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Electronic Energy Transfer in a Multiporphyrin‐Based Molecular Box
Author(s) -
Prodi Anna,
Chiorboli Claudio,
Scandola Franco,
Iengo Elisabetta,
Alessio Enzo
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600065
Subject(s) - chromophore , porphyrin , free base , chemistry , zinc , photochemistry , electron transfer , quenching (fluorescence) , spectroscopy , ultrafast laser spectroscopy , molecule , fluorescence , physics , organic chemistry , optics , salt (chemistry) , quantum mechanics
10.1002/cphc.200600065.abs 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, τ =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 Å wide, that could be used, in principle, to host a variety of guest molecules and obtain higher‐order assemblies.