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Acta Crystallogr Sect E Struct Rep Online. 2009 June 1; 65(Pt 6): o1427.
Published online 2009 May 29. doi:  10.1107/S160053680901928X
PMCID: PMC2969671

1-{2-[(4-Hydr­oxy-3-methoxy­benzyl­idene)amino]eth­yl}-3-methylimid­azolium hexa­fluoro­phosphate

Abstract

In the title Schiff base salt, C14H18N3O2 +·PF6 , the dihedral angle between the planes of the aromatic and imidazole rings is 24.84 (8)°. The mol­ecular structure exhibits an intra­molecular O—H(...)O hydrogen bond, which generates an S(5) ring motif. In the crystal structure, the cations and anions are connected via O—H(...)N and O—H(...)F hydrogen bonds, resulting in a trifurcated interaction for the phenolic H atom.

Related literature

For bond-length data, see: Allen et al. (1987 [triangle]). For the synthesis of Schiff bases, see: Pradeep (2005 [triangle]); Butcher et al. (2005 [triangle]). For information on ionic liquids and their applications, see: Xiao et al. (2004 [triangle]); Welton (1999 [triangle]); Wilkes (2002 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o1427-scheme1.jpg

Experimental

Crystal data

  • C14H18N3O2 +·PF6
  • M r = 405.28
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1427-efi1.jpg
  • a = 7.5285 (10) Å
  • b = 12.6850 (16) Å
  • c = 17.827 (2) Å
  • β = 96.245 (2)°
  • V = 1692.3 (4) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.24 mm−1
  • T = 173 K
  • 0.48 × 0.43 × 0.38 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.894, T max = 0.914
  • 8519 measured reflections
  • 3635 independent reflections
  • 2904 reflections with I > 2σ(I)
  • R int = 0.019

Refinement

  • R[F 2 > 2σ(F 2)] = 0.034
  • wR(F 2) = 0.099
  • S = 1.07
  • 3635 reflections
  • 238 parameters
  • H-atom parameters constrained
  • Δρmax = 0.26 e Å−3
  • Δρmin = −0.29 e Å−3

Data collection: SMART (Bruker, 2002 [triangle]); cell refinement: SAINT (Bruker, 2002 [triangle]); data reduction: SAINT; 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: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680901928X/su2112sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680901928X/su2112Isup2.hkl

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

Acknowledgments

The authors are grateful to the National Natural Science Foundation of China (grant No. 20672046) and the Guangdong Natural Science Foundation (grant No. 8151063201000016) for financial support.

supplementary crystallographic information

Comment

Ionic liquids have aroused considerable interest over the past decade due to their wide variety of properties such as high thermal and chemical stability, no measurable vapor pressure, non-flammability, friction reduction, and high loading capacity, etc (Xiao et al., 2004; Welton, 1999; Wilkes, 2002). Schiff base compounds are one of the most prevalent mixed-donor ligands in the field of coordination chemistry (Pradeep, 2005; Butcher et al., 2005). Our interest in this field of research lead us to synthesis the title compound, and we report here on the crystal structure of this novel ionic liquid-supported Schiff base.

The title compound is a Schiff base derived from the condensation of 4-hydroxy-3-methoxybenzaldehyde with the ionic liquid 1-(2-aminoethyl)-3- methylimidazolium hexafluorophosphate, under solvent-free conditions. The molecular structure of the title compound is illustrated in Fig. 1. The asymmetric unit comprises one cation and one PF6 anion. The bond lengths (Allen et al., 1987) and angles are generally within normal ranges. The aromatic ring and imidazole ring are not coplanar but are inclined to one another by an angle of 24.84 (8)°. In the molecular structure, the intramolocular O2—H2A···O1 hydrogen bonds form a pseudo five membered ring [S(5) motif], thus locking the molecular conformation and eliminating any flexibility (Table 1).

In the crystal structure symmetry related cations and anions are connected via O-H···N and O-H···F hydrogen bonds (Table 1).

Experimental

A mixture of the ionic liquid 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate (4 mmol) and 4-hydroxy-3- methoxybenzaldehyde (3 mmol) was stirred for 4 h at rt, under solvent-free conditions. After completion of the reaction, ethanol (30 ml) was added to the reaction mixture. The solid product was then filtered off and washed with cold ethanol. The crude product was purified by recrystallization in ethanol/ethyl acetate(3:1 v/v). Single crystals, suitable for X-ray diffraction analysis, were obtained by slow evaporation of an ethyl acetate solution of the complex at rt.

Refinement

All the H-atoms could be located in difference Fourier maps and were refined as riding atoms: O—H = 0.84 Å, with Uiso(H) = 1.5 Ueq(O); C—H = 0.95–0.98 Å with Uiso(H) = 1.2 Ueq(C).

