Mn₂(CO)₁₀‐induced controlled/living radical copolymerization of vinyl acetate and methyl acrylate: Spontaneous formation of block copolymers consisting of gradient and homopolymer segments

Abstract

The controlled/living radical polymerization of vinyl acetate (VAc) and its copolymerization with methyl acrylate (MA) were investigated in bulk or fluoroalcohols using manganese complex [Mn 2 (CO) 10 ] in conjunction with an alkyl iodide (RAI) as an initiator under weak visible light. The manganese complex induced the controlled/living radical polymerization of VAc even in the fluoroalcohols without any loss of activity. The RAI/Mn 2 (CO) 10 system was also effective for the copolymerization of MA and VAc, in which MA was consumed faster than VAc, and then the remaining VAc was continuously and quantitatively consumed after the complete consumption of MA. The 1 H and 13 C NMR analyses revealed that the obtained products are block copolymers consisting of gradient MA/VAc segments, in which the VAc content gradually increases, and homopoly(VAc). The use of fluoroalcohols as solvents increased the copolymerization rate, controllability of the molecular weights, and copolymerizability of VAc. The saponification of the VAc units in poly(MA-grad-VAc)block-poly(VAc) resulted in the corresponding poly(MA-co-c-lactone)-block-poly(vinyl alcohol) due to the intramolecular cyclization between the hydroxyl and neighboring carboxyl groups in the gradient segments.

Photochemically Enabled Iodine Degenerative Transfer Controlled Radical Homo- and Block Copolymerization of Vinylidene Fluoride at Ambient Temperatures with Mn2(CO)10and Visible Light

“…Very recently, Mn 2 (CO) 10 was nevertheless employed as a photo-activator of alkyl iodides (IDT) (116)(117)(118), or RAFT reagents (119) in controlled radical photo(co)polymerizations of VAc, acrylates, styrene and alkenes. Here, Mn(CO) 5 • was shown to irreversibly activate the iodine terminated chains or the initiator (102), but the in-situ generated Mn(CO) 5 -I (85) was not involved in the IDT.…”

Macromolecular design and application using Mn2(CO)10‐based visible light photoinitiating systems

“…This diversity was explained as a result of the reactivity of polystyryl radical to the monomers employed in the photoinitiated polymerization step. 89 Additionally, to confirm the efficiency of the photoinitiating system St was also used as monomer in a second stage as a chain extension experiment in which the molecular weight of polystyrene doubled after the irradiation. Depending on the termination mode of the monomer involved AB or ABA type block copolymers were formed.…”

Recent developments in metal-catalyzed living radical polymerization

“…72 Both monomers are simultaneously consumed, whereas MA is polymerized faster than VAc because of its higher copolymerizability. The resulting polymers possess block-like copolymer structures comprised of gradient segments of MA and VAc, where the content of the latter gradually increases, and homopoly(VAc) segments.…”

“…[71][72][73][74] The dinuclear manganese complex has been employed to generate radical species from alkyl iodides for organic synthesis of low-molecular weight compounds. In this radical reaction, the dinuclear complex generates a mononuclear manganese radical species [ÁMn(CO) 5 ] under visible light and then abstracts iodine from even secondary and primary alkyl iodides to generate unstable carbon radical species.…”