The 13C solid-state NMR measurements of specificf d0 metal alkyl complexes show that when the metal has low lying empty d orbital the α- carbon has a high chemical shift and a significant amount of anisotropy. DFT-ZORA calculations have been used to analyze these observations. The calculations reproduce the high chemical shift of the α-carbon and provide the directions of the three principal components of the magnetic tensor which describe the magnetic anisotropy at this atom. The calculations also indicate that the anisotropy is not due to the diamagnetic contribution of the magnetic tensor but to its paramagnetic term. The paramagnetic term, which contributes to deshielding and increases when the HOMO-LUMO decreases, was analyzed with the NCS method (adapted from the NBO method). This analysis reveals that the most deshielded component of the magnetic tensor is associated with the presence of a relatively low lying empty π*(metal-carbon) orthogonal to the direction of deshielding and to the M-C σ-bond. These finding will be related to the chemical reactivity of these d0 metal alkyl complexes.

Anisotropy of solid state NMR Chemical Shift signal informs on the π character of M-alkyl σ-bond in d0metal alkyl complexes

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.