Synthesis, IR, and multinuclear NMR spectroscopic studies of complexes of the type <i>cis</i>- and <i>trans</i>-Pt(amine)₂(NO₃)₂

Abstract

Compounds of the types cis- and trans-Pt(amine) 2 NO 3 ) 2 have been synthesized and characterized by IR and multinuclear ( 195 Pt, 13 C, and 1 H) NMR spectroscopies. The nitrato IR bands were compared for the two isomers. The 195 Pt 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 1 H NMR, the coupling constants 2 J( 195 Pt- 1 HN) are larger for the cis isomers (avg. 67 Hz) than for the trans compounds (avg. 58 Hz). The 3 J( 195 Pt- 1 H) are also larger for the cis complexes (avg. 40 vs. 33 Hz). In 13 C NMR, the coupling constants are also geometry dependent. The 3 J( 195 Pt- 13 C) are larger for the cis isomers (avg. 37 Hz) than for the trans compounds (avg. 28 Hz). The 2 J( 195 Pt- 13 C) are much smaller (avg. 18 Hz for the cis complexes and 16 Hz for the trans isomers).Key words: platinum, amine, nitrato, NMR, IR.