Poly(dialkylstannane) and poly(diarylstannane) homo- and random copolymers synthesized in liquid ammonia

Abstract

Random copolymers of dialkylstannanes (butyl, octyl and dodecyl) and diarylstannanes were synthesized and characterized with ¹¹⁹Sn NMR spectroscopy, UV/Vis spectroscopy and thermal analysis. These copolymers and the corresponding homopolymers were produced by reaction of dichlorodiorganostannanes, R₂SnCl₂, with sodium in liquid ammonia. In the case of dichlorodibutylstannane, Bu₂SnCl₂, and dichlorodiphenylstannane, Ph₂SnCl₂, two different reaction pathways were applied: the monomers were either directly treated with 2 molar equivalents of sodium, or reactive organostannides were formed in situ and further converted with the respective R₂SnCl₂. Copolymerization of Ph₂SnCl₂ with Oct₂SnCl₂ or Dod₂SnCl₂ did not occur by direct reaction with 2 molar equivalents of sodium, due to the low solubility of the corresponding dichlorodialkylstannanes. Therefore, synthesis of these species was conducted via the reactive phenylstannides. UV/Vis absorption spectroscopy unveiled the presence of σ-delocalization and σ-π-delocalization in the copolymers with the latter originating from the presence of SnPh₂ moieties in the polymer.