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The first chemo- and stereoselective syntheses of hitherto unknown pyrrole-based β , β′ -disubstituted ketocyanine dyes and alkyne-tethered enones through Lewis acid-catalyzed addition of pyrroles to skipped diynones (penta-1,4-diyn-3-ones) are described. The protocols feature a good substrate tolerance, mild reaction conditions, and high yields of target products. A wide synthetic utility of synthesized alkyne-tethered enones as novel building blocks is demonstrated by the synthesis of diverse pyrrole-containing compounds. The UV–vis absorption properties for selected representatives of novel adducts are studied to preliminary access their potential as photoinitiators/sensitizers in visible light induced polymerization. [Display omitted] • The chemo- and stereoselective addition of pyrroles to skipped diynones (penta-1,4-diyn-3-ones) was comprehensively studied. • ZnCl 2 -catalyzed synthesis of pyrrole-based alkyne-tethered enones was realized in high yields. • AgOTf-catalyzed synthesis of pyrrole-based β,β′-disubstituted ketocyanine dyes was realized in high yields. • The synthetic utility of obtained alkyne-tethered enones as novel building blocks is demonstrated. • The UV–vis absorption properties of synthesized adducts are studied. [ABSTRACT FROM AUTHOR]

We previously synthesized a group of carbamate-linked disazo disperse dyes that showed excellent fastness properties on polyester fabric by using the thermosol dyeing process. However, the color yield of the dyed fabric was not sufficiently high to be accepted by users, especially when using a high-temperature dyeing process. To further optimize the structures of disazo disperse dyes and observe the effect of the linking groups on the dyeing properties, in this work, we used p -phenylene diisocyanate or terephthaloyl chloride as crosslinking agents and aniline derivatives containing hydroxyl or amino groups as reactants to synthesize four disazo disperse dyes containing various characteristic groups, including ester, carbamate, amide, and urea groups. The structures of these new dyes were characterized by nuclear magnetic resonance, mass spectrometry, and Fourier-transform infrared spectroscopy analyses. The spectral properties in an N,N-dimethylformamide solvent were measured, the structural parameters of the dyes were calculated using the density functional theory method, and the dyeing properties were investigated by using high-temperature and thermosol dyeing processes, and also compared with these for the commercial dye, C·I.Disperse Red 153. The results showed that there were slight differences in the molar extinction coefficients and maximum absorbance wavelengths between the new dyes, but the effects of characteristic groups on the structural features and the dyeing properties of the new dyes were significant. The ester-linked dye (D1) had the highest color depth when a high-temperature process was used in the presence of 50 mL/L of methyl salicylate because of its highest ClogP (N-octanol/water partition coefficient) value, corresponding to its more hydrophobic nature, while all the other dyes produced lower color yields. When used in the thermosol dyeing process, the carbamate-linked dye (D2) yielded the highest color depth, followed by the ester-linked dye (D1) and amide-linked dye (D3), and the urea-linked dye (D4) produced the lowest color depth due to its highest hydrophilic properties. Finally, it was demonstrated that the new dyes had excellent color fastnesses except for the urea-linked dye (D4), which exhibited a slightly lower light fastness, While the commercial dye used as the control showed a relatively poor sublimation and light fastness although its color depth and chroma value performed slightly better than the new dyes as used by the thermosol dyeing process. • Four disperse dyes crosslinked varied characteristic groups including ester, carbamate, amide and urea were synthesized. • Four new dyes have the similar spectral properties，but their dyeing properties were very different. • The relationship between the molecular structures and dyeing properties was analysized. • Only the ester-linked dye exhibited high color yield on polyester fabric by the high temperature dyeing process. • By the thermosol dyeing process, all the dyes could dye the PET fabric to different depth and have good fastnesses. [ABSTRACT FROM AUTHOR]

Coumarin derivatives have been widely employed across a great number of applications, such as laser dyes, bioimaging or chemossensors, owing to their strong fluorescence and high-quantum yields. These properties are highly tunable through structural modification, namely by the inclusion of electron-withdrawing groups (EWG) and electron-donating groups (EDG) at positions 3 and 7 of the coumarin scaffold, respectively. Comparatively, there aren't many reports of EDGs being employed at position 3 , prompting us to investigate this new class of potential fluorophores. We undertook the synthesis of three novel ethynyl-linked aminophenyl-coumarin dyes, employing a key Sonogashira-coupling reaction to introduce the electron-rich tertiary aniline moiety. Two different amine donors were used, diphenylamino (coumarins A and B) and dimethylamino (coumarin C), as well as two alkoxy substituents, dibenzyloxy (A and C) and methylenedioxy (B), in the phenyl ring of the coumarin. All dyes show strong emission and significant positive solvatochromism. Additionally, they were employed as staining agents for the cellular membrane of S. pneumoniae , a Gram-positive bacterial pathogen. None of the three derivatives presented cytotoxic effects. Only A and B successfully labelled the bacterial membrane. In the case of B a very similar staining pattern and performance to that of standard dye Nile Red was observed, while A seemed to possess a more selective distribution. [Display omitted] • Three coumarin dyes presenting electron-donating aminophenyl groups were synthesized. • All dyes possess strong positive solvatochromism. • Membrane labelling of S. pneumoniae proved successful for two of the coumarins. [ABSTRACT FROM AUTHOR]

This study presents the design, synthesis, and application of eight novel thiophene-based acid azo dyes featuring benzoic and salicylic acid acceptors. The synthesized dyes demonstrate versatile light absorption properties, spanning the near UV, visible, and deep red regions. Notably, the thiophene acid azo dyes containing benzoic acid acceptor unit (AB series dyes) exhibited red-shifted absorption, while their salicylic acid counterparts (SR series dyes) displayed blue-shifted absorption. The influence of increased donor strength at position 4 of the thiophene ring on absorption properties is systematically explored. Theoretical findings from Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) substantiate the experimental results. Moreover, the dyes are applied to wool and nylon fabrics, displaying excellent dyeability with % exhaustion properties above 70%. The dyed fabrics manifest rich shades, ranging from blue-black to deep orange. Enhanced K/S values are observed for wool-dyed fabrics in the case of SR series dyed fabrics, whereas the AB series dyes show superior results for nylon-dyed fabrics. The dyed fabrics exhibit remarkable light, wash, and rubbing fastness. Notably, nylon-dyed fabrics outperformed wool-dyed fabrics in light and wash fastness. UV protection studies reveal the fabrics' potential to block harmful UV-A and UV-B radiation with excellent UPF ratings. [Display omitted] • Thiophene-based azo dyes with carboxylic acid and salicylic acid acceptors. • Red-shifted absorption properties with donor sat position 4 of the thiophene. • Excellent UV-A, UV-B, and UPT rating. • Very good to excellent light and wash fastness. [ABSTRACT FROM AUTHOR]

• A series of new dyes with bright colors have been synthesized and exhibit excellent dyeing performance for PLA fabrics. • Dye with lower polarity generally having higher exhaustions on PLA fabrics. • Dyes having long alkyl groups and minimal steric hindrance during its adsorption facilitate the dye-PLA interaction, increasing dye exhaustion on PLA. [ABSTRACT FROM AUTHOR]

We have installed cycloalkylamino auxochromes on naphthalimide (5a - 5e) and nitrobenzoxadiazole (6a - 6e) dyes. Their photophysical characterization revealed that the cyclobutylamino auxochrome in both dyes (5b and 6b) demonstrated high quantum yield and fluorescence brightness compared to their azetidine counterparts (5 and 6) in aqueous solution. The computational studies were performed to substantiate the experimental photophysical results. Cytotoxicity assay in breast adenocarcinoma (MDA-MB-231) and non-cancerous human embryonic kidney 293 (HEK-293) cells indicated significant biocompatibility of cyclobutylamino auxochrome. Moreover, cellular imaging and photostability experiments demonstrated the practical application of cycloalkylamino auxochromes. [Display omitted] • Cycloalkylamine substituted naphthalimides (5a-5e) and 4-nitrobenzoxadiazole (6a-6e) were synthesized and compared with azetidine substituted counterparts (5 and 6) for their fluorescent properties. • Cyclobutylaminated derivatives of naphthalimides and 4-nitrobenzoxadiazole (5b and 6b) show enhanced quantum yields and fluorescence brightness in comparison to their azetidine counterparts (5 and 6). • Compounds 5b and 6b show better biocompatibility and excellent cell penetration in MDA-MB-231 breast cancer cells than their reference standards (5 and 6). [ABSTRACT FROM AUTHOR]

