title: Binuclear complexes of bis-chelating ligands based on [1,4]dioxocino[6,5-b:7,8-b']dipyridine moieties.
abstract: Ligands based on a [1,4]dioxocino[6,5-b:7,8-b']dipyridine (doxpy) core were prepared and characterized. They all present two equal chelating moieties each one including one N, O, or S donor in addition to a pyridinic nitrogen. These ligands displayed high selectivity for the formation of binuclear complexes. At least one d(8) ion (Pd(II) or Pt(II)) complex was prepared for each type of ligand. The stereochemical behavior of the ligands is discussed on the basis of NMR spectra. Stable atropoisomers were obtained in the case of N-oxides or in case chiral centers were introduced in the ethereal bridge. As for the complexes, stable enantiomers appear to be in principle attainable for all the new compounds. A test on the cooperative ability of two Pd(II) centers has been grounded on the microstructure of the styrene/CO copolymer catalytically produced by a binuclear pyridine-imino complex. In fact, comparison with the microstructure of the copolymers produced by related single-site mono- and (open-chain) binuclear catalysts reveals significant difference, thus giving indication of possible synergic metal activity.
authors.affiliation: Dipartimento di Chimica Paolo Corradini, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, via Cintia, Napoli I 80126, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Casalino
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Felice
authors.forename: Natascia
authors.initials: N
authors.lastname: Fraldi
authors.forename: Achille
authors.initials: A
authors.lastname: Panunzi
authors.forename: Francesco
authors.initials: F
authors.lastname: Ruffo
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D002614:Chelating Agents; D008024:Ligands; D011725:Pyridines; C023666:pyridine