One-pot electrochemical generation of a porphyrin dimer with a bis(diphenylphosphonium)acetylene bridge

The electrochemical oxidation of zinc tetraphenyl-porphyrin in the presence of bis(diphenylphosphino)acetylene leads to the formation of a β-bridged dimer using 0.5 equiv. of Lewis base per mole of[Zn(tpp)]; a mixture of monomer and dimer is observed when stoichiometric amounts or an excess of diphosphine was used.