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Abstract

] complex reported as a byproduct of the reaction between (acac) 3 V and AlCl 3 (THF) 3 (right-hand column, 14th line from the top), we wish to acknowledge that this complex was previously isolated upon reaction of Cl 2 Al(acac) with 2 equiv of THF in methylene chloride (Lewinski, J.; Pasynkiewicz, S. Inorg. Chim. Acta 1987, 130, 23-27) and correctly formulated on the basis of spectroscopic characterization. Several other relevant aluminum acetylacetonate complexes have been described and characterized by NMR spectroscopy and elemental analysis (Lewinski, J.; Pasynkiewicz, A.

Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO2ionic liquid system

“…The general problem associated with vanadium catalysts is reduction to the inactive low‐valent forms . In this context, the alkylaluminium activator, which acts both as Lewis acid and alkylating agent, plays an important role because it participates in the reduction of the metal centre.…”

Monoclonal antibody MOC-31 reactivity as a marker for adenocarcinoma in cytologic preparations

“…For the β‐diketonate vanadium based catalysts, it has been proposed that the aluminum cocatalyst promotes the leaching of the ligand and thermally unstable bimetallic species are formed independently of the precatalyst 11. This study suggests a similar trend in the vanadium amide catalysts.…”

“…Attempts to improve the thermal stability of vanadium catalysts have been made, but up to now they have been far from successful. In the series of β‐diketonate derivatives, it has definitively been determined that the aluminum cocatalyst promotes the leaching of the ligand and thermally unstable bimetallic species comprising vanadium and aluminum organyls are formed independently of the precatalyst structure 11. Ligand design involving oxygen and nitrogen donors has thus been carried out to synthesize more robust V(III) and V(IV) catalysts: the set of explored ligands includes amidinate,12 amide,13, 14 diimide,15 amide–phenoxy,16 and phenoxy–imine17 ligands.…”

Ethylene polymerization and ethylene/hexene copolymerization with vanadium(III) catalysts bearing heteroatom‐containing salicylaldiminato ligands

“…It is apparent from past decades studies that the predominant cause of this phenomenon is ascribed to reduction of catalytically active vanadium species to low‐valent, less active, or inactive species 3, 4. Design and synthesize ancillary ligands to stabilize the active species has proved to be an effective approach 5–25. A series of thermal robust vanadium catalysts have been reported recently, for example, the bis (benzimidazole) amine vanadium catalysts reported by Gibson's group displayed high efficiency for ethylene (co)polymerization and showed remarkable thermal stability 5(c).…”