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

Abstract

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.