Chain transfer polymerization of methyl methacrylate initiated by organolanthanide complexes

Abstract

A novel chain transfer polymerization mediated by Cp*2 Sm(III) species and organic acids is described. The chain transfer polymerization involves the reaction of organic acids such as thiols or ketones with an active bond between samarium(III) and the enolate at a living chain end of poly(methyl methacrylate) (PMMA). This chain transfer reaction resulted in termination of the living chain end and the regeneration of the active initiator which would consist of (C5Me5)2Sm(III) and deprotonated organic acids. The chain transfer polymerization were confirmed by turnover numbers (TON). tert‐Butyl thiol exhibited the chain transfer reactivity effectively to control the molecular weight of PMMA without decreasing of the polymer yield and the stereoregularity. As a result of this chain transfer polymerization, thermal and optical properties of the PMMA obtained were improved by the control of chain end groups or by reducing a large amount of the samarium initiator.

Catalytic Activity Dependency on Catalyst Components in Aerobic Copper–TEMPO Oxidation

“…The controlled polymerization of methyl methacrylate (MMA) by metallocenes such as zirconocenes1–12 and lanthanocenes13–21 has been well documented. A neutral metallocene enolate or a cationic zirconocene enolate is believed to participate in the propagation with a propagating mechanism analogous to group‐transfer polymerization 22, 23.…”

Syndio-rich poly(methyl methacrylate) from the anionic polymerisation of methyl methacrylate in the presence of novel organoaluminium amides

“…Yasuda 2 and Nodono 3 have used organolanthanides to synthesise highly syndiotactic PMMA, in a living polymerisation, over a range of temperatures. Recently chiral metallocenes have been used to promote the formation of isotactic PMMA, 4 whereas a zircocenium aluminate complex strongly favored syndio-rich material.…”

Sustainable Polymers from Biomass‐Derived α‐Methylene‐γ‐Butyrolactones

“…Overall, the catalytic MBL polymerization by 1 can be effected by addition of MBO as a suitable CTA. Figure 8 outlines the reaction sequence, based on what has been proposed for the chain-transfer polymerization of MMA by the samarocene(III) catalyst (59,120) except that in this case two Sm centers carry a single polymer chain as a result of the redox-then-radical-coupling chaininitiation process.…”