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Acta Cryst. (2008). E64, o2159    [ doi:10.1107/S1600536808033965 ]

1,3-Bis(4-methoxyphenyl)imidazolidium chloride monohydrate

Y. Wan, H. Xin, X. Chen, H. Xu and H. Wu

Abstract top

The asymmetric unit of the title compound, C17H17N2O2+·Cl-·H2O, contains one-half of the cation, one-half of a water molecule and a chloride anion. The complete cation is generated by crystallographic two-fold symmetry, with one C atom lying on the rotation axis. The O and Cl atoms have site symmetry 2. The imidazolidium ring is oriented at a dihedral angle of 4.15 (3)° with respect to the 4-methoxyphenyl ring and an intramolecular C-H...O interaction occurs. In the crystal structure, intermolecular O-H...Cl and C-H...Cl hydrogen bonds link the molecules. There is a [pi]-[pi] contact between the imidazolidium and 4-methoxyphenyl rings [centroid-to-centroid distance = 3.625(3 Å]. There is also a C-H...[pi] contact between the methyl group and the 4-methoxyphenyl ring.

Comment top

Imidazole and its derivatives such as imidazolium cation are important compounds playing important roles in medical, organic and material chemistry (Lin & Vasam, 2005). A broad application of imidazolium now is to synthesize ionic liquids. Recently, ionic liquids are attracting much attention as alternative reaction media for synthesis and catalysis. Its applications in many different areas including separation processes, catalyst, electrochemistry, electrolytes in solar cells and lubricants are widely recognized. Therefore, the need of ionic liquids with specific chemical and physical properties become stronger. We report herein the synthesis and crystal structure of the title compound.

The asymmetric unit of the title compound (Fig. 1) contains one half-molecule, one half-water molecule and a chloride atom. The bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings A (N1/N1'/C1/C2/C2') and B (C3–C8) are, of course, planar and the dihedral angle between them is A/B = 4.15 (3)° [symmetry code: (') -x, y, -z]. Intramolecular C—H···O and O—H···Cl hydrogen bonds (Table 1) link the molecules.

In the crystal structure, intramolecular C—H···O and O—H···Cl and intermolecular C—H···Cl hydrogen bonds (Table 1) link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure. The π–π contact between the imidazolidium and 4-methoxyphenyl rings, Cg1···Cg2i [symmetry code: (i) 1 - x, y, 1 - z, where Cg1 and Cg2 are the centroids of the rings A (N1/N1'/C1/C2/C2') and B (C3–C8), respectively] may further stabilize the structure, with centroid-centroid distance of 3.625 (3) Å. There also exist a C—H···π contact (Table 1) between the methyl group and the 4-methoxyphenyl ring.

Related literature top

For general background, see: Lin & Vasam (2005). For bond-length data, see: Allen et al. (1987).

Experimental top

The reaction of 4-methoxybenzenamine (2 mmol) with formaldehyde (aq. 37%, 1 mmol) and glyoxal (aq. 40%, 1 mmol) in ethanol (95%) at 273–278 K for 8 h afforded 1-(2,3-diethoxy-4-(4-methoxyphenyl)cyclopentyl)-4-methoxybenzene (yield; 89%). The title compound was obtained through the oxidization of 1-(2,3-diethoxy-4-(4-methoxyphenyl)cyclopentyl)-4-methoxybenzene by phosgene in DMF at 268–273 K (yield 95%).

