title: Synthesis and Structural Properties of Aza[n]helicene Platinum Complexes: Control of Cis and Trans Stereochemistry.
abstract: The synthesis and structural characterization of azahelicene platinum complexes obtained from cis-PtCl2(NCEt)(PPh3) and from ligands that differ in terms of both the position of the nitrogen atom and the number of fused rings are reported. These square-planar complexes of the general formula PtCl2(nHm)(PPh3) (n = 4, 5; m = 5, 6) display mainly a cis configuration. However, by X-ray crystallographic analysis, we show that for both PtCl2(4H6)(PPh3) and PtCl2(5H6)(PPh3) there is chirality control of the cis/trans stereochemistry. Indeed, starting from a racemic mixture of aza[6]helicene, platinum complexes with a cis configuration are invariably obtained, and the more thermodynamically stable trans isomers are formed when using enantiopure ligands. We further corroborated these results by NMR analysis in solution.
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, and Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, Campus de Beaulieu , 35042 Rennes Cedex, France.|Dipartimento di Chimica Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Mendola
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, and Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, Campus de Beaulieu , 35042 Rennes Cedex, France.
authors.forename: Nidal
authors.initials: N
authors.lastname: Saleh
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, and Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, Campus de Beaulieu , 35042 Rennes Cedex, France.
authors.forename: Nora
authors.initials: N
authors.lastname: Hellou
authors.affiliation: Aix-Marseille Université, Centrale Marseille, CNRS, iSm2, UMR 7313 , 13397 Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.affiliation: Aix-Marseille Université, Centrale Marseille, CNRS, iSm2, UMR 7313 , 13397 Marseille, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, and Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, Campus de Beaulieu , 35042 Rennes Cedex, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Toupet
authors.affiliation: Dipartimento di Chimica Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Castiglione
authors.affiliation: INSTM R.U. and Dipartimento di Ingegneria e Scienze Applicate, Università di Bergamo , Viale Marconi 5, 24044 Dalmine, Bergamo, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Melone
authors.affiliation: INSTM R.U. and Dipartimento di Ingegneria e Scienze Applicate, Università di Bergamo , Viale Marconi 5, 24044 Dalmine, Bergamo, Italy.
authors.forename: Tullio
authors.initials: T
authors.lastname: Caronna
authors.affiliation: INSTM R.U. and Dipartimento di Ingegneria e Scienze Applicate, Università di Bergamo , Viale Marconi 5, 24044 Dalmine, Bergamo, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fontana
authors.affiliation: Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia , Via Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Javier
authors.initials: J
authors.lastname: Martí-Rujas
authors.affiliation: Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia , Via Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Parisini
authors.affiliation: Dipartimento di Chimica Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Malpezzi
authors.affiliation: Dipartimento di Chimica Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano , Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mele
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, and Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, Campus de Beaulieu , 35042 Rennes Cedex, France.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Crassous