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

Article abstract of DOI:10.1139/v04-012

Compounds of the types cis- and trans-Pt(amine)₂NO ₃)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 V(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).