
Rigaku SCXmini
diffractometer		2816 independent reflections
Radiation source: fine-focus sealed tube1541 reflections with I > 2σ(I)
graphiteRint = 0.086
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 3.1°
ω scansh = −20→20
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		k = −15→15
Tmin = 0.977, Tmax = 0.977l = −16→16
23254 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.067Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.209H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0947P)2 + 0.766P]
where P = (Fo2 + 2Fc2)/3
2816 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 0.30 e Å−3
0 restraintsΔρmin = −0.23 e Å−3
Crystal data top
C7H10N+·BF4−·C12H24O6V = 2344.2 (8) Å3
Mr = 459.28Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 15.439 (3) ŵ = 0.11 mm−1
b = 11.616 (2) ÅT = 293 K
c = 13.071 (3) Å0.20 × 0.20 × 0.20 mm
Data collection top
Rigaku SCXmini
diffractometer		2816 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		1541 reflections with I > 2σ(I)
Tmin = 0.977, Tmax = 0.977Rint = 0.086
23254 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.067H-atom parameters constrained
wR(F2) = 0.209Δρmax = 0.30 e Å−3
S = 1.02Δρmin = −0.23 e Å−3
2816 reflectionsAbsolute structure: ?
154 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
xyzUiso*/UeqOcc. (<1)
O10.45735 (17)0.25000.85026 (19)0.0531 (7)
O20.39198 (12)0.03619 (16)0.78258 (14)0.0548 (5)
O30.30174 (13)0.04501 (16)0.59530 (15)0.0607 (6)
O40.21893 (18)0.25000.5296 (2)0.0630 (8)
C50.4704 (2)0.0478 (3)0.8399 (2)0.0615 (8)
H5A0.51890.05920.79370.074*
H5B0.4809−0.02170.87920.074*
C30.3162 (2)−0.0608 (2)0.6496 (2)0.0640 (8)
H3A0.3188−0.12450.60170.077*
H3B0.2689−0.07470.69680.077*
C40.3988 (2)−0.0519 (3)0.7065 (2)0.0617 (8)
H4A0.4118−0.12500.73900.074*
H4B0.4455−0.03370.65960.074*
C20.2237 (2)0.0450 (3)0.5374 (3)0.0719 (9)
H2A0.17420.04760.58310.086*
H2B0.2199−0.02490.49710.086*
C60.4625 (2)0.1481 (2)0.9098 (2)0.0587 (8)
H6A0.41090.14030.95160.070*
H6B0.51240.15170.95480.070*
C10.2230 (2)0.1471 (3)0.4689 (2)0.0770 (10)
H1A0.27500.14780.42730.092*
H1B0.17320.14350.42360.092*
N10.29810 (18)0.25000.7297 (2)0.0432 (7)
H1C0.31380.32220.71670.065*0.50
H1D0.28600.21420.67120.065*0.50
H1E0.34120.21360.76130.065*0.50
C70.2212 (2)0.25000.7954 (2)0.0406 (8)
C80.18519 (19)0.1469 (3)0.8255 (2)0.0566 (7)
H8A0.20990.07750.80540.068*
C100.0727 (2)0.25000.9169 (3)0.0562 (11)
C90.11146 (19)0.1480 (3)0.8863 (2)0.0624 (8)
H9A0.08740.07840.90710.075*
C11−0.0088 (3)0.25000.9817 (4)0.0863 (15)
H11A−0.02600.32790.99540.129*0.50
H11B0.00230.21101.04500.129*0.50
H11C−0.05440.21110.94550.129*0.50
B10.3985 (3)0.25000.2064 (4)0.0572 (12)
F30.48142 (17)0.25000.1644 (2)0.0831 (8)
F10.38646 (15)0.1522 (2)0.2638 (2)0.1101 (8)
F20.3400 (2)0.25000.1254 (2)0.0999 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0597 (17)0.0518 (15)0.0479 (15)0.000−0.0094 (12)0.000
O20.0579 (12)0.0441 (10)0.0624 (12)0.0055 (8)0.0011 (9)−0.0021 (9)
O30.0587 (12)0.0543 (12)0.0692 (13)−0.0104 (9)−0.0082 (10)−0.0084 (10)
O40.0669 (19)0.080 (2)0.0418 (15)0.000−0.0083 (13)0.000
C50.0575 (18)0.0592 (18)0.0677 (19)0.0124 (14)−0.0051 (15)0.0141 (15)
C30.074 (2)0.0441 (16)0.074 (2)−0.0127 (14)0.0129 (16)−0.0112 (14)
C40.071 (2)0.0456 (16)0.0688 (19)0.0061 (14)0.0090 (16)−0.0020 (14)
C20.061 (2)0.080 (2)0.074 (2)−0.0116 (16)−0.0106 (17)−0.0257 (19)
