Multinuclear NMR study of some organoplatinum complexes containing multifunctional azines as chelating ligands.
1H-detected indirect NMR techniques were used to determine 15N and 195Pt NMR parameters for a series of organoplatinum(IV) complexes and one platinum(II) complex containing nitrogen-based azobispyridine, bispyridyltetrazine, and bipyrimidine ligands. The inverse technique permitted the detection of small 4J(Pt,H) and 5J(Pt,H) long-range couplings and the acquisition of 15N NMR data in natural isotopic abundance via nJ(N,H) intra- and inter-ligand couplings, but failed in cases where coherence transfer is quenched by rapid relaxation of the metal atom. In one case, analysis of satellite patterns in a set of 1H,15N, 1H,195Pt and 1H,13C correlation spectra allowed a positive sign to be determined for 1J(Pt,15N). Qualitative arguments are presented to explain the observed 15N coordination shifts in complexes with different azine ligands in terms of azine-M dative bond formation and LnM-azine back-donation.
Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550 Stuttgart, Germany. gudat@iac.uni-stuttgart.de
Dietrich
D
Gudat
Akbey
A
Dogan
Wolfgang
W
Kaim
Axel
A
Klein
D002614:Chelating Agents / Q000032:analysis / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000032:analysis / Q000737:chemistry; D007856:Lead Radioisotopes; D008958:Models, Molecular; D008968:Molecular Conformation; D009587:Nitrogen Isotopes; D009944:Organoplatinum Compounds / Q000032:analysis / Q000737:chemistry*; D011522:Protons
D002614:Chelating Agents; D006571:Heterocyclic Compounds; D007856:Lead Radioisotopes; D009587:Nitrogen Isotopes; D009944:Organoplatinum Compounds; D011522:Protons