Difluoroboron β-diketonate complexes (BF 2 bdks) are classic fluorescent molecules that have been applied in luminescent materials, oxygen and mechanical sensors, and most investigations concentrate on BF 2 bdks with varying aromatic groups without heteroatoms. In this work, a new molecular platform BF 2 bdks with heterocycle-substituted is prepared in one pot, and six unsymmetric π-expanded BF 2 bdks are synthesized via condensation reaction. B-1∼6 exhibit comparable fluorescence properties in solution, aggregated and solid states. B-3 (683 nm, Φ f = 13.1 %) and B-5 (700 nm, Φ f = 2.1 %) show near infra-red (NIR) emission with moderate fluorescence intensity in solution state. Solid emission of B , B-1-3 and B-5 are detected with fluorescence quantum yield from 12.8 % to 25.6 %, and B-2 , B-3 and B-5 show AIE phenomenon in aggregated state. The results are supported by crystal analysis and DFT calculation in some extent. In a word, this work enriches the heterocycle-substituted BF 2 bdks system. B-3 and B-5 with moderate intensity NIR emission in solution, aggregated and solid states at the same time, providing a simple preparation method for multi-states luminescent dyes. [Display omitted] • A new platform of BF 2 bdks with their six π-expanded dyes (B-1∼6) are synthesized. • B-3 and B-5 with moderate intensity NIR emission in solution, aggregated and solid states at the same time. • B-2 , B-3 and B-5 show AIE phenomenon in aggregated state. • Solid emission of B , B-1-3 and B-5 are detected with fluorescence quantum yield from 12.8 % to 25.6 % [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of three azonaphtharylmide dyes, APAS, APASD, and APASTR, using naphthol AS, ASD, and ASTR couplers. The research also observes the presence of a hydrazone tautomer in a DMSO solution. It was characterized through spectroscopic analysis, which revealed three characteristic carbonyl carbon peaks in the 13C NMR spectrum. The calculated low LUMOs (−3.46 eV to −3.54 eV) align closely with experimental calculations (−3.45 eV to −3.48 eV), indicating the potential of these dyes as electron acceptors. Furthermore, the alignment of frontier molecular orbital (FMO) values supports their suitability for electron acceptance. When applied to wool, silk, and polyester materials, these dyes confer UV protection properties, with wool-dyed fabrics achieving a UV Protection Factor (UPF) of 50+. Additionally, these dyes exhibit significantly improved nonlinear optical responses, with beta (β 0) values ranging from 11 × 10−30 to 23 × 10−30 esu and gamma (γ 0) values ranging from 275 × 10−36 to 365 × 10−36 esu, indicating their functionality as nonlinear optical materials. [Display omitted] • Synthesis and characterization of three azonaphtharylmide dyes using naphthol couplers AS, ASD, and ASTR. • Analysis of hydrazone form in a DMSO solution, using 13C NMR spectroscopy.–C. • Possession of electron acceptors potency based on computed (−3.46 eV to −3.54 eV) and experimental (−3.45 eV to −3.48 eV) low LUMOs. • Realisation of efficient UV protection by wool, silk, and polyester achieving a UV Protection Factor (UPF) of 50+. • Significantly improved first order (β 0) and second order(γ) hyperpolarizability values; ranging from 11 to 23 × 10−30 esu and 275 to 365 × 10−36 esu respectively. [ABSTRACT FROM AUTHOR]

Plant-derived natural extracts contain large amounts of polyphenolic compounds, presenting opportunities for chemical modification. The present study deals with the extraction of dye from Marigold (Tagetes erecta) , a widely cultivated and commercially utilised flower, using water as an extraction medium followed by its chemical modification for sustainable synthesis of yellow dye and dyeing of polyester fabric. Phytochemical analysis and FTIR spectroscopy of the natural dye extract from Marigold flowers indicated the presence of polyphenolic flavonoids. The water-extracted natural dye was subsequently chemically modified with aniline, a primary aryl amine, via diazotisation and coupling reactions to yield a semi-synthetic natural dye with a 1.2 ± 0.3 g yield. The major constituents in the marigold natural extract and the Modified Marigold Extract (MME) dye were characterised using High-Resolution Liquid Chromatography-Mass Spectrometry (LC-HRMS). The marigold water extract contained a high concentration of Gossypetin 8-Glucoside, a yellow-coloured flavonoid compound with a mass-to-charge ratio (m/z) of 480.0904. LC-HRMS analysis further confirmed the presence of a constituent (m/z 424.0485) in the MME dye, corresponding to the predicted mass of chemically modified Gossypetin 8-Glucoside. The MME dye was subsequently employed for dyeing polyester fabric, exhibiting maximum colour strength at 10 % shade under acidic condition. The dyeing performances of the MME-dyed fabrics were evaluated in terms of fastness and post-dyeing strength. This study demonstrates a unique and novel approach to develop a yellow semi-synthetic natural dye, emphasising its potential utility for polyester dyeing. [Display omitted] • Chemical modification of natural dye extract from widely cultivated marigold flower. • A novel approach for dye modification from marigold flower. • Sustainable and enhanced dyeing of polyester. • Overcoming the drawbacks of natural and synthetic dye. • Natural dyes for wider spectrum of fibres. [ABSTRACT FROM AUTHOR]

This work deals with the synthesis of hybrids formed by the natural dye chlorophyll and halloysite for their subsequent application in the textile field. Once the pigments have been synthesized, with 98 % adsorption, they are used for two textile colouring functions, namely printing and dyeing. In both cases, satisfactory and interesting results were obtained. The hybrids were characterized by FTIR, XRD, TGA, SEM-EDX, BET and all the appropriate colour measurements were carried out to obtain the coordinates in CIELAB space and also to know their total solar reflectance (TSR) 45.98 %. In addition, statistical techniques were used with the use of ANOVA to evaluate the results obtained. The dyeing was carried out by exhaustion and its use was compared with the use of nibbled and non-nibbled fabrics. The textiles were tested for fastness and the results are presented in instrumentally obtained grey scale values, achieving in some cases values of 4–5. Thus, the chlorophyll adsorption capacity of halloysite and its stabilisation for subsequent application in printing and dyeing processes on textile substrates has been demonstrated. This process could be scalable at an industrial level. • Printing with hybrid nanoclays with natural dyes • Dyeing with natural dye chlorophyll and mordants • Comparison of the use of mordants for the dyeing of natural dyestuffs [ABSTRACT FROM AUTHOR]

This study reports new carbene azulene gold(I) complexes [AuCl{C(NHAz)(NR 2)}] (R = Me (1) and nBu (2)) and [Au(C 6 F 4 OC 10 H 21){C(NHAz)(NR 2)}] (R = Me (3) and nBu (4)) prepared by reaction of 2-isocyanoazulene gold(I) complexes [AuX(CNAz)] (X = Cl and C 6 F 4 OC 10 H 21) with the corresponding secondary amines. Their photophysical properties were investigated by absorption and emission spectroscopies, and by TD-DFT calculations. All the compounds display an intense coloration based on HOMO-LUMO transitions, dominated by the azulene core. Gold-isocyanide complexes show a slight bathochromic shift related to azulene, while a hypsochromic shift was observed after formation of carbene complexes. Thus, the transformation of the gold-isocyanide group into the gold-carbene functionality produces a substantial color change from blue to deep purple. This different electronic behavior is mainly due to the stabilization of the LUMO orbital in the isocyanide complexes, and to the stabilization of the HOMO in the carbene derivatives. These carbene gold complexes show fluorescence in solution associated with the azulene core. This work illustrates how the synthetically easy isocyanide-carbene transformation open new perspectives to a fine color modulation in organometallic azulene dyes. [Display omitted] • Strongly purple colored carbene azulene gold compounds are prepared. • They show a hypsochromic shift related to the starting isocyanide complexes and azulene itself. • The spectral shift is mainly related to the stabilization of the HOMO orbital energy levels. • The carbene-gold fragment acts as an electron-donating substituent of the azulene core. • All of them are slightly fluorescent dyes. [ABSTRACT FROM AUTHOR]

