| Abstract
| - The molecular geometries and the nuclear spin−spin coupling constants of the complexes[(NC)5Pt−Tl(CN)n]n-, n = 0−3, and the related system [(NC)5Pt−Tl−Pt(CN)5]3- are studied. Thesecomplexes have received considerable interest since the first characterization of the n = 1 system byGlaser and co-workers in 1995 [J. Am. Chem. Soc.1995, 117, 7550−7551]. For instance, these systemsexhibit outstanding NMR properties, such as extremely large Pt−Tl spin−spin coupling constants. For thepresent work, all nuclear spin−spin coupling constants JPt-Tl, JPt-C, and JTl-C have been computed by meansof a two-component relativistic density functional approach. It is demonstrated by the application ofincreasingly accurate computational models that both the huge JPt-Tl for the complex (NC)5Pt−Tl and thewhole experimental trend among the series are entirely due to solvent effects. An approximate inclusion ofthe bulk solvent effects by means of a continuum model, in addition to the direct coordination, proves to becrucial. Similarly drastic effects are reported for the coupling constants between the heavy atoms and thecarbon nuclei. A computational model employing the statistical average of orbital-dependent model potentials(SAOP) in addition to the solvent effects allows to accurately reproduce the experimental coupling constantswithin reasonable limits.
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