Steroid-Bridged Anthryloligothienylporphyrins: Synthesis and Study on the Intramolecular Energy Transfer
摘要:
The novel steroid-bridged energy transfer system 2 was prepared starting from epi-androsterone, The linkage of both the anthrylthienyl and the bithienyl group in the 3- and 17-position of the steroid was achieved by Grignard reaction of the respective carbonyl function of the steroid component. The synthesis was accomplished by linkage of the porphyrin group according to Lindsey's method. This synthetic strategy also enables the approach to molecular subunits required as reference compounds. The photophysical properties were studied using time-resolved fluorescence and fluorescence excitation spectroscopy. Reference donor molecule 6 exhibits-in analogy to other anthryloligothiophenes studied-a dual fluorescence: a blue anthracene-like fluorescence and a dynamically coupled delayed red fluorescence resulting from the relaxed excited state. On the basis of these results, supermolecule 2 was investigated. Besides the typical porphyrin emission, a high energetic fluorescence (blue fluorescence) was detected in 2 which results unambiguously, as stated from spectra of 6, from the donor part of 2. The lifetime of this fluorescence is shortened compared with that of 6. Supermolecule 2 is the first in the series of our energy transfer systems exhibiting donor fluorescence despite a very efficient intramolecular energy transfer (at least 99%).
Steroid-Bridged Anthryloligothienylporphyrins: Synthesis and Study on the Intramolecular Energy Transfer
摘要:
The novel steroid-bridged energy transfer system 2 was prepared starting from epi-androsterone, The linkage of both the anthrylthienyl and the bithienyl group in the 3- and 17-position of the steroid was achieved by Grignard reaction of the respective carbonyl function of the steroid component. The synthesis was accomplished by linkage of the porphyrin group according to Lindsey's method. This synthetic strategy also enables the approach to molecular subunits required as reference compounds. The photophysical properties were studied using time-resolved fluorescence and fluorescence excitation spectroscopy. Reference donor molecule 6 exhibits-in analogy to other anthryloligothiophenes studied-a dual fluorescence: a blue anthracene-like fluorescence and a dynamically coupled delayed red fluorescence resulting from the relaxed excited state. On the basis of these results, supermolecule 2 was investigated. Besides the typical porphyrin emission, a high energetic fluorescence (blue fluorescence) was detected in 2 which results unambiguously, as stated from spectra of 6, from the donor part of 2. The lifetime of this fluorescence is shortened compared with that of 6. Supermolecule 2 is the first in the series of our energy transfer systems exhibiting donor fluorescence despite a very efficient intramolecular energy transfer (at least 99%).