The Synthesis Of Diaryl Ether-Linked Porphyrin Dimers

Since covalently linked porphyrin dimers was first reported in 1976, numerous studies have been focused on their synthesises, properties and applications. It has been demonstrated that the nature and position of the linker have a strong influence on the overall properties of the porphyrin dimers. In this paper, a facile synthesis of diaryl ether-linked porphyrin dimers, including mixed-metal porphyrin dimers, via CuI-mediated Ullmann coupling reaction has been developed.Using classical diazotization and consequent transformation reactions, 5-(4-aminophenyl)-10,15,20-triphenylporphyrin was converted to 5-(4-hydroxylphenyl) -10,15,20-triphenyl-porphyrin (70%) and 5-(4-iodinphenyl)-10,15,20-triphenyl-porphyrin (78%) which were the substrates of the Ullmann coupling reactions. Metalated porphyrin substrates were also prepared.Cul-mediated Ullmann reactions were carried out with N,N-dimethylglycine as the ligand, free base or metalated porphyrins substituents were coupled to a series of diaryl ether-linked metalloporphyrin dimers (10%-45%), It was found that the coupling of free base porphyrins substrates afforded 6-CuOCu with the highest yield. By demetalation with concentrated H2SO4, copper was removed from 6-CuOCu, giving 90% of free base dimer 6-FbOFb.The effect of central metal ions of the porphyrins on the coupling reaction was discussed, and the reaction mechanism based on copper π complex was proposed.UV-vis and stable fluorescence spectrum properties of of diarly ether-linked porphyrin dimmers were investigated, the result indicated the potential applications of the mix-metaled porphyrin dimer 6-NiOZn as models of energy and electron transfer.