Pyrene Derivatives Research Articles

Studies of cyanomethylcarbamoyl-bridged anthracene and pyrene fluorophores

Cyanomethylcarbamoyl-bridged anthracene and pyrene derivatives were prepared as functional fluorophores with diverse structural, electronic, and fluorescence properties.

Enhanced liquid phase exfoliation of graphene in water using an insoluble bis-pyrene stabiliser.

Stabilisers, such as surfactants, polymers and polyaromatic molecules, offer an effective way to produce graphene dispersions in water by Liquid Phase Exfoliation (LPE) without degrading the properties of graphene. In particular, pyrene derivatives provide better exfoliation efficiency than traditional surfactants and polymers. A stabiliser is expected to be relatively soluble in order to disperse hydrophobic graphene in water. Here, we show that exfoliation can also be achieved with insoluble pyrene stabilisers if appropriately designed. In particular, bis-pyrene stabilisers (BPSs) functionalised with pyrrolidine provide a higher exfoliation efficiency and percentage of single layers compared to traditional pyrene derivatives under the same experimental conditions. This is attributed to the enhanced interactions between BPS and graphene, provided by the presence of two pyrene binding groups. This approach is therefore attractive not only to produce highly concentrated graphene, but also to use graphene to disperse insoluble molecules in water. The enhanced adsorption of BPS on graphene, however, is reflected in higher toxicity towards human epithelial bronchial immortalized cells, limiting the use of this material for biomedical applications.

Supramolecular adducts between macrocyclic Gd(iii) complexes and polyaromatic systems: a route to enhance the relaxivity through the formation of hydrophobic interactions.

The set-up of reversible binding interactions between the hydrophobic region of macrocyclic GBCAs (Gadolinium Based Contrast Agents) and SO3−/OH containing pyrene derivatives provides new insights for pursuing relaxivity enhancements of this class of MRI contrast agents. The strong binding affinity allows attaining relaxation enhancements up to 50% at pyrene/GBCA ratios of 3 : 1. High resolution NMR spectra of the Yb-HPDO3A/pyrene system fully support the formation of a supramolecular adduct based on the set-up of hydrophobic interactions. The relaxation enhancement may be accounted for in terms of the increase of the molecular reorientation time (τR) and the number of second sphere water molecules. This effect is maintained in blood serum and in vivo, as shown by the enhancement of contrast in T1w-MR images obtained by simultaneous injection of GBCA and pyrene derivatives in mice.

Poly(dimethylsiloxane) and oligo(dimethylsiloxane) solvent effects on aromatic donor-acceptor interactions.

Solvents with a wide range of polarities, including poly(dimethylsiloxane) and oligo(dimethylsiloxane), were used to evaluate aromatic donor-acceptor interactions between pyrene and pyromellitic diimide derivatives. The donor-acceptor interactions were stronger in siloxane solvents than in aliphatic solvents, possibly because of the poor solubility of the aromatics in siloxanes.

Iridium-catalysed borylation of pyrene – a powerful route to novel optoelectronic materials

We summarized the Ir-catalysed borylation of PAHs, especially pyrene, and the optoelectronic materials generated by following this chemistry. The optoelectronic properties of pyrene derivatives have also been discussed.

Structural parameter-modulated nonlinear optical amplitude of acceptor–π–D–π–donor-configured pyrene derivatives: a DFT approach

In the present study, organic pyrene-based derivatives were selected for NLO investigation.

