Crystal Structure Studies on Arylsulphonamides and N-Chloro-Arylsulphonamides

Abstract

The effect of ring substitution and N-chlorination on the molecular geometry of arylsulphonamides and N-chloro-arylsulphonamides have been studied by determining the crystal structures of 2-methyl- 4-chloro-benzenesulphonamide (2M4CBSA) and the sodium salt of N-chloro-2-methyl-4-chlorobenzenesulphonamide (NaNC2M4CBSA). The results are analyzed along with the crystal structures of benzenesulphonamide, 4-methyl-benzenesulphonamide and 4-chloro-benzenesulphonamide. The crystal structure of NaNC2M4CBSA has also been compared and correlated with the crystal structures of the above compounds and those of the sodium salts of N-chloro-benzenesulphonamide, Nchloro- 4-methyl-benzenesulphonamide, N-chloro-4-chloro-benzenesulphonamide and N-chloro-2,4- dichloro-benzenesulphonamide. The crystal system, space group, formula units and lattice constants in Å of the new structures are: 2M4CBSA: triclinic, P1, Z = 4, a = 7.9030(10), b = 8.6890(10), c = 13.272(2), α = 100.680(10)°, β = 98.500(10)°, γ = 90.050(10)°; NaNC2M4CBSA: monoclinic, C2/c, Z =4, a = 10.9690(10), b = 6.7384(6), c = 30.438(2), β = 98.442(7)°. The structure of 2M4CBSA is quite complex with four molecules in its asymmetric unit. The S-N bond length slightly decreases with substitution of electron-withdrawing groups, while the effect is more pronounced with disubstitution. The structure of NaNC2M4CBSA confirms that there is no interaction between nitrogen and sodium, and Na+ is attached to one of the sulphonyl oxygen atoms. The Na+ coordination sphere involves oxygen atoms from water moleculess of crystallization and neighbouring molecules. The S-N distance of 1.586 Å for the compound is consistent with a S-N double bond. The molecules are held together by hydrogen bonds with distances varying from 2.12 to 2.85 Å.