3-(1H-Indol-3-yl)-2-(2-nitro-benzene-sulfonamido)-propanoic acid including an unknown solvate.

Abstract

In the title compound, C(17)H(15)N(3)O(6)S, which crystallized with highly disordered methanol and/or water solvent mol-ecules, the dihedral angle between the the indole and benzene ring systems is 5.3 (2)°, which allows for the formation of intra-molecular π-π stacking inter-actions [centroid-centroid separations = 3.641 (3) and 3.694 (3) Å] and an approximate overall U-shape for the mol-ecule. In the crystal, dimers linked by pairs of N(s)-H⋯O(c) (s = sulfonamide and c = carboxyl-ate) hydrogen bonds generate R(2) (2)(10) loops, whereas N(i)-H⋯π (i = indole) inter-actions lead to chains propagating in [100] or [010]. Together, these lead to a three-dimensional network in which the solvent voids are present as inter-secting (two-dimensional) systems of [100] and [010] channels. The title compound was found to contain a heavily disordered solvent mol-ecule, which could be methanol or water or a mixture of the two. Due to its uncertain nature and the unresolvable disorder, the data were processed with the SQUEEZE option in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155], which revealed 877.8 Å(3) of solvent-accessible volume per unit cell and 126 electron-units of scattering density or 109.7 Å(3) (16 electron units) per organic mol-ecule.. This was not included in the calculations of overall formula weight, density and absorption coefficient.

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3-(1H-Indol-3-yl)-2-(2-nitrobenzene-
sulfonamido)propanoic acid including an
unknown solvate
Islam Ullah Khan,a* Hafiz Mubashar-ur-Rehman,aSalman
Azizaand William T. A. Harrisonb
aMaterials Chemistry laboratory, Department of Chemistry, GC University, Lahore
54000, Pakistan, andbDepartment of Chemistry, University of Aberdeen, Aberdeen
AB24 3UE, Scotland
Correspondence e-mail: iuklodhi@yahoo.com
Received 19 March 2012; accepted 22 May 2012
Key indicators: single-crystal X-ray study; T = 296 K; mean ?(C–C) = 0.006 A ˚;
R factor = 0.067; wR factor = 0.168; data-to-parameter ratio = 16.5.
In the title compound, C17H15N3O6S, which crystallized with
highly disordered methanol and/or water solvent molecules,
the dihedral angle between the the indole and benzene ring
systems is 5.3 (2)?, which allows for the formation of
intramolecular ?–? stacking interactions [centroid–centroid
separations = 3.641 (3) and 3.694 (3) A˚] and an approximate
overall U-shape for the molecule. In the crystal, dimers linked
by pairs of Ns—H???Oc(s = sulfonamide and c = carboxylate)
hydrogen bonds generate R2
= indole) interactions lead to chains propagating in [100] or
[010]. Together, these lead to a three-dimensional network in
which the solvent voids are present as intersecting (two-
dimensional) systems of [100] and [010] channels. The title
compound was found to contain a heavily disordered solvent
molecule, which could be methanol or water or a mixture of
the two. Due to its uncertain nature and the unresolvable
disorder, the data were processed with the SQUEEZE option
in PLATON [Spek (2009). Acta Cryst. D65, 148–155], which
revealed 877.8 A˚3of solvent-accessible volume per unit cell
and 126 electron-units of scattering density or 109.7 A˚3(16
electron units) per organic molecule.. This was not included in
the calculations of overall formula weight, density and
absorption coefficient.
2(10) loops, whereas Ni—H???? (i
Related literature
For related structures and background references to the
biological activity of sulfonamides, see: Khan et al. (2011a,b).
For further synthetic details, see: Deng & Mani (2006).
Experimental
Crystal data
C17H15N3O6S
Mr= 389.38
Tetragonal, P41212
a = 9.6818 (5) A˚
c = 44.017 (3) A˚
V = 4126.0 (4) A˚3
Z = 8
Mo K? radiation
? = 0.19 mm?1
T = 296 K
0.30 ? 0.25 ? 0.10 mm
Data collection
Bruker Kappa APEXII CCD
diffractometer
4042 measured reflections
4042 independent reflections
3492 reflections with I > 2?(I)
Refinement
R[F2> 2?(F2)] = 0.067
wR(F2) = 0.168
S = 1.07
4042 reflections
245 parameters
H-atom parameters constrained
??max= 0.21 e A˚?3
??min= ?0.24 e A˚?3
Absolute structure: Flack (1983),
1581 Friedel pairs
Flack parameter: 0.03 (15)
Table 1
Hydrogen-bond geometry (A˚,?).
D—H???A
N1—H1???Cg1i
N2—H2???O1ii
Symmetry codes: (i) x ?1
D—HH???AD???AD—H???A
0.86
0.86
2.77
2.10
3.565 (4)
2.918 (4)
155
158
2;?y þ3
2;?z þ3
4; (ii) y;x;?z þ 1.
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT
(Bruker, 2007); data reduction: SAINT; program(s) used to solve
structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine
structure: SHELXL97 (Sheldrick,
ORTEP-3 (Farrugia, 1997); software used to prepare material for
publication: SHELXL97 and PLATON (Spek, 2009).
2008);moleculargraphics:
The authors acknowledge the Higher Education Commis-
sion of Pakistan for providing a grant for the project to
strengthen the Materials Chemistry Laboratory at GC
University Lahore, Pakistan.
Supplementary data and figures for this paper are available from the
IUCr electronic archives (Reference: SJ5218).
References
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin,
USA.
Deng, X. & Mani, N. S. (2006). Green Chem. 8, 835–838.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Flack, H. D. (1983). Acta Cryst. A39, 876–881.
Khan, I. U., Arshad, M. N., Mubashar-ur-Rehman, H., Harrison, W. T. A. &
Ali, M. B. (2011a). Acta Cryst. E67, o2325.
Khan, M. H., Khan, I. U., Arshad, M. N., Rafique, H. M. & Harrison, W. T. A.
(2011b). Crystals, 1, 69–77.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Spek, A. L. (2009). Acta Cryst. D65, 148–155.
organic compounds
Acta Cryst. (2012). E68, o2019doi:10.1107/S1600536812023446 Khan et al.
o2019
Acta Crystallographica Section E
Structure Reports
Online
ISSN 1600-5368

