title: Multichromophoric phthalocyanine-(perylenediimide)(8) molecules: a photophysical study.
abstract: 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 pi-pi 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.
authors.affiliation: Cavendish Laboratory, JJ Thomson Avenue, Cambridge, UK.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Albert-Seifried
authors.forename: Chris E
authors.initials: CE
authors.lastname: Finlayson
authors.forename: Frederic
authors.initials: F
authors.lastname: Laquai
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Swager
authors.forename: Paul H J
authors.initials: PH
authors.lastname: Kouwer
authors.forename: Michal
authors.initials: M
authors.lastname: Jurícek
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Kitto
authors.forename: Sanne
authors.initials: S
authors.lastname: Valster
authors.forename: Roeland J M
authors.initials: RJ
authors.lastname: Nolte
authors.forename: Alan E
authors.initials: AE
authors.lastname: Rowan
mesh_terms: D007094:Imides / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D013053:Spectrophotometry
chemical_list: D007094:Imides; D007211:Indoles; D054833:Isoindoles; C521332:perylenediimide; D010569:Perylene; C013647:phthalocyanine