Water-soluble Perylene Research Articles

The effects of amino acid functionalisation on the optoelectronic properties and self-assembly of perylene bisimides

Here we report on ten water-soluble perylene bisimides that are functionalised with the amino acids L-alanine, L-aspartic acid, L-glutamic acid, L-phenylalanine, L-histidine, L-leucine, L-methionine, L-valine, L-tryptophan, and L-tyrosine. Reduction potentials, absoprtion and emission spectra, molar absorptivity, quantum yield, and rheology are obtained and the data interpreted for each species in aqueous solution or hydrogels in order to provide a comprehensive understanding of the subtle effects of amino acid functionalisation on the optoelectronic and supramolecular properties.

A “turn-on” approach for rapid detection of tetracycline based on supramolecular aggregates of water soluble perylene diimide

Antibiotic residue in animal foods has aroused great attention. Herein, we report a “turn-on” approach via supramolecular aggregates of water soluble perylene diimide (PDI) for rapid detection of tetracycline (TC), which is very important to food quality and safety. The disassembly of PDI aggregate was promoted owing to the coordination of Eu3+ and TC, leading to a significant recovery of fluorescence intensity. The sensing mechanism and performance of this approach were studied by absorption and emission spectra. The limit of detection (LOD) and the operation range were 12.11 nM and 0.1–30 μM, respectively. This method features simple acquisition, free of organic solvents, rapid detection, high selectivity and sensitivity, ease of observation and operation. It could be applied to detecting TC in Chicken, Fish and Pork with good recovery. To our knowledge, this is the first report of TC based on PDI probe in aqueous media.

Evaluation of singlet oxygen generators of novel water-soluble perylene diimide photosensitizers.

In this study, novel photosensitizers using three water-soluble green perylene diimide (PDI)-based ligands were synthesized, which can be used as photosensitizing drugs in photodynamic cancer therapy (PDT). These three efficient singlet oxygen generators were prepared via reactions of three newly designed molecules, namely 1,7-di-3-morpholine propylamine-N,N'-(l-valine-t-butylester)-3,4:9,10-perylyne diimide, 1,7-dimorpholine-N,N'-(O-t-butyl-l-serine-t-butylester)-3,4:9,10-perylene diimide and 1,7-dimorpholine-N,N'-(l-alanine t-butylester)-3,4:9,10-perylene diimide. Although there have been numerous photosensitizers, most of them have a limited useable range of solvent conditions or low photostability. These sensitizers have demonstrated strong absorption and red-light excitation. The singlet oxygen production of the newly synthesized compounds was investigated using a chemical method with 1,3-diphenyl-iso-benzofuran as a trap molecule. In addition, they do not have any dark toxicity at the active concentrations. Owing to these remarkable properties, we demonstrate the singlet oxygen generation of these novel water-soluble green perylene diimide (PDI) photosensitizers with substituent groups at the 1 and 7 positions of the PDI material, which are promising for PDT.

Combined spectroscopic and theoretical analysis of the binding of a water-soluble perylene diimide to DNA/RNA polynucleotides and G-quadruplexes

We present here a combined spectroscopic and theoretical analysis of the binding of N,N’-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylenetetracarboxylic acid diimide dichloride (PZPERY) to different biosubstrates. Absorbance titrations and circular dichroism experiments, melting studies and isothermal calorimetry (ITC) titrations reveal a picture where the binding to natural double-stranded DNA is very different from that to double and triple-stranded RNAs (poly(A)∙poly(U) and poly(U)∙poly(A)⁎poly(U)). As confirmed also by the structural and energetic details clarified by density functional theory (DFT) calculations, intercalation occurs for DNA, with a process driven by the combination of aggregates disruption and monomers intercalation. Oppositely, for RNAs, no intercalation but groove binding with the formation of supramolecular aggregates is observed. Among all the tested biosubstrates, the affinity of PZPERY towards DNA G-quadruplexes (G4) is the greatest one with a preference for human telomeric G4s. Focusing on hybrid G4 forms, either sitting-atop (“tetrad-parallel”) or lateral (“groove-parallel”) binding modes were considered in the discussion of the experimental results and molecular dynamics (MD) simulations. Both turned out to be possible concurrently, in agreement also with the experimental binding stoichiometries higher than 2:1.

