Macrocyclic cobalt(III) complexes as precursors for metal-polythiophene hybrid materials

A thiophene-functionalised macrocyclic ligand trans-6,13-dimethyl-6-((thiophen-3-ylmethyl) amino)-1,4,8,1 1-tetraazacyclotetradecane-13-amine (L-1) has been prepared and complexed with Co-III. The ligand L-1 binds as a pentadentate in the crystallographically characterised complexes [CoL1(OAc)](ClO4)(2) and [(CoLCI)-C-1]Cl-2. Electro-copolymerisation of [(CoLCl)-Cl-1]Cl-2 with 3,4-ethylenedioxythiophene (EDOT) in a 1:2 ratio on a preformed poly-3,4-ethylenedioxythiophene (PEDOT) film resulted in metal-polymer hybrid films of high quality, consistency and uniformity in appearance. The copolymerised films were characterised by XPS indicating a 1:11 ratio of incorporation of complex to EDOT. Electrochemistry of the Co-PEDOT film (cast on an indium-doped tin oxide working electrode) in water revealed a Co-III/II redox couple at a potential ca. -600 mV (vs Ag/AgCl) which is similar to that seen in solution for the monomeric aqua complex [CoL1(OH2)](3+) (c) 2006 Elsevier Ltd. All rights reserved