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ISSN: 2056-9890

Bis(3-methyl­anilinium) sulfate

aDepartment of Chemistry, University of Pretoria, Pretoria 0002, South Africa
*Correspondence e-mail: melanie.rademeyer@up.ac.za

(Received 28 October 2011; accepted 30 October 2011; online 5 November 2011)

In the crystal structure of the title salt, 2C7H7NH3+·SO42−, the cations inter­act with the oxyanions through strong charge-assisted N—H⋯O hydrogen bonds.

Related literature

The crystal structure of m-toluidinium nitrate (Rademeyer & Liles, 2010[Rademeyer, M. & Liles, D. C. (2010). Acta Cryst. E66, o1685.]), and the structures of three related phosphate salts, namely bis­(m-toluidinium) dihydrogen diphosphate (Akriche & Rzaigui, 2000[Akriche, S. & Rzaigui, M. (2000). Mater. Res. Bull. 35, 2545-2553.]), tetra­kis­(m-toluidinium) cyclo­tetra­phosphate (Aloui et al., 2005[Aloui, S., Abid, S. & Rzaiguim, M. (2005). Z. Kristallogr. New Cryst. Struct. 220, 409-410.]), and hexa­kis­(m-toluidin­ium) cyclo­hexa­phosphate (Marouni et al., 2000[Marouani, H., Rzaigui, M. & Bagieu-Beucher, M. (2000). Acta Cryst. C56, 356-357.]), have been reported. For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For the most common coordination numbers for the sulfate anion, see: Chertanova & Pascard (1996[Chertanova, L. & Pascard, C. (1996). Acta Cryst. B52, 677-684.]).

[Scheme 1]

Experimental

Crystal data
  • 2C7H10N+·SO42−

  • Mr = 312.23

  • Monoclinic, C 2/c

  • a = 17.2168 (8) Å

  • b = 15.0298 (7) Å

  • c = 6.1283 (3) Å

  • β = 110.819 (3)°

  • V = 1482.25 (12) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.24 mm−1

  • T = 293 K

  • 0.23 × 0.22 × 0.20 mm

Data collection
  • Oxford Xcalibur2 diffractometer

  • 7603 measured reflections

  • 2404 independent reflections

  • 1615 reflections with I > 2σ(I)

  • Rint = 0.024

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.135

  • S = 1.04

  • 2404 reflections

  • 104 parameters

  • H-atom parameters constrained

  • Δρmax = 0.31 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯O1 0.89 2.15 2.9384 (19) 147
N1—H1A⋯O2 0.89 2.37 3.0913 (18) 139
N1—H1B⋯O2i 0.89 1.91 2.7997 (18) 173
N1—H1C⋯O1ii 0.89 1.87 2.7531 (19) 173
Symmetry codes: (i) [-x, y, -z-{\script{1\over 2}}]; (ii) [x, -y, z-{\script{1\over 2}}].

Data collection: CrysAlis CCD (Oxford Diffraction, 2006[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]); cell refinement: CrysAlis RED (Oxford Diffraction, 2006[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]); data reduction: CrysAlis RED; 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: Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Nitrate, sulfate and phosphate anions are important oxyanions in biological processes, the pharmaceutical industry and play a role in freshwater and soil quality. A fundamental understanding of the role of oxyanion geometry on the molecular packing and non-covalent interactions in salt crystal structures is central to the fields of both molecular recognition and crystal engineering.

The molecular geometry and labelling scheme of bis(m-toluidinium) sulfate, I, is illustrated in Fig. 1. The asymmetric unit of I consists of one m-toluidinium cation and half a sulfate anion, with the S atom on a special position, and the rest of the sulfate anion generated by symmetry. A layered structure, consisting of alternating organic and inorganic layers, is exhibited by I. The organic layers contain the hydrophobic part of the cation, while the inorganic layers comprise the ammonium groups and sulfate anions.

Fig. 2 (a) shows the molecular packing of I, viewed down the c-axis. Pairs of m-toluidinium cations alternate in orientation, and the aromatic groups do not pack in a single row, but forms a sinosoidal wave.

