Perylene Bisimide Dyes Research Articles

Transition metal complexes of axially chiral tetrathioether bay-substituted perylene bisimide dyes

Nucleophilic substitution of 1,6,7,12-tetrachloro perylene bisimide (PBI) with n-butanethiol provided a novel, highly twisted PBI bearing four sulphur coordination sites at the bay positions, from which silver and palladium complexes were prepared.

POSS-containing red fluorescent nanoparticles for rapid detection of aqueous fluoride ions

Polyhedral oligomeric silsesquioxane (POSS)-containing red fluorescent nanoparticles were designed and prepared for rapid detection of aqueous fluoride ions by virtue of the fluoride-triggered self-quenching of perylene bisimide dyes in nanoparticle cores.

The composite material of perylene bisimide dye in MCM-41 and its photophysical and photochemical properties

The mesoporous material MCM-41 was synthesized by a hydrothermal method, and perylene bisimide dye was incorporated into its channels by impregnation. The absorption, FTIR, fluorescence emission, and decay spectra of perylene bisimide dye in CHCl3 and in MCM-41 were studied to investigate the effect of the one-dimensional channel of MCM-41 on the photophysical and photochemical properties of the dye. The results indicated that the nanochannels of MCM-41 shifted the absorption and emission maxima to red and broadened the spectra, with loss of vibrational structure. The fluorescence decay curves fitted a double-exponential function and the lifetime of perylene bisimide dye in MCM-41 was prolonged. The huge surface area of the mesoporous molecular sieve MCM-41 prevented aggregation of dye molecules, which can thus be used at high concentration.

Perylene Bisimide Dimer Aggregates: Fundamental Insights into Self‐Assembly by NMR and UV/Vis Spectroscopy

A novel perylene bisimide (PBI) dye bearing one solubilizing dialkoxybenzyl and one bulky 2,5-di-tert-butylphenyl substituent was synthesized and its aggregation behavior was analyzed by NMR and UV/Vis spectroscopy in various chloroform/methylcyclohexane (MCH) solvent mixtures. In the presence of no less than 10 vol % chloroform, exclusive self-assembly of this PBI dye into π-stacked dimers was unambiguously confirmed by means of both concentration-dependent (1) H NMR and UV/Vis spectroscopic experiments. Based on ROESY NMR, a well-defined π-stacked dimer structure was determined and further corroborated by molecular modeling studies. By varying the solvent composition of chloroform and MCH, the solvent effects on the Gibbs free energy of PBI dimerization were elucidated and showed a pronounced nonlinearity between lower and higher MCH contents. This observation could be related to a further growth process of dimers into larger aggregates that occurs in the absence of chloroform, which is required to solvate the aromatic π surfaces. With the help of a single-crystal structure analysis for a related PBI dye, a structural model could be derived for the extended aggregates that are still composed of defined π-π-stacked PBI dimer entities.

Quantum Chemical Parametrization and Spectroscopic Characterization of the Frenkel Exciton Hamiltonian for a J-Aggregate Forming Perylene Bisimide Dye

Quantum chemical and quantum dynamical calculations are performed for a bay-substituted perylene bisimide dye up to its hexameric aggregate. The aggregate structure is determined by employing the self-consistent charge density functional tight-binding (SCC-DFTB) approach including dispersion corrections. It is characterized by a stabilization via two chains of hydrogen bonds facilitated by amide functionalities. Focusing on the central embedded dimer, the Coulomb coupling for this J-aggregate is determined by means of the time-dependent density functional theory (TDDFT) to be -514 cm(-1). Exciton vibrational coupling is treated within the shifted oscillator model from which five strongly coupled modes per monomer are selected for inclusion into a minimal dynamic model. Performing wave packet propagations for a model employing up to 7 electronic states and 30 vibrational modes using the multiconfiguration time-dependent Hartree method, aggregate absorption spectra are obtained and compared to experiment.

Isothermally Reversible Fluorescence Switching of a Mechanochromic Perylene Bisimide Dye

Isothermally rewritable fluorescence mechanochromism has been realized for a perylene bisimide dye with bulky and flexible substituents. Fluorescent patterns drawn by mechanical stimuli can be erased by thermal stimuli, treatment with solvent vapors, or spontaneous structural transition from orange-fluorescent to green-fluorescent states. The isothermal fluorescence switching of solid dye films is applicable to displays and sensory materials.

