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Acta Crystallogr Sect E Struct Rep Online. 2008 August 1; 64(Pt 8): o1480.
Published online 2008 July 12. doi:  10.1107/S160053680801790X
PMCID: PMC2962110

2,6-Diisopropyl­anilinium chloride

Abstract

The title compound, C12H20N+·Cl, crystallizes with the chloride anions situated on twofold axes, while the cation is on a general position. All conventional hydrogen-bond donors and acceptors are utilized, forming a hydrogen-bonded ladder motif along the c axis. Investigation of the torsion angles between aromatic systems and isopropyl groups reveals unusual geometrical features. One isopropyl groups exhibits an expected eclipsed conformation with respect to the aromatic ring. The other isopropyl group shows a slight twist with respect to the aromatic ring. The short Cl(...)HC(methine) contact (2.88 Å) observed in the asymmetric unit is the probable reason for the twist feature around the isopropyl area.

Related literature

For the structure of the tetra­hydro­furan solvate of the title salt, see: Bond & Doyle (2003 [triangle]).

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Object name is e-64-o1480-scheme1.jpg

Experimental

Crystal data

  • C12H20N+·Cl
  • M r = 213.74
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1480-efi1.jpg
  • a = 13.0390 (3) Å
  • b = 21.0436 (4) Å
  • c = 8.9968 (2) Å
  • V = 2468.61 (9) Å3
  • Z = 8
  • Cu Kα radiation
  • μ = 2.43 mm−1
  • T = 173 (2) K
  • 0.36 × 0.23 × 0.21 mm

Data collection

  • Bruker SMART APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2002 [triangle]) T min = 0.451, T max = 0.597
  • 23541 measured reflections
  • 2343 independent reflections
  • 2248 reflections with I > 2σ(I)
  • R int = 0.028

Refinement

  • R[F 2 > 2σ(F 2)] = 0.037
  • wR(F 2) = 0.112
  • S = 1.00
  • 2343 reflections
  • 144 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.35 e Å−3
  • Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 2006 [triangle]; cell refinement: SAINT (Bruker, 2006 [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/S160053680801790X/bh2172sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680801790X/bh2172Isup2.hkl

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

Acknowledgments

The authors acknowledge Jon Bordner for his crystallographic mentoring and support.

supplementary crystallographic information

Comment

2,6-DIPA chloride is frequently used as a starting material for pharmaceutical synthesis. Hydrochloric acid is a desirable acid for salt formation and during our efforts to purify DIPA by salt formation and crystallization, we formed the title 1:1 salt (Fig. 1). Chlorine anions have an interesting 50:50 occupancy positions, sitting on 2-fold axis with x,y,z coordinates as follows: Cl1X (0, y, 1/4) and Cl1Y (0, y, 3/4).

The structure has all conventional hydrogen-bond donors used. In the crystal structure, four of the protonated NH3 groups face the counter-ions sitting on above mentioned special positions, forming two-dimensional sheets parallel to the (010) planes (Fig. 2). Hydrogen-bond network confirms the following interactions between 50% populated Cl- anions and polar ends of DIPAH+ (NH3+ groups): Cl1X participates a hydrogen-bonding interaction with H13X (2.54 Å separation), H13Z (2.35 Å), and H13Y (2.16 Å) are hydrogen-bonded to Cl1X and Cl1Y, respectively. There is an additional short contact within van der Waals radii between Cl1X and H7 (2.88 Å) yet this interaction does not occur with the Cl1Y occupancy.

The torsion angles from the aromatic group to the isopropyl groups are interesting. The expectation is that the isopropyl groups would eclipse the aromatic ring plane so that the C7—H7 and C10—H10 bonds lie in the same plane as atoms N13, C1, C6 and C7. One of these groups exhibits such a conformation (C1—C2—C10—H10 = -0.21°), while the other shows a slight twist (C1—C6—C7—H7 = -34.62°). The above mentioned Cl1X···H7 short contact is the probable reason for the obvious twist event around C1—C6—C7—H7 area. Similar events are observed in a related DIPA chloride salt structure, where only one of isopropyl hydrogen experiences van der Waals contacts with a Cl- anion (Bond & Doyle, 2003).