Figures

Fig. 1.
The molecular structure of the title compound, showing the atom numbering Scheme. Displacement ellipsoids are drawn at the 50% probability level.

Crystal data

C14H18N3O2+·PF6F(000) = 832
Mr = 405.28Dx = 1.591 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4600 reflections
a = 7.5285 (10) Åθ = 2.3–27.1°
b = 12.6850 (16) ŵ = 0.24 mm1
c = 17.827 (2) ÅT = 173 K
β = 96.245 (2)°Block, colorless
V = 1692.3 (4) Å30.48 × 0.43 × 0.38 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer3635 independent reflections
Radiation source: fine-focus sealed tube2904 reflections with I > 2σ(I)
graphiteRint = 0.019
[var phi] and ω scansθmax = 27.1°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −7→9
Tmin = 0.894, Tmax = 0.914k = −16→13
8519 measured reflectionsl = −22→22

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)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.099H-atom parameters constrained
S = 1.07w = 1/[σ2(Fo2) + (0.0489P)2 + 0.5604P] where P = (Fo2 + 2Fc2)/3
3635 reflections(Δ/σ)max = 0.001
238 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = −0.29 e Å3

Special details

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)

xyzUiso*/Ueq
C10.4931 (2)0.59395 (12)0.15334 (9)0.0254 (3)
C20.5820 (2)0.59443 (12)0.22669 (9)0.0245 (3)
H20.59290.65820.25480.029*
C30.6536 (2)0.50227 (12)0.25801 (9)0.0246 (3)
C40.6351 (2)0.40751 (12)0.21695 (9)0.0277 (3)
C50.5435 (2)0.40639 (13)0.14557 (9)0.0302 (4)
H50.52820.34210.11820.036*
C60.4735 (2)0.49990 (12)0.11374 (9)0.0283 (3)
H60.41180.49920.06440.034*
C70.7471 (2)0.58042 (14)0.37782 (10)0.0363 (4)
H7A0.80780.64020.35680.054*
H7B0.80980.56130.42700.054*
H7C0.62360.60010.38390.054*
C80.4221 (2)0.69108 (13)0.11667 (9)0.0264 (3)
H80.36330.68590.06690.032*
C90.3561 (2)0.86914 (13)0.10164 (9)0.0286 (3)
H9A0.29470.84170.05370.034*
H9B0.45200.91760.08940.034*
C100.2231 (2)0.92900 (14)0.14407 (10)0.0324 (4)
H10A0.16020.98190.11000.039*
H10B0.13290.87920.15980.039*
C110.3670 (2)0.93695 (13)0.27651 (9)0.0281 (3)
H110.34870.86520.28890.034*
C120.4516 (2)1.10234 (13)0.28397 (10)0.0330 (4)
H120.50301.16670.30310.040*
C130.3652 (2)1.08660 (13)0.21491 (10)0.0336 (4)
H130.34451.13770.17600.040*
C140.5274 (3)0.98980 (16)0.39957 (10)0.0420 (4)
H14A0.44891.02070.43410.063*
H14B0.64571.02260.40810.063*
H14C0.53830.91380.40880.063*