Facile synthesis and replacement reactions of mono-substituted perylene bisimide dyes

Abstract Mono-substituted perylene bisimides were synthesized in high yields under mild condition. The starting material was mono-nitrified perylene bisimides instead of usual perylene bisimides halogenated at different levels. Besides phenols and amine, the nucleophilic reagents included alcohol and thiol. The substitution of nitro group was easier and more effective than the substitution of halogen atoms. But the substitution reaction of pyrrolidine afforded mono- and 1,6-disubstituted perylene bisimides owing to the high activity of nitrified perylene bisimides and pyrrolidine. Several replacement reactions between phenols and alcohol based on phenol mono-substituted perylene bisimide were also found. The replacement reactions between phenols was fast and in high yield. The absorption of the mono-substituted perylene bisimides were tunable in the whole visible region.

Molecular Assemblies of Perylene Bisimide Dyes in Water

Perylene bisimides are among the most valuable functional dyes and have numerous potential applications. As a result of their chemical robustness, photostability, and outstanding optical and electronic properties, these dyes have been applied as pigments, fluorescence sensors, and n-semiconductors in organic electronics and photovoltaics. Moreover, the extended quadrupolar π system of this class of dyes has facilitated the construction of numerous supramolecular architectures with fascinating photophysical properties. However, the supramolecular approach to the formation of perylene bisimide aggregates has been restricted mostly to organic media. Pleasingly, considerable progress has been made in the last few years in developing water-soluble perylene bisimides and their application in aqueous media. This Review provides an up-to-date overview on the self-assembly of perylene bisimides through π-π interactions in aqueous media. Synthetic strategies for the preparation of water-soluble perylene bisimides and the influence of water on the π-π stacking of perylene bisimides as well as the resulting applications are discussed.

Förster-mediated spectral diffusion in disordered organic materials

A model that describes exciton diffusion in disordered organic materials is introduced that is capable of quantitatively describing the effects of inhomogeneous broadening and energetic disorder on the energy transfer. The model is tested on a system that consists of a polymer matrix containing the perylene bisimide dye Perylene Red at high concentration as active sites. Excitons can be efficiently exchanged between the dye molecules by F\"orster energy transfer, resulting in a fairly high mobility of the excitons. Compared to polymers, the investigated system provides better insight into the parameters controlling the mobility of the excitons. Using femtosecond absorption spectroscopy, clear signatures for dispersive energy migration are found, namely, a shift of the exciton energy to lower energies within the first picoseconds and an anisotropy decay that deviates slightly from the predictions of classical F\"orster theory. Both effects are quantitatively reproduced by the model, which extends previous theories and takes explicitly into account the dependence of the F\"orster radius on the donor and the acceptor energy in a disordered sample of equal chromophores. The model predicts correctly the order of the exciton diffusion constant and provides a quantitative linkage between the exciton mobility and the inhomogeneous line width.

Energy and Electron Transfer from Fluorescent Mesostructured Organosilica Framework to Guest Dyes

Energy and electron transfer from frameworks of nanoporous or mesostructured materials to guest species in the nanochannels have been attracting much attention because of their increasing availability for the design and construction of solid photofunctional systems, such as luminescent materials, photovoltaic devices, and photocatalysts. In the present study, energy and electron-transfer behavior of dye-doped periodic mesostructured organosilica films with different host-guest arrangements were systematically examined. Fluorescent tetraphenylpyrene (TPPy)-silica mesostructured films were used as a host donor. The location of guest perylene bisimide (PBI) dye molecules, acting as an acceptor, could be controlled on the basis of the molecular design of the PBI substituent groups. PBI dyes with bulky substituents and polar anchoring groups were located at the pore surface with low self-aggregation, which induced efficient energy or electron transfer because of the close host-guest arrangement. However, PBI dye with bulky and hydrophobic substituents was located in the center of template surfactant micelles; the fluorescence emission from the host TPPy groups was hardly quenched when the host-guest distance was longer than the critical Förster radius (ca. 4.5 nm). The relationship between the energy or electron-transfer efficiency and the location of guest species in the channels of mesostructured organosilica was first revealed by molecular design of the PBI substituents.

