Nickel (II) complexes supported by a fluorinated β‐diketiminate backbone ligand: synthesis, catalytic activity toward norbornene polymerization, and the oxygenated species

Abstract

H 3 : 2). When activated by methylaluminoxane (MAO), both complexes polymerize norbornene rapidly via a vinyl-type polymerization mechanism. Treatment of nickel complex 1 with oxygen gives rise to intramolecular aerobic hydroxylation. The oxygenated species 3 was characterized by X-ray crystallography.

Metal catalysts for the vinyl/addition polymerization of norbornene

“…When the Al/Ni ratio was changed from 200 to 1200 the activity first increased and then decreased with an optimal ratio of 800 for both precatalysts Ni-16 and Ni-17. Under the same conditions Ni-17 exhibited higher catalytic activities and produced PNB with higher molecular weight than Ni-16 [138].…”

“…Precatalysts Ni-16 and Ni-17 with fluorinated ␤-diketiminato ligands yielded activities of more than 10 6 g polymer /mol Ni h in combination with MAO [138]. When the temperature was raised from 30 • C to 90 • C the activity increased and the average molecular weight decreased.…”

Homo‐ and copolymerization of ethylene and norbornene with bis(β‐diketiminato) titanium complexes activated with methylaluminoxane

“…All manipulations of air‐sensitive compounds were performed under a nitrogen atmosphere with standard Schlenk techniques. The β‐diketiminate ligands 1a – d were synthesized according to the literature 38, 39. Diethyl ether and toluene were distilled from sodium/benzophenone ketyl under nitrogen.…”

“…We have concentrated our attention on the organometallic complexes bearing β‐diketiminate ligands because of their easily modified features on steric and electronic effects. Previously, we have synthesized β‐diketiminato nickel complexes and investigated their catalytic properties for olefins polymerization 38, 39. However, there is little report on titanium catalysts bearing β‐diketiminate ligands for olefins polymerization.…”

X-ray characterization of HnacnacR and the first vanadium β-diiminate dimer (R = mesityl)

“…Although other transition metal nacnac dimers with bridging hydroxide have been reported with M ¼ Co [13], Cu [14], Zn [15,16], and Ni [17], 2 represents the first example of a vanadium nacnac dimer.…”