Synthesis and characterization of monomeric and polymeric Pd(II) and Pt(II) complexes of 3,4-ethylenedioxythiophene-functionalized phosphine ligands

Phosphine ligands bearing 3,4-ethylenedioxythiophene (EDOT) groups, in which a Ph@d2P group is either connected directly to the thiophene ring [Ph@d2P(5-EDOT), 1] or to the EDOT ethylene bridge via a methylene (4) or longer (7) spacer, have been prepared, together with their complexes @@icis@-[MCl@d2(L)@d2] (M = Pd and Pt). The electrochemical co-polymerization of the complexes with EDOT was investigated, with a view to making conducting polymers incorporating covalently-bound metal-phosphine complexes. Although polymer-coated electrodes were obtained in all experiments, XPS measurements established that polymers made in the presence of @@icis@-[MCl@d2(1)@d2] consisted only of poly(3,4-ethylenedioxythiophene) (PEDOT), whereas polymers made in the presence of @@dcis@-[MCl@d2(L)@d2] (L = 4, 7) were genuine co-polymers containing Pd(II) or Pt(II) complexes.