N,N-Bis(4-chlorophenylsulfonyl)succinamide dihydrate

The asymmetric unit of the title compound, C16H14Cl2N2O6S2·2H2O, contains one half-molecule of N,N-bis(4-chlorophenylsulfonyl)succinamide, with a centre of symmetry at the mid-point of the central C—C bond, and one water molecule. The succinamide molecules are not directly connected via hydrogen bonds, but by hydrogen bonds via the water molecules.

The asymmetric unit of the title compound, C 16 H 14 Cl 2 N 2 O 6 S 2 Á2H 2 O, contains one half-molecule of N,Nbis(4-chlorophenylsulfonyl)succinamide, with a centre of symmetry at the mid-point of the central C-C bond, and one water molecule. The succinamide molecules are not directly connected via hydrogen bonds, but by hydrogen bonds via the water molecules.
The dihedral angle between the benzene ring and the SO 2 -NH-C(O)-C segment in the two halves of the molecule is 78.0 (2)°, compared to the value of 83.5 (2)° in (I).
One of the water H-atoms exhibits bifurcated H-bonding with one of the O-atoms of SO 2 group and the amide O-atom.
A series of N-H···O(W) and O-H···O(S and C) intermolecular hydrogen bonds (Table 1)

Experimental
Succinic anhydride (0.015 mole), N,N′-dicyclohexylcarbodiimide (0.01mole) and 4-dimethylaminopyridine (0.004 mole) were added to a solution of 4-chlorobenzenesulfonamide (0.01 mole) in dichloromethane. The mixture was strirred for 24 h at room temperature and set aside for completion of the reaction.. The reaction mixture was filtered to remove the byproduct N,N′-dicyclohexylurea. The filtrate was diluted with water and then the organic layer was extracted. The latter was washed with water to remove the base and the succinic anhydride, dried over anhydrous sodium sulfate and filtered.
The filtrate was concentrated to dryness. The residue was recrystallized to constant melting point from ethyl acetate (163-165 °C). The purity of the compound was checked and characterized by its infrared spectrum.
Plate like colorless single crystals used in X-ray diffraction studies were grown in ethyl acetate solution by slow evaporation of the solvent from its solution at room temperature.

Refinement
The H atoms of the water molecule were located in difference map and were refined as riding on their parent O atom. H atoms bonded to C were positioned with idealized geometry using a riding model with the aromatic C-H = 0.93 Å, methylene C-H = 0.97 Å. All H atoms were refined with their isotropic displacement parameter set to 1.2 times of the U eq of the parent atom. The amino H atom was freely refined with the N-H distance restrained to 0.86 (2)

Figure 1
Molecular structure of the title compound, showing the atom labelling scheme with the displacement ellipsoids drawn at the 50% probability level.

Figure 2
Molecular packing of the title compound with hydrogen bonding shown as dashed lines. 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 R-factors(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq