Anthryloligothienylporphyrins: Energy Transfer and Light-Harvesting Systems

Abstract

In this paper we report on the synthesis and photophysical properties of the energy-transfer system 2 a, in which a quinquethiophene bridge is terminally linked to the 5-position of a porphyrin and to the 9-position of an anthracene group. The photoexcitedstate properties were studied by steady-state fluorescence and picosecond time-resolved fluorescence measurements as well as fluorescence excitation spectroscopy. The weak electronic interaction of the subunits anthracene, quinquethiophene and porphyrin results in localized excited states, which are seen in UV/Vis absorption spectra. In 2 a, a highly selective excitation of the anthracene donor leads to quantitative intramolecular energy transfer to the emitting porphyrin acceptor via the quinquethiophene bridge. The efficiency of energy transfer and the fluorescence properties are both independent of the length of the oligothiophene chain, as demonstrated by comparison with the model compounds 1. Various explanations for the mechanism of intramolecular energy transfer are discussed. Introduction of additional anthrylquinquethienyl units into the porphyrin ring results in an increase in the intensity of the characteristic absorption bands and fluorescence nearly proportional to the number of chromophores.

Functional Oligothiophenes: Molecular Design for Multidimensional Nanoarchitectures and Their Applications

“…The linear D-A triad 2.226 was also prepared by condensation of aldehyde 2.224 with pyrrole and hexanal in a yield of 3% which had to be separated from other possible isomers (Chart 2.37). 318 Steadystate fluorescence and picosecond time-resolved fluorescence measurements revealed that selective excitation of the anthracene donor (254 nm) leads to an efficient unidirectional intramolecular energy transfer to the emitting porphyrin (650-800 nm) Via the oligothiophene bridges.…”

“…318 Cross-coupling reactions of 5,5′-dibromoterthiophene with the Grignard reagent of 2-bromo-3-pentylthiophene yielded quinquethiophene 2.222. Lithiation of the resulting quinquethiophene followed by reaction with anthrone gave 9-anthryl-substituted dipentylquinquethiophene 2.223.…”

Synthesis, EPR and DFT calculations of rare Ag(II)porphyrins and the crystal structure of [Zn(II)tetrakis(4-bromo-2-thiophene)porphyrin]

“…Furthermore, oligomeric [10,11] and polymeric [12] meso-tetrakis-thiophene porphyrin films have shown promising properties as robust catalysts for the oxidation of organic substrates [13,14]. Despite this, and the importance of intermolecular interactions in many applications, there are only three reported Xray structures of thiophene-substituted porphyrins [15][16][17].…”

Resonance energy transfer-based fluorescent probes for Hg2+, Cu2+and Fe2+/Fe3+ions

“…27). 60 In another example, Ziessel et al reported a multichromophoric array 34 in which BODIPY dyes having different emission properties are organized around a truxene core (Fig. 28).…”