Polymerization of Isoprene by a Single Component Lanthanide Catalyst Precursor

Cationic Alkyl Rare‐Earth Metal Complexes Bearing an Ancillary Bis(phosphinophenyl)amido Ligand: A Catalytic System for Living cis‐1,4‐Polymerization and Copolymerization of Isoprene and Butadiene

“…A common feature in the reported catalyst systems is that they all require an aluminum additive, such as AlR 2 Cl, AlR 3 , or MAO, to show high activity and high cis ‐1,4 selectivity, which makes it difficult to identify the true catalytic species and to understand the mechanistic aspects of the polymerization process 2–8. Recently, cationic methylyttrium species, such as [YMe 2− n (solv) x ] n +1 ( n =0, 1; solv=solvent), have been reported to show activity for the polymerization of butadiene and isoprene in the absence of an aluminum additive, but the use of a bulky alkyl aluminum additive, such as Al( i Bu) 3 , was again essential to achieve significant cis ‐1,4 selectivity (67 % vs. 90 % for isoprene polymerization with and without Al( i Bu) 3 , respectively) 9.…”

Analysis of solution polybutadiene polymerizations performed with a neodymium catalyst

“…In the past years, distinct catalyst systems (Ni [11, 12], Co [13, 14], Nd [1–10, 15–17], Ti [18, 19], and Sm [20–22]) have been developed for 1,3‐diene polymerizations using methylaluminoxane (MAO) [2–4], borate [16], and alkylaluminum/halides [1–10] as cocatalysts. Titanocene/MAO [18–19] and samarocene/AlR 3 /borane [20–22] catalysts present single‐active catalyst sites and are able to produce high cis ‐1,4 polybutadienes (PB) with the simultaneous control of the MWD and stereoregularity of the obtained polymer material; however, these catalysts require large amounts of MAO to scavenge impurities and activate the catalyst. Therefore, there are huge incentives for development of alternative catalyst systems that do not require the use of MAO as cocatalyst, given its high costs and difficulty in handling.…”

Stereospecific Polymerization of Isoprene with Nd(BH4)3(THF)3/MgBu2 as Catalyst

“…Among numerous catalytic studies devoted to cis-homopolymerization, [1,2] lanthanide derivatives are frequently considered. [3][4][5][6] Trans-homopolymerization has not been studied so far, [7] but a new interest in this kind of polymerization has emerged recently in the high performance rubbers or tyres industry, [8] because of the high mechanical properties of such materials. [9] Moreover, some recent results show that trans-stereospecificity is an indication of potential conjugated diene-olefin copolymerization: using a trans-stereospecific samarocene catalyst, we recently performed the copolymerization of isoprene or butadiene with a-olefins and with a,odienes.…”