In this study, we describe the synthesis and characterization of three newly developed metal-free organic dyes, denoted as MRS-1-3. These dyes have been specifically designed and investigated as potential sensitizers for Dye sensitized solar cells (DSSCs). The sensitizers under consideration consist of pyrene units that function as effective electron donors, whereas furan moieties serve as π-spacers. MRS-1-3 was synthesized by including electron acceptor groups, such as cyanonitroacetonitrile, 4-nitrocyanoacetamide, and dicyanovinyl. In this study, a thorough examination was conducted to assess the individual performances of several sensitizers. The results revealed that MRS-3 , characterized by a furan π-bridge and dicyanovinyl acceptor group, had the best power conversion efficiency (PCE) of 8.77%. This PCE value surpassed that of N-719 , which was determined to be 7.37 %. To enhance the efficacy of MRS-3 , an investigation was conducted to assess the impact of co-adsorption using an unidentified co-adsorbent, chenodeoxycholic acid (CDCA), and to compare its performance with that of 2-(p -carboxybenzylidene)-2-cyano-p-(diethylamino)acetanilide (SA-10) synthesized in a previous study. Notably, MRS-3 's power conversion efficiency (PCE) went up significantly after co-adsorption with CDCA, reaching 8.83%. Furthermore, the substitution of CDCA with the co-adsorbent SA-10 resulted in enhanced performance of the MRS-3 organic dyes in terms of key parameters such as Jsc (short-circuit current density), Voc (open-circuit voltage), and PCE (Jsc = 21.50 mA cm−2, Voc = 0.750 e V; PCE = 10.15 %). A system composed of MRS-3 and SA-10 exhibits exceptional performance, making it a suitable option for creating highly effective DSSCs. The results of this study provide a valuable contribution to the development of new sensitizers that can be used in future photovoltaic applications. These findings present excellent prospects for improving the efficiencies of solar cells. [Display omitted] • Novel organic sensitizer MRS-1-3 as sensitizer comparing with Ru-based N719 dyes in DSSCs. • MRS-3 exploits the ability of dicyanovinyl group to bind acids on TiO 2 , reducing dye competition and increasing voltage. • Co-sensitized device with SA-10 + MRS-3 demonstrated highest efficiency of 10.15 %. • Compatible co-sensitizers at optimal concentrations provide insights into improving DSSC performance. [ABSTRACT FROM AUTHOR]

In this study, we present a novel natural dye extracted from Laurus nobilis L (bay leaf: BL) intended for application in Natural Dye-Sensitized Solar Cells (NDSSCs). The extraction process involved utilizing a maceration method with methanol as the solvent. A comparative analysis was conducted on NDSSCs fabricated with fluorine-doped tin oxide (FTO) and indium-doped tin oxide (ITO) substrates. Comprehensive characterization of the extracted natural dye and the fabricated NDSSCs was performed using various techniques, including ultraviolet–visible (UV–Vis) and Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), solar simulation (current–voltage characteristics), and electrochemical impedance spectroscopy (EIS). UV–Vis and FTIR spectroscopy confirmed the bonding of chlorophyll, a key component in the extracted dye, to the TiO 2 surface. The BL dye exhibited a broad absorbance spectrum, and its adherence to the TiO 2 surface was affirmed through UV–Vis spectroscopy. SEM analysis revealed a uniform distribution of the BL dye on the TiO 2 surface, and EDX analysis confirmed the composition of the dye. XPS analysis provided evidence of the adherence of chlorophyll pigment to the TiO 2 surface. Upon optimization, the NDSSC fabricated with the BL dye and FTO substrate demonstrated notable performance metrics, including a short–circuit current density (J sc) of 0.528 mA/cm2, open–circuit voltage (V oc) of 0.615 V, a high fill factor (FF) of 69.9%, and a photoelectron conversion efficiency (ⴄ) of 0.227%. Conversely, the cell utilizing the ITO substrate exhibited lower performance, with values of V oc , J sc , P max , FF, and ⴄ at 0.589 V, 0.394 mA/cm2, 0.163 mW/cm2, 69.9%, and 0.163%, respectively. Additionally, electrochemical impedance spectroscopy (EIS) analysis provided insights into the charge transport properties of the fabricated NDSSCs. The best-performing FTO-NDSSC with the BL dye displayed a recombination resistance (R 2) of 90.8 Ω and a photoanode–electrolyte interface resistance of 83.2 Ω, surpassing that of the N 3 -based DSSC. The overall evaluation of parameters and performance indicators underscores the promising potential of the BL dye for diverse applications, warranting further exploration and investigation. • Natural dye-sensitized solar cells (NDSSCs) were fabricated using Laurus nobilis leaves (bay leaf: BL) as a dye sensitizer. • Optical, morphological, elemental, structural, and cyclic voltammetry studies of the BL dye were conducted. • The V oc of the fabricated NDSSC was similar to that of the DSSC using conventional dye (N3). • FTO and ITO were used as the conductive glass substrates to study the photoelectron conversion efficiency of the BL dye. • FTO substrate exhibited a high photoelectron conversion efficiency of fabricated NDSSCs. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) are considered the newest entry in the list of green solvents and they are analogues of ionic liquids (ILs), with excellent solvent characteristics better than commonly used organic solvents and ILs. Owing to this, We have prepared DES using benzyltrialkylammonium chloride (BTAAC) including benzyltrimethylammonium chloride (BTMAC), benzyltriethylammonium chloride (BTEAC), and benzyltributylammonium chloride (BTBAC) as hydrogen bond acceptors (HBA) and glycols, like ethylene glycol (EG), diethylene glycol (DEG) and triethylene glycol (TEG) as hydrogen bond donors (HBD). Aqueous biphasic systems (ABS) were developed using the synthesized DESs and K 3 PO 4 , K 2 HPO 4 , and K 2 CO 3 at 298.15 K and atmospheric pressure. The phase-forming ability of DES has been evaluated based on the nature of potassium salts, HBA and HBD. In most cases, the influence of salts on ABS formation was found to follow the order: K 3 PO 4 > K 2 HPO 4 > K 2 CO 3 , while HBAs follow: BTBAC > BTEAC > BTMAC. The performance of the ABSs was experimentally applied for the extraction of Methyl orange (MO), Eriochrome black T (EBT), and Eosin Y (EY). In most ABS, the extraction order for the studied dyes noticed was: MO < EBT < EY, consistent with their hydrophobic nature. ABS consisting of BTBAC:TEG + K 2 HPO 4 and BTBAC:TEG + K 3 PO 4 was found to lead to the complete extraction of MO, EBT, and EY. The recovery of extracted EY dye was performed by adsorption method using starch-modified chitosan as an adsrobent. • ABSs of DES composed of BTAAC and potassium salts were investigated. • The effect of HBAs and HBDs on the phase splitting capacity of the DESs was investigated. • MO, EBT, EY dyes with higher hydrophobic nature displayed greater extraction. • ABS composed of BTBAC:TEG + K 2 HPO 4 and BTBAC:TEG + K 3 PO 4 demonstrated 100% extraction for the three investigated dyes. • Starch-modified chitosan successfully recovered 97.26% of EY dye after 60 h at 55 °C. [ABSTRACT FROM AUTHOR]

