Palladium(II) complexes bearing the new pincer ligand 3,5-bis(indazol-2-ylmethyl)toluene; synthesis and catalytic properties

Organonickel(II) complexes with anionic tridentate 1, 3-bis(azolylmethyl)phenyl ligands. synthesis, structural characterization and catalytic behavior

“…For this reason we did not test complex 3 in this reaction. 23,29,30 Thus, the behavior of the nickel complex 4 as an initiator for ethylene polymerization under mild conditions was evaluated and compared to the activity of some related palladium complexes bearing the ligands 3,5-bis(azolylmethyl) toluene. 23 The catalytic activity of the complex in the presence of MAO and the properties of the polymers obtained in these essays are summarized in Table 2.…”

“…As expected, the catalytic activity of 4 increases with an increase in the Al MAO /Ni ratio; however, the complex presents lower activity compared with those shown by the related [PdCl{3, 5- ; Al/Pd = 2500). 23 Due to the modest activity found for this complex we evaluated the catalytic activity only at 60 ºC. We suggest that the polymerization reaction catalyzed by 4 occurs by a mechanism similar to those proposed for square-planar cyclopalladate complexes derived from phenylhydrazones (C,N,N-donor), 31 where the first step is the replacement of the halide by a methyl group, increasing the electron density of the metal atom, followed by cleavage of the M-N bond to generate a vacancy at the metal center (Scheme 3).…”

“…9, 2011 Recently we reported the synthesis and properties o f t h e p i n c e r-t y p e p a l l a d i u m ( I I ) c o m p l e x e s [PdCl{bis(azolylmethyl)tolyl-N,C,N}] showing that they are active in the polymerization of ethylene. 23 Following our interest in these types of compounds, we report in this paper the synthesis and properties of new nickel(II) bromide complexes bearing bis(azolylmethyl)phenyl type ligands, acting as anionic tridentate (N,C,N) donors. The crystal structure of the ligand 2-bromo-1,3-bis(indazol-2-ylmethyl) benzene and the complex {bis(indazol-2-ylmethyl)phenyl} bromonickel(II), determined by single crystal X-ray diffraction analysis, are also reported.…”

Complejos pincer y su comportamiento como iniciadores en polimerización de etileno

“…Estos complejos fueron obtenidos como sólidos de color amarillo, estables al aire y con altos rendimientos. Fueron caracterizado mediante técnicas espectroscópicas: FTIR, RMN de 1 H y 13 C (mono y bidimensional), análisis elemental y espectrometría de masas (Hurtado et al, 2010 Al observar los datos de la Tabla 1, se aprecia que la actividad catalítica crece al incrementar la relación Al/ [Pd]. Al comparar los complejos, se observa que 3 resultó más activo.…”

Copper(II) Complexes with Tridentate Bis(pyrazolylmethyl)pyridine Ligands: Synthesis, X‐ray Crystal Structures and ϵ‐Caprolactone Polymerization

“…As a consequence, the search of new metal complexes capable of efficiently generating polymer chains with specific properties remains of great importance. Consequently, and following our interest in pincer ligands in transition metal complexes in catalysis, and taking into account the work reported by Ojwach et al., we synthetized, characterized and applied complexes 4–6 in CL polymerization. They among the first complexes of Cu(II) with pyrazole‐ and pyridine‐derived tridentate ligands that are active for CL polymerization.…”