REACTIONS OF NITROPLATINUM COMPLEXES .1. N-15 AND PT-195 NMR-SPECTRA OF PLATINUM(II) NITRITE COMPLEXES

N-15 and Pt-195 NMR spectra have been used to characterize the products of reaction of Pt((NO2)-N-15)4(2-) with sulfamic acid, Pt((NO2)-N-15)3(H2O)- and cis-Pt((NO2)-N-15)2(H2O)2, and the hydroxo complexes Pt((NO2)-N-15)3(OH)2- and cis-Pt((NO2)-N-15)2(OH)2(2-) derived from them by deprotonation. At intermediate pH values, the dinitro complexes rapidly form the hydroxo-bridged compounds [{Pt-((NO2)-N-15)2(mu-OH)}n]n- (n = 2, 3). The acid dissociation constant for Pt((NO2)-N-15)3(H2O)- (pK(a) 5.32) was determined from the variation with pH of delta-N for nitro ligands cis to water/hydroxide. N-15 and Pt-195 NMR parameters were obtained for the series Pt((NO2)-N-15)3Z(m-). The changes in these parameters as Z was changed correlated with those in the series Pt((NH3)-N-15)3Z(n+). Delta-N and J(Pt-N) values are much more sensitive to change in the ligand Z for the nitro ligand trans to Z than for that cis to Z.