title: A new totally flat N(sp(2))C(sp(2))N(sp(2)) pincer palladacycle: synthesis and photoluminescent properties.
abstract: The Sonogashira coupling of 2-bromopyridine with 8-quinolinyl-acetylene affords 2-pyridinyl-8-quinolinyl-acetylene (1) in high yields. The chloropalladation of 1 with Li(2)PdCl(4) in methanol at room temperature affords the pincer palladacycle (C(5)H(4)N-2-C=C(Cl)-8-C(9)H(6)kappaN,kappaC,kappaN)PdCl (2) in 63% yield. The X-ray molecular structure of (2) shows that it is totally flat and that it is associated in pairs though pi-stacking between alternate pyridine-quinoline moieties (3.448 A). The pairs are also connected by pi-stacking with an interpair distance of 3.452 A between quinoline-quinoline moieties. A very low fluorescence emission was also revealed by the pincer palladacycle 2 in both solution and the solid state, which has been ascribed to an excimeric emission due to the particular structure (rigid and totally flat) of 2 in the solid state.
authors.affiliation: Laboratory of Molecular Catalysis, Institute of Chemistry-UFRGS Av. Bento Gonçalves, 9500 Porto Alegre 91501-970 RS Brazil.
authors.forename: Crestina S
authors.initials: CS
authors.lastname: Consorti
authors.forename: Gunter
authors.initials: G
authors.lastname: Ebeling
authors.forename: Fabiano
authors.initials: F
authors.lastname: Rodembusch
authors.forename: Valter
authors.initials: V
authors.lastname: Stefani
authors.forename: Paolo R
authors.initials: PR
authors.lastname: Livotto
authors.forename: Frank
authors.initials: F
authors.lastname: Rominger
authors.forename: Frank H
authors.initials: FH
authors.lastname: Quina
authors.forename: Chang
authors.initials: C
authors.lastname: Yihwa
authors.forename: Jairton
authors.initials: J
authors.lastname: Dupont