Insight into the local environment of magnesium and calcium in low-coordination-number organo-complexes using 25Mg and 43Ca solid-state NMR: A DFT study

Christel Gervais, Cameron Jones, Christian Bonhomme, Danielle Laurencin

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)

Abstract

With the increasing number of organocalcium and organomagnesium complexes under development, there is a real need to be able to characterize in detail their local environment in order to fully rationalize their reactivity. For crystalline structures, in cases when diffraction techniques are insufficient, additional local spectroscopies like 25Mg and 43Ca solid-state NMR may provide valuable information to help fully establish the local environment of the metal ions. In this current work, a prospective DFT investigation on crystalline magnesium and calcium complexes involving low-coordination numbers and N-bearing organic ligands was carried out, in which the 25Mg and 43Ca NMR parameters [isotropic chemical shift, chemical shift anisotropy (CSA) and quadrupolar parameters] were calculated for each structure. The analysis of the calculated parameters in relation to the local environment of the metal ions revealed that they are highly sensitive to very small changes in geometry/distances, and hence that they could be used to assist in the refinement of crystal structures. Moreover, such calculations provide a guideline as to how the NMR measurements will need to be performed, revealing that these will be very challenging.DFT calculations of 25Mg and 43Ca NMR parameters were performed on the crystal structures of organomagnesium and organocalcium complexes involving low coordination numbers and N-bearing ligands. It is shown how these spectroscopies may be used for these systems for NMR crystallography approaches.

Original languageEnglish
Pages (from-to)208-218
Number of pages11
JournalActa Crystallographica Section C: Structural Chemistry
Volume73
Issue number3
DOIs
Publication statusPublished - 1 Mar 2017

Keywords

  • Mg
  • Ca
  • computational chemistry
  • DFT
  • GIPAW
  • NMR crystallography
  • organo-complexes
  • solid-state NMR

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