Experimental

A stock solution of DIPA was made in 2-propanol (85 mg, 2 ml). To a crystallizer vessel, 0.43 ml of stock solution was added with 1 equivalent of concentrated hydrochloric acid. For salt formation participation we gradually added 6 ml of methyl t-butyl ether, then the sample was purged with dry nitrogen for evaporation until dryness, allowed to evaporate over 24 h mark. A crystal of the title salt was removed from the crystallizer vessel and mounted on a MiTeGen loop with Paratone-N oil.

Refinement

H atoms bonded to C atoms were placed in idealized positions and refined using a riding model with C—H = 0.93 Å for Csp2—H, 0.96 Å for CH3, and 0.98 Å for CH. Uiso(H) values were fixed to 0.08 Å2. H atoms bound to N3 were located in a difference maps and their positions and isotropic displacement parameters were refined freely.

Figures

Fig. 1.
View of the constituents of (I), showing the atom-labeling scheme and displacement ellipsoids drawn at the 30% probability level. H atoms are represented by circles of arbitrary size.
Fig. 2.
The crystal structure viewed along the [001] direction, showing four Cl- anions spaced between four DIPA+ cations.

Crystal data

C12H20N+·ClF000 = 928
Mr = 213.74Dx = 1.150 Mg m3
Orthorhombic, PbcnCu Kα radiation λ = 1.54178 Å
Hall symbol: -P 2n 2abCell parameters from 9259 reflections
a = 13.0390 (3) Åθ = 4.0–70.8º
b = 21.0436 (4) ŵ = 2.43 mm1
c = 8.9968 (2) ÅT = 173 (2) K
V = 2468.61 (9) Å3Prism, colourless
Z = 80.36 × 0.23 × 0.21 mm

Data collection

Bruker SMART APEXII CCD diffractometer2343 independent reflections
Radiation source: Rotating Anode2248 reflections with I > 2σ(I)
Monochromator: Montel Multilayer OpticsRint = 0.028
T = 173(2) Kθmax = 71.7º
[var phi] and ω scansθmin = 4.0º
Absorption correction: multi-scan(SADABS; Sheldrick, 2002)h = −15→15
Tmin = 0.451, Tmax = 0.597k = −25→20
23541 measured reflectionsl = −10→9