F1−0.02389 (14)0.28060 (9)−0.01415 (7)0.0477 (3)
F20.17917 (17)0.21418 (9)−0.08507 (6)0.0500 (3)
F30.07180 (16)0.11320 (8)0.00376 (7)0.0503 (3)
F40.35699 (15)0.17051 (10)0.02179 (7)0.0536 (3)
F50.15258 (16)0.23765 (10)0.09197 (6)0.0485 (3)
F60.26139 (15)0.33750 (8)0.00272 (6)0.0474 (3)
N10.43423 (18)0.78152 (10)0.14719 (7)0.0288 (3)
N20.31202 (17)0.98250 (10)0.21108 (8)0.0279 (3)
N30.45170 (18)1.00816 (11)0.32170 (8)0.0291 (3)
O10.74720 (16)0.49223 (9)0.32760 (6)0.0325 (3)
O20.70614 (18)0.31595 (9)0.24688 (7)0.0409 (3)
H2A0.76840.32880.28790.061*
P10.16710 (6)0.22501 (3)0.00298 (2)0.02858 (13)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0204 (7)0.0258 (8)0.0301 (8)−0.0006 (6)0.0031 (6)0.0002 (6)
C20.0254 (7)0.0209 (7)0.0274 (8)−0.0027 (6)0.0036 (6)−0.0027 (6)
C30.0240 (7)0.0249 (8)0.0249 (8)−0.0043 (6)0.0027 (6)0.0006 (6)
C40.0300 (8)0.0210 (7)0.0316 (9)−0.0009 (6)0.0011 (6)0.0015 (6)
C50.0332 (9)0.0234 (8)0.0334 (9)−0.0014 (6)0.0006 (7)−0.0063 (7)
C60.0265 (8)0.0299 (8)0.0272 (8)−0.0018 (6)−0.0024 (6)−0.0023 (7)
C70.0422 (10)0.0370 (10)0.0285 (9)0.0013 (8)−0.0018 (7)−0.0083 (7)
C80.0234 (7)0.0305 (8)0.0248 (8)0.0001 (6)0.0005 (6)0.0000 (6)
C90.0331 (8)0.0259 (8)0.0255 (8)0.0028 (6)−0.0024 (6)0.0015 (6)
C100.0286 (8)0.0317 (9)0.0351 (9)0.0054 (7)−0.0052 (7)−0.0021 (7)
C110.0296 (8)0.0258 (8)0.0291 (8)−0.0015 (6)0.0043 (6)−0.0003 (7)
C120.0326 (9)0.0247 (8)0.0429 (10)−0.0022 (7)0.0101 (7)−0.0038 (7)
C130.0357 (9)0.0234 (8)0.0427 (10)0.0041 (7)0.0087 (7)0.0029 (7)
C140.0475 (11)0.0507 (12)0.0272 (9)−0.0067 (9)0.0018 (8)−0.0051 (8)
F10.0338 (6)0.0458 (7)0.0599 (7)0.0069 (5)−0.0110 (5)−0.0037 (5)
F20.0641 (8)0.0555 (7)0.0306 (6)−0.0080 (6)0.0059 (5)−0.0050 (5)
F30.0612 (8)0.0312 (6)0.0591 (8)−0.0099 (5)0.0093 (6)0.0020 (5)
F40.0404 (6)0.0603 (8)0.0592 (7)0.0186 (6)0.0011 (5)0.0041 (6)
F50.0596 (7)0.0563 (7)0.0293 (6)0.0083 (6)0.0042 (5)0.0001 (5)
F60.0505 (7)0.0366 (6)0.0513 (7)−0.0149 (5)−0.0111 (5)0.0023 (5)
N10.0337 (7)0.0258 (7)0.0259 (7)0.0046 (6)−0.0006 (5)0.0016 (6)
N20.0263 (7)0.0256 (7)0.0317 (7)0.0044 (5)0.0033 (5)−0.0004 (6)
N30.0293 (7)0.0290 (7)0.0297 (7)−0.0026 (6)0.0064 (5)−0.0031 (6)
O10.0436 (7)0.0250 (6)0.0267 (6)0.0000 (5)−0.0057 (5)−0.0007 (5)
O20.0582 (9)0.0214 (6)0.0388 (7)0.0025 (6)−0.0149 (6)−0.0013 (5)
P10.0299 (2)0.0267 (2)0.0283 (2)0.00017 (17)−0.00086 (16)0.00051 (17)

