title: Upon the intriguing stereoselective formation of organobismuth(V) complexes.
abstract: The preparation of triphenylbismuth(V) 3a-k and antimony(V) 4e-k bis-carboxy ester complexes is described. A range of studies in solution suggest that the diastereoselective formation of (RR,SS)-3a-j is governed by the thermodynamic stability of rapidly interconverting epimeric species. Diastereoselectivity is absent in the case of the corresponding Sb complexes, leading to the conclusion that a combination of both ligand-ligand (steric) and metal-ligand (hyperconjugative) interactions govern stereoselectivity. The formation of homochiral complexes (RR,SS)-3a-j is rationalised using a simple model, invoking for the first time a palindromic BiPh3 propeller moiety, which correlates the chirality of the trans axial carboxy-ester ligands. The X-ray crystal structures of both hetero- and homochiral diastereoisomeric antimony complexes (4h and 4i, respectively) are presented in support of this model.
authors.affiliation: Department of Chemistry, University of the West of England, Bristol, UK.
authors.forename: Hubert
authors.initials: H
authors.lastname: Barucki
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.forename: James F
authors.initials: JF
authors.lastname: Costello
authors.forename: Michael B
authors.initials: MB
authors.lastname: Hursthouse