Premium
Multichromophoric Phthalocyanine–(Perylenediimide) 8 Molecules: A Photophysical Study
Author(s) -
AlbertSeifried Sebastian,
Finlayson Chris E.,
Laquai Frederic,
Friend Richard H.,
Swager Timothy M.,
Kouwer Paul H. J.,
Juríček Michal,
Kitto Heather J.,
Valster Sanne,
Nolte Roeland J. M.,
Rowan Alan E.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201000677
Subject(s) - photoexcitation , molecule , monomer , photochemistry , phthalocyanine , chromophore , excited state , chemistry , singlet state , steric effects , alkyl , polymer , stereochemistry , organic chemistry , physics , nuclear physics
We describe the synthesis of a series of phthalocyanine (Pc)–perylenediimide (PDI) 8 “octad” molecules, in which eight PDI moieties are attached to a Pc core through alkyl‐chain linkers. There is clear spectroscopic evidence that these octads can exist as non‐aggregated “monomers” or form aggregates along the Pc cores, depending on the type of Pc and the solvent medium. In the low dielectric constant solvents, into which the octads are soluble, photoexcitation of the PDI units leads to rapid energy transfer to the Pc centre, rather than a charge separation between moieties. In octad monomers, the Pc singlet excited‐state decays within tens of ps, whereas the excitons are stabilised in the aggregated form of the molecules, typically with lifetimes in the order of 1–10 ns. By contrast, in an octad design in which π–π interactions are suppressed by the steric hindrance of a corona of incompatible glycol tails around the molecule, a more straightforward photophysical interaction of Förster energy transfer between the PDI moieties and Pc core may be inferred. We consider these molecules as prototypical multichromophoric aggregates, giving delocalised states with considerable flexibility of design.