Synthesis and multinuclear magnetic resonance spectroscopy of the novel ionic Pt(II) mixed-ligands complexes cis- and trans-[Pt(amine)2(pyrimidine)2](NO3)2
作者:Fernande D. Rochon、Hyem Titouna、Laurence Piche
DOI:10.1016/j.ica.2010.01.001
日期:2010.5
Novel ionic mixed-ligands complexes of the types cis- and trans-[Pt(amine)(2)(pm)(2)](NO3)(2) (where pm = pyrimidine) were synthesized and studied in the solid state by IR spectroscopy and in aqueous solution by multinuclear (Pt-195, H-1 and C-13) magnetic resonance spectroscopy. The results of the solution NMR characterization have shown that the isolated compounds are pure. In Pt-195 NMR, the cis RNH2 complexes were observed at slightly lower fields (ave.-2441 ppm) than the equivalent trans analogues (ave.-2448 ppm). For Me2NH, the difference between the two isomers is larger (29 ppm). The complexes are observed at lower fields (difference of 100 ppm) than the corresponding [Pt(amine)(4)](2+) complexes, which might indicate the presence of pi-backdonation in the Pt-pm bond. In H-1 NMR, the coupling constants (3)J(Pt-195-H-1(amine)) are larger in the cis compounds (38-48 Hz) than in the trans analogues (30-36 Hz). The (3)J(Pt-195-H-1(pm)) values are also larger for the cis isomers. In C-13 NMR spectroscopy, the coupling constants (3)J(Pt-195-C-13(amine)) are 36 Hz (ave.) for the cis complexes and 26 Hz (ave.) for the trans isomers, while the (2)J(Pt-195-C-13(amine)) are 18 Hz (cis) and 14 Hz (trans), respectively. The (3)J(Pt-195-C-13(5(pm))) values are 36 Hz (cis) and 28 Hz (trans). A few (2)J(Pt-195-C-13(pm)) couplings were observed (7-10 Hz). (C) 2010 Elsevier B.V. All rights reserved.