Three fluorescent dyes (DI-TB, ICZ-TB and ITPA-TB) were synthesized based on 1,3-indindanedione substituted Tröger's base (TB). All the dyes exhibited AIE properties in the mixed system of chloroform and n -hexane. The compounds showed reversible MCL properties with obvious fluorescence changes, which were confirmed by XRD and DSC. The fluorescence of ITPA-TB showed high contrast (68 nm) before and after grinding, and the fluorescence changed from yellow (546 nm) to red (614 nm). In addition, the three solid compounds showed good thermal stability by thermogravimetric analysis. The TB dyes further opened up new ideas for the development of TB-based mechanochromic luminescent materials. [Display omitted] • AIE-active fluorescent dyes were synthesized based on 1,3-indindanedione substituted Tröger's base. • The dyes exhibited good reversible mechanochromic luminescence behavior. • The fluorescence change caused by MCL performance was significant (yellow to red: 68 nm). • The MCL mechanism were carried out by theoretical calculation and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is an effective method to treat diseases, especially for tumor treatment, with remarkable characteristics including good therapeutic results and low drug resistance, which has attracted the attention of researchers. The performances of photosensitizer dye largely determine the tumor treatment results. However, most of the reported photosensitive dyes belong to the "always-on" photosensitive property, which cannot avoid the photodamage caused to normal tissues during tumor PDT. By contrast, activatable photosensitizers possess the desirable characteristic of controllable phototoxicity, ensuring tumor safety treatment. Until now, ideal photosensitizer dye scaffold is still lacking. Therefore, constructing a universal photosensitive dye scaffold is a vital issue to be solved urgently. In this work, inspired by the single atom substitution strategy, the oxygen atom in classical hemicyanine dye has been replaced by selenium (Se) atom to obtain a novel Se-substituted hemicyanine dye with hydroxy group, HCySe-OH, as a novel dye platform for constructing activatable photosensitizers. We found that HCySe-OH had high singlet oxygen (1O 2) generation ability and longer absorption and emission in contrast to the classical O-substituted hemicyanine, endowing its better biomedical application. Additionally, HCySe-OH was successfully utilized to kill cancer cells and bacteria under 760 nm laser irradiation. More importantly, we believe that numerous smart activatable photosensitizers will be developed based on this platform, HCySe-OH. [Display omitted] • A Se-substituted hemicyanine dye with hydroxyl group, HCySe-OH, was first reported. • Dye HCySe-OH exhibited a good 1O 2 generation capacity. • Dye HCySe-OH can be used as an ideal scaffold for constructing activatable photosensitizers. [ABSTRACT FROM AUTHOR]

Developing new reactive disperse dyes and applying them to dye natural fiber substrates in the supercritical fluid of carbon dioxide (SCF–CO 2) is of great importance for ecological protection and the sustainable development of the textile industry. In this work, a reactive disperse dye with an anthraquinonoid chromogen in blue hue and a dichlorotriazine reactive group was successfully designed and synthesized. The precursor of the anthraquinonoid derivative reactive disperse dye was synthesized with a one-pot amination reaction method by employing the reactions between 1, 4-dihydroxyanthraquinone or its cryptochrome 1, 4-diaminoanthraquinone and aniline, ethylenediamine. Then, the precursor was subjected to continuously react with a reactive group of cyanuric chloride to obtain a dichlorotriazine type reactive disperse dye. Moreover, the chemical structures and color characteristics of the final dye, as well as the precursor, were characterized and confirmed by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), and ultraviolet–visible absorption spectroscopy (UV–Vis). Additionally, the anthraquinonoid derivative reactive disperse dye was preliminarily applied to the coloration of cotton and wool substrates in SCF-CO 2. The coloration results show that the staining fastness and the dry, wet rubbing fastness of the reactive disperse dye on both cotton and wool substrates were satisfactory. [Display omitted] • A blue Anthraquinonoid dye precursor was synthesized via a one-pot amination reaction. • Cyanuric chloride was utilized as a reactive group for the blue anthraquinonoid dye. • The structure and color characteristics were confirmed by FT-IR, 1H NMR and UV–Vis. • Good coloration results on natural fibers were achieved in SCF-CO 2 with the blue dye. [ABSTRACT FROM AUTHOR]

Color filters (CF) are essential integral parts of the liquid crystal display (LCD) and image sensor. Compared to traditional pigment colorants, organic dyes offer a promising alternative to realize CF with improved optical properties and higher resolution. However, organic dyes usually suffer from inferior thermal and photo-stability, limiting their applications in CF. Herein, four robust donor-acceptor organic dyes based on phenanthrenequinone chromophore were designed and synthesized by introducing aromatic amine derivatives as the electron donors. The strong donor-acceptor interactions in these dyes contribute to intense broad charge-transfer absorption bands from 375 nm to 600 nm with high molar extinction coefficients, thus realizing red color. Also, these dyes exhibit high thermal and photo-stability, good compatibility with the polymer binder and low aggregation tendencies, resulting in high thermal and photo-stability for the fabricated CF films. Remarkably, among these phenanthrenequinone dyes, DTPAP with multi-donor substitution and extended π-conjugation exhibited the best performance in terms of molar extinction coefficient, thermal and photo-stability, contributing to the highest thermal and photo-stability for the CF film with color difference values (Δ E ab) below 0.75 under simulated industrial manufacturing processes. This work confirms that phenanthrenequinone is a robust chromophore and is conducive to developing thermal and photo-stable CF dyes, and paves a way to improve the optical properties and stability of donor-acceptor dyes for CF. [Display omitted] • Robust phenanthrenequinone chromophore with high bond dissociation energies. • High thermal and photo-stability via multi-donor substitution and π-conjugation extension. • Improved optical properties and stability of donor-acceptor dyes for color filters. [ABSTRACT FROM AUTHOR]

The optical properties of cyanine-based compounds are determined by single molecules as well as the dimers and aggregates formed. In our work, we show the influence of the molecular structure of the dye, through the use of modified cyanine derivatives, both on the negative solvatochromic effect and on a tunable, two-band lasing coming from the vibrational states of the molecules. Thus, we demonstrate the dependence of the dye form on optical properties, including nonlinear optical ones. • Extension of the side chain of cyanine derivatives red-shifts the lasing emission. • α -CD facilitates encapsulation of the dye into the cut cone structure and enables laser emission from a selective dye forms. • Independent random lasing signal from two different forms of the cyanine dyes was observed. • Selected cyanine derivatives maintain centrosymmetric structure, for different forms of dye. [ABSTRACT FROM AUTHOR]

The present study aimed to explore the antibacterial activity of a group of nature-inspired and structurally similar amino-based flavylium dyes: 7-diethylamino-4′-dimethylaminoflavylium (7NEt 2 4′NMe 2); 7-diethylamino-2-(dimethylaminostyryl)-1-benzopyrylium (7NEt 2 st4′NMe 2); 7-diethylamino-4′-aminoflavylium (7NEt 2 4′NH 2); 7-diethylamino-4′-hydroxyflavylium (7NEt 2 4′OH). Except for 7NEt 2 4′OH, all the other tested compounds showed inhibitory activity on the bacterial growth of Gram-positive bacteria (Staphylococcus aureus ATCC 29213 and S. epidermidis ATCC 14990) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853), with MIC values in the range of 2.61–24.4 μM and 359–669 μM, respectively. Besides their toxicity in the dark, remarkable light-induced killing effects were observed (light dose treatment of 22.5 J/cm2), causing significant morphological changes detected by atomic force microscopy. The photoinactivation effect was particularly effective against Gram-positive bacteria, where complete eradication of bacterial growth was achieved at concentrations in the range of 3–12 μM. Photochemical mechanistic studies suggested the occurrence of both type I (free radicals) and type II (singlet oxygen) reactions, although light-induced damages appear to be predominantly caused by singlet oxygen action. Altogether, these results highlight the dual-antibacterial action of this group of dyes, showing antibiotic activity in the dark and photosensitizer behavior under visible light exposure. These findings underline a new application for amino-based flavylium dyes in the management of microbial skin infections. • Four nature-inspired flavylium dyes were synthesized, showing absorption in the range of 550-650 nm. • The presence of an amine group at C'4 position enhanced the overall antibacterial effect. • Amino-substituted flavylium dyes displayed potent photosensitizer action mainly by 1O 2 generation. • Microscopy analysis confirmed compounds' adsorption/internalization and severe morphological changes in bacterial membranes. [ABSTRACT FROM AUTHOR]