How to reprogram the excitonic properties and solid-state morphologies of π-conjugated supramolecular polymers.

The development of supramolecular tools to modulate the excitonic properties of non-covalent assemblies paves the way to engineer new classes of semicondcuting materials relevant to flexible electronics. While controlling the assembly pathways of organic chromophores enables the formation of J-like and H-like aggregates, strategies to tailor the excitonic properties of pre-assembled aggregates through post-modification are scarce. In the present contribution, we combine supramolecular chemistry with redox chemistry to modulate the excitonic properties and solid-state morphologies of aggregates built from stacks of water-soluble perylene diimide building blocks. The n-doping of initially formed aggregates in an aqueous medium is shown to produce π-anion stacks for which spectroscopic properties unveil a non-negligible degree of electron-electron interactions. Oxidation of the n-doped intermediates produces metastable aggregates where free exciton bandwidths (ExBW) increase as a function of time. Kinetic data analysis reveals that the dynamic increase of free exciton bandwidth is associated with the formation of superstructures constructed by means of a nucleation-growth mechanism. By designing different redox-assisted assembly pathways, we highlight that the sacrificial electron donor plays a non-innocent role in regulating the structure-function properties of the final superstructures. Furthermore, supramolecular architectures formed via a nucleation-growth mechanism evolve into ribbon-like and fiber-like materials in the solid-state, as characterized by SEM and HRTEM. Through a combination of ground-state electronic absorption spectroscopy, electrochemistry, spectroelectrochemistry, microscopy, and modeling, we show that redox-assisted assembly provides a means to reprogram the structure-function properties of pre-assembled aggregates.

Self-assembly system based on water-soluble perylene diimide for sensitive detection and discrimination of tea polyphenols

Tea polyphenols have become one of the promising healthcare molecules due to their anti-cancer, anti-oxidant, and anti-obesity capacities, making tea among the most popular and functional beverages worldwide. However, the sensitive and simple detection and discrimination of tea polyphenols is difficult to achieve since the analogues usually have similar chemical structures with polyhydroxy. Herein, a self-assembly system based on a cationic perylene diimide molecule tagging with phenylboric acid group (PDI-PBA) was constructed for detection and discrimination of catechin molecules (Epicatechin, Epicatechin gallate, Epigallocatechin, Epigallocatechin gallate), a subgroup of tea polyphenols. PDI-PBA could recognize tea polyphenols by dynamic borate ester bonds between PBA groups on PDI-PBA and cis-diols on tea polyphenols. Moreover, the fluorescence quench ratios of PDI-PBA were determined by the different aggregation degrees induced by every tea polyphenol with the unique chemical structure, especially cis-diol numbers. Thus, the selective discrimination could be easily realized by linear discriminant analysis (LDA). The developed system relies mainly on dynamic borate ester bonds between the probe and substrates, the self-assembly of PDI-PBA, and polyhydroxy characteristic of tea polyphenols. This work provides a new strategy for sensitive detection and discrimination of tea polyphenols.

Sensitive and reversible perylene derivative-based fluorescent probe for acetylcholinesterase activity monitoring and its inhibitor

A reversible fluorescence probe for acetylcholinesterase activity detection was developed based on water soluble perylene derivative, N,N′-di(2-aspartic acid)-perylene-3,4,9,10-tetracarboxylic diimide (PASP). Based on the photo-induced electron transfer (PET), PASP fluorescence in aqueous is quenched after combining with copper ions (Cu2+). Acetylcholinesterase (AChE) is well known to catalyze the hydrolysis of acetylcholine (ATCh) to produce thiocholine, whose affinity is strong enough to capture Cu2+ by thiol (-SH) group from the complex PASP-Cu, resulting in the fluorescence signal of PASP recovers up to 90%. This optical switch is highly sensitive depended on the coordination and dissociation between PASP and Cu2+. We proposed its application for AChE activity detection, as well as its inhibitor screening. According to the change of fluorescence intensity, quantifying the detection limit of AChE was 1.78 mU·mL−1. Classical inhibitors, tacrine and organophosphate pesticide diazinon, were further evaluated for drug screening. The IC50 value of tacrine was calculated to be 0.43 μM, and the detection limit of diazinon was 0.22 μM. Both of these performances were much better than previous results, revealing our probe is sensitive and reversible for screening applications.

