Transition-metal complexes of phenoxy-imine ligands modified with pendant imidazolium salts: Synthesis, characterisation and testing as ethylene polymerisation catalysts

Olefin Polymerization with Non-metallocene Catalysts (Early Transition Metals)

“…The observed activities by certain complexes were slightly/apparently higher than those by VCl 3 (THF) 3 , and the activities decreased at 70 8C probably due to the rapid deactivation even for short period (5 min) and in the presence of excess amount of re-oxidant (300 equivalent to V). On the basis of these data, it seems that 26b (R [101][102][103][104]. Placement of neutral donor ligands (amine, pyridine) into the phenoxy-imine ligands in 27 was not effective; the observed activity by 27 h was relatively close to 26e.…”

“…A series of vanadium(III) complexes containing b-enaminoketonato [99, 100], phenoxy-imine [101][102][103][104], imino-pyrrolide [105] ligands (exemplified in Scheme 3.11) were tested as olefin polymerization catalyst in the presence of Et 2 AlCl and Cl 3 CCO 2 Et. The selected results are summarized in Table 3.5 [99,100,103,105].…”

Chromium, molybdenum and tungsten

“…The zirconium, vanadium and chromium complexes were active as precatalysts for ethylene polymerisation using methylaluminoxane co-catalyst. 52 A new compound containing a cubane tungsten chalcogenide cluster, [(Ca(phen) 2 (H 2 O))(Ca(phen)(H 2 O) 4 )(Ca(phen) 2 (H 2 O) 3 )][W 4 Te 4 (CN) 12 ] Á 5H 2 O was synthesised and characterised. This compound showed a heterogeneous catalytic activity in the transesterification of a range of esters with methanol under mild conditions.…”

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“…The earlier research on various generations of olefin polymerization catalysts demonstrated that the type of central metal makes a more important factor within those, which are decisive for the catalytic properties; in many cases, it is even more significant than the ligand structure. It should be noted, however, that titanium1, 5–18 and zirconium1–6, 15, 16, 18, 19 are most frequently used as metallic centers, whereas hafnium1, 7 or vanadium16, 20–21 are used much less frequently in complexes, which contain phenoxy‐imine ligands. The effect of the type of transition metal in bis(phenoxy‐imine) complexes on their catalytic activity and on the properties of the polymerization products was shown directly in ref 1.…”

“…Very little is known about catalytic vanadium bis(phenoxy‐imine) complexes. Some few vanadium catalysts, which had been investigated until today, were supported systems—MgCl 2 /R m Al(OR) n was used as a support and as an activator at the same time,16 they contained atypical chiral phenoxy‐imine ligands with pendant imidazolium moieties,20 or they contained vanadium at the state of oxidation +3, and one or two phenoxy‐imine ligands 21. It seams that FI complexes of vanadium should be investigated more extensively.…”