Synthesis and characterization of polymeric derivatives containing grafted triorganotin cinnamates with electrochemical chloride response

Poly[(p-vinyl) cinnamic acid] and the corresponding copolymers with styrene were prepared. Subsequent functionalization with bis (tributytin) oxide or bis(triphenyltin) oxide afforded the corresponding homo- and copolymeric tributyltin cinnamates, respectively. The coordination at tin in solution and in the solid state was investigated by 117Sn solution and solid-state NMR. The polymeric triphenyltin carboxylates exhibit four-coordination at tin, in solution as well as in the solid state. While this also holds for the tributyltin analogues in solution, they exhibit mixed four- and five-coordination in the solid state, the relative amount of five-coordination increasing with increasing tin functionalization. The difference between the tributyl- and triphenyltin compounds is interpreted in terms of both steric factors, and rigidity of the cinnamate side chain of the polymers. The electrochemical anionic response of the polymeric tributyltin carboxylates to chloride has been assessed by potentiometric measurements with liquid membranes. The response is weaker for the polymers than for analogous non-polymeric reference compounds, probably as a consequence of the hydrophobic barrier created by the polystyrene backbone. No evidence for carrier leaching by hydrolysis of the tin moiety could be found.