An efficient approach for rapid detection of polymyxins B based on the optically active supramolecular aggregates of water-soluble perylene diimide

Antibiotic residue in food products has aroused considerable public concerns all over the world. It is of great significance to develop an efficient approach for rapid detection of antibiotics in food. In this work, a selective and sensitive method for detecting Polymyxins B (PMB) was established in 100 % aqueous media based on the supramolecular aggregates of water-soluble perylene diimide (PDI) derivative. We have designed and synthesized a series of PDI derivatives (PDI-1, 2, 3, 4, Scheme 1). The sensing performance and mechanism of PDI-based probes werestudied by absorption, emission, and circular dichroism (CD) techniques. It was found that the formation of the supramolecular aggregate driven by the non-covalent interactions between PMB and PDIs accounted for the fluorescence quenching of PDIs. PDI-1 was screened to be the most effective probe, which has the characteristics of detecting PMB rapidly and intuitively in both solution state and solid support. The detection limit can be extended to be 18.5 nmol/L by the aid of fluorometry. PDI-1 can also be used for the determination of PMB in practical samples with high sensitivity and large operative range. To the best of our knowledge, this work is the first example of fluorescent sensing PMB based on organic molecular probes in 100 % aqueous media.

Rapid and visual detection of folic acid via supramolecular recognition with a perylene bisimide probe in aqueous media

In this report, we have established a novel approach for the rapid detection of folic acid (FA) with a water soluble perylene bisimide-based probe in 100% aqueous media. The sensing performance and mechanism of this probe were investigated systematically using spectroscopic techniques. After optimizing conditions, the limit of detection in this assay is as low as 29.2 nmol/L and linear operation range is from 0.1 to 1.2 μmol/L. It relies on the supramolecular recognition between the probe and FA under the synergistic effects of non-covalent interactions such as electrostatic, hydrophobic and π−stacking interactions. Monitoring the FA concentrations in real-world samples is also confirmed.

Rapid and visual detection of protamine based on ionic self-assembly of a water soluble perylene diimide derivative

In this report, a water soluble perylene diimide derivative (PDI-Glu) was designed and prepared for rapid and visual detection of protamine. The sensing performance and mechanism of this probe toward protamine was investigated systematically by absorption and emission spectroscopic techniques. The fluorescence quenching caused by the aggregation of PDI-Glu in the presence of protamine could be outputted by spectrometer and observed by naked eyes. This method showed an excellent selectivity towards protamine in comparison of other analytes. It also featured good water solubility, large operable range, fast and visualized detection. The detection limit of protamine was calculated to be 0.09 μg mL−1. Finally, this probe can be also applied in serum samples and monitoring trypsin activity.

Controllable fabrication of perylene bisimide self-assembled film and patterned all-solid-state electrochromic device

A water-soluble perylene bisimide derivative of N,N-bis(2-phosphonoethyl)-3,4,9,10-perylenediimide (PPDI) was synthesized by introducing phosphoric acid units. PPDI self-assembled films were prepared controllably on hydroxylated ITO glass through a zirconium-phosphonate approach. There is a linear increase between the film thickness and the number of self-assembly layers. Electrochemical and spectroelectrochemical analysis reveal that the PPDI self-assembled films show excellent reversible redox behavior and cathodic electrochromic character which can be switched from a neutral orange-red color to deep purple color in the reduced state. In particular, the PPDI self-assembled film with 10 layers have good integrated performance in term of reasonable optical contrast (31%), fast switching time (0.75 s) and good cycle stability. A large-scale patterned all-solid-state electrochromic device (50 mm × 60 mm) was fabricated by utilizing PPDI self-assembled film as the electrochromic layer and the device shows obvious reversible electrochromism, which provides a new direction for the production of electrochromic device, like smart-window, sunglasses and electronic tags.

Selective Detection of Pyrophosphate Anions in Aqueous Medium Using Aggregation of Perylene Diimide as a Fluorescent Probe.