Bis(carbazol-9-yl)phenyl end-caped polyaromatics as solution-processed deep blue fluorescent emitters for simple structure solution-processed electroluminescent devices

Development of organic emitters, particularly blue color, is a crucial factor that impacts the extent of organic light emitting diodes (OLEDs) in panel display applications. As blue emitting materials are sparse but greatly desired for high efficiency performing devices, a series of different conjugated core organic small molecules fluorescent emitters (C-A-C, C-BA-C, C-PA-C, C-NA-C, C–P–C, and C-BP-C) have been designed and synthesized in this contribution for blue OLED application. The molecules are constructed from basic building blocks of blue chromophores (anthracene or pyrene derivatives) and end-capped with charge transporting (1,3-phenylene)bis(3,6-di-tert-butyl-9H-carbazole) units which provided the tunable emission in the blue spectral range. Their optical, electrochemical, photophysical, and thermal properties along with device performances were investigated systematically. The best device performance based on C-A-C as the emitter offered low turn on voltage of 3.7 V, external quantum efficiency of 3.24%, strong deep-blue emission (424 nm) with high color purity (FWHM = 59) at CIE coordinates x = 0.155, y = 0.066.

Preparation of Transparent Film of Layered Double Hydroxide with Anionic Pyrene Derivatives and Its Luminous Toluene Detection Ability

To prepare the transparent solid film of layered double hydroxide, the filtration-film transfer (FFT) method using LDH nanosheet colloidal suspension was investigated. It was found that the homogeneous LDH solid film with enough transparency in the visible light range could be prepared by the FFT method. Moreover, anionic pyrene (Pyr−) molecules could be incorporated into the transparent LDH solid film by immersing in anionic pyrene solution. From both absorption and emission spectra of the transparent Pyr−/LDH solid film, Pyr− incorporated in the LDH solid film formed aggregates and mainly showed the strong excimer emission. Additionally, the luminous response of the transparent Pyr−/LDH solid film was investigated in ethanol-toluene mixed solution with various toluene contents. As results, the ratio of luminescence intensities from static excimer and monomer of incorporated Pyr− molecules depended on the toluene content, and excimer emission decreased with an increase in the toluene content. This luminous response can be caused by an increase of the monomeric Pyr− species, because Pyr− aggregates are broken by adsorption of toluene molecules into the LDH interlayer space. The obtained transparent hybrid film may be useful as a detectable material of toluene in solvent by luminous change.

Direct Measure of the Local Concentration of Pyrenyl Groups in Pyrene-Labeled Dendrons Derived from the Rate of Fluorescence Collisional Quenching

The model-free analysis (MFA) was applied to measure the average rate constant (<k>) for pyrene excimer formation (PEF) in a series of pyrene-labeled dendrons referred to as Pyx-G(N), where x (= 2N) is the number of pyrenyl labels born by a dendron of generation N ranging from 1 to 6. <k> was measured in four different solvents, namely tetrahydrofuran (THF), toluene, N,N-dimethylformamide (DMF), and dimethylsulfoxide (DMSO). <k> was found to increase linearly with increasing local pyrene concentration ([Py]loc), where [Py]loc had been determined mathematically for the Pyx-G(N) dendrons. The slope of each straight line changed with the nature of the solvent and represented kdiff, the bimolecular rate constant for PEF. kdiff depended on the solvent viscosity (η) and the probability (p) for PEF upon encounter between an excited and a ground-state pyrene. In a same solvent, kdiff for the Pyx-G(N) dendrons was about 360 ± 30 times smaller than kdiff obtained for ethyl 4-(1-pyrene)butyrate (PyBE), a pyrene model compound similar to the pyrene derivative used to label the dendrons. The massive decrease in kdiff observed for the Pyx-G(N) samples reflected the massive loss in mobility experienced by the pyrenyl labels after being covalently attached onto a macromolecule compared to freely diffusing PyBE. Interestingly, the kdiff values obtained for the Pyx-G(N) dendrons and the PyBE model compound followed similar trends as a function of solvent, indicating that the difference in behavior between the kdiff values obtained in different solvents were merely due to the changes in the η and p values between the solvents. Normalizing the <k> values obtained with the Pyx-G(N) dendrons by the kdiff values obtained for PyBE in the same solvents accounted for changes in η and p, resulting in a master curve upon plotting <k>/(fdiff × kdiff) as a function of [Py]loc, where fdiff was introduced to account for some pyrene aggregation in the higher generation dendron (Py64-G(6)). This result demonstrates that <k> represents a direct measure of [Py]loc in pyrene-labeled macromolecules.

