Folding versus Self‐Assembling

Li, Alexander D. Q.; Wang, Wei; Wang, Yu

doi:10.1002/chem.200305025

Cited by 220 publications

(190 citation statements)

References 77 publications

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“…The formation of this new band in the emission spectrum of PBIs has been extensively discussed in the literature. According to Wang et al 35,[76][77][78] who examined the self-organization of a PEG functionalized PBI in chloroform solution, such a red shifted band in the emission spectrum of PBIs may be attributed to the fluorescence properties of molecular assemblies of increased size. The same conclusions have also been outlined by Neuteboom and coworkers 79 when studying the optical features of polytetrahydrofuran substituted PBI polymers in ODCB.…”

Section: Resultsmentioning

confidence: 99%

Novel EDTA-ligands containing an integral perylene bisimide (PBI) core as an optical reporter unit

et al. 2014

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The synthesis, characterization and metal complexation of a new class of perylene bisimides (PBIs) as an integral part of ethylenediaminetetraacetic acid (EDTA) are reported. The simplest representative, namely derivative 1a, was synthesized both by a convergent as well as a direct approach while the elongated derivatives, 1b and 1c, were obtained only via a convergent synthetic pathway. All these new prototypes of water-soluble perylenes are bolaamphiphiles and were fully characterized by 1 H-and 13 C-NMR spectroscopy, matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and IR spectroscopy. In order to acquaint ourselves with the behaviour in solution of our PBIs bearing dendritic wedges, the simplest derivative, 1a, was chosen and tested by means of UV/Vis and fluorescence spectroscopy as well as by zeta-potential measurements. A photoexcitation induced intramolecular photo-electron transfer (PET) can be observed in these molecules. Therefore their potential applications as sensors can be imagined. Model compound 1a efficiently coordinates trivalent metal cations both in water and dimethyl sulfoxide (DMSO). Significantly, the effects of the complexation strongly depend on the aggregation state of the PBI molecules in solution. As a matter of fact, in water, the presence of M 3+ ions triggers the formation of light emitting supramolecular aggregates (excimers). On the other hand, in DMSO-rich solutions metal complexation leads to the suppression of the PET and leads to a strong fluorescence enhancement.

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Section: Resultsmentioning

confidence: 99%

Novel EDTA-ligands containing an integral perylene bisimide (PBI) core as an optical reporter unit

et al. 2014

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“…[39] Thei nverse intensity distribution amid their vibronic states seen for 1 with the 500 nm peak being stronger than the one at 533 nm, has been assigned to intermolecular collisions. [41] Tw ow ell-defined maxima at 545 and 587 nm with an intensity ratio of 2.5:1 are found in the fluorescence spectrum of 1.T he fluorescence quantum yields were determined to be 5.9 %, from which we conclude that the fluorescence originates from monomeric rather than aggregated PDIs,i nl ine with the fluorescence lifetime measurements,i nw hich only as ingle lifetime of 4.7 ns was found.…”

Section: Introductionmentioning

confidence: 98%

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides

et al. 2015

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We describe the formation of charge-transfer complexes that feature electron-donating carbon nanodots (CND) and electron-accepting perylenediimides (PDI). The functionalities of PDIs have been selected to complement those of CNDs in terms of electrostatic and π-stacking interactions based on oppositely charged ionic head groups and extended π-systems, respectively. Importantly, the contributions from electrostatic interactions were confirmed in reference experiments, in which stronger interactions were found for PDIs that feature positively rather than negatively charged head groups. The electronic interactions between the components in the ground and excited state were characterized in complementary absorption and fluorescence titration assays that suggest charge-transfer interactions in both states with binding constants on the order of 8×10(4) M(-1) (25 L g(-1) ). Selective excitation of the two components in ultrafast pump probe experiments gave a 210 ps lived charge-separated state.

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“…This result indicates that the p-stacked P chromophores are exciton-coupled. [19][20][21] Moreover, the A 0!0 /A 0!1 ratio for the vibronic bands decreased as the number of P units increased, and there was a notable difference between dimers 2 s and 2 o, presumably as a result of the conformational changes imposed by the attachment of the two P units to either one strand or opposite strands within the duplex. Upon the partial chemical reduction of P with sodium dithionite, peaks corresponding to the radical anion appeared at 727, 815, and 980 nm, whereas the vibronic progression in the visible region decreased in intensity (see Figure S1 in the Supporting Information).…”

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confidence: 95%

Electron Hopping among Cofacially Stacked Perylenediimides Assembled by Using DNA Hairpins

et al. 2010

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The self-assembly of redox-active molecules into ordered arrays capable of rapid, long-distance charge transport is important for the development of functional nanomaterials for organic electronics. In this regard, DNA shows great promise as a structural scaffold for the helical arrangement of chromophores and other (semi)conducting materials. [1][2][3] Base substitutions and modifications, sugar modifications, and noncovalent interactions have all been used for the construction of such DNA-based structures. Perylenediimides (PDIs), which have the advantages of strong absorptivity, high fluorescence quantum yields, high photochemical and thermal stability, strong hydrophobic p-p stacking interactions, and semiconducting properties, have been incorporated in a variety of structures. [4][5][6][7][8][9][10][11][12][13][14][15][16] Recently, Wagner and Wagenknecht [10] reported the preparation of a PDI derivative, P (Figure 1), which is readily incorporated into an oligonucleotide and serves as a base-pair surrogate when located opposite an abasic site in a duplex structure. The incorporation of P in opposite complementary oligonucleotides has been shown to result in the formation of stable duplexes in which the P units are located in a zipperlike fashion within the hydrophobic interior of the resulting duplex. [5,17] The stacking of P units within the duplex resulted in an excimer-like state following photoexcitation. [16] We report herein the results of our investigation of intramolecular electron hopping within a series of synthetic DNA hairpins 1-4 (Figure 1). These hairpins possess compact 3'-CCA loop regions connecting poly(T)-poly(A) stems containing a single P moiety located opposite an abasic site (1), two P moieties located opposite abasic sites and attached either to the same strand (in 2 s) or to opposite strands (in 2 o), or three or four P moieties positioned adjacent to one another but on opposite strands in a zipperlike fashion (in 3 and 4). The EPR spectra of the singly reduced duplexes were consistent with electron hopping between two sites in both dimers (the hairpins containing two P moieties) and the trimer 3, and among three sites in the tetramer 4. Herein, we discuss the origin and implications of partial electron sharing.Oligonucleotides containing P were synthesized by the method of Wagner and Wagenknecht; [10] the CCA linker in hairpins 1-4 has been employed previously in the synthesis of stable minihairpins. [13,17,18] The characterization of 1-4, including mass spectrometry and circular dichroism (CD), is described in the Supporting Information.An intensity reversal was observed in the UV/Vis absorption spectra for the 0!0 and 0!1 transitions in 2-4 with respect to those of 1 (Figure 2). This result indicates that the p-stacked P chromophores are exciton-coupled. [19][20][21] Moreover, the A 0!0 /A 0!1 ratio for the vibronic bands decreased as the number of P units increased, and there was a notable difference between dimers 2 s and 2 o, presumably as a result of the conformational changes...

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Folding versus Self‐Assembling

Cited by 220 publications

References 77 publications

Novel EDTA-ligands containing an integral perylene bisimide (PBI) core as an optical reporter unit

Novel EDTA-ligands containing an integral perylene bisimide (PBI) core as an optical reporter unit

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides

Electron Hopping among Cofacially Stacked Perylenediimides Assembled by Using DNA Hairpins

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