A water-soluble perylene diimide, aspartic acid-functionalized perylene diimide (APDI), has shown significant sequential “turn-off” and “turn-on” responses toward Cu2+ and inorganic pyrophosphate (PPi), respectively. APDI was found to show selectivity toward Cu2+ and inorganic PPi over adenosine monophosphate, adenosine diphosphate, and adenosine triphosphate. The detection has been studied by absorption and emission spectroscopy techniques. Incorporation of Cu2+ into the solution of APDI results in a distinct quenching of the fluorescence intensity, while there was no spectral change in the presence of other metal ions. The formed APDI–Cu2+ ensemble can turn on its fluorescence signal when PPi is present. The detection of PPi could be traced by looking at the change in color of the solution under the naked eye. No interference was observed from other anions, making the APDI–Cu2+aggregate a highly selective biosensor for PPi.

A Water-Soluble Perylene Bisimide Cyclophane as a Molecular Probe for the Recognition of Aromatic Alkaloids.

Herein, we report a water-soluble macrocyclic host based on perylene bisimide (PBI) chromophores that recognizes natural aromatic alkaloids in aqueous media by intercalating them into its hydrophobic cavity. The host-guest binding properties of our newly designed receptor with several alkaloids were studied by UV/Vis and fluorescence titration experiments as the optical properties of the chromophoric host change significantly upon complexation of guests. Structural information on the host-guest complexes was obtained by 1D and 2D NMR spectroscopy and molecular modelling. Our studies reveal a structure-binding property relationship for a series of structurally diverse aromatic alkaloids with the new receptor and higher binding affinity for the class of harmala alkaloids. To our knowledge, this is the first example of a chromophoric macrocyclic host employed as a molecular probe for the recognition of aromatic alkaloids.

Resonance Raman study of the J-type aggregation process of a water soluble perylene bisimide.

Perylene bisimides (PBIs) are dyes known for combining high absorption and emission in the visible region with thermal and photochemical stability. H-bond-directed aggregation driven by free imide groups has been reported to promote the uncommon J-type aggregate formation of PBIs. J-aggregates are highly desired thanks to their bathochromically shifted narrow absorption and fluorescence due to excitonic coupling, together with hyperchromicity and superradiance compared to the monomer. Herein we present the water soluble MEG-PBI showing interesting aggregation in water and in the solid state. Unlike its hydrophobic counterparts, MEG-PBI aggregates in water with increasing temperature, indicating entropy-driven self-assembly. Temperature-dependent Resonance Raman (RR) spectroscopy was employed for the structural characterization of MEG-PBI in aqueous solution versus toluene and in aggregated thin films, employing excitation at different wavelengths to probe the contribution of various chromophores to the supramolecular structure of the aggregate. We find that the perylene core distorts upon aggregation, where the bonds along the perylene long N-N axis lengthen and the ones perpendicular to that shorten, suggesting a head-to-tail arrangement due to H-bonding between neighboring units.

Visible light induced aqueous RAFT polymerization using a supramolecular perylene diimide/cucurbit[7]uril complex

A water-soluble perylene diimide (PDI), in the presence of triethanolamine (TEOA), is used as a metal-free photocatalyst for aqueous reversible addition–fragmentation chain transfer (RAFT) polymerization under green light.

Insight into the self-assembly of water-soluble perylene bisimide derivatives through a combined computational and experimental approach.

We use a combination of computational and experimental techniques to study the self-assembly and gelation of water-soluble perylene bisimides derivatised at the imide position with an amino acid. Specifically, we study the likely structure of self-assembled aggregates of the alanine-functionalised perylene bisimide (PBI-A) and the thermodynamics of their formation using density functional theory and predict the UV-vis spectra of such aggregates using time-dependent density functional theory. We compare these predictions to experiments in which we study the evolution of the UV-Vis and NMR spectra and the rheology and neutron scattering of alkaline PBI-A solutions when gradually decreasing the pH. Based on the combined computational and experimental results, we show that PBI-A self-assembles at all pH values but that aggregates grow in size upon protonation. Hydrogel formation is driven not by aggregate growth but reduction of the aggregation surface-charge and a decrease in the colloidal stability of the aggregation with respect to agglomeration.

