Dyes and Pigments最新文献

The influence of multiple factors often leads to the unexpected performances of the designed AIEgens. It is difficult to precisely conclude the influence of the substituted sites and role of isomers on the photophysical properties of the AIEgens which therefore brings uncertainty in the molecular design strategies. Isomer engineering of AIEgens is a less explored domain. There are only a few reports that substantiate the effects and positions of the substituents on the AIE properties. The present investigation explores two isomeric benzofuran-derived luminogens GBY-1 and GBY-4, both featuring a TPE moiety and showcasing AIE and AIEE properties respectively inherited from TPE. The isomeric effect resulting from TPE incorporation at different positions across benzofuran significantly influenced their photophysical properties, mechanofluorochromic properties, and AIE effect. Their distinctive luminogenic features were evident in mechanochromic property as well as in cancer cell imaging. GBY-1 was found to be uniformly dispersed in the cytoplasm, not co-localized with the nucleus, while GBY-4 accumulated near the cell membrane. Furthermore, post-functionalization of one of the luminogens, GBY-1, derived another AIEgen, GBY-5 with a dramatic improvement in the PLQE along with its ability to selectively sense Fe³⁺ in aqueous environments, within a detection limit of 0.00035 mM.

Two novel tetra-dansyl derivatives incorporating cyclen (1,4,7,10-tetraazacyclododecane) and cyclam (1,4,8,11-tetraazacyclotetradecane) macrocycles have been synthesized, thoroughly characterized, and their photophysical properties examined, both in solution and in the solid state. These compounds exhibit fluorescence emission with quantum yields up to 40 %, varying significantly with different solvents. They also display positive solvatofluorochromic behavior, with emissions ranging from green to yellow colours. Kamlet-Taft studies were conducted to better understand solute-solvent interactions. Furthermore, aggregation-induced emission was observed in solutions with high water content, confirmed via dynamic light scattering. Given the intrinsic properties of these compounds, their potential for environmental remediation was explored through metal ion sensing studies. Compounds L1 and L2 demonstrated high sensitivity to Cu²⁺ and Hg²⁺ ions, significantly modulating their emission, with L2 capable of detecting and quantifying Hg²⁺ concentrations as low as 2–3 μM. Additionally, the solid-state emission of these compounds encouraged an investigation into their potential as temperature sensors. Several doped polymer thin films were fabricated, establishing a linear relationship with temperature beyond their melting point. These findings suggest that these tetra-chromophoric compounds hold promise as molecular thermometers.

In the present study, four new organic fluorophores, consisting of a central 9H-carbazole (CBZ) or indolo[3,2-b]indole (IDID) moiety, functionalized with (S)-3,7-dimethyl-1-octyl branched chains and connected to lateral 2-thienylethynyl or 2-thiophenylpropynone units, were synthesized by means of Pd-catalyzed cross-coupling reactions and investigated for potential application in luminescent solar concentrator (LSC) systems. The photophysical properties of four final dyes were first evaluated in solution of four solvents with different polarity (toluene, chloroform, acetone, acetonitrile). For the IDID-based compound 4, which proved to be the best candidate, the photophysical properties in thin films with PMMA matrix at different concentrations (0.4–2.0 wt%) were also investigated. Finally, their efficiency parameters as LSC systems connected to a photovoltaic (PV) cell were evaluated, obtaining a maximum device efficiency (η_dev) of 0.46 ± 0.02 % at 1.2 wt%: these are very promising PV performances for a N-heteroarene-based dye, coupled with a sufficient stability in accelerated aging tests.