Refinement top

H atoms were positioned geometrically, with O—H = 0.85 Å (for H2O) and C—H = 0.93 and 0.96 Å for aromatic and methyl H, respectively, and constrained to ride on their parent atoms with Uiso(H) = xUeq(C,O), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); 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: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme [symmetry code: (') -x, y, -z].
[Figure 2] Fig. 2. A partial packing diagram. Hydrogen bonds are shown as dashed lines.
1,3-Bis(4-methoxyphenyl)imidazolidium chloride monohydrate top
Crystal data top
C17H17N2O2+·Cl−·H2OF(000) = 352
Mr = 334.79Dx = 1.394 Mg m−3
Monoclinic, C2Melting point = 492–494 K
Hall symbol: -C 2yMo Kα radiation, λ = 0.71073 Å
a = 15.6706 (19) ÅCell parameters from 1340 reflections
b = 9.4198 (9) Åθ = 2.5–28.3°
c = 5.4026 (4) ŵ = 0.26 mm−1
β = 90.156 (1)°T = 298 K
V = 797.50 (14) Å3Block, colourless
Z = 20.20 × 0.11 × 0.09 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer		749 independent reflections
Radiation source: fine-focus sealed tube688 reflections with I > 2σ(I)
graphiteRint = 0.021
φ and ω scansθmax = 25.0°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −18→13
Tmin = 0.951, Tmax = 0.977k = −9→11
2026 measured reflectionsl = −6→6
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)] = 0.029Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.076H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0503P)2 + 0.1521P]
where P = (Fo2 + 2Fc2)/3
749 reflections(Δ/σ)max < 0.001
107 parametersΔρmax = 0.11 e Å−3
1 restraintΔρmin = −0.22 e Å−3
Crystal data top
C17H17N2O2+·Cl−·H2OV = 797.50 (14) Å3
Mr = 334.79Z = 2
Monoclinic, C2Mo Kα radiation
a = 15.6706 (19) ŵ = 0.26 mm−1
b = 9.4198 (9) ÅT = 298 K
c = 5.4026 (4) Å0.20 × 0.11 × 0.09 mm
β = 90.156 (1)°
Data collection top
Bruker SMART CCD area-detector
diffractometer		749 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		688 reflections with I > 2σ(I)
Tmin = 0.951, Tmax = 0.977Rint = 0.021
2026 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.029H-atom parameters constrained
wR(F2) = 0.076Δρmax = 0.11 e Å−3
S = 1.01Δρmin = −0.22 e Å−3
749 reflectionsAbsolute structure: ?
107 parametersFlack parameter: ?
1 restraintRogers parameter: ?
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
Cl10.50000.84927 (12)0.50000.0800 (5)
O10.24434 (13)0.4740 (2)0.9080 (3)0.0519 (5)
O20.50000.6808 (3)0.00000.0567 (8)
H20.50000.73350.12770.068*
N10.45802 (12)0.27396 (19)0.1594 (3)0.0334 (5)
C10.50000.3560 (4)0.00000.0350 (7)
H10.50000.45470.00000.042*
C20.47435 (17)0.1342 (3)0.0983 (5)0.0444 (6)
H2A0.45340.05450.17950.053*
C30.40340 (14)0.3225 (3)0.3567 (4)0.0335 (5)
C40.39574 (17)0.4670 (3)0.4036 (5)0.0420 (6)
H40.42620.53220.30940.050*
C50.34270 (17)0.5135 (3)0.5903 (5)0.0449 (6)
H50.33780.61010.62250.054*
C60.29642 (15)0.4164 (3)0.7309 (5)0.0386 (6)
C70.30558 (17)0.2728 (3)0.6859 (5)0.0446 (6)
H70.27580.20730.78120.054*
C80.35934 (16)0.2262 (3)0.4979 (5)0.0440 (6)
H80.36540.12960.46780.053*
C90.19340 (19)0.3780 (4)1.0497 (5)0.0580 (8)
H9A0.15880.32190.94020.087*
H9B0.15730.43091.15940.087*