Interaction of spermine-alanine functionalized perylene bisimide dye aggregates with ds-DNA/RNA secondary structure

We report for the first time on the interaction of self-assembled perylene bisimide (PBI) dye aggregates with polynucleotides, revealing very high (nM) binding constants and exceptional thermal stabilization of double-stranded (ds)-DNA/RNA. Induced CD profiles of PBI dimer aggregates formed within DNA/RNA grooves show high sensitivity on the steric properties of the binding site, suggesting the applicability of such self-adjusting excitonically coupled PBI dimers for the sensing of the DNA/RNA secondary structure.

Reorganization of perylene bisimide J-aggregates: from delocalized collective to localized individual excitations

Water-induced reorganization of individual one-dimensional J-aggregates of perylene bisimide (PBI) dyes was observed by fluorescence microscopy. Fluorescence spectra and decay kinetics of individual J-aggregates immobilized on glass surfaces were measured under a dry nitrogen atmosphere and under humid conditions. The fluorescence properties of PBI J-aggregates arisen from collective excitons under dry nitrogen atmosphere were changed to those of non-interacting dye monomers when water vapor was introduced into the environment (sample chamber). Time-dependent changes of the fluorescence spectra and lifetimes upon exposure to water vapor suggest an initial coordination of water molecules at defect sites leading to the formation of H-type dimer units that act as exciton quenchers, and a subsequent slower disintegration of the hydrogen-bonded J-aggregate into monomers that lack resonance coupling. Our present studies resulted in a direct demonstration of how drastically the optical properties of molecular ensembles and characteristics of their excited states can be changed by delicate reorganization of dye molecules at nanometre scales.

Bay-substituted perylene bisimide dye with an undistorted planar scaffold and outstanding solid state fluorescence properties

Single crystal X-ray analysis reveals a flat perylene π-scaffold for a perylene bisimide bearing bulky 2,6-diphenylphenoxy substituents at the 1,7 bay positions. The flat structure provides sharp vibronic progressions in the absorption and fluorescence spectra, the sterical shielding outstanding fluorescence quantum yields in the solid state.

Helical Assembly Induced by Hydrogen Bonding from Chiral Carboxylic Acids Based on Perylene Bisimides

The control over self-assembly behavior becomes absolutely critical because it is dependent on the orientation and morphology. The motivation is focused on borrowing the help of O-H···O hydrogen bonding interactions to realize the control in chiral self-assembly. A series of perylene bisimide (PBI) dyes 3a-3d bearing chiral amino acid derivatives on the imide N atoms and four phenoxy-type substituents at the bay positions of the perylene core were synthesized. Optical properties and aggregation behavior of PBIs were investigated by absorption, fluorescence, circular dichroism (CD), and (1)H NMR spectroscopy. Except for the chiral ester 3c and achiral 3d, chiral dyes 3a and 3b show bisignated CD signals, indicating that the chiral carboxylic acid-functionalized PBI systems are found to be spontaneously self-assembled into supramolecular helices via intermolecular hydrogen bonding rather than π-π stacking. Furthermore, the chirality-controlled helical superstructures are strongly dependent on several factors, such as solvent polarity, concentration, and temperature. The supramolecular helical chirality can be well-controlled by the chiral amino acid residues in the PBI system; that is, the assembled clockwise (plus, P) or anticlockwise (minus, M) helices can be induced by L- or D-isomers, respectively.

