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ISSN: 2056-9890

1-{2-[(2-hydroxybenzyl­idene)-amino]-ethyl}-3-methyl-3H-imidazolium hexa­fluorophosphate

aDepartment of Chemistry, Jinan University, Guangzhou, Guangdong 510632, People's Republic of China, and bSchool of Chemistry and the Environment, South China Normal University, Guangzhou, Guangdong 510631, People's Republic of China
*Correspondence e-mail: tlyq@jnu.edu.cn

(Received 29 October 2008; accepted 10 November 2008; online 13 November 2008)

The title Schiff base compound, C13H16N3O+·PF6, was derived from the condensation of 2-hydroxy­benaldehyde with the ionic liquid 1-(2-amino­ethyl)-3-methyl­imidazolium hexa­fluoro­phosphate in an ethanol solution. The asymmetric unit comprises one cation and two PF6 anions. The dihedral angle between the aromatic and imidazole rings is 15.2 (2)°. An intra­molecular O—H⋯N hydrogen bond is found which generates an S(6) ring motif.

Related literature

For the synthesis of Schiff bases, see: Pradeep (2005[Pradeep, C. P. (2005). Acta Cryst. E61, o3825-o3827.]); Butcher et al. (2005[Butcher, R. J., Basu Baul, T. S., Singh, K. S. & Smith, F. E. (2005). Acta Cryst. E61, o1007-o1009.]). For background on ionic liquids and their applications, see: Cai et al. (2006[Cai, Y.-Q., Peng, Y.-Q. & Song, G.-H. (2006). Catal. Lett. 109, 61-64.]); Peng & Song (2006[Peng, Y.-Q. & Song, G.-H. (2006). Catal. Commun. 8, 111-114.]).

[Scheme 1]

Experimental

Crystal data
  • C13H16N3O+·PF6

  • Mr = 375.26

  • Monoclinic, C 2/c

  • a = 28.239 (15) Å

  • b = 7.134 (4) Å

  • c = 18.017 (9) Å

  • β = 118.342 (6)°

  • V = 3194 (3) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.24 mm−1

  • T = 298 (2) K

  • 0.32 × 0.25 × 0.15 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.926, Tmax = 0.965

  • 8091 measured reflections

  • 2969 independent reflections

  • 1965 reflections with I > 2σ(I)

  • Rint = 0.043

Refinement
  • R[F2 > 2σ(F2)] = 0.066

  • wR(F2) = 0.215

  • S = 1.01

  • 2969 reflections

  • 221 parameters

  • H-atom parameters constrained

  • Δρmax = 0.72 e Å−3

  • Δρmin = −0.29 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯N1 0.82 1.85 2.572 (5) 147

Data collection: SMART (Bruker, 1998[Bruker (1998). SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 1999[Bruker (1999). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

The use of functionalized ionic liquids continues to receive attention in chemical synthesis and engineering, including as catalysts in organic synthesis (Cai et al., 2006; Peng & Song, 2006). Schiff base compounds are one of most prevalent mixed-donor ligands in the field of coordination chemistry (Pradeep, 2005; Butcher et al., 2005). Herein, we report the crystal structure of the title salt, (I).

Compound (I) is a Schiff base formed from the reaciton of 2-hydroxybenaldehyde and ionic liquid 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate. The molecular structure of the cation is shown in Fig. 1. The aromatic and imidazole rings form a dihedral angle of 15.2 (2)°. In the cation, an intramolecular O1—H1···N1 hydrogen bond leads to a six-membered ring S(6) motif, Table 1.

Related literature top

For the synthesis of Schiff bases, see: Pradeep (2005); Butcher et al. (2005). For background on ionic liquids and their applications, see: Cai et al. (2006); Peng & Song (2006).

Experimental top

A mixture of the ionic liquid 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate (5 mmol) and 2-hydroxybenzaldehyde (5 mmol) in ethanol was stirred for 4 h. After the completion of the reaction, the excess ethanol was removed by distillation. The colorless solid obtained was filtered and washed with ethanol. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethyl acetate solution of (I) at room temperature.

Refinement top

The H atom bound to O1 was located from a difference Fourier map and refined as riding, with O—H = 0.82 Å, and with Uiso(H) = 1.5 Ueq(O). The remaining H atoms were located in a difference syntheses and refined with C—H = 0.93–0.97 Å, and with Uiso(H) = 1.2 - 1.5Ueq(C)].

