Synthesis of OH-functionalized poly(p-xylylene)s by reductive coupling polymerization of aromatic dialdehydes with stoichiometric 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 (TMSiCI). High educt and no side products have been observed using 10 mol% of SmI 2 and excess of Mg turnings activated by C 2 H 4 Br 2 in the presence of TMSiCI. Low yields of hydrobenzoin were observed when SmCp 2 replaced SmI 2 . The reductive coupling polymerization of aromatic dialdehydes can be conducted under catalytic conditions with 12 mol% of SmI 2 and excess of Mg or Mg/Hg in the presence of TMSiCl in THF. OH-functionalized PPXs [PhO-Ar-OPh-CHOH-CHOH] n (Ar= Ph-CMe 2 -Ph, Ph-C(CF 3 ) 2 -Ph) were obtained with moderate yields polymer and M n of up to 16 000 g/mol.