Affordable Access

deepdyve-link deepdyve-link
Publisher Website

Enantiomer recognition of amides by dirhodium(II) tetrakis[methyl 2-oxopyrrolidine-5(S)-carboxylate].

Authors
  • Xu, Xichen
  • Doyle, Michael P
Type
Published Article
Journal
Inorganic Chemistry
Publisher
American Chemical Society
Publication Date
Aug 15, 2011
Volume
50
Issue
16
Pages
7610–7617
Identifiers
DOI: 10.1021/ic200609u
PMID: 21736309
Source
Medline
License
Unknown

Abstract

Association constants of the chiral dirhodium(II) carboxamidate Rh(2)(5S-MEPY)(4) with Lewis bases including acetonitrile and amides have been determined by UV-vis titration experiments. With chiral lactams and acyclic acetamides in their R- and S-configurations equilibrium constants with chiral dirhodium carboxamidates are measures of chiral differentiation, and equilibrium constant ratios as high as three have been determined. From equilibrium associations with acetamide, N-methylacetamide, and N,N-dimethylacetamide, as well as equilibrium constants for lactams and acyclic amides, higher values occur when both the amide carbonyl oxygen and N-H are bound to Rh(2)(5S-MEPY)(4). This cooperative bonding mode is confirmed by NMR measurements that show a distinctive shift of a N-H absorption, as well as perturbation of the ligands on dirhodium compound, and they suggest N-H association with a ligated oxygen of Rh(2)(5S-MEPY)(4). Measurements were made on the dirhodium(II) compound from which protective axial ligands have been removed to enhance their reliability.

Report this publication

Statistics

Seen <100 times