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SMART (Bruker, 1998); data reduction: SAINT (Bruker, 1999); 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: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the cation in (I) showing the atom numbering Scheme. Displacement ellipsoids are drawn at the 50% probability level.
1-{2-[(2-hydroxybenzylidene)-amino]-ethyl}-3-methyl-3H-imidazolium hexafluorophosphate top
Crystal data top
C13H16N3O+·PF6F(000) = 1536
Mr = 375.26Dx = 1.561 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2060 reflections
a = 28.239 (15) Åθ = 2.9–22.9°
b = 7.134 (4) ŵ = 0.24 mm1
c = 18.017 (9) ÅT = 298 K
β = 118.342 (6)°Prism, yellow
V = 3194 (3) Å30.32 × 0.25 × 0.15 mm
Z = 8
Data collection top
Bruker SMART CCD area-detector
diffractometer
2969 independent reflections
Radiation source: fine-focus sealed tube1965 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.043
ϕ and ω scansθmax = 25.5°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1934
Tmin = 0.926, Tmax = 0.965k = 88
8091 measured reflectionsl = 2119
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)] = 0.066Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.215H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.095P)2 + 15.5678P]
where P = (Fo2 + 2Fc2)/3
2969 reflections(Δ/σ)max < 0.001
221 parametersΔρmax = 0.72 e Å3
0 restraintsΔρmin = 0.29 e Å3
Crystal data top
C13H16N3O+·PF6V = 3194 (3) Å3
Mr = 375.26Z = 8
Monoclinic, C2/cMo Kα radiation
a = 28.239 (15) ŵ = 0.24 mm1
b = 7.134 (4) ÅT = 298 K
c = 18.017 (9) Å0.32 × 0.25 × 0.15 mm
β = 118.342 (6)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
2969 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1965 reflections with I > 2σ(I)
Tmin = 0.926, Tmax = 0.965Rint = 0.043
8091 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0660 restraints
wR(F2) = 0.215H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.095P)2 + 15.5678P]
where P = (Fo2 + 2Fc2)/3
2969 reflectionsΔρmax = 0.72 e Å3
221 parametersΔρmin = 0.29 e Å3
Special details top

