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

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 [sigma]-delocalization and [sigma]-[small pi]-delocalization in the copolymers with the latter originating from the presence of SnPh2 moieties in the polymer.