Synthesis and characterization of anthracene-clustering dendrimers: observation of fluorescence resonance energy transfer in the multichromophoric system
摘要:
A series of anthracene-clustering dendrimers bearing various aliphatic substituents at the terminal positions were synthesized using a direct coupling strategy. A remarkable effect of the side chains was imparted to chemical properties of the dendrimers such as drastically increased solubility. Although the multibranched anthracene arrays in the dendritic architectures exhibited no cooperativity in terms of the absorption feature and behaved as single chromophoric systems, investigations focusing on fluorescence properties revealed that a type of cooperativity was present as expressed in the reduced quantum yields of fluorescence. An alternative approach utilizing time-resolved fluorescence decay measurements clearly demonstrated that the most reasonable mechanism of the cooperative action should involve two discernible channels of intramolecular fluorescence resonance energy transfer (FRET) occurring from one chromophore to the others within and across junctions of the branching units. (C) 2004 Elsevier Ltd. All rights reserved.
Quantitative evaluation of Förster-type fluorescence resonance energy transfer (FRET) was undertaken by statistical investigations on perylene-cored anthracene dendrimers.
对以苝为核心的蒽树枝状聚合物进行了荧光共振能量转移(FRET)的定量评估,采用了统计调查的方法。
Construction of divergent anthracene arrays within dendritic frameworks
This publication presents simple methodologies for construction of divergent anthracene arrays either within structural interior or at peripheral positions of dendritic frameworks. The synthetic approaches employed multiple coupling reactions between two types of 10-functionalized 9-anthryl chlorides and two types of polyphenolic linkers, resulting in four types of dendritic architectures. Successful implementation of the syntheses was confirmed by a range of spectroscopies along with elemental analyses and size exclusion chromatography studies. The resulting dendritic molecules showed a range Of Solubilities in chloroform fairly affected by the dendritic backbone structures. Fluorescence spectroscopic experiments of the multichromophoric dendritic systems indicated pronounced energy delocalization functionalities via an energy migration within the branched molecular frameworks as expressed in reduced fluorescence quantum yields and complex emission decay profiles. (c) 2006 Elsevier Ltd. All rights reserved.
Mechanistic investigation of energy transfer in perylene-cored anthracene dendrimers
In this publication, we describe results of investigations focusing on detailed mechanisms of directed energy transfer in perylene-cored anthracene dendrimers. To obtain definitive statistical data for probing the energy transfer pathways, we synthesized four analogous dendrimers, which were designed to funnel the energy only from remote anthracene groups to the perylene cores. Static fluorescence studies with these dendrimers revealed that excitation of the anthracene groups led to the core emissions, indicating efficient energy transfer should be involved. Inspection of the energy transfer efficiencies obtained from all ten dendrimers demonstrated that single-step energy transfer should represent a key mechanism for the long-range energy transport in these dendrimers.
Synthesis and characterization of anthracene-clustering dendrimers: observation of fluorescence resonance energy transfer in the multichromophoric system
A series of anthracene-clustering dendrimers bearing various aliphatic substituents at the terminal positions were synthesized using a direct coupling strategy. A remarkable effect of the side chains was imparted to chemical properties of the dendrimers such as drastically increased solubility. Although the multibranched anthracene arrays in the dendritic architectures exhibited no cooperativity in terms of the absorption feature and behaved as single chromophoric systems, investigations focusing on fluorescence properties revealed that a type of cooperativity was present as expressed in the reduced quantum yields of fluorescence. An alternative approach utilizing time-resolved fluorescence decay measurements clearly demonstrated that the most reasonable mechanism of the cooperative action should involve two discernible channels of intramolecular fluorescence resonance energy transfer (FRET) occurring from one chromophore to the others within and across junctions of the branching units. (C) 2004 Elsevier Ltd. All rights reserved.