188686-60-4Relevant academic research and scientific papers
A New Totally Flat N(sp2)C(sp2)N(sp2) Pincer Palladacycle: Synthesis and Photoluminescent Properties
Consorti, Crestina S.,Ebeling, Gunter,Rodembusch, Fabiano,Stefani, Valter,Livotto, Paolo R.,Rominger, Frank,Quina, Frank H.,Yihwa, Chang,Dupont, Jairton
, p. 530 - 536 (2004)
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 Li2PdCl4 in methanol at room temperature affords the pincer palladacycle (C5H 4N-2-C=C(Cl)-8-C9H6κN,κC,κ N)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 π-stacking between alternate pyridine-quinoline moieties (3.448 A). The pairs are also connected by π-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.
Towards to the trans-bromination of 2-styrylpyridine with a palladacycle intermediary and structure analysis for trans-1,2-dibromo-2-styrylpyridine
Mafud, Ana Carolina,Gambardella, Maria Teresa Do Prado,Caires, Antonio Carlos Fávero
, p. 87 - 90 (2011/04/23)
The simple halogenation of alkynes in conventional organic reactions gives a blend of cis and trans isomers. It is proposed then, a synthesis of stereospecific halogenation of alkynes in trans position, using palladacycle as intermediaries. The recrystallization of the compound obtained by bromination of 2-Styrylpyridine, with cyclepalladium intermediary results in a single crystal, which is subjected to X-ray diffraction. The crystal packing is established through weak interactions of three types. The first one is of the type π × π interactions, from symmetry operation, between the centroids. The second one is of the type C-X?π interactions. And the last type is an anomalous intermolecular interaction between halogens, C-X?X-C, with bond distances smaller than the sum of the van der Waals radii. The conformation on the C=C bond is trans and the dihedral angle between the aromatic rings is (with esd approximate) 18.1(3)°.