Understanding the physiological functions and monitoring the dynamics of lipid droplets (LDs) in living cells are crucial, because they play important roles in energy reservoir and as sources of lipid molecules, and can be potentially used as biomarkers in cancer diagnose. Organic small-molecule based luminogens with long-wavelength emission are advantageous imaging tools for visualizing the dynamics of LDs, as the long wavelength fluorescence has lower scattering and absorption by biomolecules, deeper penetration ability into tissues, and reduced interference effect. In this work, we report the design, synthesis and LDs imaging properties of two long-wavelength emitting organic luminogens (OLs) APBM and PyBM. The two materials have typical donor-acceptor-donor (D-A-D) structure with a benzylidenemalononitrile moiety as the acceptor, bridging different electron donors, i.e., N,N-dimethylamino phenyl for APBM, and pyrene for PyBM, respectively. The strong electron-withdrawing benzylidenemalononitrile moiety inducing intense intramolecular charge transfer effect, which endows the emissions of APBM and PyBM as far as 668 nm and 605 nm in the solid state, and on the other hand, creates their twisted molecular conformation. As a result, the OLs exhibit aggregation-induced-emission behaviors, due to the restriction of intramolecular motions, evolving the “washing-free” properties of the materials in bioimaging. APBM and PyBM both have low cytotoxicity and good photostability, and are able to light up HepG2 cells efficiently. In addition, APBM shows excellent LDs targeting ability, and it is successfully used to discriminate normal cells and cancer cells, and monitor the dynamics of LDs under different nutritional conditions, and the interactions with mitochondria.

Perylene diimides (PDIs), particularly the parent core-unsubstituted PDI chromophores, exhibit a pronounced tendency to aggregate in water, resulting in significant fluorescence quenching. Herein we present a new class of highly fluorescent, water-soluble tetrapodal PDI dyes PDI-4Py-n, with the chromophore core surrounded by four pyridinium pendants, which have been fully characterized by several techniques including X-ray crystallography. Due to the spatial isolation and charge repulsion from four cationic pendants, PDI-4Py-n can effectively suppress the chromophore aggregation in relatively concentrated aqueous solutions, thereby preserving the characteristic PDI fluorescence with high photoluminescence quantum yield. Owing to the outstanding fluorescence properties and good biocompatibility, one of PDI-4Py-n has been successfully employed as a lysosome-targetable fluorescent probe for live-cell imaging. This work presents a straightforward synthetic strategy to water-soluble non-aggregating organic dyes and highlights their potential for biomedical applications.

Three new D-A-π-A organic dyes (1a-c) containing a 2,3-diphenylquinoxaline core as the main chromophore were designed to act as sensitizers for the TiO₂-based photoanode of dye-sensitized photoelectrochemical cells (DS-PEC) for water splitting. The dyes structures featured a cyanoacrylic acid group as the terminal acceptor/anchoring moiety and three different donor groups of moderate strength, namely mono- and dialkoxy-substituted benzenes, which were introduced to modulate the energies of the respective HOMO levels and enable the electron transfer from a Ru-based molecular water oxidation catalyst (WOC). Dyes 1a-c were synthesized following a C–H activation strategy and fully characterized. In addition, the previously known catalyst Ru(bda)(PyP)₂ (bda = 2,2′-bipyridine-6,6′-dicarboxylate; PyP = pyridin-4-methyl phosphonic acid) was also prepared by modification of a reported procedure. The dynamics of charge transfer processes involving the dyes adsorbed on nanocrystalline TiO₂ films were investigated by means of transient absorption spectroscopy. Photo-electrochemical experiments carried out on photoanodes functionalized with 1a-c and Ru(bda)(PyP)₂ in 0.1 M aq. Na₂SO₄ electrolyte showed the production of photocurrents up to ca. 0.15 mA cm⁻² at + 0.5 V vs. NHE, and highlighted how modifications of the TiO₂ staining procedure can lead to significant differences in cell performances.

