Different Coordinative (N,N) and (N,O) Bidentate Behaviour of N‐2‐Pyridyl‐Sulfonamides. Electrochemical Synthesis and Characterization of Cadmium(II) Complexes

Electrochemical oxidation of cadmium in an acetonitrile solution of N‐2‐pyridyl‐sulfonamides (HL) afforded cadmium coordination compounds of composition [CdL₂]. Heteroleptic complexes of composition [CdL₂L′] (L′ = 2, 2′‐bipyridine or 1, 10‐phenanthroline) were obtained when the coligand L′ was added to the electrolytic phase. The crystal structures of several compounds have been determined by X‐ray diffraction. In all cases the cadmium atom is hexacoordinated, but the coordinative behaviour of the N‐2‐pyridyl‐sulfonamide ligand depends on the location of the substituents in the pyridyl ring. When the substituent is in position 3, the ligands act as N, O‐donors. In all other cases, the ligands act as N, N′‐bidentate systems.