Highly Fluorescent Lyotropic Mesophases and Organogels Based on J‐Aggregates of Core‐Twisted Perylene Bisimide Dyes

Li, Xueqing; Zhang, Xin; Ghosh, Suhrit; Würthner, Frank

doi:10.1002/chem.200800915

Cited by 177 publications

(149 citation statements)

References 63 publications

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“…Going from THF to MCH, for DAN-U the emission intensity increased by 2.5 times with peak sharpening, which is a well-known signature for J aggregates. [10] In contrast, the fluorescence of DAN-A was found to be almost quenched with peak broadening as a result of aggregation, which further supports that the mode of self-assembly in these two chromophores is significantly different.…”

mentioning

confidence: 73%

Contrasting Self‐Assembly and Gelation Properties among Bis‐urea‐ and Bis‐amide‐Functionalised Dialkoxynaphthalene (DAN) π Systems

Das

Ghosh

2010

Chemistry A European J

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Precise control over the spatial arrangement of various functional chromophores [1] plays an important role in modulating the inter-chromophoric interactions and consequently the photophysical properties. The motivation to study these properties stems from the desire to understand the effect of molecular-level interactions on macroscopic properties because of the relevance in organic electronic device applications.[2] In the recent past, there have been many efforts aimed towards developing suitable supramolecular strategies for achieving long-range order in the self-assembled structure of various p systems, such as p- [3] and n-type [4] semiconductors, push-pull-type chromophores, [5] and donor-acceptor charge-transfer systems.[6] The design of the building blocks in most of these systems ensure that self-assembly can be facilitated by gaining the synergistic effect of several non-covalent forces, such as p-p interactions, hydrogen bonding, dipole-dipole interactions, and the hydrophobic effect. In most cases, the role of hydrogen-bonding functionalities has been restricted only to strengthen the propensity for self-assembly, except for a few recent examples in which the nature of the chromophore arrangements could be drastically changed (H-vs. J-type aggregation) by varying the peripheral functional groups [7] or the hydrogen-bonding motif. [8] Amide and urea are the two most common self-complementary hydrogen-bonding motifs and have been extensively used for various dye assemblies. [3][4][5] However, to the best of our knowledge there have not been any studies to exclusively compare the influence of these two functionalities in deciding the chromophoric arrangements in the self-assembled structure. The question we asked is whether, due to the mismatch in number of hydrogen-bonding ( À NH···O À ) interaction sites, they only differ in terms of providing differential stability to the self-assembled structure or are they also capable of altering the mode of the chromophoric arrangements? To answer this question, we have synthesised two derivatives of the dialkoxynaphthalene (DAN) p system, namely, DAN-U and DAN-A (Scheme 1), which differ only in amide and urea functionalities. Herein, we report the contrasting solution self-assembly and gelation behaviour of DAN-U and DAN-A and our studies related to understanding the correlation between these two phenomena.Firstly, we studied the self-assembly in solution by solvent-dependent absorption spectroscopy. In a recent report we have shown that DAN-A forms H-type p stacks in nonpolar medium such as methylcyclohexane (MCH)/CHCl 3 (95:5).[9] However, DAN-U was found to be insoluble in CHCl 3 at room temperature and so to avoid ambiguity in the comparative self-assembly studies in solution, herein we have used a THF and MCH solvent composition.In Figure 1 a, we show the UV-visible absorption spectral changes of DAN-A as a function of solvent composition. With gradual addition of non-polar solvent MCH to the solution of the chromophore in THF, there was almost no cha...

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confidence: 73%

Contrasting Self‐Assembly and Gelation Properties among Bis‐urea‐ and Bis‐amide‐Functionalised Dialkoxynaphthalene (DAN) π Systems

Das

Ghosh

2010

Chemistry A European J

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“…In the presence of hydrogen-bonding amide (PBI 5) or urea (PBI 6) functionalities self-assembly is, however, still possible in aliphatic solvents. [272,273] The UV/Vis spectra of self-assembled PBI 3 and PBI 4 ( Figure 19c) illustrate an interesting transformation from H-aggregates (major absorption peak of the aggregate at λ max = 490 nm) to J-aggregates (major absorption peak of the aggregate at λ max = 620 nm) that has been explained by differences in the longitudinal slipping between adjacent dyes. [274,275] A more slipped arrangement with J-type coupling results from the larger sterical demand of the branched alkyl groups of PBI 4.…”

Section: Supramolecular Systems: Perylene Bisimide H-and J-aggregatesmentioning

confidence: 99%

Exciton Transport in Molecular Aggregates – From Natural Antennas to Synthetic Chromophore Systems

Brixner

Hildner

Köhler

et al. 2017

Advanced Energy Materials

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The transport of excitation energy in molecular aggregates is of crucial importance for the function of organic optoelectronic devices and next‐generation solar cells. First, this review summarizes the theoretical background of the nature of the electronically excited states of molecular aggregates. For these systems, the electronic interaction between the monomers leads to the formation of exciton states. This goes along with a shift of the excitation energies and a redistribution of the oscillator strength with respect to the monomers. Next, a brief overview is provided over experimental techniques that allow to study the properties of excitons in molecular aggregates. This includes single‐molecule spectroscopy, coherent two‐dimensional (2D) spectroscopy, and single‐molecule coherent spectroscopy. Finally, examples of molecular aggregates spanning the range from natural systems that act in photosynthesis as light‐harvesting antennas to artificial aggregates built from synthetic chromophores are illustrated.

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“…The emission wavelength is red-shifted by 17 nm relative to that of monomer 3, and the fluorescence quantum yield drops to almost one third of the monomer, which is obviously different from that observed for the typical "J-type" aggregates [6] [7]. The fluorescence lifetime increases slightly from 6.1 ns for the monomer 3 to 7.8 ns for dimer 8.…”

Section: Fluorescence Spectra and Fluorescence Lifetimementioning

confidence: 58%

Photophysical Properties of Perylenetetracarboxylic Diimide Dimers with Slipped “Face-to-Face” Stacked Structure and Different Bay Substitutions

Qingdao¹

2016

MSCE

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A series of perylenetetracarboxylic diimides (PDIs) dimers with slipped "face-to-face" stacked structure and different substituents at the bay positions have been synthesized and the molecular structures are characterized by 1 H NMR, MALDI-TOF and elemental analysis. And different substituents at the bay positions of the PDI ring bring about various steric hindrances. These different steric hindrances have caused significant differences on the absorption and emission spectra. The correlation between the photophysical properties and the molecular structure is discussed.

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Highly Fluorescent Lyotropic Mesophases and Organogels Based on J‐Aggregates of Core‐Twisted Perylene Bisimide Dyes

Cited by 177 publications

References 63 publications

Contrasting Self‐Assembly and Gelation Properties among Bis‐urea‐ and Bis‐amide‐Functionalised Dialkoxynaphthalene (DAN) π Systems

Contrasting Self‐Assembly and Gelation Properties among Bis‐urea‐ and Bis‐amide‐Functionalised Dialkoxynaphthalene (DAN) π Systems

Exciton Transport in Molecular Aggregates – From Natural Antennas to Synthetic Chromophore Systems

Photophysical Properties of Perylenetetracarboxylic Diimide Dimers with Slipped “Face-to-Face” Stacked Structure and Different Bay Substitutions

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