1,721,133 research outputs found
Palladium and nitrogen-donor ligands: a good combination for the synthesis of CO/aromatic olefins polyketones
No full textPd-catalyzed oligo- and polymerization reactions: how subtle changes in the ligand properties can induce large effects
No full text
Ligand symmetry and polymer tacticity in Pd-catalyzed stereocontrolled polyketones synthesis
No full textControl of productivity, molecular weight and atereochemistry in Pd-catalysed synthesis of polyketones
No full textNew atropoisomeric bidentate nitrogen-donor ligands as potential stereocontrollers in the CO/olefins copolymerization catalysed by Pd(II) salts
No full textPalladium catalyzed CO/vinyl arene and ethylene/acrylate copolymerizations: analogies and differences
No full textHomogeneous catalysis represents a powerful tool for the controlled synthesis of polymeric materials.1 During the last decades considerable attention has been focused on two polymerization reactions: the CO/alkene copolymerization to yield perfectly alternating polyketones,2 and the ethylene/polar vinyl monomer copolymerization to yield functionalized polyolefins.3 Both reactions are catalyzed by Pd(II) complexes with -diimines as ancillary ligands. Despite the extensive studies in this field, there is a lack of a direct comparison between the two reactions, thus limiting to highlight their analogies and differences.
For several years we have been investigating the CO/vinyl arene copolymerization, and, more recently, we have started to study the ethylene/methyl acrylate (MA) copolymerization, too. With the aim to fill in this gap of knowledge, we have now investigated two series of -diimines (N-N) featured by the acenaphthene (BIAN) or the 1,4-diazabutadiene skeleton (DAB) and sharing the substituents on the N-donor atoms that are 1-naphthyl (1-napht)4 and 2-naphthyl (2-napht) groups (Figure).
These ligands were used to synthesize the corresponding neutral and monocationic Pd(II) complexes [Pd(CH3)(CH3CN)(N-N)][PF6], the latter being tested as precatalysts in both copolymerization reactions. The detailed catalytic study proves that: i. in the CO/vinyl arene copolymerization BIAN ligands generate more productive and more stable catalysts than the DAB derivatives; ii. in ethylene/MA copolymerization DAB-containing catalysts are more productive than BIAN-analogues; iii. for both reactions, regardless to the ligand skeleton, catalysts with 2-naphthyl-substituted ligands show a catalytic behaviour analogous to that of catalysts with meta-substituted aryl-BIANs, while catalysts with 1-naphthyl-substituted ligands show a catalytic behaviour analogous to that of catalysts with ortho-substituted aryl-BIANs
Pd(II) Complexes with Bidentate Nitrogen-donor Chelating Ligands: Very Versatile and Active Catalyst Precursors for the CO/olefin Co- and Terpolymerization Reactions.
No full textHelvetica Chimica ActaVol. 89 (8)
No full textSi è curata come guest Editor la pubblicazione di un volume della rivista indicata sopra per celebrare il 65° compleanno del Prof. Giambattista Consigli
- …