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) top
xyzUiso*/Ueq
P10.75000.75000.00000.0501 (5)
P21.00000.6525 (3)0.25000.0583 (5)
F10.81350 (11)0.7434 (5)0.05733 (18)0.0696 (9)
F20.74441 (13)0.5737 (5)0.04985 (19)0.0742 (9)
F30.74598 (13)0.8887 (5)0.06617 (18)0.0737 (9)
F41.0089 (2)0.5007 (9)0.3170 (3)0.159 (2)
F50.93929 (17)0.6504 (10)0.2199 (4)0.162 (2)
F61.0081 (3)0.8057 (8)0.3156 (3)0.156 (2)
O10.80570 (15)0.2094 (7)0.2303 (3)0.0801 (12)
H10.81370.19730.19230.120*
N10.86812 (17)0.1728 (6)0.1638 (3)0.0551 (10)
N20.86519 (16)0.3299 (5)0.0349 (2)0.0513 (10)
N30.85173 (18)0.3101 (6)0.1622 (3)0.0591 (11)
C10.8504 (2)0.1958 (7)0.3054 (3)0.0566 (12)
C20.8461 (3)0.2063 (8)0.3792 (4)0.0671 (15)
H20.81260.22180.37620.081*
C30.8914 (3)0.1938 (8)0.4566 (4)0.0722 (16)
H30.88820.20280.50550.087*
C40.9408 (3)0.1686 (8)0.4625 (4)0.0719 (16)
H40.97100.15970.51520.086*
C50.9460 (2)0.1563 (7)0.3911 (3)0.0626 (13)
H50.97990.13810.39560.075*
C60.90111 (19)0.1708 (6)0.3114 (3)0.0491 (11)
C70.9077 (2)0.1593 (7)0.2363 (3)0.0536 (12)
H70.94190.14160.24200.064*
C80.8777 (2)0.1599 (7)0.0908 (3)0.0600 (13)
H8A0.85960.05080.05710.072*
H8B0.91600.14750.10950.072*
C90.8567 (2)0.3333 (8)0.0397 (3)0.0634 (14)
H9A0.81850.34500.02170.076*
H9B0.87480.44160.07410.076*
C100.9137 (2)0.3503 (8)0.0329 (3)0.0612 (13)
H100.94660.36860.01500.073*
C110.9053 (2)0.3392 (8)0.1120 (3)0.0627 (13)
H110.93120.34940.12970.075*
C120.8285 (2)0.3056 (7)0.1133 (3)0.0612 (13)
H120.79200.28810.13190.073*
C130.8247 (3)0.2925 (10)0.2541 (3)0.087 (2)
H13A0.78730.26490.27420.131*
H13B0.84100.19300.26990.131*
H13C0.82800.40800.27860.131*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.0469 (10)0.0621 (11)0.0450 (9)0.0109 (8)0.0248 (8)0.0034 (8)
P20.0526 (11)0.0736 (13)0.0541 (10)0.0000.0296 (9)0.000
F10.0422 (16)0.088 (2)0.0708 (19)0.0081 (15)0.0202 (14)0.0014 (16)
F20.084 (2)0.075 (2)0.0696 (19)0.0024 (17)0.0408 (17)0.0159 (16)
F30.084 (2)0.082 (2)0.0611 (18)0.0150 (17)0.0393 (17)0.0107 (15)
F40.181 (5)0.157 (5)0.135 (4)0.002 (4)0.073 (4)0.072 (4)
F50.063 (3)0.243 (7)0.174 (5)0.004 (3)0.051 (3)0.033 (5)
F60.209 (6)0.150 (5)0.108 (4)0.003 (4)0.076 (4)0.052 (3)
O10.055 (2)0.116 (3)0.080 (3)0.006 (2)0.040 (2)0.018 (2)
N10.058 (3)0.061 (2)0.057 (2)0.001 (2)0.035 (2)0.002 (2)
N20.056 (2)0.051 (2)0.046 (2)0.0114 (18)0.0238 (19)0.0029 (17)
N30.069 (3)0.056 (2)0.051 (2)0.004 (2)0.027 (2)0.0005 (19)
C10.062 (3)0.053 (3)0.070 (3)0.009 (2)0.043 (3)0.004 (2)
C20.078 (4)0.063 (3)0.089 (4)0.009 (3)0.062 (4)0.006 (3)
C30.111 (5)0.056 (3)0.077 (4)0.003 (3)0.067 (4)0.005 (3)
C40.092 (4)0.068 (4)0.060 (3)0.007 (3)0.040 (3)0.009 (3)
C50.064 (3)0.063 (3)0.063 (3)0.011 (3)0.033 (3)0.010 (3)
C60.056 (3)0.046 (2)0.053 (3)0.002 (2)0.031 (2)0.003 (2)
C70.057 (3)0.050 (3)0.069 (3)0.005 (2)0.042 (3)0.005 (2)
C80.072 (3)0.061 (3)0.062 (3)0.003 (3)0.044 (3)0.006 (2)
C90.079 (4)0.065 (3)0.057 (3)0.016 (3)0.042 (3)0.003 (2)
C100.049 (3)0.068 (3)0.063 (3)0.003 (2)0.024 (2)0.003 (3)
C110.065 (3)0.067 (3)0.067 (3)0.006 (3)0.040 (3)0.008 (3)
C120.056 (3)0.062 (3)0.066 (3)0.001 (2)0.029 (3)0.005 (3)
C130.105 (5)0.101 (5)0.047 (3)0.002 (4)0.029 (3)0.005 (3)
Geometric parameters (Å, º) top
P1—F1i1.589 (3)C1—C61.396 (7)
P1—F11.589 (3)C2—C31.377 (8)
P1—F31.594 (3)C2—H20.9300
P1—F3i1.594 (3)C3—C41.359 (8)
P1—F2i1.596 (3)C3—H30.9300
P1—F21.596 (3)C4—C51.366 (7)
P2—F5ii1.533 (4)C4—H40.9300
P2—F51.533 (4)C5—C61.398 (7)
P2—F61.544 (5)C5—H50.9300
P2—F6ii1.544 (5)C6—C71.454 (6)
P2—F4ii1.550 (5)C7—H70.9300
P2—F41.550 (5)C8—C91.487 (7)
