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Polymerization of Methyl Methacrylate Initiated by a Divalent Samarium Phenoxide Complex with an Alkyl Aluminium Compound
Author(s) -
Nodono Mitsufumi,
Tokimitsu Toru,
Makino Takayuki
Publication year - 2003
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200390053
Subject(s) - samarium , polymer chemistry , tacticity , polymerization , methyl methacrylate , chemistry , monomer , divalent , copolymer , polymer , organic chemistry
A divalent samarium complex that bears two bulky phenoxide ligands promotes the living polymerization of methyl methacrylate in the absence of cocatalyst. The initiation involves a tail‐to‐tail coupling reaction of the samarium‐enolate radical followed by a one‐electron reduction of the monomer with the divalent samarium initiator. The polymerization takes place stereospecifically and the samarium initiator affords highly syndiotactic poly(methyl methacrylate). The stereoregularity of the polymer is variable with the ratio of the samarium initiator to aluminium compound (2,6‐di‐ tert ‐butyl‐4‐methylphenoxy) 2 AlMe. The polymer obtained when the [Al]/[Sm] ratio is 4.0 has a unique tacticity, [ mm ]/[ mr ]/[ rr ] = 42:11:47, and the polymer has a melting point at 161 °C, which suggests the formation of a stereocomplex between syndiotactic and isotactic poly(methyl methacrylate).Part of the possible initiation mechanism and equimolar reaction of BHT‐Sm II with MMA.