Probing the stereo-electronic properties of cationic rhodium complexes bearing chiral diphosphine ligands by 103Rh NMR
✍ Scribed by Amandine Fabrello; Chiara Dinoi; Lionel Perrin; Philippe Kalck; Laurent Maron; Martine Urrutigoity; Odile Dechy-Cabaret
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 236 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.2677
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✦ Synopsis
Abstract
^103^Rh NMR represents a powerful tool to assess the global electronic and steric contribution of diphosphine ligands on [Rh(COD)(diphosphine)]^+^ complexes. In the case of DIOP, BINAP and MeDUPHOS, this approach proved to be more informative than classical CO‐stretching frequency measurements. After validation, this method has been extended to a set of seven diphosphines. ^103^Rh NMR measurements on [Rh(COD)(diphosphine)]PF~6~ lead to the following order of donor properties: dppe > MeBPE > MeDUPHOS > dppb > DIOP > BINAP > Tol‐BINAP. This trend has been validated by DFT in the case of DIOP, BINAP and MeDUPHOS. In conjunction, ^31^P NMR chemical shift has been shown to reflect the ring constraints of the Rh‐diphosphine scaffold. This contribution is a step towards a mechanistic investigation of the catalytic hydrogenation of unsaturated substrates by ^103^Rh NMR and DFT. Copyright © 2010 John Wiley & Sons, Ltd.