Synthesis, NMR spectroscopic characterization and structure of a divinyldisilazane‐(triphenylphosphine)platinum(0) complex: observation of isotope‐induced chemical shifts ¹Δ^12/13C(¹⁹⁵Pt)

Abstract

Tetramethyldivinyldisilazane-(triphenylphosphine)platinum(0) was prepared, characterized in solid state by X-ray crystallography and in solution by multinuclear magnetic resonance spectroscopy ((1)H, (13)C, (15)N, (29)Si, (31)P and (195)Pt NMR). Numerous signs of spin-spin coupling constants were determined by two-dimensional heteronuclear shift correlations (HETCOR) and two-dimensional (1)H/(1)H COSY experiments. Isotope-induced chemical shifts (1)Δ(12/13)C((195)Pt) were measured from (195)Pt NMR spectra of the title compound as well as of other Pt(0), Pt(II) and Pt(IV) compounds for comparison. In contrast to other heavy nuclei such as (199)Hg or (207)Pb, the "normal" shifts of the heavy isotopomers to low frequencies are found, covering a range of >500 ppb.

Isotope Effects in 195Pt NMR Spectroscopy: Unique 35/37Cl- and 16/18O-Resolved “Fingerprints” for All [PtCl6–n(OH)n]2– (n = 1–5) Anions in an Alkaline Solution and the Implications of the Trans Influence

“…In particular, isotope effects arising from the substitution of a heavier isotope for a lighter one of the same element usually directly bound to an NMR-active nucleus result in small but detectable changes in the magnetic shielding of the nucleus, particularly in high magnetic fields. − Typically, substitution of a lighter isotope for a heavier one results in increased magnetic shielding of the NMR-active nucleus in such a molecule (although not always), ,, while generally such isotope-induced shifts are approximately additive. Anet and Dekmezian distinguish between intrinsic and equilibrium chemical-shift isotope effects, with the former relating to a single species on a single minimum energy surface and the latter involving more than one chemical species usually undergoing rapid chemical exchange of the isotopes between two or more sites, as is typically observed in 1 H/ 2 H exchange in 1 H NMR.…”