O1—C11.346 (6)C8—H8A0.9700
O1—H10.8200C8—H8B0.9700
N1—C71.256 (6)C9—H9A0.9700
N1—C81.467 (6)C9—H9B0.9700
N2—C121.308 (6)C10—C111.333 (7)
N2—C101.360 (6)C10—H100.9300
N2—C91.474 (6)C11—H110.9300
N3—C121.324 (6)C12—H120.9300
N3—C111.360 (7)C13—H13A0.9600
N3—C131.464 (6)C13—H13B0.9600
C1—C21.392 (7)C13—H13C0.9600
F1i—P1—F1180.00 (12)C1—C2—H2119.9
F1i—P1—F390.50 (16)C4—C3—C2120.9 (5)
F1—P1—F389.50 (16)C4—C3—H3119.6
F1i—P1—F3i89.50 (16)C2—C3—H3119.6
F1—P1—F3i90.50 (16)C3—C4—C5120.1 (6)
F3—P1—F3i180.0 (2)C3—C4—H4120.0
F1i—P1—F2i89.62 (17)C5—C4—H4120.0
F1—P1—F2i90.38 (17)C4—C5—C6120.8 (5)
F3—P1—F2i89.60 (17)C4—C5—H5119.6
F3i—P1—F2i90.40 (17)C6—C5—H5119.6
F1i—P1—F290.38 (17)C1—C6—C5119.1 (4)
F1—P1—F289.62 (17)C1—C6—C7121.1 (5)
F3—P1—F290.40 (17)C5—C6—C7119.8 (4)
F3i—P1—F289.60 (17)N1—C7—C6121.3 (4)
F2i—P1—F2180.0 (2)N1—C7—H7119.4
F5ii—P2—F5178.9 (5)C6—C7—H7119.4
F5ii—P2—F690.1 (4)N1—C8—C9108.2 (4)
F5—P2—F690.7 (3)N1—C8—H8A110.1
F5ii—P2—F6ii90.7 (3)C9—C8—H8A110.1
F5—P2—F6ii90.1 (3)N1—C8—H8B110.1
F6—P2—F6ii89.9 (5)C9—C8—H8B110.1
F5ii—P2—F4ii90.6 (3)H8A—C8—H8B108.4
F5—P2—F4ii88.6 (3)N2—C9—C8111.1 (4)
F6—P2—F4ii179.0 (4)N2—C9—H9A109.4
F6ii—P2—F4ii89.3 (3)C8—C9—H9A109.4
F5ii—P2—F488.6 (3)N2—C9—H9B109.4
F5—P2—F490.6 (3)C8—C9—H9B109.4
F6—P2—F489.3 (3)H9A—C9—H9B108.0
F6ii—P2—F4179.0 (4)C11—C10—N2107.4 (5)
F4ii—P2—F491.4 (5)C11—C10—H10126.3
C1—O1—H1109.5N2—C10—H10126.3
C7—N1—C8118.3 (4)C10—C11—N3107.3 (5)
C12—N2—C10108.3 (4)C10—C11—H11126.4
C12—N2—C9126.8 (5)N3—C11—H11126.4
C10—N2—C9124.9 (4)N2—C12—N3109.1 (5)
C12—N3—C11107.9 (4)N2—C12—H12125.5
C12—N3—C13126.4 (5)N3—C12—H12125.5
C11—N3—C13125.7 (5)N3—C13—H13A109.5
O1—C1—C2119.5 (5)N3—C13—H13B109.5
O1—C1—C6121.6 (4)H13A—C13—H13B109.5
C2—C1—C6118.9 (5)N3—C13—H13C109.5
C3—C2—C1120.3 (5)H13A—C13—H13C109.5
C3—C2—H2119.9H13B—C13—H13C109.5
O1—C1—C2—C3179.6 (5)C7—N1—C8—C9123.0 (5)
C6—C1—C2—C30.6 (8)C12—N2—C9—C8107.3 (6)
C1—C2—C3—C40.9 (8)C10—N2—C9—C872.1 (7)
C2—C3—C4—C50.4 (9)N1—C8—C9—N2179.9 (4)
C3—C4—C5—C60.5 (9)C12—N2—C10—C110.5 (6)
O1—C1—C6—C5179.6 (5)C9—N2—C10—C11180.0 (5)
C2—C1—C6—C50.3 (7)N2—C10—C11—N30.6 (6)
O1—C1—C6—C70.3 (7)C12—N3—C11—C100.5 (6)
C2—C1—C6—C7179.9 (5)C13—N3—C11—C10178.9 (5)
C4—C5—C6—C10.8 (8)C10—N2—C12—N30.1 (6)
C4—C5—C6—C7179.3 (5)C9—N2—C12—N3179.6 (4)
C8—N1—C7—C6180.0 (4)C11—N3—C12—N20.2 (6)
C1—C6—C7—N10.5 (7)C13—N3—C12—N2178.6 (5)
C5—C6—C7—N1179.7 (5)
Symmetry codes: (i) x+3/2, y+3/2, z; (ii) x+2, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.821.852.572 (5)147

Experimental details

Crystal data
Chemical formulaC13H16N3O+·PF6
Mr375.26
Crystal system, space groupMonoclinic, C2/c
Temperature (K)298
a, b, c (Å)28.239 (15), 7.134 (4), 18.017 (9)
β (°) 118.342 (6)
V3)3194 (3)
Z8
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.32 × 0.25 × 0.15
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.926, 0.965
No. of measured, independent and
observed [I > 2σ(I)] reflections
8091, 2969, 1965
Rint0.043
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.066, 0.215, 1.01
No. of reflections2969
No. of parameters221
H-atom treatmentH-atom parameters constrained
w = 1/[σ2(Fo2) + (0.095P)2 + 15.5678P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)0.72, 0.29

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.821.852.572 (5)147
 

Acknowledgements

We are grateful to the National Natural Science Foundation of China (No. 20672046) and the Guangdong Natural Science Foundation (No. 04010458) for financial support.

References

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