Phosphorus-bridged metallocenes: New homogeneous catalysts for the polymerization of propene

Syntheses of rac/meso-{PhP(3-t-Bu-C5H3)2}-Zr{RN(CH2)3NR}, structural analyses of rac-{PhP(3-t-Bu-C5H3)2}Zr{RN(CH2)3NR} (where R is SiMe3 or Ph), and meso to rac isomerization

“…For example, rac-3 displays six cyclopentadienyl signals, two trimethylsilyl methyl signals, and two tert-butyl methyl signals. The upfield 31 P NMR chemical shifts for meso-3 and rac-3 (À43.6 (meso) and À37.1 (rac) in benzene-d 6 solvent; À40.3 (meso) and À33.8 (rac) in THF-d 8 solvent) are consistent with those reported for related phosphine-bridged zirconocenes [12,14,17]. COSY and HETCOR methods were used to assist with NMR peak assignments.…”

“…Ligands (such as ([Me 2 P(fluorenyl) 2 ] À ) [7] and [R 2 P(2-Me-4-t-Bu-C 5 H 2 ) 2 ] À where R = Me or n-Bu [8]) and group 4 metallocenes with a phosphorus-containing ansa-bridge are the subject of two recent review articles [9,10]. A few of these group 4 ansa-metallocenes have been tested as ethylene [11][12][13] and a-olefin polymerization precatalysts [14] (Fig. 2).…”

Alkyl(amino)- and Alkyl(chloro)phosphanyl-Substituted Cyclopentadienyl Complexes of Titanium and Zirconium

“…Cp or MeCp, are a thermally labile class of compounds and readily undergo DielsϪAlder reaction. [37] The most recent examples were reported by Alt and co-workers [38] and by researchers at Shell [39] as intermediate compounds in the synthesis of symmetrical and unsymmetrical ansa-metallocenes with the phenylphosphanylidene bridge. In both cases subsequent nucleophilic substitutions by different cyclopentadienyl-, indenyl-and fluorenyllithium salts have been carried out.…”

Hexadecahydrotetrabenzo[a,c,d,f]fluorene – Ligand, available by Friedel–Crafts fluorene cycloalkylation. Synthesis, crystal and molecular structure of (η5-C29H34)(η5-C5H5)ZrCl2

“…Mixed fluorenyl-cyclopentadienyl [4,5] and fluorenyl-indenyl [6,7] complexes demonstrate high activity in homopolymerization and copolymerization processes. The study of catalytic properties of fluorenyl-based zirconocenes has been well established, so that the presence of alkyl substituents in fluorenyl fragments in some cases increases the activity of catalysts [8e10].…”