title: Electronic energy transfer in a multiporphyrin-based molecular box.
abstract: The molecular box 1 comprises of two zinc-porphyrin metallacycles connected by two free-base 4'-trans-dipyridylporphyrins, axially coordinated to the zinc centers. The photophysics of 1 were studied in chloroform by emission and ultrafast absorption spectroscopy. In the molecular box, fast singlet energy transfer (main component, tau=32 ps) is observed to occur from the zinc-porphyrin metallacycles to the free-base chromophores. From wavelength-dependent spectrofluorimetric data, the efficiency of the energy-transfer (ET) process is estimated as 0.5. The lower-than-unity value is tentatively attributed to the possibility of a competing electron-transfer quenching pathway. Molecular box 1 can be considered to be a simple, self-assembling, six-chromophore antenna system. It has an inner cavity, 11.4 Angstrom wide, that could be used, in principle, to host a variety of guest molecules and obtain higher-order assemblies.
authors.affiliation: Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Prodi
authors.forename: Claudio
authors.initials: C
authors.lastname: Chiorboli
authors.forename: Franco
authors.initials: F
authors.lastname: Scandola
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Iengo
authors.forename: Enzo
authors.initials: E
authors.lastname: Alessio