Novel platinum(II) and (IV) complexes of naphthaldimine schiff bases

Naphthaldimines containing N₂O₂ donor centers react with platinum(II) and (IV) chlorides to give two types of complexes depending on the valence of the platinum ion. For Pt(II)], the ligand is neutral, (H₂L¹)PtCl₂]·3H₂O (1) and (H₂L³)₂Pt₂Cl₄]·5H₂O (3), or monobasic (HL²)₂Pt₂Cl₂]·2H₂O (2) and (HL⁴)₂Pt]·2H₂O (4). These complexes are all diamagnetic having square-planar geometry. For Pt(IV)], the ligand is dibasic, (L¹)Pt₂Cl₄(OH)₂]·2H₂O (5), (L²)Pt₃Cl₁₀]·3H₂O (6), (L³)Pt₂Cl₄(OH)₂]·C₂H₅OH (7) and (L⁴)Pt₂Cl₆]·H₂O (8). The Pt(IV) complexes are diamagnetic and exhibit octahedral configuration around the platinum ion. The complexes were characterized by elemental analysis, UV-Vis and IR spectra, electrical conductivity and thermal analyses (DTA and TGA). The molar conductances in DMF solutions indicate that the complexes are non-ionic. The complexes were tested for their catalytic activities towards cathodic reduction of oxygen.