C60.0621 (18)0.0637 (19)0.0503 (15)0.0038 (14)−0.0086 (13)0.0117 (15)
C10.070 (2)0.109 (3)0.0524 (17)−0.0058 (19)−0.0146 (15)−0.020 (2)
N10.0446 (17)0.0441 (16)0.0411 (16)0.000−0.0027 (13)0.000
C70.0379 (19)0.047 (2)0.0374 (18)0.000−0.0074 (15)0.000
C80.0599 (18)0.0526 (17)0.0574 (17)−0.0035 (13)0.0064 (14)−0.0007 (13)
C100.040 (2)0.086 (3)0.042 (2)0.000−0.0028 (17)0.000
C90.0597 (19)0.068 (2)0.0599 (17)−0.0157 (15)0.0048 (14)0.0030 (15)
C110.067 (3)0.122 (4)0.070 (3)0.0000.009 (3)0.000
B10.049 (3)0.047 (3)0.076 (3)0.000−0.010 (2)0.000
F30.0672 (17)0.0736 (18)0.109 (2)0.0000.0040 (15)0.000
F10.1019 (17)0.0984 (17)0.1301 (18)−0.0018 (13)0.0172 (14)0.0433 (15)
F20.081 (2)0.114 (2)0.105 (2)0.000−0.0178 (17)0.000
Geometric parameters (Å, °) top
O1—C6i1.419 (3)C1—H1A0.9700
O1—C61.419 (3)C1—H1B0.9700
O2—C51.431 (3)N1—C71.465 (4)
O2—C41.431 (3)N1—H1C0.8900
O3—C21.423 (3)N1—H1D0.8900
O3—C31.436 (4)N1—H1E0.8900
O4—C11.436 (4)C7—C81.378 (3)
O4—C1i1.436 (4)C7—C8i1.378 (3)
C5—C61.486 (4)C8—C91.388 (4)
C5—H5A0.9700C8—H8A0.9300
C5—H5B0.9700C10—C9i1.386 (4)
C3—C41.480 (4)C10—C91.386 (4)
C3—H3A0.9700C10—C111.517 (6)
C3—H3B0.9700C9—H9A0.9300
C4—H4A0.9700C11—H11A0.9600
C4—H4B0.9700C11—H11B0.9600
C2—C11.487 (5)C11—H11C0.9600
C2—H2A0.9700B1—F11.374 (4)
C2—H2B0.9700B1—F1i1.374 (4)
C6—H6A0.9700B1—F31.392 (5)
C6—H6B0.9700B1—F21.393 (5)
C6i—O1—C6113.0 (3)O4—C1—H1A109.8
C5—O2—C4111.7 (2)C2—C1—H1A109.8
C2—O3—C3113.2 (2)O4—C1—H1B109.8
C1—O4—C1i112.7 (3)C2—C1—H1B109.8
O2—C5—C6109.0 (2)H1A—C1—H1B108.2
O2—C5—H5A109.9C7—N1—H1C109.5
C6—C5—H5A109.9C7—N1—H1D109.5
O2—C5—H5B109.9H1C—N1—H1D109.5
C6—C5—H5B109.9C7—N1—H1E109.5
H5A—C5—H5B108.3H1C—N1—H1E109.5
O3—C3—C4108.8 (2)H1D—N1—H1E109.5
O3—C3—H3A109.9C8—C7—C8i120.7 (3)
C4—C3—H3A109.9C8—C7—N1119.65 (17)
O3—C3—H3B109.9C8i—C7—N1119.65 (17)
C4—C3—H3B109.9C7—C8—C9119.1 (3)
H3A—C3—H3B108.3C7—C8—H8A120.4
O2—C4—C3109.6 (2)C9—C8—H8A120.4
O2—C4—H4A109.7C9i—C10—C9117.4 (4)
C3—C4—H4A109.7C9i—C10—C11121.28 (18)
O2—C4—H4B109.7C9—C10—C11121.28 (18)
C3—C4—H4B109.7C10—C9—C8121.8 (3)
H4A—C4—H4B108.2C10—C9—H9A119.1
O3—C2—C1109.0 (3)C8—C9—H9A119.1
O3—C2—H2A109.9C10—C11—H11A109.5
C1—C2—H2A109.9C10—C11—H11B109.5
O3—C2—H2B109.9H11A—C11—H11B109.5
C1—C2—H2B109.9C10—C11—H11C109.5
H2A—C2—H2B108.3H11A—C11—H11C109.5
O1—C6—C5108.7 (2)H11B—C11—H11C109.5
O1—C6—H6A109.9F1—B1—F1i111.6 (4)
C5—C6—H6A109.9F1—B1—F3109.9 (2)
O1—C6—H6B109.9F1i—B1—F3109.9 (2)
C5—C6—H6B109.9F1—B1—F2109.1 (3)
H6A—C6—H6B108.3F1i—B1—F2109.1 (3)
O4—C1—C2109.4 (2)F3—B1—F2107.3 (4)
Symmetry codes: (i) x, −y+1/2, z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1C···O2i0.892.212.958 (2)141
N1—H1C···O3i0.892.222.960 (2)140
N1—H1D···O40.892.162.887 (4)138
N1—H1D···O30.892.222.960 (2)141
N1—H1E···O10.892.182.920 (4)140
N1—H1E···O20.892.222.958 (2)140
Symmetry codes: (i) x, −y+1/2, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1C···O2i0.892.212.958 (2)141
N1—H1C···O3i0.892.222.960 (2)140
N1—H1D···O40.892.162.887 (4)138
N1—H1D···O30.892.222.960 (2)141
N1—H1E···O10.892.182.920 (4)140
N1—H1E···O20.892.222.958 (2)140
Symmetry codes: (i) x, −y+1/2, z.
Acknowledgements top

The authors thank the start-up projects for Postdoctoral Research Funds of Southeast University (grant No. 1112000047) and the starter fund of Southeast University for financial support to buy the X-ray diffractometer.

references
References top

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