Synthesis of OH-functionalized poly(p-xylylene)s by reductive coupling polymerization of aromatic dialdehydes with catalytic amounts of divalent samarium compounds

Abstract

The focus of this study is on reductive couplings of aromatic monoaldehydes and dialdehydes utilizing catalytic amounts of Sm(II) compounds and different co-reductants such as Mg turnings and Mg/Hg alloy in the presence of trimethylsilylchloride (TMSiCl). High educt and no side products have been observed using 10 mol% of SmI₂ and excess of Mg turnings activated by C₂H₄Br₂ in the presence of TMSiCl. Low yields of hydrobenzoin were observed when SmCp₂ replaced SmI₂. The reductive coupling polymerization of aromatic dialdehydes can be conducted under catalytic conditions with 12 mol% of SmI₂ and excess of Mg or Mg/Hg in the presence of TMSiCl in THF. OH-functionalized PPXs were obtained with moderate yields polymer and M_n of up to 16 000 g/mol.