Light‐Driven Charge Separation in Isoxazolidine–Perylene Bisimide Dyads

Abstract

A series of arrays for light-driven charge separation is presented, in which perylene tetracarboxylic bisimide is the light-absorbing chromophore and electron acceptor, whereas isoxazolidines are colourless electron donors, the electron-releasing properties of which are increased with respect to the amino group by means of the alpha-effect. Charge separation (CS) in toluene over a distance ranging from approximately 10 to approximately 16 A, with efficiencies of approximately 95 to approximately 50 % and CS lifetimes from 300 ps to 15 ns, are demonstrated. In dichloromethane the charge recombination reaction is faster than charge separation, preventing accumulation of the CS state. The effects of solvent polarity and molecular structure are discussed in the frame of current theories.

On/Off Switching of Perylene Tetracarboxylic Bisimide Luminescence by Means of Substitution at the N‐Position by Electron‐Rich Mono‐, Di‐, and Trimethoxybenzenes

“…The absence of, basically, any effect on the absorption spectra indicates that there are very little perturbations in the electronic properties of the PI core by the presence at the N‐position of differently substituted methoxyphenyl groups. This has been observed before6, 8 and is due to the fact that orbital nodes in the HOMO and LUMO at the N atom are present 12. Due to the decoupling between the PI core and the N‐substituents, the present compounds can be regarded as assemblies made of two independent components, PI and methoxybenzene, and we will refer to them as dyads.…”

“…Perylene tetracarboxylic bisimides (PIs) are a class of efficient luminophores, very stable and easily processable, with intense absorption in the visible range of the light spectrum; they can easily be functionalized to provide a variety of spectroscopic features 3–5. PIs, like other aromatic bisimides, are liable to a facile reduction ( E 0 ≈−0.6 V vs. SCE) that leads to the formation of a radical anion characterized by distinctive and intense absorption bands in the NIR region of the spectrum 6–8. This class of molecules is therefore well suited to mechanistic studies on electron‐transfer processes.…”

Photoinduced Electron Transfer in an Amine–Corrole–Perylene Bisimide Assembly: Charge Separation over Terminal Components Favoured by Solvent Polarity

“…Design and synthesis : We chose to decorate meso ‐substituted corrole with two units known for their excellent performance in electron‐transfer model systems. Perylene bisimides are very popular building blocks in multichromophoric systems because of their outstanding photophysical properties such as their intense absorption in the green region of the visible spectrum, high photostability, fluorescence quantum yield of approximately 1, and characteristic spectral signature of anion radicals 14. The only feature complicating their use is their very low solubility, which is incompatible with the typical conditions for corrole synthesis 15.…”

“…Perylene bisimides are very popular building blocks in multichromophoric systems because of their outstanding photophysical properties such as their intense absorption in the green region of the visible spectrum, high photostability, fluorescence quantum yield of approximately 1, and characteristic spectral signature of anion radicals. [14] The only feature complicating their use is their very low solubility, which is incompatible with Abstract in Polish: Barwnik funkcjonalny składający się z czterech podjednostek: mezo-podstawionego korolu, perylenobisimidu oraz dwóch trifenyloamin został zsyntetyzowany i poddany badaniom spektroskopowym i fotofizycznym. Analiza różnych strategii doprowadziła do opracowania efektywnej, sześcioetapowej syntezy finalnego układu wielochromoforowego.…”

Fluorescence and fluorescent dyes

“…On the other hand, the electron transfer in Figure 15 causes a charge separation and may initiate photochemically induced reductions. The charge separation may proceed to other chromophores such as corroles [111,112] or even by more distant colorless electron rich groups [113] where colorless local electron rich structures may be realized by the α-effect [114,115]; this is given in isoxazolidines where a charge separation of 1.6 nm cold be induced [116].…”