Short axially asymmetrically 1,3-disubstituted pyrene-based color-tunable emitters: Synthesis, characterization and optical properties

In contrast to conventional pyrene-based emitters which feature D-π-A type structures, a new class of emitters possessing a short axis are gaining interest owing to both their academic importance and promising applications in organic optoelectronic materials. Herein, donor and acceptor substituents were introduced at 1-, 3-positions by employing a two step bromination reaction. Two 1-donor-3-acceptor pyrenes were systematically investigated by 1 H/ 13 C NMR spectroscopy, optical spectroscopy, and theoretical calculations. The preliminary research of the substituent positions and substitutions pattern on the properties of the materials as well as on the frontier orbitals is reported. The experimental results indicated the strong impact on the photophysical properties endowed with the possibility of precise color-control of pyrene derivatives through substituent variation. A strategy to access a new class of D-π-A pyrene-based emitters has been established. The strategy is not only useful in the design of novel chromophores but it could also enable the preparation of high-efficiency opto-electronic materials. • A new class of D-π-A pyrene-based emitters at 1,3-positions on pyrene ring was successfully designed and synthesized. • Short axially asymmetrically 1-donor-3-acceptor pyrenes, two compounds exhibit efficient color-tunable properties. • Two compounds exhibit high thermal stability and good solubility.

Photocontrolled Light‐Harvesting Supramolecular Assembly Based on Aggregation‐Induced Excimer Emission

AbstractPhotocontrolled light‐harvesting supramolecular assembly with aggregation‐induced excimer emission is fabricated by polyanionic γ‐cyclodextrin (COONa‐γ‐CD), pyrene derivative (PYC12), Nile red (NiR), and diarylethene derivative (DAE) in aqueous solution. Benefiting from the COONa‐γ‐CD‐induced aggregation of PYC12, the fluorescence can be modulated from monomeric state to assembled state with a large red‐shift around 100 nm, which exhibits aggregation‐induced excimer emission enhancement and makes PYC12 a remarkable energy donor. Subsequently, NiR can function as energy acceptor loaded into PYC12/COONa‐γ‐CD supramolecular assembly, and highly efficient energy transfer process occurs from PYC12/COONa‐γ‐CD to NiR, with energy transfer efficiency up to 83% at donor/acceptor ratio of 160:1. Moreover, multicolor tunable emission can be achieved simply by tuning the molar ratios of donor and acceptor, notably including white‐light emission. Interestingly, loading photoresponsive energy acceptor DAE into PYC12/COONa‐γ‐CD/NiR assembly endows the light‐harvesting system with excellent photocontrolled energy transfer, and this process can be efficiently regulated upon distinct light irradiation.

Photocytotoxicity of heavy-atom-free thiobarbituric acid functionalized pyrene derivatives against MCF-7 cancer cells.

Two thiobarbituric acid-functionalized pyrene derivatives (P1, P2) have been synthesized to explore the photophysical properties and photodynamic activity of dyes of this type. Both compounds exhibit an intense intramolecular charge transfer (ICT) band at ca. 470 nm, which is absent in the spectra of the precursor. P1 and P2 exhibit singlet oxygen generation on irradiation with light with moderate singlet oxygen yields of 0.36 and 0.32, respectively, in DMSO. P1 showed better photodynamic activity against MCF-7 cells with an IC50 value of 18.3 μM under illumination at 455 nm for 60 min with a Thorlabs M455L3 LED (330 mW.cm-2).