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Acta Cryst. (2012). E68, o2019
supplementary materials
Acta Cryst. (2012). E68, o2019 [doi:10.1107/S1600536812023446]
3-(1H-Indol-3-yl)-2-(2-nitrobenzenesulfonamido)propanoic acid including an
unknown solvate
Islam Ullah Khan, Hafiz Mubashar-ur-Rehman, Salman Aziz and William T. A. Harrison
Comment
As part of our ongoing studies of chiral sulfonamides with possible biological activity (Khan et al., 2011a,b), we now
report the structure of the title compound, (I). Compound (I) was found to contain a heavily disordered solvent molecule,
which could be methanol or water or a mixture of the two. Due to its uncertain nature and the unresolvable disorder, the
data were processed with the SQUEEZE option in PLATON (Spek, 2009), to remove the solvent contribution to the
scattering.
The molecular structure of (I) (Fig. 1) approximates to a U-shape, with the indole ring system (C1—C8/N1; r.m.s.
deviation = 0.007 Å) and benzene ring (C12–C17) lying approximately parallel to each other [dihedral angle = 5.3 (2)°].
This allows intramolecular aromatic π-π stacking to occur: the separations of the centroid of the C12–C17 benzene ring
with those of the C1–C6 and C1/C6/C7/C8/N1 rings are 3.641 (3) Å and 3.694 (3) Å, respectively. The N3/O5/O6 nitro
group is twisted out of the plane of its atttached ring by 48.9 (4)°. The configuration of the stereogenic carbon atom (C10)
in (I) is S, which is consistent with that of the equivalent atom in the starting material.
In the crystal, the molecules are linked into dimers via pairs of Ns–H···Oc (s = sulfonamide, c = carboxylate) hydrogen
bonds (Fig. 2, Table 1), which result in R22(10) loops. A crystallographic twofold axis directed along [110] generates the
second molecule from the asymmetric molecule. In addition, weak Ni—H···π (i = indole) interactions occur: these lead to
[100] chains for the asymmetric molecule and [010] chains for symmetry-generated molecules in other locations in the
unit-cell (Fig. 3). The carboxylic acid O—H group is directed towards the solvent void and probably forms a hydrogen
bond to the solvent.
Together, the N–H···O and N–H···π bonds generate a three-dimensional network of molecules within the distinctive
"tall" tetragonal unit-cell (Fig. 3). The solvent voids are apparent as square grids of intersecting [100] and [010] pseudo
channels lying at z = 0, z = 1/4 and symmetry equivalent locations.
The molcular conformation and crystal structure (Khan et al., 2011a) of the closely related compound 3-(1H-indol-3-
yl)-2-(toluene-4-sulfonylamino)-propionic acid monohydrate, (II), are completely different to (I). In (II), where a para-
toluene substituent has replaced the 2-nitrobebzene substituent in (I), the organic molecule adopts an extended Z-shaped
conformation and no intramolecular π-π stacking can occur. In the crystal of (II), in which the solvent water molecule was
located, Ns–H···Os hydrogen bonds and Oc–H···Ow (s = sulfonamide, c = carboxylic acid, w = water) hydrogen bonds
generate chains and the crystal symmetry is monoclinic. Another feature of (II) not seen in (I) is the presence of a short
intermolecular C—H···O interaction arising from the α (chiral) C atom (Khan et al., 2011b). However, it is interesting to
note that (I) and (II) both feature an unusual Ni–H···π (i = indole) interaction.

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Acta Cryst. (2012). E68, o2019
Experimental
The title compound was prepared following the literature method (Deng & Mani, 2006) and recrystalized from methanol
by slow evaporation to yield yellow blocks of (I).
Refinement
Due to the disordered solvent molecule and its uncertain identity, the data were processed with SQUEEZE in PLATON
(Spek, 2009). This revealed 877.8 Å3 of solvent accessible volume per unit cell and 126 electron-units of scattering
density or 109.7 Å3 (16 electron units) per organic molecule. This was not included in the calculations of overall formula
weight, density and absorption coefficient. The original data set consisted of 31099 measured reflections (-11 ≤ h ≤ 11,
-11 ≤ k ≤ 11, -54 ≤ l ≤ 54), for which Rint was 0.068.
The C- and N-bound H-atoms were geometrically placed (C—H = 0.93–0.98 Å, N—H = 0.86 Å) and refined as riding
with Uiso(H) = 1.2Ueq(carrier). The O-bound H was located in a difference map and refined as riding in its as-found
relative position with Uiso(H) = 1.5Ueq(O).
Computing details
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007);
program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97
(Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication:
SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
Figure 1
The molecular structure of (I) with displacement ellipsoids drawn at the 40% probability level and the intramolecular π-π
stacking interactions shown as double-dashed lines betweent the ring centroids.

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Acta Cryst. (2012). E68, o2019
Figure 2
Detail of the structure of (I) showing the formation of dimers linked by pairs of N—H···O hydrogen bonds, thus
generating R22(10) loops. All C-bonded H atoms omitted for clarity. Symmetry code: (ii) y, x, 1 - z.
Figure 3
Detail of the structure of (I) showing the formation of [100] chains linked by N—H···π interactions. Cg1 (pink circle) is
the centroid of the C1–C6 ring. Symmetry code: (i) x - 1/2, 3/2 - y, 3/4 - z.

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Figure 4
The unit-cell packing for (I) viewed approximately down [010] showing the solvent voids.
3-(1H-Indol-3-yl)-2-(2-nitrobenzenesulfonamido)propanoic acid
Crystal data
C17H15N3O6S
Mr = 389.38
Tetragonal, P41212
Hall symbol: P 4abw 2nw
a = 9.6818 (5) Å
c = 44.017 (3) Å
V = 4126.0 (4) Å3
Z = 8
F(000) = 1616
Dx = 1.254 Mg m−3
Mo Kα radiation, λ = 0.71073 Å
Cell parameters from 9980 reflections
θ = 2.8–26.9°
µ = 0.19 mm−1
T = 296 K
Block, yellow
0.30 × 0.25 × 0.10 mm