Natural colorants could serve as a bio-based alternative for synthetic textile dyes. Most natural colorants exhibit limited affinity to cellulosic fibres. As a result only light shades are obtained and the efficiency in use of the valuable plant extracts is low. By addition of a cationic polymer to the viscose spin dope regenerated cellulose, fibres with incorporated cationic groups are obtained. The presence of accessible cationic sites increases sorption of natural dyes substantially. In dyeing experiments with extracts from canadian goldenrod, green nut shell and ashes bark darker dyeings were obtained the modified viscose fibres compared to results on cotton or viscose fibres. The higher sorption of the natural dyes can be explained with dissociation of the extracted natural dye molecules under dyebath conditions. The formation of negatively charged dye molecules was confirmed with model calculations for species distribution using representative natural dye molecules as examples. The results indicate a strategy for a more economic use of plant based colorants, which is a condition for wider use of this renewable dye source. [Display omitted] • Incorporation of cationic polymer into viscose fibre increases natural dye uptake. • Cationisation of viscose improves colour yield with natural colorants. • Dissociation of natural dyes in the dyebath leads to negatively charged molecules. • Negatively charged natural dyes exhibit high sorption on cationic sites in fibre. • Extracts from ashes bark, canadian goldenrod, green nut shell show behave similar. [ABSTRACT FROM AUTHOR]

Herein, four heterobifunctional brilliant yellow dyes containing different numbers of sulfonic groups (MRY-1–MRY-4) were designed to investigate the relationship between the dye structure, dyeing properties, and the eco-friendly dyeing technique. The solubility, stability, substantivity, reactivity, and colorimetric properties of the dyes were studied. The substantivity of the dyes was significantly reduced when the diazo component of the chromophores contained two sulfonic groups. The four dyes were then used to dye cotton fabrics using eco-friendly low liquor ratio dyeing and cold pad-batch dyeing techniques. For low liquor ratio dyeing, when the liquor ratio was 1:6, the fixation rates of MRY-1, MRY-2, and MRY-3 were 84.9 %, 71.1 %, and 75.0 %, respectively. MRY-4 was not suitable for exhaust dyeing but could be used in cold pad-batch dyeing, in which its fixation rate on cotton fabric reached 93.8 %. However, MRY-1 cannot be used to dye cotton by cold pad-batch dyeing due to its low alkali resistance and resulting poor stability. In a similar chromophore structure, increasing the number of sulfonic groups increased the brightness value of the dye but also made the dye greener and bluer. The dry and wet rubbing fastness of cotton dyed with the four reactive dyes was grade 4–5 and 3–4, respectively. The wash fastness to color change and staining reached grades 4 or 4–5, while the light fastness of MRY-1 and MRY-3 was grade 3–4 and that of MRY-2 and MRY-4 was grade 4–5. [Display omitted] • Four heterobifunctional brilliant yellow dyes were developed and used to dye cotton fabric through eco-friendly dyeing techniques. • Eco-friendly dyeing technique can be selected accurately by controlling the dye structure. • Dye physical properties can be controlled by adjusting the diazo component of the chromophores. • The high fixation rate (>93 %) of dye on cotton fabric can be achieved. [ABSTRACT FROM AUTHOR]

The dyeing performance of different disperse dyes in D5 non-aqueous media dyeing varies greatly, and dye structure is closely related to dyeing performance. Therefore, in this paper, the influence of dye molecular structure on the dyeing properties in D5 non-aqueous media was studied by incorporating X-ray crystal diffraction analysis, density functional theory (DFT), and dyeing experiments. The results showed that cyano group on the azo component increased the coplanarity of the aromatic ring, forming a stronger π-π stacking. Meanwhile, introducing a smaller steric effect substituent on the coupling component also facilitated the formation of tighter molecular arrangements. The thermodynamic and kinetic parameters of dyeing showed that the close molecular stacking and arrangement could effectively increase the adsorption amount of disperse dye on the polyester fabric but reduce the diffusion in the fiber, which helped to improve the dyeing uptake. These results helped us understand the relationship between dye structure, molecular stacking, and dyeing performance in D5 non-aqueous medium dyeing and provided a theoretical basis for screening and optimizing D5 dyeing system-specific dyes. • The relationship between dye structure, molecular stacking, and dyeing performance in D5 medium dyeing was studied. • Molecular planarity and steric effects affect the arrangement of dye molecules. • Compact molecular arrangement contributes to increase dyeing uptake. [ABSTRACT FROM AUTHOR]

Chromenoxanthenes are colorful dyes which do not suffer from any fluorescence turn-off induced by spirocyclic forms as usually observed for conventional rhodamine and fluorescein xanthene analogues. In that way, wide variety of applications in particular in bioimaging can be foreseen for those underexplored fluorophores. Herein, a one-pot synthesis of rhodol-like chromenoxanthene dyes is reported, which are further modified at the periphery of the core structure to tune the optical properties. Resulting neutral derivatives are bright fluorophores in the orange-red spectral window, while cationic counterparts are almost non-emissive. These optical properties are fully characterized and are also rationalized via first-principles calculations. In particular, the occurrence of twisted intramolecular charge transfers is shown to account for the dark-state quenching occurring in the charged compounds. This feature is harvested in the construction of an activity-based fluorescent probe for mitochondria imaging. Excellent organelle localization is achieved, while the emission signal is proportional to the hydrogen peroxide concentration in the mitochondria. Furthermore, the absence of cytotoxicity bestows rhodol-like chromenoxanthene dyes a bright future in cellular imaging applications. [Display omitted] • An innovative one-pot synthesis of rhodol-like chromenoxanthene dyes is reported. • The chromenoxanthene core is converted to an activity-based fluorescent probe for mitochondria imaging. • Detailed computational studies are conducted to understand the optical properties of the probes. • Bio-imaging studies are done in melanoma cancer cells. [ABSTRACT FROM AUTHOR]

The traditional development of dyes for biological applications typically begins with synthesis, is followed by spectroscopic/photophysical characterization, and culminates in testing with cultured cells or in animals. The present work describes a set of facile, low-technology, in vitro , largely quantitative absorption spectrophotometric assays in aqueous solution as a prelude to biological studies. The assays include the following: (1) Self-aggregation in phosphate-buffered saline (PBS), with or without the presence of 3 % bovine serum albumin (BSA), via reciprocal change in concentration and pathlength; (2) Adsorption to solid materials as biomolecular surrogates, including cellulose, chitosan, polyethylene (PE), styrene-divinylbenzene beads (XAD-4), polyacrylic beads (XAD-7), anion exchange beads (IRA-67), cation exchange beads (CG-50), polytetrafluoroethylene (PTFE) membranes, and Nylon membranes; (3) Hydrophilicity/hydrophobicity assessment, by measurement (not calculation) of logP values; and (4) Metabolic integrity, by exposure to a rat liver homogenate. Twenty-two dyes were examined in the assays. The dyes represent diverse classes (acridine, anthraquinone, azo, benzimidazole, coumarin, cyanine, flavonoid, naphthalene, phthalocyanine, polyene, tetrapyrrole, triarylmethine, xanthene), polarity (anionic, cationic, nonionic, hydrophobic, amphipathic), and absorption (ultraviolet, visible, near-infrared). As one example, indocyanine green (ICG), an FDA-approved dye for in vivo use, (i) aggregates at the concentration of 5 μM but disaggregates in the presence of BSA; (ii) in PBS is very adsorptive (>80 % binding) to various materials (cellulose, chitosan, PE, IRA-67, CG-50, PTFE, Nylon) and quite adsorptive (50–80 % binding) to XAD-4 and XAD-7, (iii) exhibits only marginal preference for water versus 1-octanol (1.5:1), and (iv) is largely digested by rat liver homogenate. A single dye can be examined in the span of one day. The quantitative metrics should prove valuable for establishing biologically relevant features of diverse dyes by simple studies in aqueous solution. [ABSTRACT FROM AUTHOR]