In this structure four cations point to a pair of anions, which places the sulfate anions in a pocket created by ammonium groups. Each sulfate anion accepts six hydrogen bonds from six different cations. This high coordination number indicates the important cohesive role of the sulfate anions in the structure. It has been reported by Chertanova and Pascard (1996) that the most common coordination numbers of the sulfate anion are eight to ten. In I each ammonium group is hydrogen bonded to three different sulfate anions, with hydrogen bonding interactions listed in Table 1. The interactions result in a pseudo-one-dimensional hydrogen bonded ribbon extending along the c-direction, which can be described by the graph set notation R44(12) (Bernstein, 1995). Hydrogen bonding interactions are illustrated in Fig. 2 (b). Pairs of cations interact through aromatic interactions in a slipped, head-to-tail fashion, with a centroid-to-centroid distance of 3.6025 (9) Å. Planes through neigbouring cation pairs intersect at an angle of 58°.

Related literature top

The crystal structure of m-toluidinium nitrate (Rademeyer & Liles, 2010), and the structures of three related phosphate salts, namely bis(m-toluidinium) dihydrogen diphosphate (Akriche & Rzaigui, 2000), tetrakis(m-toluidinium) cyclotetraphosphate (Aloui et al., 2005), and hexakis(m-toluidinium) cyclohexaphosphate (Marouni et al., 2000), have been reported.

For related literature, see: Bernstein et al. (1995); Chertanova & Pascard (1996).

Experimental top

Bis(m-toluidinium) sulfate was prepared by the dropwise addition of excess concentrated sulfuric acid (0.35 ml, 98%, Aldrich) to a solution of m-toluidine (0.50 ml, 99%, Aldrich) in 20 ml chloroform (99%, Saarchem). The resulting precipitate was filtered, dried in air and re-crystallized from distilled water. Colourless crystals formed on evaporation, open to the air, at room temperature.

Refinement top

All H atoms were refined using a riding model, with C—H distances either 0.93 or 0.96 Å and N—H distances of 0.89 Å, and Uiso(H) = 1.5Ueq(C) or 1.2Ueq(C) or 1.2Ueq(N). The highest residual peak is 0.71 Å from atom O2.

Structure description top

Nitrate, sulfate and phosphate anions are important oxyanions in biological processes, the pharmaceutical industry and play a role in freshwater and soil quality. A fundamental understanding of the role of oxyanion geometry on the molecular packing and non-covalent interactions in salt crystal structures is central to the fields of both molecular recognition and crystal engineering.

The molecular geometry and labelling scheme of bis(m-toluidinium) sulfate, I, is illustrated in Fig. 1. The asymmetric unit of I consists of one m-toluidinium cation and half a sulfate anion, with the S atom on a special position, and the rest of the sulfate anion generated by symmetry. A layered structure, consisting of alternating organic and inorganic layers, is exhibited by I. The organic layers contain the hydrophobic part of the cation, while the inorganic layers comprise the ammonium groups and sulfate anions.

Fig. 2 (a) shows the molecular packing of I, viewed down the c-axis. Pairs of m-toluidinium cations alternate in orientation, and the aromatic groups do not pack in a single row, but forms a sinosoidal wave.

In this structure four cations point to a pair of anions, which places the sulfate anions in a pocket created by ammonium groups. Each sulfate anion accepts six hydrogen bonds from six different cations. This high coordination number indicates the important cohesive role of the sulfate anions in the structure. It has been reported by Chertanova and Pascard (1996) that the most common coordination numbers of the sulfate anion are eight to ten. In I each ammonium group is hydrogen bonded to three different sulfate anions, with hydrogen bonding interactions listed in Table 1. The interactions result in a pseudo-one-dimensional hydrogen bonded ribbon extending along the c-direction, which can be described by the graph set notation R44(12) (Bernstein, 1995). Hydrogen bonding interactions are illustrated in Fig. 2 (b). Pairs of cations interact through aromatic interactions in a slipped, head-to-tail fashion, with a centroid-to-centroid distance of 3.6025 (9) Å. Planes through neigbouring cation pairs intersect at an angle of 58°.

The crystal structure of m-toluidinium nitrate (Rademeyer & Liles, 2010), and the structures of three related phosphate salts, namely bis(m-toluidinium) dihydrogen diphosphate (Akriche & Rzaigui, 2000), tetrakis(m-toluidinium) cyclotetraphosphate (Aloui et al., 2005), and hexakis(m-toluidinium) cyclohexaphosphate (Marouni et al., 2000), have been reported.