H9C0.22990.31681.14470.087*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.1591 (13)0.0423 (5)0.0387 (5)0.0000.0069 (6)0.000
O10.0545 (11)0.0522 (12)0.0491 (11)0.0011 (9)0.0158 (9)0.0059 (9)
O20.092 (2)0.0344 (15)0.0434 (14)0.0000.0109 (14)0.000
N10.0365 (11)0.0278 (10)0.0358 (10)−0.0015 (8)−0.0027 (8)0.0024 (8)
C10.0400 (18)0.0271 (15)0.0379 (15)0.0000.0009 (14)0.000
C20.0572 (16)0.0300 (13)0.0461 (13)−0.0031 (11)0.0030 (11)0.0012 (11)
C30.0319 (12)0.0362 (13)0.0323 (10)−0.0010 (10)−0.0018 (9)0.0024 (10)
C40.0473 (15)0.0333 (14)0.0455 (14)−0.0024 (11)0.0086 (11)0.0080 (11)
C50.0510 (15)0.0339 (13)0.0499 (14)0.0029 (12)0.0085 (11)0.0012 (12)
C60.0356 (14)0.0442 (15)0.0360 (12)−0.0008 (11)0.0001 (11)0.0027 (11)
C70.0480 (15)0.0421 (16)0.0438 (14)−0.0081 (12)0.0045 (11)0.0072 (12)
C80.0518 (16)0.0319 (13)0.0484 (15)−0.0044 (12)0.0012 (13)0.0019 (12)
C90.0485 (16)0.069 (2)0.0566 (16)−0.0036 (14)0.0137 (13)0.0109 (15)
Geometric parameters (Å, °) top
O1—C61.371 (3)C4—C51.380 (4)
O1—C91.430 (3)C4—H40.9300
O2—H20.8500C5—C61.394 (4)
N1—C11.332 (3)C5—H50.9300
N1—C21.382 (3)C6—C71.382 (4)
N1—C31.443 (3)C7—C81.392 (4)
C1—N1i1.332 (3)C7—H70.9300
C1—H10.9300C8—H80.9300
C2—C2i1.334 (5)C9—H9A0.9600
C2—H2A0.9300C9—H9B0.9600
C3—C81.372 (3)C9—H9C0.9600
C3—C41.390 (4)
C6—O1—C9117.2 (2)C4—C5—H5119.8
C1—N1—C2107.8 (2)C6—C5—H5119.8
C1—N1—C3126.1 (2)O1—C6—C7124.9 (2)
C2—N1—C3126.1 (2)O1—C6—C5115.6 (2)
N1i—C1—N1109.1 (3)C7—C6—C5119.5 (2)
N1i—C1—H1125.5C6—C7—C8120.0 (2)
N1—C1—H1125.5C6—C7—H7120.0
C2i—C2—N1107.63 (14)C8—C7—H7120.0
C2i—C2—H2A126.2C3—C8—C7120.2 (2)
N1—C2—H2A126.2C3—C8—H8119.9
C8—C3—C4120.1 (2)C7—C8—H8119.9
C8—C3—N1120.1 (2)O1—C9—H9A109.5
C4—C3—N1119.8 (2)O1—C9—H9B109.5
C5—C4—C3119.8 (2)H9A—C9—H9B109.5
C5—C4—H4120.1O1—C9—H9C109.5
C3—C4—H4120.1H9A—C9—H9C109.5
C4—C5—C6120.4 (2)H9B—C9—H9C109.5
C2—N1—C1—N1i0.12 (13)C3—C4—C5—C6−0.4 (4)
C3—N1—C1—N1i−178.4 (2)C9—O1—C6—C7−2.5 (4)
C1—N1—C2—C2i−0.3 (3)C9—O1—C6—C5177.7 (2)
C3—N1—C2—C2i178.2 (2)C4—C5—C6—O1−178.7 (2)
C1—N1—C3—C8175.65 (18)C4—C5—C6—C71.5 (4)
C2—N1—C3—C8−2.6 (3)O1—C6—C7—C8178.9 (2)
C1—N1—C3—C4−4.5 (3)C5—C6—C7—C8−1.3 (4)
C2—N1—C3—C4177.3 (2)C4—C3—C8—C71.1 (3)
C8—C3—C4—C5−0.9 (4)N1—C3—C8—C7−179.0 (2)
N1—C3—C4—C5179.2 (2)C6—C7—C8—C30.0 (4)
Symmetry codes: (i) −x+1, y, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···Cl10.852.293.133 (3)173
C1—H1···O20.932.133.060 (3)180
C2—H2A···Cl1ii0.932.693.474 (3)142
C4—H4···O20.932.473.391 (3)170
C9—H9C···Cg2iii0.962.913.629 (3)133
Symmetry codes: (ii) x+1/2, y−1/2, z; (iii) x, y, z+1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···Cl10.852.293.133 (3)173
C1—H1···O20.932.133.060 (3)180
C2—H2A···Cl1i0.932.693.474 (3)142
C4—H4···O20.932.473.391 (3)170
C9—H9C···Cg2ii0.962.913.629 (3)133
Symmetry codes: (i) x+1/2, y−1/2, z; (ii) x, y, z+1.
Acknowledgements top

The authors are grateful to the National Natural Science Foundation of China (grant No. 20772103), the Natural Science Foundation of Jiangsu Province (grant No.BK 2007028) and the Surpassing Project of Jiangsu Province (grant No. CX07S_016z) for financial support.

references
References top

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