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.037H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.112  w = 1/[σ2(Fo2) + (0.0758P)2 + 1.0624P] where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max = 0.029
2343 reflectionsΔρmax = 0.35 e Å3
144 parametersΔρmin = −0.21 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
C10.79245 (10)0.88741 (6)0.98360 (14)0.0207 (3)
C20.77502 (10)0.84000 (6)1.08919 (15)0.0238 (3)
C30.67345 (11)0.82064 (6)1.11109 (16)0.0276 (3)
H30.65920.78911.18060.080*
C40.59411 (11)0.84748 (7)1.03134 (17)0.0296 (3)
H40.52710.83411.04760.080*
C50.61414 (10)0.89426 (7)0.92708 (16)0.0276 (3)
H50.56010.91190.87380.080*
C60.71389 (11)0.91548 (6)0.90040 (15)0.0229 (3)
C70.73500 (11)0.96575 (6)0.78298 (16)0.0250 (3)
H70.79310.99130.81790.080*
C80.64526 (13)1.01091 (8)0.75817 (17)0.0356 (4)
H8A0.59160.98910.70590.080*
H8B0.66781.04670.70050.080*
H8C0.61991.02540.85240.080*
C90.76786 (13)0.93367 (8)0.63763 (16)0.0357 (4)
H9A0.82420.90540.65680.080*
H9B0.78870.96550.56740.080*
H9C0.71130.91000.59770.080*
C100.85921 (11)0.80846 (6)1.17924 (16)0.0276 (3)
H100.92490.82711.14930.080*
C110.84443 (14)0.82083 (9)1.34518 (18)0.0418 (4)
H11A0.84560.86581.36350.080*
H11B0.89870.80081.39990.080*
H11C0.77970.80371.37640.080*
C120.86270 (15)0.73722 (8)1.1448 (2)0.0491 (5)
H12A0.79920.71791.17420.080*
H12B0.91820.71801.19850.080*
H12C0.87290.73111.04010.080*
N130.89957 (8)0.90795 (6)0.95727 (13)0.0218 (3)
H13X0.9045 (14)0.9424 (9)0.899 (2)0.034 (5)*
H13Y0.9357 (15)0.8761 (9)0.908 (2)0.036 (4)*
H13Z0.9318 (14)0.9187 (8)1.045 (2)0.030 (4)*
Cl1X1.00000.97357 (2)1.25000.02472 (17)
Cl1Y1.00000.80980 (2)0.75000.03006 (18)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0213 (6)0.0208 (6)0.0200 (6)−0.0023 (4)0.0011 (5)−0.0029 (5)
C20.0270 (7)0.0224 (6)0.0221 (7)−0.0008 (5)0.0012 (5)−0.0014 (5)
C30.0306 (7)0.0243 (6)0.0279 (7)−0.0061 (5)0.0033 (6)0.0016 (5)
C40.0244 (7)0.0315 (7)0.0329 (8)−0.0085 (5)0.0015 (6)−0.0022 (6)
C50.0238 (7)0.0307 (7)0.0282 (7)−0.0025 (5)−0.0039 (5)−0.0015 (6)
C60.0255 (7)0.0229 (6)0.0204 (7)−0.0018 (5)−0.0013 (5)−0.0023 (5)
C70.0247 (7)0.0267 (7)0.0237 (6)−0.0012 (5)−0.0028 (5)0.0032 (5)
C80.0318 (8)0.0357 (8)0.0392 (9)0.0041 (7)−0.0018 (6)0.0106 (6)
C90.0462 (9)0.0374 (8)0.0235 (7)−0.0010 (7)0.0013 (6)0.0029 (6)
C100.0296 (7)0.0275 (7)0.0258 (7)−0.0001 (5)−0.0005 (6)0.0059 (5)
C110.0436 (9)0.0560 (10)0.0259 (8)−0.0009 (7)−0.0025 (7)0.0044 (7)
C120.0539 (11)0.0319 (8)0.0614 (12)0.0133 (7)−0.0163 (9)−0.0029 (8)
N130.0217 (6)0.0230 (6)0.0208 (6)−0.0015 (4)0.0001 (4)0.0008 (5)
Cl1X0.0248 (3)0.0249 (3)0.0244 (3)0.000−0.00197 (15)0.000
Cl1Y0.0339 (3)0.0247 (3)0.0315 (3)0.0000.00491 (17)0.000

Geometric parameters (Å, °)

