Palladium–thiophene complexes as precursors of metal-doped polymers: synthesis, X-ray structural determination and electropolymerization

Abstract

Three complexes of palladium and 3,4-diaminothiophene (L) have been synthesized: [PdL₂]Cl₂·4H₂O (1), PdLCl₂(2) and PdLBr₂(3). These complexes can be electrochemically oxidized and yield thin-film polymers. One of them, derived from 3, gives a material which can be doped with palladium particles by electroreduction. Crystal data for 1, C₈H₂₀Cl₂N₄O₄PdS₂, are as follows: M= 441.68, monoclinic, a= 6.6206(2)Å, b= 9.8983(1)Å, c= 13.2854(1)Å, β= 94.47(2)°, V= 868(1)ų, space group P2₁/c(no. 14), Z= 4, R= 0.0456 and R_w= 0.0677. The ligand is bound to the metal by the amino substituents. The complexes are stacked in parallel columns with short stacking distances (3.27 Å).