Reactivity estimation of polybutylene terephthalate with noncovalently functionalized multiwalled carbon nanotubes and reactivity effect on the composite reinforcement

Multiwalled carbon nanotubes (MWCNTs) with physically absorbed pyrene derivatives containing a hydroxyl group are investigated as an effective filler for polybutylene terephthalate (PBT) composites. During extrusion, transesterification reaction occurred between the hydroxyl group of 1-pyrenebutanol (PBOH) and ester group of PBT, thereby grafting PBT onto MWCNTs. Reactions between PBT and 1-hydroxypyrene (POH) and 1-pyrenemethanol (PMOH) absorbed onto the MWCNTs were also observed. Compared to the POH and PMOH absorbed MWCNTs, the higher amount of PBT was grafted onto PBOH absorbed MWCNTs (PBOH-MWCNTs). Calculation results using the density functional theory suggest that the reactivity of PBT was higher with PBOH than that with POH and PMOH, due to the lowest free energy change at the rate determining step and most stable intermediate formation at the rate determining step for PBOH. PBT/PBOH-MWCNT composite exhibited the highest tensile strength and fatigue life. The highest reactivity of PBT with PBOH among the pyrene derivatives resulted in the greatest amount of PBT grafting onto the PBOH-MWCNTs, best interfacial adhesion between PBT and the PBOH-MWCNTs, and highest mechanical reinforcement in the PBT/PBOH-MWCNT composite.

Pyrene appended terpyridine derivatives as electrochemiluminescence material for OLEDs: Characterization of photo-physical, thermal and electrochemical properties

Three new terpyridine appended pyrene derivatives ( Pyr-Tp , Pyr-Ph-Tp , and Pyr-Bp-Tp ) have been synthesized by condensation and Suzuki-Miyaura reaction. The photo-physical, electro-chemical and thermal properties of these compounds have been investigated in detail. DFT studies have been carried out to understand the structure-property relationships at the molecular level. Synthesized fluorophores displayed high quantum yield (70-96%) of fluorescence due to triplet to singlet intramolecular energy transfer, delayed fluorescence and positive solvatochromism indicating the presence of intra-molecular charge transfer excited state. In addition, they have high thermal decomposition temperature (T d : 390-450°C), melting temperature (T m : 180-220°C) and further with suitable oxidation and reduction potentials makes them favourable molecules for OLED fabrications.

Multi‐Color Emitting Pyrene Derivatives: Synthesis, Optoelectronic and Electroluminescent Properties

AbstractGiven the high fluorescence quantum yield and modifiability of pyrene, we designed, synthesized and characterized three novel pyrene derivatives (1‐‐3) bearing electron donors and/or acceptors. All of them exhibited strong emission bands at 470 nm, 527 nm, 606 nm in toluene and slightly red‐shifted bands in the solid state due to intermolecular interactions in the densely packed state. In addition, these compounds exhibited high thermal stability with decomposition temperatures of up to 372 °C for 1, 462 °C for 2 and 429 °C for 3. Fabrication of organic light emitting diodes with 1–3 as active layers were conducted, and the devices gave multi‐color fluorescence, including cyan, chartreuse and orange light with the CIE coordinates of (0.14, 0.35), (0.38, 0.59) and (0.58, 0.41), respectively.

A cationic cyclodextrin assisted aggregation of an anionic pyrene derivative and its stimuli responsive behavior

Stimuli-responsive supramolecular host assisted guest aggregation has attracted tremendous attention, of late, because of its various technological applications. However, a large majority of them involve anionic supramolecular hosts such as p-sulfonato calixarenes, sulfated cyclodextrin and so on, in combination with cationic guests. On the other hand, the phenomenon of host-assisted aggregation of anionic guests with cationic supramolecular hosts, which can significantly broaden the scope of this exciting field, has rarely been reported in the literature. In the present work, we report, host assisted aggregation of an anionic organic probe molecule, pyrene tetrasulfonate (PTS), in the presence of a cationic cyclodextrin derivative, amino-β-CD (AβCD), which has been studied, in detail, using various spectroscopic techniques including UV–Vis spectroscopy, fluorescence spectroscopy, time-resolved spectroscopy, and molecular docking calculations. The effect of ionic strength of the medium on the photophysical properties of PTS-AβCD complex indicates that electrostatic interaction is the predominant force in assisting the formation of PTS-AβCD complex. The monomer-aggregate equilibrium of PTS in the present system is also found to be extremely sensitive towards external stimuli like temperature, and pH of the medium. Finally, the PTS-AβCD assembly has been used for sensing an important charged bio-analyte, adenosine triphosphate (ATP), demonstrating the applicability of the present host-guest system.

Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111).

The controlled modification of electronic and photophysical properties of polycyclic aromatic hydrocarbons by chemical functionalization, adsorption on solid supports, and supramolecular organization is the key to optimize the application of these compounds in (opto)electronic devices. Here, we present a multimethod study comprehensively characterizing a family of pyridin-4-ylethynyl-functionalized pyrene derivatives in different environments. UV–vis measurements in toluene solutions revealed absorption at wavelengths consistent with density functional theory (DFT) calculations, while emission experiments showed a high fluorescence quantum yield. Scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of the pyrene derivatives adsorbed on a Cu(111)-supported hexagonal boron nitride (hBN) decoupling layer provided access to spatially and energetically resolved molecular electronic states. We demonstrate that the pyrene electronic gap is reduced with an increasing number of substituents. Furthermore, we discuss the influence of template-induced gating and supramolecular organization on the energies of distinct molecular orbitals. The selection of the number and positioning of the pyridyl termini in tetrasubstituted, trans- and cis-like-disubstituted derivatives governed the self-assembly of the pyrenyl core on the nanostructured hBN support, affording dense-packed arrays and intricate porous networks featuring a kagome lattice.

Supramolecular Induction of Topological Chirality from Nanoscale Helical Silica Scaffolds to Achiral Molecular Chromophores

Chiral induction from macroscopic objects possessing topological chirality to small molecules is demonstrated using nonchiral organic chromophores based on pyrene and perylene derivatives covalentl...

Self-Assembly of a Dual-Targeting and Self-Calibrating Ratiometric Polymer Nanoprobe for Accurate Hypochlorous Acid Imaging.

Exploiting an intelligent fluorescent probe, which can precisely target to the lysosome of hepatoma cells and enable accurate molecular imaging, is a key challenge in hepatoma diagnoses. Herein, a single-dye-based polymer nanoprobe (named SPN) with dual-targeting and self-calibrating ratiometric characteristics is rationally fabricated via a simple self-assembly strategy for accurate hypochlorous acid (HClO) imaging in the lysosome of HepG2 cells. Of note, the covalent incorporation of self-calibrating ratiometric fluorophore (pyrene derivatives) into the core of polymer nanoparticles can not only validly avoid the leakage of fluorophores but also greatly enhance their brightness. Besides, this polymer nanoprobe (SPN) displays high water dispersibility, ultrafast response (<1s), favorable selectivity, outstanding long-term stability (>90 days), and good biocompatibility. Furthermore, thanks to the hepatocyte-targeting moiety (galactose) and the interplay of surface charge and size of nanoparticles, the SPN is able to enter into asialoglycoprotein receptor-positive HepG2 cells and further locate at lysosomes, successfully enabling accurate HClO detection in lysosomes of HepG2 cells. This study demonstrates that the versatile SPN can provide more precise dual-targeting and accurate molecular imaging.

Tuning the Properties of Corannulene-Based Polycyclic Aromatic Hydrocarbons by Varying the Fusing Positions of Corannulene.

The selective fusions with pyrene derivative to the rim and flank bonds of corannulene generated 4 and 7, respectively, which underwent a Scholl reaction to provide novel distorted PAHs CORA-1 and CORA-2, consisting of corannulene and dibenzocoronene units with different connections between them. The studies revealed that the properties of these PAHs are highly dependent on the fusing positions of corannulene.