Synthesis of bis(phenylethynyl)arylene-linked diporphyrins designed for studies of intramolecular energy transfer
Journal article, 1999
A series of donor-bridge-acceptor systems has been designed to give information on how the medium between the donor and the acceptor influences the excitation energy transfer process. The donor and the acceptor are zinc and free base porphyrins, respectively. The systems were obtained by a synthetic strategy that guarantees a precise state of metalation, i.e. by a building block approach in which a third chromophore is formed as the two porphyrins are covalently linked together in a geometrically well defined structure. The porphyrins are linked by one of the three different bridge chromophores; 9,10-bis(phenylethynyl)anthracene, or 1,4-bis(phenylethynyl)-substituted benzene or naphthalene. The different units were assembled using copper-free, palladium-catalyzed cross-coupling of aryl iodides with terminal alkynes. Reference compounds that correspond to different parts of the systems have also been prepared.