Excited State Interactions in Calix[4]arene−Perylene Bisimide Dye Conjugates:  Global and Target Analysis of Supramolecular Building Blocks

Abstract

The photophysical properties of two supramolecular building blocks oc and oc2 consisting of a perylene bisimide chromophore substituted with either one or two calix [4]arene units in the N-imide position as well as those of the reference compound oref without calix[4]arene substituents were investigated. A complete picture of the processes taking place after photoexcitation in toluene, CH 2 Cl 2 , and benzonitrile was obtained by means of UV/vis absorption, steady state and time-resolved emission, and femtosecond transient absorption spectroscopy. It has been found that the fluorescence emission of compounds oc (Φ fl ) 0.03 in CH 2 Cl 2 ) and oc2 (Φ fl < 0.01 in CH 2 Cl 2 ) is almost completely quenched compared with the highly emissive reference compound oref (Φ fl ) 0.99 in CH 2 Cl 2 ) because of fast electron-transfer processes from the calix[4]arene moieties to the perylene bisimide chromophore. This predominantly takes place with rate constants of k CS ) 3 × 10 10 s -1 (τ CS ) 32 ps) for compound oc and k CS ) 9 × 10 10 s -1 (τ CS ) 11 ps) for compound oc2 (in CH 2 Cl 2 ) leading to a short-lived charge-separated state consisting of the reduced perylene bisimide unit and the oxidized calix[4]arene moiety.

DiiodoBodipy-Perylenebisimide Dyad/Triad: Preparation and Study of the Intramolecular and Intermolecular Electron/Energy Transfer

“…These values are close to the electron transfer rate constant observed in calix [4]arene-PBI dyad (k CS intra = 4.0 × 10 10 s −1 in toluene; k CS intra is solvent-dependent). 62 To further confirm the intramolecular electron transfer in B-1, the fluorescence of B-1 in solvents with different polarities was studied ( Figure 4). The electron transfer induced fluorescence quenching will be more significant in polar solvents.…”

Exciton delocalization and dynamics in helical π-stacks of self-assembled perylene bisimides

“…S1). 39,40 The aggregate form 65 of PBI 4 in MCH solvent also reveals slightly red-shifted absorption spectra as compared with that of PBI 1. Thus, we expect that PBI 4 is supposed to act as an exciton quencher in the self-assembled hetero-PBI aggregates composed of PBI 1 and PBI 4 (vide infra).…”

Perylene Bisimide Dye Assemblies as Archetype Functional Supramolecular Materials

“…Thus, it has been shown that already modestly electron-rich aromatic substituents such as alkylated and in particular alkoxylated phenyl groups quench the fluorescence in solvents of intermediate or high polarity by photoinduced electron transfer from the substituent to the electron-poor PBI scaffold. 33,34 In contrast to the imide substituents, substituents at core positions have a pronounced influence on the redox potentials and absorption properties of these dyes ( Figure 3). This opened the possibility to tune the dyes' functional properties while maintaining the self-assembly properties encoded at the imide subunits.…”