In this work, new D-π-A dyes bearing thieno[3,2- b ]indole, 7-(tert -butyl)thieno[3,2- b ]indole or benzo[ g ]thieno[3,2- b ]indole as an electron-donating part, 2,2′-bithiophene unit as π-linker and 2-cyanoacrylic acid as an electron acceptor-anchoring part have been readily synthesized and used for dye-sensitized solar cells (DSSCs). In addition, thermal stability, optical and electrochemical properties of these dyes were investigated. The DSSCs based on dyes IS-BTh exhibited values of PCE in the range of 3.43–4.41 % under AM 1.5 G irradiation. The highest PCE value of 4.41 % (J sc = 11.61 mA cm−2, V oc = 0.64 V, FF = 0.59) was achieved for DSSC based on dye IS-BTh-1 , bearing thieno[3,2- b ]indole as an electron-donating part. The temperature dependencies of the photovoltaic parameters for DSSC based on dye IS-BTh-1 were investigated. Three new D-π-A compounds were synthesized and used as photosensitizers for dye-sensitized solar cells (DSSCs), and the highest power conversion efficiency of 4.41 % was achieved for DSSC based on dye IS-BTh-1. [Display omitted] • Novel D-π-A thieno[3,2- b ]indole based photosensitizers were synthesized and used for dye-sensitized solar cells (DSSCs). • The effect at modifying thieno[3,2- b ]indole donor part in the structure of these dyes was investigated. • The highest PCE value of 4.41 % was achieved for DSSC based on dye IS-BTh-1 , bearing thieno[3,2- b ]indole as an electron-donating part. • The temperature dependencies of the photovoltaic parameters for DSSC based on dye IS-BTh-1 were investigated. [ABSTRACT FROM AUTHOR]

Two triphenylamines with thieno [3,2- b ] thiophene units were designed and synthesized. The radical cations obtained by the one-electron oxidation of these amines show a significant absorption in the near-infrared region. In particular, the derivative with three hexyl groups has excellent solubility, and its radical cation has a maximum absorption wavelength above 1400 nm. DFT calculations support these experimental results. A novel design strategy for NIR-II dyes is described. Two triphenylamines with thieno [3,2- b ] thiophene units were designed and synthesized. The radical cation with long-chain hexyl groups was stable in solution and showed a maximum absorption at 1430 nm. [Display omitted] • Novel triphenylamine with three thieno[3,2- b ]thiophenes. • The derivative with hexyl groups has excellent solubility. • The radical cation with hexyl groups was stable at room temperature in solution, and showed an absorption at 1430 nm. • Near-infrared absorbing dyes with high solubility and absorption in longer wavelength regions. [ABSTRACT FROM AUTHOR]

Herein, we have developed photosensitive ternary cholesteric liquid crystals (T-N*-LCs) by doping achiral dichroic dye PBCy and chiral inducer R / S -1 in 5CB. Under alternating UV and visible light treatment, different isomers of PBCy exhibited varying order parameter (S F) values in 5CB, resulting in T-N*-LCs showing a dynamic CPL switch from strong (S F = 0.18. g lum = +0.45/-0.48) to weak (S F = 0.10. g lum = +0.23/-0.21). This alteration allows for the regulation of the CPL signal of T-N*-LCs, while keeping the helical pitch and chiral spin of T-N*-LCs unchanged. Based on these phototunable CPL and fluorescence behaviors, a geminate mode device carrying different information could be prepared. A photosensitive chiral emissive liquid crystal (T-N*-LCs) was prepared by doping achiral dichroic dye PBCy and chiral inducer R / S -1 in 5CB. Under alternating UV and visible light treatment, different isomers of PBCy exhibited varying fluorescent order parameter (S F) values in 5CB, resulting in T-N*-LCs showing a dynamic CPL switch from strong (S F = 0.18. g lum = +0.45/-0.48) to weak (S F = 0.10. g lum = +0.23/-0.21). [Display omitted] [ABSTRACT FROM AUTHOR]

A significant amount of wastewater is generated in printing and dyeing processes of nylon textiles. The wastewater pollutes the environment and increases the post-treatment costs. To simultaneously obtain the excellent dye utilization and color fastness, low-water-soluble reactive dyes (LWSRDs) with vinylsulfone group as a reactive group were developed in this paper. The LWSRDs have dual characteristics of high exhaustion and forming covalent bonds with nylon fibers in neutral conditions. These characteristics result in higher fixation on nylon 6 traditional fibers (NTF) using Traditional dyeing process (TDP) compared with commercial reactive dyes. Based on the characteristics of LWSRDs, modified dyeing process (MDP), which was conducted in one-pot, significantly reduces the costs of chemicals and wastewater. Moreover, the fixation of LWSRDs on nylon fibers using MDP was higher than that using TDP. Notably, the dyed nylon fibers were uniform and vibrant, and demonstrated exceptional color fastness against washing and rubbing, exceeding grade 4. The results of innovative LWSRDs and their corresponding MDP offer an effective approach to dyeing nylon fibers, with good application prospects in dyeing industry. • The vinylsulfone can increase the fixation to nylon fiber, compared with traditional sulfatoethylsulfone reactive dyes. • The low-water-soluble reactive dyes had better affinity to nylon fiber, and superior exhaustion and fixation. • The dyeing progress of low-water-soluble reactive dyes was easier than that of the existing commercial reactive dyes. [ABSTRACT FROM AUTHOR]

It is vital to create supramolecular dyes with excellent photo-luminescence properties based on host-gust interaction. In this study, we present three novel self-assembled cationic supramolecular dyes driven by host-guest electrostatic interaction and with ultrasmall cavities. These cationic dyes were developed and synthesized using pyridine-substituted phenanthrene, triphenylamine (TPA), and tetraphenyl ethylene (TPE) as chromophores through the pyridine quaternary ammonium salt reaction. These anion-trapped supramolecular dyes exhibit outstanding aggregation-induced emission (AIE) characteristics as well as reversible mechanochromism behavior and high solid-state fluorescence quantum yields (∼60.87 %). Furthermore, the cationic supramolecular dyes directly stain cotton fibers with 50 % dyeing rate in water-methanol solutions, in which the deprotonated glucose-O- guest possibly interacts with the cationic dye through host-guest encapsulation. Additionally, we characterized the dyeing process through IR spectroscopy, UV–vis spectroscopy, fluorescence spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). Due to the reversible, tractable, and high-contrast mechanochromism of the dyes, they can make up a color-changing flower pattern. Thus, we anticipate that these dyes will have potential applications in information security storage and anti-counterfeiting. Anion-trapped supramolecular dyes : These multicomponent supramolecular dyes self-assembled via host-guest interaction exhibited excellent not only aggregation-induced emission (AIE) properties with high solid-state fluorescence quantum yields but also exhibit reversible and high contrast mechanochromism and good property in dyeing. [Display omitted] • Three cationic supramolecular dyes with ultrasmall cavities were synthesized through host-guest encapsulation. • These dyes encapsulate hexafluorophosphate through multiple hydrogen bonding and electrostatic interactions. • Cationic dyes exhibit outstanding aggregation-induced emission characteristics and reversible mechanochromism behavior. • The emissive cationic dyes effectively stain cotton fibers in water-methanol solution. [ABSTRACT FROM AUTHOR]

Herein, six new thiazole-dipehenylamine-based azo dyes containing azo and thiazole bridges and diphenylamine donor with different donor/acceptor groups were synthesized. All the synthesized dyes were characterized by FT-IR, NMR and HRMS analyses. The structure of (E)- N -methyl-4-((thiazol-2-yl)diazenyl)- N -phenylaniline (4) was conclusively confirmed by single crystal X-ray diffraction analysis. Photophysical studies were performed in different solvents with various polarity. Although the three synthesized compounds can be represented as potential azo-hydrazone tautomers only the azo form was observed in all solvents used. UV/vis spectroscopic studies showed that the color changed dramatically when the dyes contain a strong electron accepting nitro substituent. Moreover, after protonation of azo dyes, with the exception of the azo dyes with nitro group, a bathochromic shift was observed. The effects of protonation on the geometry and electronic structure of the compounds were studied, and the NLO properties were also investigated using DFT calculations. In addition, the thermal stability of the azo dyes was investigated using thermal gravimetry (TGA). Dyeing performance was evaluated with these dyes on polyester fabric in an aqueous medium. All dyes except dyes 3 and 6 showed good color fastness properties. Therefore, these compounds can be used as textile dyes for polyester fabrics. [Display omitted] • Six new D-π-A azo dyes bearing thiazole-diphenylamine units were synthesized. • The dyes showed bathochromic shift with increasing solvent polarity. • NLO properties of azo dyes were determined theoretically using DFT method. • The highest hyperpolarization value was found in dye 3 , 801 βx10−3 esu. • Dyes 3 and 6 have good dye ability and color fastness on a polyester substrate. [ABSTRACT FROM AUTHOR]