For related literature, see: Bernstein et al. (1995); Chertanova & Pascard (1996).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2009) and WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of I, showing the atomic numbering scheme. Displacement ellipsoids are shown at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Symmetry operator i:x, -y, z - 1/2.
[Figure 2] Fig. 2. (a) Packing diagram of I viewed down the c-axis. (b) N—H···O hydrogen bonding network in I.
Bis(3-methylanilinium) sulfate top
Crystal data top
2C7H10N+·SO42F(000) = 664
Mr = 312.23Dx = 1.399 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3393 reflections
a = 17.2168 (8) Åθ = 3.6–32.1°
b = 15.0298 (7) ŵ = 0.24 mm1
c = 6.1283 (3) ÅT = 293 K
β = 110.819 (3)°Block, colourless
V = 1482.25 (12) Å30.23 × 0.22 × 0.20 mm
Z = 4
Data collection top
Oxford Xcalibur2
diffractometer
1615 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.024
Graphite monochromatorθmax = 32.1°, θmin = 3.6°
ω–2θ scansh = 2424
7603 measured reflectionsk = 2120
2404 independent reflectionsl = 88
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)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.135H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0795P)2]
where P = (Fo2 + 2Fc2)/3
2404 reflections(Δ/σ)max = 0.017
104 parametersΔρmax = 0.31 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
2C7H10N+·SO42V = 1482.25 (12) Å3
Mr = 312.23Z = 4
Monoclinic, C2/cMo Kα radiation
a = 17.2168 (8) ŵ = 0.24 mm1
b = 15.0298 (7) ÅT = 293 K
c = 6.1283 (3) Å0.23 × 0.22 × 0.20 mm
β = 110.819 (3)°
Data collection top
Oxford Xcalibur2
diffractometer
1615 reflections with I > 2σ(I)
7603 measured reflectionsRint = 0.024
2404 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.135H-atom parameters constrained
S = 1.04Δρmax = 0.31 e Å3
2404 reflectionsΔρmin = 0.27 e Å3
104 parameters
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
N10.11567 (8)0.10113 (10)0.1357 (2)0.0333 (3)
H1A0.10020.11710.01740.053 (6)*
H1B0.08680.13210.26240.057 (6)*
H1C0.10610.04330.16410.054 (6)*
C10.20457 (9)0.11906 (9)0.0750 (3)0.0280 (3)
C20.23035 (10)0.16302 (11)0.2339 (3)0.0361 (4)
H20.19280.17860.38010.043 (5)*
C30.31438 (10)0.18371 (12)0.1699 (3)0.0417 (4)
H30.33320.21380.27410.081 (7)*
C40.36970 (10)0.15994 (11)0.0457 (3)0.0385 (4)
H40.42550.17500.08630.066 (7)*
C50.34354 (9)0.11370 (10)0.2051 (3)0.0325 (3)
C60.25958 (9)0.09370 (10)0.1415 (3)0.0305 (3)
H60.24040.06330.24450.038 (5)*
C70.40487 (11)0.08698 (13)0.4386 (3)0.0490 (5)
H7A0.37580.06150.53130.073*
H7B0.43530.13840.51650.073*
H7C0.44280.04390.41740.073*
S10.00000.13146 (3)0.25000.02700 (17)
O10.07354 (8)0.07574 (8)0.2846 (2)0.0472 (3)
O20.01386 (7)0.18692 (7)0.04230 (19)0.0432 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0271 (6)0.0429 (8)0.0312 (7)0.0030 (6)0.0119 (5)0.0038 (6)
C10.0257 (7)0.0288 (7)0.0318 (7)0.0002 (6)0.0130 (6)0.0036 (6)
C20.0374 (8)0.0407 (9)0.0325 (9)0.0031 (7)0.0154 (7)0.0034 (7)
C30.0415 (9)0.0435 (10)0.0493 (10)0.0004 (7)0.0274 (8)0.0087 (7)
C40.0282 (7)0.0360 (8)0.0545 (10)0.0014 (6)0.0186 (7)0.0015 (7)
C50.0271 (7)0.0273 (7)0.0408 (9)0.0052 (6)0.0093 (6)0.0007 (6)
C60.0296 (7)0.0293 (7)0.0338 (8)0.0000 (6)0.0127 (6)0.0040 (6)
C70.0365 (9)0.0502 (11)0.0515 (12)0.0048 (8)0.0049 (8)0.0068 (8)
S10.0270 (3)0.0297 (3)0.0256 (3)0.0000.0108 (2)0.000
O10.0413 (7)0.0497 (7)0.0526 (8)0.0160 (6)0.0190 (6)0.0040 (6)
O20.0554 (8)0.0420 (7)0.0309 (6)0.0104 (6)0.0137 (5)0.0067 (5)
Geometric parameters (Å, º) top
N1—C11.4659 (17)C4—H40.9299
N1—H1A0.8899C5—C61.390 (2)
N1—H1B0.8901C5—C71.500 (2)
N1—H1C0.8899C6—H60.9299
C1—C21.374 (2)C7—H7A0.9600
C1—C61.382 (2)C7—H7B0.9600
C2—C31.393 (2)C7—H7C0.9600
C2—H20.9300S1—O2i1.4684 (11)
C3—C41.373 (2)S1—O21.4684 (11)
C3—H30.9300S1—O1i1.4692 (12)
C4—C51.397 (2)S1—O11.4692 (12)
C1—N1—H1A109.4C6—C5—C4118.22 (15)
C1—N1—H1B109.5C6—C5—C7121.27 (15)
H1A—N1—H1B109.5C4—C5—C7120.50 (15)
C1—N1—H1C109.5C1—C6—C5119.97 (14)
H1A—N1—H1C109.5C1—C6—H6120.0
H1B—N1—H1C109.5C5—C6—H6120.0
C2—C1—C6121.94 (14)C5—C7—H7A109.5
C2—C1—N1118.66 (14)C5—C7—H7B109.5
C6—C1—N1119.37 (13)H7A—C7—H7B109.5
C1—C2—C3118.21 (15)C5—C7—H7C109.5
C1—C2—H2121.0H7A—C7—H7C109.5
C3—C2—H2120.8H7B—C7—H7C109.5
C4—C3—C2120.56 (15)O2i—S1—O2110.82 (9)
C4—C3—H3119.7O2i—S1—O1i108.34 (7)
C2—C3—H3119.8O2—S1—O1i109.42 (7)
C3—C4—C5121.08 (15)O2i—S1—O1109.42 (7)
C3—C4—H4119.4O2—S1—O1108.34 (7)
C5—C4—H4119.5O1i—S1—O1110.51 (11)
C6—C1—C2—C31.3 (2)C3—C4—C5—C7179.07 (17)
N1—C1—C2—C3176.82 (14)C2—C1—C6—C50.9 (2)
C1—C2—C3—C40.5 (3)N1—C1—C6—C5177.23 (13)
C2—C3—C4—C50.7 (3)C4—C5—C6—C10.3 (2)
C3—C4—C5—C61.2 (3)C7—C5—C6—C1179.89 (15)
Symmetry code: (i) x, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O10.892.152.9384 (19)147
N1—H1A···O20.892.373.0913 (18)139
N1—H1B···O2ii0.891.912.7997 (18)173
N1—H1C···O1iii0.891.872.7531 (19)173
Symmetry codes: (ii) x, y, z1/2; (iii) x, y, z1/2.

