Solid-state NMR of a paramagnetic DIAD-FeII catalyst: sensitivity, resolution enhancement, and structure-based assignments

J Am Chem Soc. 2006 Oct 18;128(41):13545-52. doi: 10.1021/ja063510n.

Abstract

A general protocol for the structural characterization of paramagnetic molecular solids using solid-state NMR is provided and illustrated by the characterization of a high-spin Fe(II) catalyst precursor. We show how good NMR performance can be obtained on a molecular powder sample at natural abundance by using very fast (>30 kHz) magic angle spinning (MAS), even though the individual NMR resonances have highly anisotropic shifts and very short relaxation times. The results include the optimization of broadband heteronuclear (proton-carbon) recoupling sequences for polarization transfer; the observation of single or multiple quantum correlation spectra between coupled spins as a tool for removing the inhomogeneous bulk magnetic susceptibility (BMS) broadening; and the combination of NMR experiments and density functional theory calculations, to yield assignments.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • Anisotropy
  • Carbon / chemistry
  • Carbon Isotopes / chemistry
  • Catalysis
  • Cations, Divalent
  • Crystallography, X-Ray
  • Deuterium / chemistry
  • Iron / chemistry*
  • Magnetic Resonance Spectroscopy / methods*
  • Magnetics
  • Organometallic Compounds / chemistry*
  • Protons
  • Quantum Theory
  • Spin Labels

Substances

  • Carbon Isotopes
  • Cations, Divalent
  • Organometallic Compounds
  • Protons
  • Spin Labels
  • Carbon
  • Deuterium
  • Iron