Iron ion (Fe³⁺) is crucial for both biological organisms and the environment, and iron dyshomeostasis can lead to a variety of diseases and environmental issues. Therefore, the detection of Fe³⁺ is of significant importance across various fields. For this purpose, through the co-assembly of water-soluble tetralactam macrocycle H and 1,1,2,2-tetraphenylethylene (TPE), we prepared a new type of tetralactam macrocycle based aggregation-induced emission dots (AIE-dots), namely TPE@H. TPE@H exhibitted good water-solubility and allowed the water-insoluble TPE to aggregate and exhibit strong fluorescence emission in water. Furthermore, the fluorescence of TPE@H could be quenched by Fe³⁺ through the inner filter effect, making TPE@H a potential “turn-off” fluorescent probe for Fe³⁺ detection. TPE@H exhibited a limit of detection as low as 1 μM with high selectivity, and also retained good detection performance in domestic water, human serum, and even drugs, indicating its great potential for biological and environmental monitoring of Fe³⁺. This study not only provides a green and efficient method for detecting Fe³⁺, but also expands the approach for application of water-insoluble dyes in the aqueous environment.

Reaction-based fluorescent probes have proved to be promising tools for endogenous formaldehyde (FA) analysis. Among them, analyte regeneration fluorescent probes have attracted much attention due to their ability to maintain FA homeostasis in imaging analysis, but remain to be explored. Herein, we proposed a novel analyte regeneration near-infrared fluorescent probe Cy-MB for endogenous FA detection. Cy-MB was developed on the basis of hemicyanine-based NIR probe CyOH via connecting a 2-(methylamino)benzoate acid. The 2-(methylamino)benzoate in Cy-MB act not only as a fluorescence quenching group, but also a FA regeneration substrate. Such an analyte regeneration NIR probe can be specifically activated by endogenous FA, resulting in a significant fluorescence signal turn on and accompanied by FA regeneration. Probe Cy-MB possesses good analytical performance such as high selectivity and sensitivity toward FA with a detection limit at 0.67 μM. Furthermore, Cy-MB was successfully applied to image endogenous FA in cancer cells and tumor-bearing mice. Additionally, mass spectrometry imaging (MSI) was further performed to qualitatively identified the spatial distribution of the FA activation products of Cy-MB on molecules level in tumor and major organs of mice. We envision that Cy-MB will provide a widespread application in precise imaging of endogenous FA in biosystems.

Modern medicine is exploring new approaches to combat bacterial infections associated with antibiotic-resistant bacteria and biofilms. Among these, antimicrobial photodynamic therapy (aPDT) stands out for its ability to target pathogenic microbes effectively. In this study, we investigated the antimicrobial potential of the newly synthesized indium metalated pyridinyl-based trans-A₂B₂ porphyrin complexes, 1a,b and 2a,b. The dicationic porphyrins, 1b and 2b, exhibited remarkable aPDT efficacy against both S. aureus and E. coli planktonic forms. Further investigation into the antimicrobial effects of the cationic porphyrins against E. coli and S. aureus biofilms revealed that both complexes (1b and 2b) exhibited high efficacy in aPDT attributed to tert-butyl and thiophene groups that enhance photo-physicochemical properties and bacterial membrane accumulation. Scanning electron microscopy (SEM) showed disruption of cell membranes following light exposure. Our work highlights the potential of aPDT as an effective strategy for managing biofilms. By harnessing the power of these innovative compounds, we contribute to the ongoing battle against microbial threats.

A series of novel fluorophores were obtained based on azolo[1,5-a]pyrimidines (APs) through multicomponent and oxidation reactions, starting from aminoazoles, morpholineacrylonitrile, and 4-(dimethylamino)benzaldehyde. Photophysical studies, as well as DFT calculations have been performed for the obtained APs. Aggregation-induced emission (AIE) phenomenon was demonstrated for fluorophores containing an aromatic substituent at the C-2 position of the azolo[1,5-a]pyrimidine core. It was observed that fluorophore 6d exhibited reversible mechanochromic luminescence. Two-photon absorption cross-section was measured for all obtained APs. In addition, cell staining resulted in identical intracellular distribution under excitation at 405 nm, 488 nm and 561 nm.