Geometric parameters (Å, °)

C1—C61.386 (2)C10—N21.470 (2)
C1—C21.403 (2)C10—H10A0.9900
C1—C81.468 (2)C10—H10B0.9900
C2—C31.380 (2)C11—N31.327 (2)
C2—H20.9500C11—N21.327 (2)
C3—O11.3644 (18)C11—H110.9500
C3—C41.406 (2)C12—C131.343 (3)
C4—O21.3629 (19)C12—N31.371 (2)
C4—C51.380 (2)C12—H120.9500
C5—C61.393 (2)C13—N21.379 (2)
C5—H50.9500C13—H130.9500
C6—H60.9500C14—N31.461 (2)
C7—O11.433 (2)C14—H14A0.9800
C7—H7A0.9800C14—H14B0.9800
C7—H7B0.9800C14—H14C0.9800
C7—H7C0.9800F1—P11.6008 (11)
C8—N11.269 (2)F2—P11.5880 (11)
C8—H80.9500F3—P11.5902 (11)
C9—N11.4618 (19)F4—P11.5905 (11)
C9—C101.521 (2)F5—P11.6101 (11)
C9—H9A0.9900F6—P11.5941 (11)
C9—H9B0.9900O2—H2A0.8400
C6—C1—C2119.47 (14)N3—C11—N2108.71 (15)
C6—C1—C8118.84 (14)N3—C11—H11125.6
C2—C1—C8121.68 (14)N2—C11—H11125.6
C3—C2—C1119.96 (14)C13—C12—N3107.13 (15)
C3—C2—H2120.0C13—C12—H12126.4
C1—C2—H2120.0N3—C12—H12126.4
O1—C3—C2125.97 (14)C12—C13—N2107.25 (15)
O1—C3—C4113.93 (13)C12—C13—H13126.4
C2—C3—C4120.09 (14)N2—C13—H13126.4
O2—C4—C5119.19 (14)N3—C14—H14A109.5
O2—C4—C3120.81 (14)N3—C14—H14B109.5
C5—C4—C3120.00 (14)H14A—C14—H14B109.5
C4—C5—C6119.71 (15)N3—C14—H14C109.5
C4—C5—H5120.1H14A—C14—H14C109.5
C6—C5—H5120.1H14B—C14—H14C109.5
C1—C6—C5120.73 (14)C8—N1—C9116.33 (14)
C1—C6—H6119.6C11—N2—C13108.20 (14)
C5—C6—H6119.6C11—N2—C10125.74 (14)
O1—C7—H7A109.5C13—N2—C10125.87 (14)
O1—C7—H7B109.5C11—N3—C12108.71 (14)
H7A—C7—H7B109.5C11—N3—C14125.50 (15)
O1—C7—H7C109.5C12—N3—C14125.77 (14)
H7A—C7—H7C109.5C3—O1—C7117.38 (12)
H7B—C7—H7C109.5C4—O2—H2A109.5
N1—C8—C1124.21 (14)F2—P1—F390.34 (6)
N1—C8—H8117.9F2—P1—F491.38 (7)
C1—C8—H8117.9F3—P1—F490.37 (7)
N1—C9—C10110.50 (14)F2—P1—F690.07 (6)
N1—C9—H9A109.6F3—P1—F6179.46 (7)
C10—C9—H9A109.6F4—P1—F689.96 (7)
N1—C9—H9B109.6F2—P1—F189.80 (7)
C10—C9—H9B109.6F3—P1—F189.88 (6)
H9A—C9—H9B108.1F4—P1—F1178.80 (7)
N2—C10—C9111.62 (13)F6—P1—F189.78 (6)
N2—C10—H10A109.3F2—P1—F5179.03 (7)
C9—C10—H10A109.3F3—P1—F590.06 (7)
N2—C10—H10B109.3F4—P1—F589.50 (6)
C9—C10—H10B109.3F6—P1—F589.52 (6)
H10A—C10—H10B108.0F1—P1—F589.32 (6)
C6—C1—C2—C31.8 (2)N3—C12—C13—N20.31 (19)
C8—C1—C2—C3−177.20 (14)C1—C8—N1—C9179.71 (14)
C1—C2—C3—O1178.08 (14)C10—C9—N1—C8125.58 (16)
C1—C2—C3—C4−1.0 (2)N3—C11—N2—C130.40 (18)
O1—C3—C4—O20.3 (2)N3—C11—N2—C10175.73 (14)
C2—C3—C4—O2179.53 (15)C12—C13—N2—C11−0.44 (19)
O1—C3—C4—C5−179.91 (15)C12—C13—N2—C10−175.77 (15)
C2—C3—C4—C5−0.7 (2)C9—C10—N2—C11−78.2 (2)
O2—C4—C5—C6−178.65 (15)C9—C10—N2—C1396.36 (19)
C3—C4—C5—C61.6 (3)N2—C11—N3—C12−0.20 (19)
C2—C1—C6—C5−1.0 (2)N2—C11—N3—C14178.01 (15)
C8—C1—C6—C5178.10 (15)C13—C12—N3—C11−0.08 (19)
C4—C5—C6—C1−0.8 (3)C13—C12—N3—C14−178.29 (16)
C6—C1—C8—N1−179.14 (16)C2—C3—O1—C710.9 (2)
C2—C1—C8—N1−0.1 (2)C4—C3—O1—C7−169.95 (15)
N1—C9—C10—N266.34 (18)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O2—H2A···O10.842.202.6589 (16)114
O2—H2A···N1i0.842.483.1584 (18)139
O2—H2A···F2ii0.842.493.0487 (18)125

Symmetry codes: (i) −x+3/2, y−1/2, −z+1/2; (ii) x+1/2, −y+1/2, z+1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2112).

References

  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Bruker (2002). SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Butcher, R. J., Basu Baul, T. S., Singh, K. S. & Smith, F. E. (2005). Acta Cryst. E61, o1007–o1009.
  • Pradeep, C. P. (2005). Acta Cryst. E61, o3825–o3827.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Welton, T. (1999). Chem. Rev.99, 2071–2083. [PubMed]
  • Wilkes, J. S. (2002). Green Chem.4, 73–80.
  • Xiao, Y. & Malhotra, S. V. (2004). Tetrahedron Lett.45, 8339–8342.

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