Experimental details

Crystal data
Chemical formula2C7H10N+·SO42
Mr312.23
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)17.2168 (8), 15.0298 (7), 6.1283 (3)
β (°) 110.819 (3)
V3)1482.25 (12)
Z4
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.23 × 0.22 × 0.20
Data collection
DiffractometerOxford Xcalibur2
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7603, 2404, 1615
Rint0.024
(sin θ/λ)max1)0.748
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.135, 1.04
No. of reflections2404
No. of parameters104
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.31, 0.27

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006), PLATON (Spek, 2009) and WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O10.892.152.9384 (19)147.2
N1—H1A···O20.892.373.0913 (18)138.6
N1—H1B···O2i0.891.912.7997 (18)172.5
N1—H1C···O1ii0.891.872.7531 (19)172.6
Symmetry codes: (i) x, y, z1/2; (ii) x, y, z1/2.
 

Acknowledgements

Funding received for this work from the University of Pretoria, the University of KwaZulu-Natal and the National Research Foundation (GUN: 2054350) is acknowledged.

References

First citationAkriche, S. & Rzaigui, M. (2000). Mater. Res. Bull. 35, 2545–2553.  Web of Science CSD CrossRef CAS Google Scholar
First citationAloui, S., Abid, S. & Rzaiguim, M. (2005). Z. Kristallogr. New Cryst. Struct. 220, 409–410.  CAS Google Scholar
First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationChertanova, L. & Pascard, C. (1996). Acta Cryst. B52, 677–684.  CrossRef Web of Science IUCr Journals Google Scholar
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First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationMarouani, H., Rzaigui, M. & Bagieu-Beucher, M. (2000). Acta Cryst. C56, 356–357.  CSD CrossRef CAS IUCr Journals Google Scholar
First citationOxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.  Google Scholar
First citationRademeyer, M. & Liles, D. C. (2010). Acta Cryst. E66, o1685.  Web of Science CSD CrossRef IUCr Journals Google Scholar
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First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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