N,N′-Bis(4-chlorophenylsulfonyl)adipamide

In the title compound, C18H18Cl2N2O6S2, the asymmetric unit contains half a molecule with a center of symmetry at the mid-point of the central C—C bond. The dihedral angle between the benzene ring and the SO2—NH—C(O) segment in the two halves of the molecule is 83.5 (2)°. In the crystal, N—H⋯O(S) intermolecular hydrogen bonds link the molecules into infinite chains running along the c axis. The O atom involved in the hydrogen bond has a longer S—O bond than the other O atom bonded to S [1.403 (4) versus 1.361 (4) Å].

In the title compound, C 18 H 18 Cl 2 N 2 O 6 S 2 , the asymmetric unit contains half a molecule with a center of symmetry at the midpoint of the central C-C bond. The dihedral angle between the benzene ring and the SO 2 -NH-C(O) segment in the two halves of the molecule is 83.5 (2) . In the crystal, N-HÁ Á ÁO(S) intermolecular hydrogen bonds link the molecules into infinite chains running along the c axis. The O atom involved in the hydrogen bond has a longer S-O bond than the other O atom bonded to S [1.403 (4) versus 1.361 (4) Å ].
VZR thanks the University Grants Commission, Government of India, New Delhi, for the award of an RFSMS research fellowship.
In the two C-SO 2 -NH-CO-CH 2 -CH 2 central segments of the structure, the N-H, C=O and C-H bonds are anti to the adjacent bonds, similar to that observed in N,N-bis(2-chlorophenylsulfonyl)-adipamide (II) (Rodrigues et al., 2011a) and N,N-bis(4-chlorophenylsulfonyl)-suberamide (III) (Rodrigues et al., 2011b). The orientations of sulfonamide groups with respect to the attached phenyl rings are given by the torsion angles of C2-C1-S1-N1 = -117.1 (6)° and C6-C1-S1-N1 = 60.5 (6)°. The molecule is bent at the S atom with the C1-S1-N1-C7 torsion angle of 55.0 (6) (Table 1) link the molecules into infinite chains running along c-axis (Fig. 2). The hydrogen bonding preferences of sulfonamides is described elsewhere (Adsmond & Grant, 2001) Experimental N,N-Bis(4-chlorophenylsulfonyl)-adipamide was prepared by refluxing a mixture of adipic acid (0.01 mol) with 4chlorobenzenesulfonamide (0.02 mol) and POCl 3 for 1 hr on a water bath. The reaction mixture was allowed to cool and added ether to it. The solid product obtained was filtered, washed thoroughly with ether and hot ethanol. The compound was recrystallized to the constant melting point and was characterized by its infrared and NMR spectra.
Needle like colorless single crystals used in the X-ray diffraction studies were grown by a slow evaporation of a solution of the compound in ethanol at room temperature.

Refinement
The H atom of the NH group was located in a difference map and later restrained to N-H = 0.86 (2) %A. The other H atoms were positioned with idealized geometry using a riding model with the aromatic C-H = 0.93Å and the methylene C-H = 0.97 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).
The distance C1-C6 in the benzene ring was restrained to 1.39 (1) Å.   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.