The hydrolyis or the aquation reactions of the compounds cis- and trans-Pt(amine)2(NO3)2 were studied in D2O in different conditions of pH. The products were characterized by multinuclear (195Pt, 13C, and 1H) magnetic resonance spectroscopy. In acidic medium, the product was [Pt(amine)2(D2O2)]2+ and for a few amines, trans- [Pt(amine)2(D2O)(NO3)]+ was detected. The 195Pt NMR resonances of the diaqua complexes were observed at higher fields for the cis compounds (avg. 1727 ppm) than for the trans isomers (avg. 1560 ppm). At basic pH, Pt(amine)2(OD)2 was formed and for ethylamine, trans-Pt(EtNH2)2(OD)(NO3) was detected. The cis compounds were also observed at higher fields than the trans isomers (1706 ppm vs. 1574 ppm). The coupling constants with 195Pt were geometry dependent. The avg. 2J(195Pt-1H) values for the diaqua species were 66 (cis) and 57 (trans) Hz, while the avg. 3J(195Pt-1H) were 43 (cis) and 34 (trans) Hz for the diaqua compounds, and 43 and 37 Hz, respectively, for the dihydroxo species. The 2J(195Pt-13C) avg. values were 18 (cis) and 12 (trans) Hz and the avg. 3J(195Pt-13C) were 31 (cis) and 23 (trans) Hz for both the diaqua and dihydroxo compounds. For the cis isomers, at neutral pH, the monoaquamonohydroxo species (avg. 1721 ppm) and the dihydroxo-bridged dimer (avg. 1353 ppm) were observed. For a few amines, the monohydroxo-bridged dimer was observed (avg. 1684 ppm) and its concentration increased with time. For the trans compounds, the monoaquamonohydroxo species was observed at 1563 ppm (avg.). For a few amines, the hydroxo-bridged dimer was present. For methylamine, a third species assigned to a higher oligomer was observed after 6 months.Key words: platinum, amine, nitrato, hydrolysis, NMR, aquation.
Compounds of the types cis- and trans-Pt(amine)2NO3)2 have been synthesized and characterized by IR and multinuclear (195Pt, 13C, and 1H) NMR spectroscopies. The nitrato IR bands were compared for the two isomers. The 195Pt NMR resonances of the trans complexes were observed at lower fields (avg. 1570 ppm for primary amines) than the cis analogues (avg. 1698 ppm) for an average Δδ value of 124 ppm. The complexes containing a secondary amine were observed at about the same field for the cis isomers (avg. 1682 ppm) and surprisingly at much higher fields for the trans compounds (avg. 1638 ppm). In 1H NMR, the coupling constants 2J(195Pt-1HN) are larger for the cis isomers (avg. 67 Hz) than for the trans compounds (avg. 58 Hz). The 3J(195Pt-1H) are also larger for the cis complexes (avg. 40 vs. 33 Hz). In 13C NMR, the coupling constants are also geometry dependent. The 3J(195Pt-13C) are larger for the cis isomers (avg. 37 Hz) than for the trans compounds (avg. 28 Hz). The 2J(195Pt-13C) are much smaller (avg. 18 Hz for the cis complexes and 16 Hz for the trans isomers).Key words: platinum, amine, nitrato, NMR, IR.