Efficient aerobic oxidation of alcohols using CuBr2 and a series of a-? pyridyl-imine terminated polydimethylsiloxane ligands

1
Efficient aerobic oxidation of alcohols using
CuBr2 and a series of a-? pyridyl-imine
terminated polydimethylsiloxane ligands

• Zhenzhong Hultzhenzhong.hu_at_mun.cagt, Fran M.
  Kertonltfkerton_at_mun.cagt
• Department of Chemistry, Memorial University of
  Newfoundland,
• St. Johns, NL, Canada, A1B 3X7

• Introduction
• From the point of view of Green Chemistry,
  polymer-based catalysts are very environmentally
  friendly. These catalysts can be used and
  recycled in green solvents such as liquid
  polymers and supercritical carbon dioxide. They
  can also be very selective.
• In our recent studies, a series of a-?
  pyridyl-imine terminated polydimethylsiloxane
  ligands have been synthesized and characterized.
  It is interesting that these carbon dioxide
  miscible ligands form metallocyclic complexes
  when coordinated with copper(I) salt. Meanwhile,
  they provide perfect binding sites for copper
  (II) ions which then work as catalysts for more
  efficient aerobic oxidations of primary and
  secondary alcohols.

Ligand Synthesis
Solubility in Supercritical CO2
Coordination Chemistry
Aerobic oxidation of selected alcohols with in
situ made TEMPO/Cu/L1 system

• Summary
• a-w Pyridyl-imine terminated PDMS compounds have
  been prepared and characterised.
• Coordination chemistry with Cu(I) shows the
  formation of 11 metallocycles.
• The TEMPO/CuBr2/L1 catalytic system is very
  effective for the aerobic oxidation of alcohols.
• Future studies will involve the study of
  catalytic reaction mechanism and the recycling
  of the catalyst.
• Attempts will also be made to obtain further
  evidence for the structures of these
  metallocyclic polymers.

a GC conversion, selectivity gt 99 b
Reaction temperature 45 oC, using compressed
air c Reaction time 48 h
Acknowledgements Prof. Christopher M. Kozak
Green Chemistry and Catalysis Group Dr. Celine
Schneider C-CART (Brent, Linda Julie)
Chemistry Department, Memorial University