Homogeneous organolanthanide catalysts for the selective polymerization of styrene without aluminium cocatalysts

Abstract

Anionic or neutral allylic samarium or neodymium species catalyse the polymerization of styrene (catalyst/styrene ratio = 1:1000) without addition of a cocatalyst. Random syndiotacticrich material is obtained from tetra-allyllanthanides, whereas neutral trisallyl-lanthanides or anionic ansa-bis(cyclopentadienyl)bisallyl-lanthanides afford isotactic-rich polystyrene.

Diene/olefin/polar monomer copolymerisation: unprecedented functional polymers from a rare earth catalyst

“…All the experiments were performed with the same samarocene allyl initiator25, 26 designated as SmA.…”

“…The catalyst is a solid obtained from the reaction between [(Me 2 CC 5 H 4 ) 2 SmCl,MgCl 2 (THF) 3 ] 2 24 and allylLi(dioxane) as previously described, and stored in a glove box 25. 26…”

Novel cycloaurated gold(III) complexes and their effects on styrene polymerization

“…When gold complexes added to the reaction media s-PS was formed ( Fig. 2; Table 1; run nos., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] After these results were evaluated, series of experiments were conducted at room temperature with different solvents and results. Bulk polymerization was carried out at different catalyst concentrations but conversion did not pass 25% yield.…”

“…The stereoregular state of the polymer is important because it determines the crystallinity and physical properties of the resulting polymer. In general, transition metals are used for styrene polymerization in radicalic polymerization reaction and polystyrene obtained are generally isotactic reach atactic form [14]. But syndiotactic polystyrene (s-PD) is more useful than atactic polystyrene (a-PS) with a high melting point of ∼270°C, a glass transition temperature similar to atactic polystyrene, a fast crystallization rate, a high modulus of elasticity and an excellent resistant to heat and chemical agents [15].…”

Transition metal-based polymer chemistry: a critical micro-review

“…As a consequence, REEs have strong basicity and allow anionic polymerization to take place, although appreciable results in standard 1-ole n polymerization have been achieved [8], e.g. using co-catalyst-free allylic Sm-and Nd-based catalysts [9]. Nevertheless, compared with the properties of Ziegler -Natta and metallocene-based PE, PP, and PS in terms of molecular weight, PDI, and stereoregularity (see below), lanthanidebased systems certainly still play a minor role in this eld of polymer chemistry.…”