Synthesis, Characterization and Radical Scavenging Ability of 3,5-di-tert-Butyl-4-hydroxyphenoxy-Functionalized Polynorbornenes Synthesized Using Ring-Opening Metathesis Polymerization

Novel norbornene derivatives bearing a 3,5-di-tert-butyl-4-hydroxyphenoxy (DBHO) group were synthesized and used as sterically hindered phenol functionalized norbornene monomers (1–4). The ring-opening metathesis polymerization (ROMP) of these functional monomers was carried out with a typical ruthenium catalyst (bis(tricyclohexylphosphine)benzylidene ruthenium (IV) dichloride, a Grubbs first-generation catalyst) to prepare sterically-hindered phenol-functionalized polymers possessing radical scavenging function. The resulting polymers bearing a DBHO side-chain were characterized by means of gel-permeation chromatography, 1H-NMR and 13C-NMR. The radical scavenging ability of polymers was determined using the α,α-diphenyl-β-picrylhydrazyl (DPPH⋅) free radical. Due to the electron-donating effect of the oxygen atom located in the para-position of phenol, the resulting polymers showed high efficiency to scavenge DPPH⋅free radical. The molecular weight of polymers was dependent on the molar ratio of monomer to catalyst ([M]/[C]), and the ROMP activity was dependent on the stereostructure of monomers themselves.

[1]  A. Toyota,et al.  Synthesis of polymeric antioxidants based on ring-opening metathesis polymerization (ROMP) and their antioxidant ability for preventing polypropylene (PP) from thermal oxidation degradation , 2008 .

[2]  A. Toyota,et al.  Synthesis and radical scavenging ability of new polymers from sterically hindered phenol functionalized norbornene monomers via ROMP , 2007 .

[3]  T. Nonaka,et al.  Synthesis of chloromethylstyrene-tetraethyleneglycol dimethacrylate copolymer beads having various phenolic derivatives immobilized via amide bond and their antioxidation activity , 2005 .

[4]  A. Kenwright,et al.  Nature of the Propagating Species in Ring-Opening Metathesis Polymerizations of Oxygen-Containing Monomers Using Well-Defined Ruthenium Initiators , 2005 .

[5]  A. Kenwright,et al.  Ring opening metathesis polymerisations of norbornene and norbornadiene derivatives containing oxygen: a study on the regeneration of Grubbs catalyst , 2004 .

[6]  C. Slugovc.  The Ring Opening Metathesis Polymerisation Toolbox , 2004 .

[7]  Jadranka Travas-Sejdic,et al.  The antioxidant activity of conducting polymers in biomedical applications , 2004 .

[8]  J. Travas-sejdic,et al.  Conducting polymers as free radical scavengers , 2004 .

[9]  D. Flynn,et al.  High-load, ROMP-generated oligomeric bis-acid chlorides: design of soluble and insoluble nucleophile scavengers. , 2003, Organic letters.

[10]  Joseph D. Rule,et al.  ROMP Reactivity of endo- and exo-Dicyclopentadiene , 2002 .

[11]  R. Grubbs,et al.  New insights into the mechanism of ruthenium-catalyzed olefin metathesis reactions. , 2001, Journal of the American Chemical Society.

[12]  Y. Ohkatsu,et al.  Effect of para-substituents of phenolic antioxidants , 2001 .

[13]  Y. Ohkatsu,et al.  Phenolic antioxidants-effect of ortho-substituents , 2000 .

[14]  E. Komarova,et al.  Sterically hindered phenol–dextran conjugates: synthesis and radical scavenging activity , 1999 .

[15]  K. J. Ivin,et al.  Olefin metathesis and metathesis polymerization , 1997 .

[16]  J. Näsman,et al.  Polar Activation in Copolymerization of Propylene and 6-tert-Butyl-[2-(1,1-dimethylhept-6-enyl)]-4-methylphenol over a Racemic [1,1'-(Dimethylsilylene)bis(.eta.5-4,5,6,7-tetrahydro-1- indenyl)]zirconium Dichloride/Methylalumoxane Catalyst System , 1994 .

[17]  A. Albertsson,et al.  New developments in speciality polymers: polymeric stabilizers , 1985 .

[18]  J. Arbiser,et al.  Simple, inexpensive procedure for the large-scale production of alkyl quinones , 1983 .