Crystallographic study on metal (II) complexes with N-(2-nitrophenylsulfonyl)glycine

The interaction of M^II ions (M^II = Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Cd^II, Pb^II) with N-(2-nitrophenylsulfonyl)-glycine (NO₂psglyH₂) leads to the formation at acidic pH of the complex carboxylate-type M(NO₂psglyO)₂.xH₂O species. At higher pH the deprotonation reaction of the sulfonamide nitrogen takes place, leading to the formation of the M(NO₂psgly-N,O).xH₂O species where the ligand acts as a chelating agent toward the metal ion through the carboxylic oxygen and the deprotonated sulfonamide nitrogen. In ternary systems the addition of 2,2′-bipyridine (bpy) allows the deprotonation of the sulfonamide nitrogen also in presence of metal ions such as Zn^II, Co^II and Ni^II, which were inactive in the binary system, and the solid compounds isolated are in the M/bpy/L molar ratio 1:1:1 (M^II = Cu^II, Zn^II) or 1:2:1 (M^II = Co^II, Ni^II, Cd^II). Here we describe the crystal and molecular structures of NO₂2psglyH₂ (1), [Pb(NO₂Psgly-N,0)]_n (2), [Cd(bpy)₂(NO₂psgly-N,O)].H₂O (3) and [Cu(bPy)(NO₂psgly-N,O)(H₂O)] (4).