ASPECTS OF THE SOLUTION CHEMISTRY OF TRANS-DIAMMINEPLATINUM(II) COMPLEXES

A convenient method for small-scale preparations of trans-[PtCl2(NH3)2] (e.g., for preparing N-15-labeled compounds) is to heat [Pt(NH3)4]Cl2 at 190-195-degrees-C, under vacuum. N-15 and Pt-195 NMR spectra have been used to characterize in solution trans-diammineplatinum(II) complexes with aqua, chloro, nitrato, sulfato, acetato, and phosphato ligands. A solution of trans- [Pt(OH)(H2O)(NH3)2]+ allowed to stand gives a precipitate [{trans-Pt(mu-OH)(NH3)2}n](NO3)n. N-15 NMR spectra have been used to determine acid dissociation constants for trans-([Pt(H2O)2(NH3)2]2+)-N-15 (pK(a1) 4.35, pK(a2) 7.40) and for trans-([PtCl(H2O)(NH3)2]+)-N-15 (pK(a1) 5.63).