Self-Organization of Polymethine Dyes in Thin Solid Layers

Daehne, Lars

doi:10.1021/ja00156a024

Cited by 46 publications

(35 citation statements)

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“…ϭ 75 nm for this transition, which allows us to conclude that very similar self-assembled structures are actually obtained in both cases, giving rise to red-shifted spectra as for Jaggregates. [22] The anchoring group is hydroxy(m)ethyl, which binds a zinc atom of a neighboring porphyrin, while the direction of the Q y transition is determined by the carbonyl group, which must thus have slightly different relative orientations in the two supramolecules, as indicated by the Figure 5. Stacking interactions in 10-Zn (left) and 15-Zn (right); R ϭ 3,5-di-tert-butylphenyl; only two porphyrin rings are shown in each case, together with the directions of the Q y transition dipole moments (arrows); the geometries were obtained by successive optimizations with the semiempirical force-field PM3 and molecular mechanics (MMϩ) by use of the HyperChem [23] program package and should be regarded only as a crude approximation molecular models shown in Figure 5.…”

Section: Resultsmentioning

confidence: 99%

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

Balaban¹,

Linke‐Schaetzel²,

Bhise³

et al. 2004

Eur J Org Chem

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Novel porphyrins and chlorins that self-assemble in nonpolar solvents in a manner similar to that of the bacteriochlorophylls c, d, and e have been synthesized by a common protective group approach. The supramolecular assemblies have broad and red-shifted absorption spectra in comparison to those of the monomeric building blocks. The presence of a carbonyl group in conjugation with the tetrapyrrolic macrocycle produces green colors both in the free bases and in their zinc complexes, which, after self-assembly, are thus perfect artificial mimics of the chlorosomal antennas encountered in green photosynthetic bacteria. Enantiopure building blocks produce large helical aggregates with M or P helicity determined by the chirality of the 1-hydroxyethyl substituent. It is demonstrated that the groups essential for self-or- IntroductionThe ubiquitous green color of light-harvesting apparata is encountered in (bacterio)chlorophyll-based photosynthetic organisms. In conjunction with other pigments, such as carotenoids, the light absorption characteristics, which include broad wavelength ranges and high extinction coefficients, have been optimized during evolution in order to ensure conversion of light into biochemical energy by adaptation to different habitats. Thus, bacteria that live under the water surface at depths of over 50 m have evolved antenna systems different to those of bacteria or algae living at the surface, and these differ in turn from terrestrial plants in their light-harvesting systems. While the last, more highly evolved, of these species have developed protein complexes to bind chromophores, in the early green photosynthetic bacteria, due to the pressures of synthetic and genetic economy, self-assembly of bacteriochlorophylls c, d, and e (Figure 1) is used. [1,2] This much simpler architectural construct, which is fully functional, is worth mimicking [a] Forschungszentrum Karlsruhe,

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Section: Resultsmentioning

confidence: 99%

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

Balaban¹,

Linke‐Schaetzel²,

Bhise³

et al. 2004

Eur J Org Chem

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“…Dye aggregation is often characterized through broadening of the absorption spectra4 or appearance of a new bands or shoulders either hypsochromically shifted (H-aggregate) or bathocromically shifted (J-aggregate)10 as compared to the monomer absorption band. This effect is attributed to the excitonic splitting due to Coulomb coupling of the transition dipoles of the individual molecules forming such aggregates 11.…”

Section: Introductionmentioning

confidence: 99%

Nontemplated Approach to Tuning the Spectral Properties of Cyanine-Based Fluorescent NanoGUMBOS

Das¹,

Bwambok²,

El‐Zahab³

et al. 2010

Langmuir

113

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Template free controlled aggregation and spectral properties in fluorescent organic nanoparticles (FONs) is highly desirable for various applications. Herein, we report a non-templated method for controlling the aggregation in NIR cyanine-based nanoparticles derived from a Group of Uniform Materials Based on Organic salts (GUMBOS). The cationic heptamethine cyanine dye, 1,1′,3,3,3′,3′-hexamethylindotricarbocyanine (HMT), was coupled with five different anions viz. [NTf2−], [BETI−], [TFPB], [AOT−] and [TFP4B] by ion exchange method to obtain the respective GUMBOS. The nanoGUMBOS obtained via a reprecipitation method were primarily amorphous and spherical (30-100 nm) as suggested by selected area electron diffraction (SAED) and transmission electron micrographs (TEM). The formation of tunable self-assemblies within the nanoGUMBOS was characterized using absorption and fluorescence spectroscopy, in conjunction with molecular dynamic simulations. Counterion controlled spectral properties observed in the nanoGUMBOS were attributed to variations in J/H ratios with different anions. Association with the anion [AOT−] afforded predominant J-aggregation enabling highest fluorescence intensity, while [TFP4B−] disabled the fluorescence due to predominant H-aggregation in the nanoparticles. Analyses of the stacking angle of the cations based on molecular dynamic simulation results in [HMT][NTf2], [HMT][BETI] and [HMT][AOT] dispersed in water and visual analysis of representative simulation snapshots also imply that the type of aggregation was controlled through the counterion associated with the dye cation.

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“…Typical methods for obtaining thin films are spin-coating [8], Langmuir-Blodgett [9], evaporation [10]. The advantages of spin-coating method are homogeneity of the fi .…”

Section: Introductionmentioning

confidence: 99%

Formation mechanisms of the component composition for thin films and aqueous solutions of symmetric cyanine dyes

Starovoytov

Kaliteevskaya

Krutyakova

et al. 2014

2014 IEEE 9th Nanotechnology Materials and Devices Conference (NMDC)

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The equilibrium component composition of films and aqueous solutions of symmetric cyanine dye was studied by the absorption spectroscopy. Films as well as aqueous solution contain several monomeric components (different isomers) and aggregate forms (dimers and J-aggregates). The observed components are the ionic pairs. The relative concentrations of the components depended on the structure of dye (anion, bulk and electron-donation ability of terminal groups) and its concentration.�ywords-thin 111m; cyanine; dye; J-agreggate; isomer; component

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Self-Organization of Polymethine Dyes in Thin Solid Layers

Cited by 46 publications

References 0 publications

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

Nontemplated Approach to Tuning the Spectral Properties of Cyanine-Based Fluorescent NanoGUMBOS

Formation mechanisms of the component composition for thin films and aqueous solutions of symmetric cyanine dyes

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