This study presents a defect passivation approach using coumarin dye (7-diethylaminobenzopyran-2-one) as a multi-functional passivating agent of perovskite films to boost power conversion efficiency (PCE) and operating stability of PSCs. The coumarin dye could offer strong interaction with under-coordinated Pb2+ and vacant I − in [PbI 6 ] octahedral frameworks due to multiple functional groups, which could serve as potential Lewis bases or hydrogen bonding sites, as well as highly conjugated aromaticity. The incorporation of coumarin dye contributes to improved film morphology of perovskite films, leading to compact and uniform grains without compromising crystallinity. Correspondingly, enhanced carrier extraction/transport and suppressed trap-assisted recombination are promoted in the perovskite films modified with coumarin dye. As a result, the coumarin dye incorporation improved the photovoltaic performance delivering a PCE of 20.85 % in planar p-i-n PSCs. The optimized device also recorded excellent indoor photovoltaic performance (PCE = 30.35 %) under dim-light condition. Furthermore, the devices passivated with coumarin dye also maintained >90 % of their initial PCEs after exposed under continuous indoor lighting irradiation (1000 lux) in ambient atmosphere for 2000 h, exhibiting impressive reliability and practical applicability. • A passivation strategy of defective trap-sites of perovskite films by coumarin dye is demonstrated. • High-quality perovskite films are prepared by defect passivation by coumarin dye. • High-efficiency perovskite solar cells are demonstrated by incorporation coumarin dye into the perovskite films. [ABSTRACT FROM AUTHOR]

Week interactions between traditional dye molecules and synthetic fibers requires addition of numerous chemical additives during the dyeing process, resulting in the generation of a significant amount of printing and dyeing wastewater, thereby causing environmental pollution. Herein, three novel carbene dyes containing diazirine were rationally designed, whose decomposition into carbenes at 145 °C subsequently forms covalent bonds with the C–H bonds present in the fibers. The structure-property relationships of the dyes were analyzed based on the results of density functional theory (DFT) calculations. Additionally, the calculations of Yoshida correlations demonstrated that all three dyes exhibit non-explosive properties, thereby indicating their feasibility for large-scale production. The dyeing process of polyester (polyethylene terephthalate/PET), polypropylene (PP), aramid, spandex, and polyester/spandex (P/S) blended fabrics was performed using a non-aqueous solvent dyeing method without the addition of any additives, and the optimal dyeing and color fixation conditions were determined. The samples dyed with carbene dyes displayed similar K/S values compared to conventionally dyed samples, higher color fixation rates, and improved blended dyeing effects, and the reaction mechanism between the carbene dyes and the fibers was elucidated, which proved the versatility and environmental friendliness of the novel carbene dyes and non-aqueous solvent dyeing method. Furthermore, it is noteworthy that all of these dyed fabrics exhibited exceptional color fastness, highlighting the immense potential of the novel carbene dyes in promoting green production in the textile industry. [Display omitted] • Three new carbene dyes were synthesized and characterized. • The carbene dyes form covalent bonds with fibers containing C–H bonds through carbene reactive intermediates. • Dyeing fabrics with non-aqueous solvent dyeing method does not require the addition of chemical additives. • The reaction mechanism of carbene dyes with various fabrics was investigated. • All dyed fabrics have excellent fastness levels. [ABSTRACT FROM AUTHOR]

Leuco dyes are important commercial and useful compounds capable of switching between two different chemical structures, one of which is commonly a pale color or colorless substance. Fluoran compounds are a category of leuco dyes that can switch between colorless spirolactone (closed-ring) and zwitterionic open-ring forms, and depending on their substituents, would provide a wide variety of colors from black and dark violet to orange and red. This property of fluoran molecules to often alternate reversibly between two colors, distinguishable by naked eyes, has encouraged organic chemists to synthetically manipulate fluoran structures to tailor them for desired applications in various fields of science and technology. In this review, after presenting a short literature survey on fluoran compounds, recent advancements in the synthesis, encapsulation, and characterization of fluoran dyes are summarized. In the following, various applications of fluorans as thermo-, hydro-, and electrochromic compounds or as chemosensors and fluorescent probes is discussed. Other uses of these compounds such as in radiation detection and radiotherapy are also pointed out. • Fluorans are a group of dyes that switch between colorless and colored structures. • Fluorans provide a variety of colors from black and dark violet to orange and red. • Fluorans are designed for desired applications in science and technology. • Recent advancements of fluoran chemistry are summarized. • Various applications of fluorans as sensors and fluorescent probes are discussed. [ABSTRACT FROM AUTHOR]

This research aims to synthesize highly visible, bright emission fluorescent dye molecules in daylight to produce PU films and PU resource safety materials. Here we have developed four different types of highly visible PU films in which a cyano-substituted methoxyphenylene core with an additional electron-withdrawing and-donating unit is used to produce a bright orange color with twisted rigid conformational dyes. Modifications in the mechanical behavior and thermal stability properties of PU films were tested by tensile tests, TGA and DSC. The samples of PU film exhibit exceptional elasticity, with a high elongation breaking point and good young's modulus value. Furthermore, these synthesized dyes were measured for photophysical properties and other parameters such as solvent effect, quantum yield and lifetime. The quantum yields of highly visible dyes were measured in both solution and solid phase and found to be in the range of 0.25–0.48 and 0.15 to 0.55, respectively. The HOMO-LUMO energy gap of the dyes in the solid state is significantly lower than that in the solution state. This related to the dyes which exhibiting a lifetime in THF solution of about 1.96–2.41 ns, whereas in the solid state, the lifetime is much better about 6.43–19.61 ns. This indicating that the dyes in the solid state are energetically easier and hence the solid state of dyes shows higher lifetime. [Display omitted] • Bright daylight visible fluorescent materials were synthesized in two steps. • The dye used as a day-light high visibility material in PU films for making safety gear. • The quantum yield and lifetime for these dyes were higher in the solid than in solution. [ABSTRACT FROM AUTHOR]

Eight donor-acceptor-donor type croconium dyes with different donor moieties, such as indole, N -methylindole, benzo[ e ]indole, N -methylbenzo[ c,d ]indole, benzothiazole and quinoline groups, have been designed and discussed their pH response, near-infrared fluorescence/photoacoustic (NIR/PA) imaging and photothermal properties in solutions and tumor cells. Croconium dye with bisbenzothiazole CBT exhibited the best NIR-imaging. Croconium dye with bisindole CBI-1 showed the best PA-imaging. Dye CBI-3 with bisbenzo[ e ]indole showed the best photothermal. Four dyes with either indole or benzo[ e ]indole group CBI-1 , CBI-3 , CIT and CIQ showed pH response on fluorescence and photoacoustic spectra and photothermal. This study proves that preserving the indole group in croconium dyes was beneficial for their pH response and NIR/PA imaging, and the introduction of quinoline and thiazole groups was detrimental to the photostability. Gathered with pH response, NIR/PA imaging and photothermal property, dye CBI-1 is suitable for structural modification in the future for developing better cancer theranostic reagents. [Display omitted] • Croconium dyes with indole, benzo[ e ]indole, benzo[ c,d ]indole, benzothiazole and quinoline were synthesized. • The impact of these donors on their pH response, NIR/PA imaging and photothermal properties was discussed. • Croconium dye with bisindole CBI-1 is suitable for structural modification to develop better cancer theranostic reagents. [ABSTRACT FROM AUTHOR]

A pyrene dye bearing a flexibly rotated hydrophobic group (3,4,5-tri(dodecyloxy)benzoyl-) was synthesized and fully characterized. In cooling processes for the dye monomer in CHCl 3 /CH 3 OH, the monomer was transformed into the J-aggregates which were characterized to possess a typically nanowired shape. A thermodynamic hysteresis of the molar fraction of the aggregates was observed explicitly between the cooling and heating processes. A pronounced self-absorption was involved in the aggregate solutions of the dye at high concentrations. Clearly, the J-aggregation conferred a few intriguing attributes such as a red-shift of maximum absorption peak, a higher quantum yield of absolute fluorescence and a shorter fluorescence lifetime than the monomer. Collectively, these attributes brought about a phenomenon of aggregation-induced emission enhancement (AIEE). In addition, the HOMO and LUMO energies were calculated by DFT for both the monomeric and aggregated states. Furthermore, the stacking parameters in the J-aggregates were evaluated according to the molecular exciton theory. It can be concluded that the J-aggregation enhanced substantially the emission of the dye. Undoubtedly, the strategy for the development of the AIEE molecules containing a flexible rotation group via J-aggregation as revealed in this work will be very useful in the future design of new organic light-emitting dyes. [Display omitted] • A pyrene dye bearing a flexibly rotated hydrophobic group was synthesized and fully characterized. • Polymerization of the dye generated nanowire-shaped J-aggregates, conferring an AIEE effect concurrently. • Energy gap between LUMO and HOMO for the J-aggregates was larger than that for the monomer. • Emission enhancement by J-aggregation was more pronounced than by self-absorption quench. [ABSTRACT FROM AUTHOR]

