New Phenomena in Organometallic‐Mediated Radical Polymerization (OMRP) and Perspectives for Control of Less Active Monomers

Abstract

The impact of reversible bond formation between a growing radical chain and a metal complex (organometallic-mediated radical polymerization (OMRP) equilibrium) to generate an organometallic intermediate/dormant species is analyzed with emphasis on the interplay between this and other one-electron processes involving the metal complex, which include halogen transfer in atom transfer radical polymerization (ATRP), hydrogen-atom transfer in catalytic chain transfer (CCT), and catalytic radical termination (CRT). The challenges facing the controlled polymerization of "less active monomers" (LAMs) are outlined and, after reviewing the recent achievements of OMRP in this area, the perspectives of this technique are analyzed.

Photocatalysts in Polymerization Reactions

“…. During the radical polymerization, side reactions occur, leading to polymer death, for example, polymer radical coupling or polymer radical disproportionation . To avoid such reactions, a radical trapping agent is added to react with the growing polymer chains affording the dormant species but, to maintain the living polymerization, this reaction must be reversible .…”

“…To avoid such reactions, a radical trapping agent is added to react with the growing polymer chains affording the dormant species but, to maintain the living polymerization, this reaction must be reversible . The main CRP processes are atom transfer radical polymerization (ATRP), nitroxide‐mediated polymerization (NMP), reversible fragmentation chain transfer (RAFT), organometallic radical mediated polymerization (OMRP), iodine‐transfer polymerization (ITP), and tellurium‐mediated radical polymerization (TERP) . Although these CRP processes adopt very different chemical strategies, the balance between deactivation of radical chains and reactivation of the dormant species remains the main issue for the CRP.…”

Organometallic‐Mediated Alternating Radical Copolymerization of tert‐Butyl‐2‐Trifluoromethacrylate with Vinyl Acetate and Synthesis of Block Copolymers Thereof

“…This contribution aims at developing a well‐controlled radical copolymerization of VAc and MAF‐TBE by organometallic‐mediated radical polymerization (OMRP) using cobalt(II) acetylacetonate, [Co(acac) 2 ], as a controlling agent . It is focused on this particular RDRP technique due to its ability to efficiently control the polymerization of several nonconjugated monomers, in particular VAc . Notably, RDRP of VAc was only achieved using a few techniques: RAFT polymerization, ITP, and OMRP .…”

Fluoroalkyl Pentacarbonylmanganese(I) Complexes as Initiators for the Radical (co)Polymerization of Fluoromonomers

“…polymerization (RDRP) of VDF has been possible via iodine transfer polymerization (ITP) [3,[9][10][11][12][13] and, more recently, by reversible addition−fragmentation chain-transfer (RAFT) polymerization [14,15] and by organometallic-mediated radical polymerization (OMRP) [16,17]. Specifically, OMRP is based on the reversible trapping of the growing radical chain by a transition metal complex to generate an organometallic dormant species [18][19][20][21]. ITP and RAFT led to a loss of control once the inverted monomer additions led to the full conversion of the dormant species to the tail isomer, respectively PVDF T -I and PVDF T -xanthate, which are less easily reactivated than the corresponding PVDF H -I and PVDF H -xanthate species.…”