Options
Stoeckli-Evans, Helen
Nom
Stoeckli-Evans, Helen
Affiliation principale
Fonction
Professeur.e émérite
Email
helen.stoeckli-evans@unine.ch
Identifiants
Résultat de la recherche
Voici les éléments 1 - 6 sur 6
- PublicationAccès libreCarbonate binding to copper(II) in solution: mixed-ligand complex formation and its application to the isolation and separation of the three isomers of [Cu(bpp)(H2O)][ClO4]2 [bpp = 2,6-bis(pyrrolidin-2-yl)pyridine](2002)
; ; The binding of the carbonate anion to [Cu(meso-bpp)(H2O)]2+ and rac-[Cu(bpp)(H2O)]2+ [bpp = 2,6-bis(pyrrolidin-2-yl)pyridine] in aqueous solution has been investigated. Formation constants of the carbonato complexes [Cu(meso-bpp)(CO3)] and rac-[Cu(bpp)(CO3)] (1.02 × 103 M–1 and 1.77 × 103 M–1, respectively, µ= 0.70 M) have been calculated from spectrophotometric measurements. The formation of these Cu2+ complexes can also be used for an improved synthesis and an easy isolation of the three diastereoisomers of bpp. The mixture of [Cu(meso-bpp)(H2O)]2+ and rac-[Cu(bpp)(H2O)]2+ is separated by elution from SP Sephadex C-25, either as hydroxo or carbonato derivatives. rac-[Cu(bpp)(H2O)]2+ is then resolved into the enantiomers [Cu(S,S-bpp)(H2O)]2+ and [Cu(R,R-bpp)(H2O)]2+, again on SP Sephadex C-25, by means of L-(+)-tartrate as chiral eluent. The three stereoisomers, meso-bpp, (S,S)-bpp and (R,R)-bpp are liberated from the corresponding copper(II) complexes by ligand displacement using trans-1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid (H4cdta). The structure of the meso isomer was solved by a single crystal X-ray analysis using the perchlorate salt [meso-bppH2][ClO4]2•2H2O. - PublicationMétadonnées seulementReactions of the cluster anion [HRu3(CO)(11))](-) with dicyclohexylphosphine: Synthesis and molecular structure of H2Ru3(CO)(8)(PCy2)(2) and H2Ru3(CO)(6)(PCy2)(2)(HPCy2)(2)(2001)
; - PublicationMétadonnées seulementElectron-deficient triruthenium and triosmium clusters from the reaction of the cluster anions [HM3(CO)(11)](-) (M = Ru, Os) with tricyclohexylphosphine in methanol(1999)
; ; - PublicationMétadonnées seulementElectron-deficient triruthenium clusters: synthesis and molecular structure of the anion [HRu3(CO)(7)(PCy3)(2)](-), a second example of an Ru-3 cluster presenting an electron count of 44 electrons(1999)
; The reaction of [HRu3(CO)(11)](-) (1) with an excess of PCy3 in refluxing THF gives the electron-deficient anion [HRu3(CO)(7)(PCy3)(2)](-) (2) which has the rare electron count of 44e. As evidenced by the H-1 and P-31 NMR spectra, 2 exists in solution in the form of two isomers 2a and 2b, one of which crystallises from acetone as the tetraethylammonium salt. The single-crystal X-ray analysis shows a closed Ru, framework with the hydride ligand bridging the metal-metal bond between a phosphine-substituted and a phosphine-free ruthenium atom (isomer 2b). (C) 1999 Elsevier Science S.A. All rights reserved. - PublicationAccès libreSaturated and unsaturated triruthenium clusters containing three sterically demanding phosphine ligands : synthesis and structure of [Ru3(CO)9(PCy3)3] and [Ru3H2(CO)6(PCy3)3](1998)
; - PublicationAccès libreSaturated and unsaturated tetraruthenium clusters containing sterically demanding dicyclohexylphosphido ligands: synthesis and structure of [H4Ru4(CO)8(PCy2)4] and [H5Ru4(CO)8(PCy2)3](1998)
;