Article

DNA‐Assisted Self‐Assembly of Pyrene Foldamers

Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
Chemistry - A European Journal (Impact Factor: 5.73). 05/2009; 15(23):5701-8. DOI: 10.1002/chem.200900369
Source: PubMed

ABSTRACT

Folding in the tides: Upon hybridization, pyrene molecules assemble through interstrand stacking interactions to form double-stranded, helical structures. Structural organization of the pyrene molecules is an intrinsic property of the oligoaryl part and takes place independently of the sequence of the attached DNA. Pyrene helicity is most pronounced in a bi-segmental chimera, in which a DNA stem is present only at one end of the pyrene section.
The self-organization of oligopyrene foldamers is described. Bi- and tri-segmental oligomers composed of nucleotides and non-nucleosidic, achiral pyrene monomers form double-stranded helical structures, as shown by absorbance, fluorescence, and CD spectroscopy. The mixed nature of alternating aromatic and phosphate groups ensures water solubility which, in turn, favors folding of the aromatic units. Pyrene molecules also assemble though interstrand stacking interactions. Structural organization of the pyrene units is an intrinsic property of the oligoaryl part and takes place independently from the sequence of the attached DNA. Chirality transfer from DNA to the pyrene segment leads to formation of a double helix, in which neighboring pyrene units are, in the present case, twisted in a right-handed manner. Pyrene helicity is most pronounced in a bi-segmental chimera, in which a DNA stem is present only at one end of the pyrene section.

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    • "Specific colorimetric and ratiometric fluorescence responses toward trivalent metals have been exhibited by pyridinyl-functionalized tetraphenylethene [2]. Moreover, only a few reports of AIE behavior were demonstrated by excimer formations of fluorophores containing pyrene rings [32] [33] [34] [35] [36] [37] [38] [39] [40] [41]. Surprisingly, present results of our pyrene-based fluorophore with Schiff-base probes showed another special aggregation induced ratiometric emission (AIRE) processes upon increasing water content. "
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    ABSTRACT: We synthesize a newly designed pyrene-based fluorescent probe FBP containing a Schiff base and amide linkage as a receptor, which demonstrates selective UV–vis and fluorometric detections of trivalent metal ions in various semi-aqueous solution conditions. Interestingly, by increasing water contents the aggre- gation induced ratiometric emissions (AIREs) of photoluminescence in FBP solutions (in DMSO/H2O) are enhanced from blue to green due to the excimer formation of the aggregates in water. In addition, the enhanced aggregated ratiometric green fluorescence behaviors of FBP in the presence of trivalent metal ions (Al3+, Fe3+, and Cr3+) are observed in semi-aqueous solutions as well as the solid state, which is well utilized to detect trivalent metal ions in living cells. Further verification of the probe detections, their interactions toward trivalent metal ions are well characterized by the time-resolved photoluminescence (TRPL) of spectroscopic responses as well as theoretical calculations. Therefore, we believe the applica- tion of such a new AIRE-based approach is first reported among Schiff base and pyrene-based fluorescent chemo- and bio-sensors.
    Full-text · Article · Oct 2014 · Sensors and Actuators B Chemical
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    • "Some moieties with AIE appearances in stimuli-responsive nano-materials and active layers of efficient organic light emitting diodes have also been found to serve as sensors [30] [31]. Specific colorimetric and ratiometric fluorescence responses towards trivalent metals have been exhibited by pyridinyl-functionalized tetraphenylethene. 2 Moreover, only a few reports of AIE behaviour were demonstrated by excimer formations of fluorophores containing pyrene rings [32] [33] [34] [35] [36] [37] [38] [39] [40]. "
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    ABSTRACT: A new pyrene-based aggregation induced ratiometric emission probe for selective detections of trivalent metal ions and its living cell application, Sensors and Actuators B: Chemical (2014), http://dx.doi.org/10.1016/j.snb.2014.09.105 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
    Full-text · Article · Sep 2014 · Sensors and Actuators B Chemical
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    ABSTRACT: Switched on: The fluorescence emission of a DNA-based optical switch can be reversibly switched from blue to green using modulating light of different wavelengths (see picture). The device is based on the hybridization of two pyrene-functionalized DNA strands in the presence of a photochromic azobenzene-containing effector ligand. Hybridization occurs only with the cisconfigured ligand, and results in pyrene excimer fluorescence.
    No preview · Article · Sep 2009 · Angewandte Chemie International Edition
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