Synthesis of DNA with Green Perylene Bisimides as DNA Base Substitutions

AbstractPerylene‐3,4:9,10‐tetracarboxylic acid bisimide represents a particularly attractive building block for DNA‐based multichromophores and nanoassemblies due to its unique combination of optical and electronic properties. Despite the broad applicability of the perylene bisimide dye for DNA‐based assemblies, significant fluorescence quenching by photoinduced charge‐transfer processes to guanines in DNA represents a major disadvantage. In order to develop a redox actively and optically tuned perylene bisimide derivative with fluorescence that does not photooxidize guanines in DNA, we chose to attach two N‐pyrrolidinyl substituents as strongly electron‐donating substituents at the 1‐ and 7‐positions of the bay area (“APBI”). The corresponding phosphoramidite 1 was synthesized and incorporated synthetically into oligonucleotides by using the automated DNA building block chemistry. The 2′‐deoxyribofuranoside of natural nucleosides was replaced by (S)‐1‐aminopropane‐2,3‐diol as an acyclic linker between the phosphodiester bridges that is tethered to one of the imide nitrogen atoms of the APBI dye. Electrochemical and optical characterization of the isolated APBI dye shows that photoinduced charge transfer with guanines is indeed very unlikely. Single APBI DNA base substitutions show an exciplex‐type emission with pH sensitivity. The interstrand APBI dimer in DNA could be regarded as a hydrophobically interacting base pair that stabilizes the thermal stability of the double strand. The APBI dimer behaves like an H aggregate, and the fluorescence is quenched quantitatively.

Vibronic Spectra of Perylene Bisimide Oligomers: Effects of Intermolecular Charge-Transfer Excitation and Conformational Flexibility

We have recently presented a theoretical study on the temperature-dependent absorption and photoluminescence spectroscopy of rubrene multichromophores by combining the time-dependent long-range-corrected density functional theory with the Frenkel exciton model (Gao; et al. J. Phys. Chem. A2009, 113, 12847). The spectra of rubrene multichromophores up to heptamers have been calculated and the effects of exciton-phonon coupling and temperature on the photophysical properties of both H- and J-aggregated oligomers were addressed. However, in that work the contribution of intermolecular charge-transfer excitons (CTEs) to vibronic spectra was not addressed. Here we take into account the effect of CTEs for the absorption and emission spectra of the aggregated perylene bisimide (PBI) oligomers in order to have a quantitative explanation to the experimental absorption and emission spectra of the PBI dyes. The role of intermolecular CTEs is discussed for different intermolecular orientations and distances. The simulations demonstrate that the contribution of CTEs becomes significant when the intermolecular distance is less than 4.5 Å for the π-π stacked PBI aggregates, and the mixed exciton model is prerequisite to explain the experimentally observed red-shift of the absorption spectra in this case. The large Stokes shift of the emission spectra can be reproduced by our model, and it is induced by the asymmetric nature of the lowest excitonic state of the H-aggregated oligomers. The experimentally observed broad emission bands come from two species with different conformations. As for J-aggregated PBI oligomers, the interactions of FEs induce the red-shift and the increase of the relative intensity of 0-0 peak of the absorption spectra with more aggregated units.

New fluorescent perylene bisimide indicators—a platform for broadband pH optodes

Asymmetric perylene bisimide (PBI) dyes are prepared and are shown to be suitable for the preparation of fluorescence chemosensors for pH. They carry one amino-functional substituent which introduces pH sensitivity via photoinduced electron transfer (PET) while the other one increases solubility. The luminescence quantum yields for the new indicators exceed 75% in the protonated form. The new indicators are non-covalently entrapped in polyurethane hydrogel D4 and poly(hydroxyalkylmethacrylates). Several PET functions including aliphatic and aromatic amino groups were successfully used to tune the dynamic range of the sensor. Because of their virtually identical spectral properties, various PBIs with selected PET functions can easily be integrated into a single sensor with enlarged dynamic range (over 4 pH units). PBIs with two different substitution patterns in the bay position are investigated and possess variable spectral properties. Compared with their tetrachloro analogues, tetra-tert-butyl-substituted PBIs yield more long-wave excitable sensors which feature excellent photostability. Cross-sensitivity to ionic strength was found to be negligible. The practical applicability of the sensors may be compromised by the long response times (especially in case of tetra-tert-butyl-substituted PBIs).Electronic supplementary materialThe online version of this article (doi:10.1007/s00216-010-4647-y) contains supplementary material, which is available to authorized users.

