Vinyl-addition polymerization of norbornene catalyzed by (pyrazol-1-ylmethyl)pyridine divalent iron, cobalt and nickel complexes

Nickel(II) complexes bearing pyrazolylpyridines: synthesis, structures and ethylene oligomerization reactions

“…Much effort has particularly been devoted to the modification of known ligands or to the design and development of new ligand systems with a view to enhancing both activity and selectivity . We have previously reported the use of pyrazolyl late transition metal catalysts in ethylene oligomerization and polymerization reactions . The results from those studies, which are also consistent with other recent reports, indicate that catalytic properties greatly depend on reaction conditions, aluminium co‐catalysts and ligand architecture.…”

Dichlorido{2-[(3,5-diphenyl-1H-pyrazol-1-yl-κN2)methyl]pyridine-κN}palladium(II)

“…Interestingly, the cobalt analogues do not adhere to this trend. While the L2 analogue shields a smaller percentage of the metal than the L3 analogue, it is CoCl 2 (L2) that has a longer metal-N pz distance than CoCl 2 (L3) (Balamurugan et al, 2004;Benade et al, 2011). Steric effects alone cannot explain the latter observations for a metal with different electronic properties; thus, electronic effects must contribute to the solid-state geometry of the Co complexes.…”

“…The shielding is expressed by the percentage of the metal coordination sphere blocked by the ligand from molecular attack. Tables 2 and 3 compile the data of the shielding percentage (Guzei & Wendt, 2006) and the metal-N pz distance for (I), literature data and other related compounds in the Cambridge Structural Database (see Scheme; Allen, 2002) (Ojwach et al, 2009;Segapelo et al, 2009;Balamurugan et al, 2004;Benade et al, 2011;Kilpin & Crowley, 2010;Allen, 2002).…”

Positional and compositional disorder in a ruthenium(II) piano-stool complex

“…The folding angle of the L ligand defined as the dihedral angle between the Ru1-N1-C5-C6 and Ru1-N3-N2-C6 planes is 125.41 (12) . Relevant values for Co II (Benade et al, 2011), Ni II (Ojwach, Guzei, Benade et al, 2009) and Pd II complexes Segapelo et al, 2009;Spencer et al, 2012) averaged 121 (6) . In none of the four comparisons is the difference statistically significant and the geometrical parameters are therefore typical.…”