Multinuclear magnetic resonance studies of the aqueous products of the complexes cis- and trans-Pt(Ypy)2(NO3)2 where Ypy = pyridine derivative

The hydrolyis or the aquation reactions of compounds of the types cis- and trans-Pt(Ypy)2(NO3)2 (Ypy = pyridine derivative) were studied in D2O and characterized by multinuclear ( 195 Pt, 13 C, and 1 H) NMR spectroscopy. In acidic pD, the product of the cis complexes is cis-(Pt(Ypy)2(D2O)2) 2+ , whereas in basic medium cis-Pt(Ypy)2(OD)2 is formed. The 195 Pt NMR resonances of the products containing ligands with an ortho substituent were observed at lower fields than the other complexes. The average coupling constant ( 3 J( 195 Pt- 1 H) and 3 J( 195 Pt- 13 C)) is 44 Hz for the diaqua species and 42 Hz for the dihydroxo compounds. At neutral pD, several hydrolyzed species were observed, except for the 2-picoline and 2,4-lutidine complexes, which contained only one compound, cis-(Pt(Ypy)2(D2O)(OD)) + . The other hydrolyzed products for the ligands with no ortho substituent were identified as the dihydroxo-bridged dimer, the monohydroxo-bridged dimer, the trimer, and possibly the tetramer. The trans analogues have shown two signals in acidic pD corresponding to the diaqua monomer and the monohydroxo-bridged aqua dimer. Two species (the dihydroxo compound and the monohydroxo-bridged hydroxo dimer) were also observed in basic pD. In neutral medium, a third signal assigned to a longer chain hydroxo-bridged oligomer or polymer was detected.