Long distance energy transfer in a polymer matrix doped with a perylene dye

Exciton migration over long distances is a key issue for various applications in organic electronics. We investigate a disordered material system which has the potential for long exciton diffusion lengths in combination with a high versatility. The perylene bisimide dye Perylene Red is incorporated in a polymer matrix with a high concentration. The dye molecules represent active sites with a narrow energy distribution for the electronically excited states. Excitons can be efficiently exchanged between them by Förster resonance energy transfer (FRET). The narrow energy distribution reduces drastically the trapping probability of the excitons compared to polymers and allows for long transfer distances. To characterize the mobility of the excitons and their diffusion length the dye Oxazine 1 is added as an acceptor in low concentration and the transfer probability to the acceptor is determined by measuring the reduction of Perylene Red fluorescence. The quenched quantum yield is measured for dye concentrations varying from 0.05M to 0.15 M for Perylene Red and from 0.3 mM to 3 mM for Oxazine 1. The experimental results are compared to a model which assumes that excitons can diffuse through the material by FRET between Perylene Red sites and are trapped at an acceptor with a final hetero FRET step. We find a quite good match between theory and experiment though the observed diffusion constant is about two times smaller than the calculated one. The exciton diffusion length extracted from the data is 30 nm for a Perylene Red concentration of 0.1 M and demonstrates that long distance energy transfer is possible in this disordered material system.

Photoinduced Processes in Self-Assembled Porphyrin/Perylene Bisimide Metallosupramolecular Boxes

Two new supramolecular boxes, (ZnMC)(2)(rPBI)(2) and (ZnMC)(2)(gPBI)(2), have been obtained by axial coordination of N,N'-dipyridyl-functionalized perylene bisimide (PBI) dyes to the zinc ion centers of two 2+2 porphyrin metallacycles (ZnMC = [trans,cis,cis-RuCl(2)(CO)(2)(Zn·4'-cis-DPyP)](2)). The two molecular boxes involve PBI pillars with different substituents at the bay area: the "red" PBI (rPBI = N,N'-di(4-pyridyl)-1,6,7,12-tetra(4-tert-butylphenoxy)perylene-3,4:9,10-tetracarboxylic acid bisimide) containing tert-butylphenoxy substituents and the "green" PBI (gPBI = N,N'-di(4-pyridyl)-1,7-bis(pyrrolidin-1-yl)perylene-3,4:9,10-tetracarboxylic acid bisimide) bearing pyrrolidinyl substituents. Due to the rigidity of the modules and the simultaneous formation of four pyridine-zinc bonds, these discrete adducts self-assemble quantitatively and are remarkably stable in dichloromethane solution. The photophysical behavior of the new supramolecular boxes has been studied in dichloromethane by emission spectroscopy and ultrafast absorption techniques. A different photophysical behavior is observed for the two systems. In (ZnMC)(2)(rPBI)(2), efficient electron transfer quenching of both perylene bisimide and zinc porphyrin chromophores is observed, leading to a charge separated state, PBI(-)-Zn(+), in which a perylene bisimide unit is reduced and zinc porphyrin is oxidized. In the deactivation of the perylene bisimide localized excited state, an intermediate zwitterionic charge transfer state of type PBI(-)-PBI(+) seems to play a relevant role. In (ZnMC)(2)(gPBI)(2), singlet energy transfer from the Zn porphyrin chromophores to the perylene bisimide units occurs with an efficiency of 0.7. This lower than unity value is due to a competing electron transfer quenching, leading to the charge separated state PBI(-)-Zn(+). The distinct photophysical behavior of these two supramolecular boxes is interpreted in terms of energy changes occurring upon replacement of the "red" rPBI by "green" gPBI.

Spermine‐Functionalized Perylene Bisimide Dyes—Highly Fluorescent Bola‐Amphiphiles in Water

A series of four spermine-functionalized perylene bisimide dyes without linkers (1) and with linkers (2-4) between the chromophore and the polyamine was synthesized. Protonation of the spermine moieties resulted in the formation of highly water-soluble dyes with up to six positively charged ammonium ions. The aggregation behavior of these strongly fluorescent bola-amphiphiles was studied in pure water as solvent by UV/Vis and fluorescence spectroscopy, and an astonishingly high fluorescence quantum yield of up to Phi(fl)=0.90 was observed for PBI 1. Atomic force microscopy and transmission electron microscopy were applied for the visualization of the aggregates on surfaces. Molecular modeling studies were performed by force-field calculations to explore the aggregate morphologies, which also provided valuable information on the influence of the additional alkylcarbonyl linkers. Our detailed spectroscopic and microscopic investigations revealed that the excellent optical properties of perylene bisimide chromophores can be used even in pure deionized water if their aggregation is efficiently suppressed.