title: Mono- and dinuclear bioxazoline-palladium complexes for the stereocontrolled synthesis of CO/styrene polyketones.
abstract: The coordination chemistry of the chiral bioxazoline ligand (4S,4'S)-2,2'-bis(4-isopropyl-4,5-dihydrooxazole) to Pd(II) provides evidence that the ligand bonding can occur either through chelation of one Pd(II) ion leading to a mononuclear species with the expected cis geometry, or by double bridging of two Pd(II) ions giving a dinuclear complex with trans geometry. The species in solution are identified by 1H NMR spectroscopy. Both the mononuclear and the dinuclear complexes promote the CO/styrene copolymerization, yielding the corresponding polyketone with a fully or a predominantly isotactic microstructure, depending on the reaction medium. The nature of the anion present in the palladium precatalysts affects the polyketone stereochemistry. MALDI-TOF analysis of the copolymers synthesized reveals the presence of p-hydroxyphenolic end-groups, thus confirming and explaining the role of 1,4-hydroquinone as a molecular weight regulator.
authors.affiliation: Dipartimento di Scienze Chimiche,Università di Trieste, Via Licio Giorgieri 1, 34127 Trieste, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Scarel
authors.forename: Jérôme
authors.initials: J
authors.lastname: Durand
authors.forename: Davide
authors.initials: D
authors.lastname: Franchi
authors.forename: Ennio
authors.initials: E
authors.lastname: Zangrando
authors.forename: Giovanni
authors.initials: G
authors.lastname: Mestroni
authors.forename: Carla
authors.initials: C
authors.lastname: Carfagna
authors.forename: Luca
authors.initials: L
authors.lastname: Mosca
authors.forename: Roberta
authors.initials: R
authors.lastname: Seraglia
authors.forename: Giambattista
authors.initials: G
authors.lastname: Consiglio
authors.forename: Barbara
authors.initials: B
authors.lastname: Milani