C1—C21.3962 (18)C8—H8C0.9600
C1—C61.3994 (19)C9—H9A0.9600
C1—N131.4812 (16)C9—H9B0.9600
C2—C31.3996 (19)C9—H9C0.9600
C2—C101.5171 (19)C10—C111.528 (2)
C3—C41.380 (2)C10—C121.532 (2)
C3—H30.9300C10—H100.9800
C4—C51.385 (2)C11—H11A0.9600
C4—H40.9300C11—H11B0.9600
C5—C61.3959 (19)C11—H11C0.9600
C5—H50.9300C12—H12A0.9600
C6—C71.5202 (19)C12—H12B0.9600
C7—C81.524 (2)C12—H12C0.9600
C7—C91.533 (2)N13—H13X0.90 (2)
C7—H70.9800N13—H13Y0.93 (2)
C8—H8A0.9600N13—H13Z0.921 (19)
C8—H8B0.9600
C2—C1—C6123.12 (12)C7—C9—H9A109.5
C2—C1—N13118.08 (11)C7—C9—H9B109.5
C6—C1—N13118.79 (11)H9A—C9—H9B109.5
C1—C2—C3117.24 (12)C7—C9—H9C109.5
C1—C2—C10123.93 (12)H9A—C9—H9C109.5
C3—C2—C10118.83 (12)H9B—C9—H9C109.5
C4—C3—C2121.14 (13)C2—C10—C11110.86 (12)
C4—C3—H3119.4C2—C10—C12109.97 (12)
C2—C3—H3119.4C11—C10—C12111.61 (14)
C3—C4—C5120.12 (13)C2—C10—H10108.1
C3—C4—H4119.9C11—C10—H10108.1
C5—C4—H4119.9C12—C10—H10108.1
C4—C5—C6121.31 (13)C10—C11—H11A109.5
C4—C5—H5119.3C10—C11—H11B109.5
C6—C5—H5119.3H11A—C11—H11B109.5
C5—C6—C1117.07 (12)C10—C11—H11C109.5
C5—C6—C7120.72 (12)H11A—C11—H11C109.5
C1—C6—C7122.20 (12)H11B—C11—H11C109.5
C6—C7—C8113.37 (12)C10—C12—H12A109.5
C6—C7—C9109.69 (11)C10—C12—H12B109.5
C8—C7—C9111.36 (12)H12A—C12—H12B109.5
C6—C7—H7107.4C10—C12—H12C109.5
C8—C7—H7107.4H12A—C12—H12C109.5
C9—C7—H7107.4H12B—C12—H12C109.5
C7—C8—H8A109.5C1—N13—H13X113.4 (11)
C7—C8—H8B109.5C1—N13—H13Y110.0 (12)
H8A—C8—H8B109.5H13X—N13—H13Y105.1 (16)
C7—C8—H8C109.5C1—N13—H13Z111.5 (11)
H8A—C8—H8C109.5H13X—N13—H13Z105.7 (15)
H8B—C8—H8C109.5H13Y—N13—H13Z110.9 (16)
C6—C1—C2—C3−0.23 (19)N13—C1—C6—C5179.19 (11)
N13—C1—C2—C3−179.18 (11)C2—C1—C6—C7−178.28 (12)
C6—C1—C2—C10179.28 (12)N13—C1—C6—C70.66 (18)
N13—C1—C2—C100.33 (19)C5—C6—C7—C828.51 (18)
C1—C2—C3—C40.0 (2)C1—C6—C7—C8−153.01 (13)
C10—C2—C3—C4−179.55 (13)C5—C6—C7—C9−96.67 (15)
C2—C3—C4—C50.2 (2)C1—C6—C7—C981.80 (16)
C3—C4—C5—C6−0.2 (2)C1—C2—C10—C11118.08 (15)
C4—C5—C6—C10.0 (2)C3—C2—C10—C11−62.42 (16)
C4—C5—C6—C7178.53 (13)C1—C2—C10—C12−118.01 (16)
C2—C1—C6—C50.25 (19)C3—C2—C10—C1261.49 (18)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N13—H13X···Cl1Xi0.90 (2)2.54 (2)3.3777 (12)154.7 (15)
N13—H13Y···Cl1Y0.93 (2)2.16 (2)3.0753 (12)167.2 (16)
N13—H13Z···Cl1X0.921 (19)2.352 (19)3.2493 (12)164.8 (14)

Symmetry codes: (i) −x+2, −y+2, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BH2172).

References

  • Bond, A. D. & Doyle, E. L. (2003). Chem. Commun. pp. 2324–2325. [PubMed]
  • Bruker (2006). SMART for WNT/2000 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Sheldrick, G. M. (2002). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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