Electrochemical polymerization of tetraphenylporphyrinatoruthenium(II) complexes with diaza compounds as axial ligands

The tetraphenylporphyrinatoruthenium(II) polymers bridged by the diaza compound (so called ‘shish kebab’-type polymers) were formed on the electrode by the two-electron oxidation of [Ru(tpp)L 2] (H 2tpp=5,10,15,20-tetraphenylporphyrin; L=4,4′-bipyridine, trans-1,2-bis(4-pyridyl)ethene, 1,2-bis(4-pyridyl)ethine, 4,4′-azopyridine, 1,2-bis(4-pyridyl)disulfide)) in 0.1 mol dm −3 (C 4H 9) 4N(ClO 4)CH 2Cl 2. This is the first example of electrochemical formation of shish kebab-type polymers, which until now have only been synthesized chemically. The polymer formed electrochemically was different from the polymer synthesized chemically. The former has the positively charged bridging ligands. The polymers showed reversible oxidation waves corresponding to the oxidation of Ru II to Ru III, and a reduction wave corresponding to the reduction of a positively charged bridging ligand.