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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.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536808037124/tk2322sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536808037124/tk2322Isup2.hkl
Contains datablock I

CCDC reference: 712469

Key indicators

  • Single-crystal X-ray study
  • T = 298 K
  • Mean [sigma](C-C) = 0.009 Å
  • R factor = 0.066
  • wR factor = 0.215
  • Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level C Value of measurement temperature given = 298.000 Value of melting point given = 0.000 SHFSU01_ALERT_2_C Test not performed. _refine_ls_shift/su_max and _refine_ls_shift/esd_max not present. Absolute value of the parameter shift to su ratio given 0.001 PLAT083_ALERT_2_C SHELXL Second Parameter in WGHT unusually Large. 16.00 PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density .... 2.48 PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ... 9 PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT234_ALERT_4_C Large Hirshfeld Difference N2 -- C12 .. 0.11 Ang. PLAT244_ALERT_4_C Low 'Solvent' Ueq as Compared to Neighbors for P1 PLAT244_ALERT_4_C Low 'Solvent' Ueq as Compared to Neighbors for P2
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 8 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 3 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 3 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

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
 

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