Potassium N-bromo-2-methylbenzenesulfonamidate sesquihydrate

In the structure of the title compound, K+·C7H7BrNO2S−·1.5H2O, the K+ ion is heptacoordinated by three O atoms from water molecules and by four sulfonyl O atoms of N-bromo-2-methylbenzenesulfonamide anions. The S—N distance of 1.577 (5) Å is consistent with an S=N double bond. The crystal structure comprises sheets in the ac plane which are further stabilized by O—H⋯Br and O—H⋯N hydrogen bonds.

In the structure of the title compound, K + ÁC 7 H 7 BrNO 2 S À Á-1.5H 2 O, the K + ion is heptacoordinated by three O atoms from water molecules and by four sulfonyl O atoms of N-bromo-2methylbenzenesulfonamide anions. The S-N distance of 1.577 (5) Å is consistent with an S N double bond. The crystal structure comprises sheets in the ac plane which are further stabilized by O-HÁ Á ÁBr and O-HÁ Á ÁN hydrogen bonds.

Comment
To explore the substituent effects and the effect of replacing sodium ion by potassium ion on the solid state structures of N-halo-arylsulfonamidates (Gowda & Kumar, 2003;Gowda et al., 2009Gowda et al., , 2011Usha & Gowda, 2006), in the present work, the structure of potassium N-bromo-2-methyl-benzenesulfonamidate sesquihydrate (I) has been determined (Fig. 1).
In the title compound, K + ion is hepta coordinated by three O atoms from water molecules and by four sulfonyl O atoms of N-bromo-2-methyl-benzenesulfonamide anions. The replacement of Na + ion by K + ion changes co-ordination from hexa to hepta in the metal co-ordination (Gowda et al., 2009) and other parameters.
The S-N distance of 1.577 (5) Å is consistent with an S-N double bond and is in agreement with the observed values of 1.582 (4)Å in (II) and 1.590 (2) Å in (III).

Experimental
The title compound was prepared according to the literature method (Usha & Gowda, 2006). The purity of the compound was checked by determining its melting point (176 °). It was characterized by recording its infrared and NMR spectra. Yellow prisms of the title compound used in X-ray diffraction studies were obtained from its aqueous solution at room temperature.

Refinement
The O bound H atoms were located in a difference map and later restrained to O-H = 0.82 (2) Å. The other H atoms were positioned with idealized geometry using a riding model with aromatic C-H = 0.93 Å and methyl C-H = 0.96 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).