N-(4-Aminophenyl)-4-methylbenzenesulfonamide

The title compound, C13H14N2O2S, crystallized with two independent molecules in the asymmetric unit. They both have V-shaped conformations: the dihedral angles between their benzene rings are identical [45.86 (13)°] and their C—S—N—C torsion angles are similar [67.9 (3) and 70.2 (3)°]. In the crystal, the molecules are linked by N—H⋯O and N—H⋯N hydrogen bonds, generating a three-dimensional network.

IUK thanks the Higher Education Commission of Pakistan for financial support under the project to strengthen the Materials Chemistry Laboratory at GCUL. title compound, (I) (Fig. 1), are now described. Related stuctures with different substituents replacing the para-amino group in (I) include 4-methyl-N-(4-nitrophenyl)benzenesulfonamide, (II), (Xing and Zeng, 2005) and 4-methyl-N-(4methylphenyl)benzenesulfonamide, (III), (Khan et al., 2010). Also worthy of mention is the remarkable sudy of Gelbrich et al. (2007), who made a systematic structural comparison of no fewer than 133 crystal structures of 4,4'-disubstituted benzenesulfonamidobenzenes. However, no compounds with an amino substituent were incorporated into their survey.
There are two independent molecules (A containing S1 and B containing S2) in the asymmetric unit of (I), as shown in In the crystal of (I), the molecules are linked by N-H···O and N-H···N hydrogen bonds (Table 1). Both the sulfonamide NH groups make intermolecular hydrogen bonds to the sulfonamide O-atom acceptors such that separate [100] C(4) chains of A and B are generated, with adjacent molecules related only by a unit-cell translation. The amine groups each form an N-H···N and an N-H···O link. The former bonds lead to distinctive [100] -N-H···N-H···N-C(2) chains of alternating A and B molecules, and serve to link the C(4) chains into a sheet. The latter bonds generate [001] chains of alternating A and B molecules and overall a three-dimensional array is generated (Fig. 2).
Because of the presence of the -NH 2 group, the hydrogen bonding patterns in (I) are not expected to show close similarities to those of the Gelbrich et al. (2007) study. There, the sulfonamide -NH-group was the only possible donor and the structure of (I) does not appear to match any of the groups of structures described by these workers.
Experimental p-Toluene sulfonyl chloride (2 mmol, 0.3813 g) was added to p-phenylenediamine (1 mmol, 0.108 g) in distilled water (20 ml) in a round-bottom flask (100 ml). The suspension was stirred for 10 h at room temperature while keeping the pH between 8-9 with sodium carbonate solution (3%). The light brown precipitate formed was filtered, washed with distilled water and dried. Light brown needles of (I) were grown from methanol.
supplementary materials sup-2 Refinement The N-bound H-atoms were located in difference Fourier maps and their positions were freely refined with the constraint U iso (H) = 1.2U eq (N). The C-bound H-atoms were placed in calculated positions treated as riding atoms: C-H = 0.93 and 0.96 Å for CH and CH 3 H-atoms, respectively, with U iso (H) = k × U eq (C), where k = 1.5 for CH 3 H-atoms and k = 1.2 for all other H-atoms. Fig. 1. The molecular structure of the two independent molecules (A and B) of compound (I), showing the numbering scheme and displacement ellipsoids drawn at the 50% probability level.  Table 1 for details). Molecule A is shown in blue and molecule A in red. All C-bound H atoms have been omitted for clarity. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.