Calculation of NMR shielding tensors based on density functional theory and a scalar relativistic Pauli-type Hamiltonian. The application to transition metal complexes
✍ Scribed by Georg Schreckenbach; Tom Ziegler
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 253 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
This article deals with the calculation of the shielding tensor of nuclear magnetic Ž . resonance NMR spectroscopy based on a scalar relativistic two-component Pauli-type Hamiltonian. A complete formulation of the method within the framework of the gauge Ž . including atomic orbitals GIAO is given. Further, an implementation, based on density Ž . 17 functional theory DFT is presented. The new method is applied to the O shielding in w x n y Ž . transition-metal oxo complexes MO M s Cr, Mo, W; Mn, Tc, Rh; Ru, Os and to the 4 Ž . Ž . metal chemical shift in transition-metal carbonyls M CO M s Cr, Mo, W . This 6 represents the first calculation of heavy-element shifts that is based on a relativistic first-principle quantum mechanical method. The inclusion of relativity is crucial for a proper description of ligand and metal shieldings in 5d complexes, but it is also important in 4 d complexes. Limitations of the method, among them the neglect of the spin᎐orbit coupling, are discussed in detail. ᮊ 1997 John