title: Organometallic mediated radical polymerization of vinyl acetate using bis(imino)pyridine vanadium trichloride complexes.
abstract: The synthesis and characterization of one novel proligand and six novel vanadium(III) trichloride complexes is described. The controlled radical polymerization activity towards vinyl acetate of these, and eight other bis(imino)pyridine vanadium trichloride complexes previously reported, is investigated. Those complexes possessing variation at the N-aryl para-position with no steric protection offered by ortho-substituents (4 examples) result in poor control over poly(vinyl acetate) polymerization. Control is improved with increasing steric bulk at the ortho-position of the N-aryl substituent (4 examples) although attempts to increase steric bulk past isopropyl were unsuccessful. Synthesizing bis(imino)pyridine vanadium trichloride complexes with substituted imine backbones restores polymerization control when aliphatic substituents are used (4 examples) but ceases to make any drastic improvements on catalyst lifetime. Modification of the polymerization conditions is also investigated, in an attempt to improve the catalyst lifetime. Expansion of the monomer scope to include other vinyl esters, particularly those derived from renewable resources, shows promising results.
authors: University of Prince Edward Island, 550 University Avenue, C1A 4P3, Charlottetown, PE, Canada.
authors: Mitchell R
authors: MR
authors: Perry
authors: Laura E N
authors: LE
authors: Allan
authors: Andreas
authors: A
authors: Decken
authors: Michael P
authors: MP
authors: Shaver
mesh_terms: D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D058105:Polymerization; D014639:Vanadium / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D009942:Organometallic Compounds; D014753:Vinyl Compounds; D014639:Vanadium; C011566:vinyl acetate