Organometallic mediated radical polymerization of vinyl acetate using bis(imino)pyridine vanadium trichloride complexes

Dalton Trans. 2013 Jul 7;42(25):9157-65. doi: 10.1039/c3dt32625j. Epub 2013 Jan 23.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Free Radicals / chemical synthesis
  • Free Radicals / chemistry
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry*
  • Polymerization
  • Vanadium / chemistry*
  • Vinyl Compounds / chemistry*

Substances

  • Free Radicals
  • Organometallic Compounds
  • Vinyl Compounds
  • Vanadium
  • vinyl acetate