Water-Soluble Perylene Diimide for Highly Sensitive and Repeatable Metal Ion Detection with Novel Logic Gate Operation

In this paper, we report a synthesised water soluble perylene derivative, N,N′-di(2-aspartic acid)-perylene-3,4,9,10-tetracarboxylic diimide (PASP), for highly sensitive and repeatable detection of copper (Cu2+) and aluminium ions (Al3+) and novel logic gate operation. In the presence of metal ions, a dramatic decrease in PASP optical intensity was induced based on the strong interaction between terminal carboxy groups and the metal ions. Detection limits of 0.22 and 0.24 μM were respectively obtained at physiological pH. The signals could be recovered upon the addition of ethylenediaminetetraacetate (EDTA) and P2O74−, which competed for Cu2+ and Al3+ in the PASP-CuII and PASP-AlIII systems and induced their dissociation as secondary sensors for anions. At least four detection cycles were performed with a high recovery efficiency. Based on these phenomena, a novel three-level logic gate (OR-IMP-OR) was performed for smart signal readout with metal ions (Cu2+ and Al3+) and anions (EDTA and P2O74−) as input signals, and the relative change of optical intensity of PASP as output signal. Furthermore, the prepared PASP molecule also responded sensitively to Cu2+ and Al3+ in 10 % diluted serum medium.

Self-assembly of water soluble perylene tetracarboxylic acid with metal cations: Selective fluorescence sensing of Cu2+ and Pb2+ ions in paper strips, zebrafish and yeast

Self-assembly of water soluble highly fluorescent perylene tetracarboxylic (PTCA, Φf = 0.67) dye via metal coordination has been leads to the selective fluorescence sensing of Cu2+ and Pb2+ ions at neutral pH and Ag+ ions sensing via nanoparticles formation at basic medium. High-resolution transmission electron microscopic (HR-TEM) analysis revealed the conversion 1-D nanostructures of PTCA to spherical aggregates with Cu2+ and hexagonal prisms with Pb2+ ions. However, Ag+ ions were reduced to silver nanoparticles (AgNPs) at higher pH. The concentration dependent studies showed detection of both metal ions up to µM concentration level. Interference studies suggested good selectivity for both Cu2+ and Pb2+ ions at neutral pH in presence of other metal cations. Importantly, application potential of PTCA for selective fluorescence sensing of Cu2+ and Pb2+ ions have been demonstrated in filter paper as well as biological environment such as zebrafish and yeast.

Tuning Structure–Function Properties of π-Conjugated Superstructures by Redox-Assisted Self-Assembly

Controlling structure–function properties of hierarchical assemblies that feature stacks of π-conjugated building blocks represents an important challenge to engineer optoelectronic materials. In this regard, the development of new tools to navigate the free energy landscape of supramolecular assembly can lead to the creation of kinetically trapped superstructures equipped with emergent electronic properties. In the present contribution, we demonstrate that redox-assisted self-assembly of supramolecular polymers built from water-soluble perylene diimide enforces formation of superstructures with optoelectronic properties not manifested in parent assemblies. Leveraging on a theoretical model developed for H-aggregates in semiconducting polymers, free-exciton bandwidth has been calculated and increases by more than 30% in kinetically trapped superstructures (380 meV) when compared to initially prepared assemblies (290 meV). Electronic structure of intermediate assemblies is believed to perturb intermolecula...

Tuning the Optical Properties of Silicon Quantum Dots via Surface Functionalization with Conjugated Aromatic Fluorophores

Silicon Quantum Dots (SQDs) have recently attracted great interest due to their excellent optical properties, low cytotoxicity, and ease of surface modification. The size of SQDs and type of ligand on their surface has a great influence on their optical properties which is still poorly understood. Here we report the synthesis and spectroscopic studies of three families of unreported SQDs functionalized by covalently linking to the aromatic fluorophores, 9-vinylphenanthrene, 1-vinylpyrene, and 3-vinylperylene. The results showed that the prepared functionalized SQDs had a highly-controlled diameter by HR-TEM, ranging from 1.7–2.1 nm. The photophysical measurements of the assemblies provided clear evidence for efficient energy transfer from the fluorophore to the SQD core. Fӧrster energy transfer is the likely mechanism in these assemblies. As a result of the photogenerated energy transfer process, the emission color of the SQD core could be efficiently tuned and its emission quantum efficiency enhanced. To demonstrate the potential application of the synthesized SQDs for bioimaging of cancer cells, the water-soluble perylene- and pyrene-capped SQDs were examined for fluorescent imaging of HeLa cells. The SQDs were shown to be of low cytotoxicity