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Corrole–Porphyrin Conjugates with Interchangeable Metal Centers
Author(s) -
Ngo Thien H.,
Nastasi Francesco,
Puntoriero Fausto,
Campagna Sebastiano,
Dehaen Wim,
Maes Wouter
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200836
Subject(s) - corrole , porphyrin , chemistry , free base , photochemistry , supramolecular chemistry , ultrafast laser spectroscopy , singlet state , absorption spectroscopy , fluorescence , absorption (acoustics) , spectroscopy , molecule , organic chemistry , excited state , materials science , salt (chemistry) , physics , quantum mechanics , nuclear physics , composite material
Oligoporphyrinoid materials composed of two or three tetrapyrrolic macrocycles have been synthesized by either mono‐ or disubstitution (S N Ar) of a phenolic Zn‐AB 3 ‐porphyrin on a meso ‐dichloropyrimidinyl‐substituted Cu‐AB 2 ‐corrole. Selective metallation/demetallation sequences were carried out on these mixed corrole–porphyrin conjugates to afford multichromophoric systems with variable metal centers. The absorption spectra of the free‐base corrole–porphyrin systems were essentially additive, which demonstrates that only weak intercomponent interactions take place in these assemblies and therefore they can be regarded as supramolecular systems. Photophysical studies of the free‐base conjugates showed that these species are highly fluorescent, with fluorescence occurring from the lowest‐energy singlet state of the porphyrin subunit(s), which is (are) the lowest‐energy state(s) of the assemblies. Pump‐probe transient absorption spectroscopy experiments demonstrated that very efficient (>95 %) corrole‐to‐porphyrin singlet–singlet energy transfer takes place in these pyrimidinyl‐bridged multichromophoric systems by a coulombic mechanism with rate constants on the picosecond timescale.