The current study investigates the photophysical interactions of xanthene dyes such as fluorescein (FL) and rose bengal (RB) dyes with cetyltrimethylammonium bromide stabilized gold nanorods (CTAB-AuNRs) using optical spectral techniques, and computational interaction analyses. When xanthene dyes are conjugated with CTAB-AuNRs, significant modifications in their optical spectroscopic characteristics are found. In the absorption spectrum analyses of dye-AuNRs systems, the appearance of longitudinal plasmon resonance bands and the hypochromic behavior of xanthene dyes were observed in response to the interaction of CTAB-AuNRs. The gathered extinction spectral results indicated that there were significant electrostatic interactions between the positively charged CTAB-AuNRs and the negatively charged xanthene dye molecules. At the same time, the substantial quenching with a reduced quantum yield of the dye molecules is shown in the emission spectra of xanthene dyes with CTAB-AuNRs. The strong electrostatic interactions and ground state complex between xanthene dyes and CTAB-AuNRs have been suggested as the mechanism of emission quenching. The results of the emission quenching are supported by the calculated high binding constant values. Additionally, the results of computational interaction investigations also demonstrate the near closeness of xanthene dye molecules and CTAB-AuNRs. Finally, the cytotoxicity of free dyes and dye-nanoconjugates was next tested against breast (MCF-7) and lung (A-549) cancer cells. All the tested samples exhibit significant antiproliferative activity against MCF-7 and A-549 cancer cells. These cytotoxic study results showed that cells treated with xanthene dyes were less sensitive than FL-AuNRs and RB-AuNRs dye nanoconjugates. [Display omitted] • Spectral measurements are used to describe the photophysical interactions of fluorescein/rose Bengal with gold nanorods. • The electrostatic interactions between dyes and AuNRs played a crucial role in the spectrum variations of the dyes-AuNRs system. • The computational findings demonstrate the close connection between xanthene dyes and AuNRs. • The MTT assay, used as an in vitro model in A-549 and MCF-7 cells, demonstrates that the binding of AuNRs increases the toxicity of free dyes. [ABSTRACT FROM AUTHOR]

Single-atom hybrid photocatalysts (Co/g-C 3 N 4 /C4EOP) composed of hydrophilic calixarene dyes (C4EOP) and graphite-phase carbon nitrite with monodispersed Co atoms (Co/g-C 3 N 4) are prepared by a facile solution impregnation method, and their photocatalytic performances are evaluated in visible light-driven H 2 evolution from water and CO 2 conversion. The optimized Co/g-C 3 N 4 /C4EOP (1.0 wt%) catalyst exhibits moderate H 2 production activity (511 μmol g−1 h−1) and good durability within 60 h (TON C4EOP value of 2255) under visible light. In contrast, the Co/g-C 3 N 4 /C4BTP (1.0 wt%) and Co/g-C 3 N 4 /M-EOP (1.0 wt%) show much lower activities than Co/g-C 3 N 4 /C4EOP (1.0 wt%) under the same conditions. This could be attributed to the higher molar extinction coefficient and better hydrophilicity of C4EOP compared to C4BTP with hydrophobic alkane groups and M-EOP with single D-π-A chain. In addition, Co/g-C 3 N 4 /C4EOP (1.0 wt%) catalyst displays highly selective photocatalytic activity for CO 2 reduction to CO. This work provides a promising example for the development of efficient dye-sensitized photocatalytic system based on g-C 3 N 4 with non-noble metal for the chemical utilization of solar energy. Single-atom hybrid photocatalysts (Co/g-C 3 N 4 /C4EOP) composed of hydrophilic calixarene dyes (C4EOP) and graphite-phase carbon nitrite with monodispersed Co atoms (Co/g-C 3 N 4) exhibit moderate visible light-driven H 2 production activity and good stability, or highly selective photocatalytic activity for CO 2 reduction to CO in different reaction solutions. [Display omitted] • Hydrophilic calixarene dyes are first designed and synthesized. • Single-atom photocatalysts based on calixarene dyes and g-C 3 N 4 are first prepared. • The hybrid photocatalysts exhibit H 2 production activity and good durability. • The photocatalysts display highly selective activity for CO 2 reduction to CO. [ABSTRACT FROM AUTHOR]

The successful synthesis of organoboron complexes with novel core structures facilitates the development of new functional dyes. In this context, synthesizing stable seven-membered organoboron complexes poses substantial challenges, so dyes of this type have seldom been studied. The successful synthesis of a series of pyrrole hemithioindigo-derived organoboron complexes is reported. The photophysical properties have been analyzed, and the results have been compared to those predicted by rigorous theoretical calculations. The presence of a seven-membered ring N,O boron-chelated moiety in these complexes was definitively confirmed by single crystal X-ray diffraction studies. Confocal laser experiments demonstrated the ability of one of the complexes studied to effectively permeate HeLa cells and selectively stain the cytoplasmic region. The reported synthetic strategy provides a framework for synthesizing a wide range of versatile organoboron dyes and opening up new avenues for developing innovative materials. [Display omitted] • Pyrrole hemithioindigo-derived organoboron complexes were designed and fully characterized. • Theoretical calculations were employed to disclose the structure-property relationships. • Cellular imaging of the dye was studied by confocal laser imaging. [ABSTRACT FROM AUTHOR]

In this paper, readily obtainable hydroxyquinolinate diarylboron complexes were characterized by UV–vis measurements, computational calculations and they were tested as photocatalysts in perfluoroalkylation of unsaturated bonds through a photocatalytic ATRA process. Amongst the studied compounds the respective diphenyl derivative was selected as the most economic photocatalyst. It was next utilized in a visible-light driven aerobic oxidative hydroxylation of arylboronic acids using air as the oxygen source. • Six dyes based on boron 8-oxyquinolinate ligand were tested as photocatalysts. • The diphenyl derivative was selected as the most economic photocatalyst. • The activity was tested in the ATRA of iodoperfluoroalkanes to terminal unsaturated bonds. • High yields (70–95%) using 2 mol % of the photocatalyst within 3 h were obtained. • The activity of the dyes in the oxidative hydroxylation of arylboronic acids has been revealed. [ABSTRACT FROM AUTHOR]

Genipin, a naturally occurring iridoid, represents an interesting class of reactive dyes. This colorless molecule produces brilliant blue dyes in the presence of primary aliphatic amines. The mechanism behind this unique reaction has been suggested to proceed via an oxidative polymerization reaction. By utilizing aromatic amines, we demonstrate that the dye absorption properties can be redshifted to form green dyes as opposed to the blue that is most associated with aliphatic amines. These results led us to explore the mechanism of dye formation using X-Ray crystallography, DFT calculations, electrochemical experiments, mass spectrometry, and EPR spectroscopy on slightly structurally perturbed genipin scaffolds. Herein we report the first findings of a crystallographically characterized pseudoazulenic genipin dye intermediate and the impacts of redox chemistry on the resulting dyes, which shows electrochromic reversibility. [Display omitted] • Reaction of genipin with aromatic amines result in the formation of brilliant green dyes. • Mechanistic insights are supported by the first crystallographically characterized genipin-amine dye intermediate. • Genipin-dye intermediates have electrochromic behavior, showing the importance of redox processes in the formation of dyes. [ABSTRACT FROM AUTHOR]

Pyranoanthocyanins and pyranoflavylium analogous pigments occurring either naturally or from the synthetic origin are a family of flavylium derivatives that have risen the attention from the scientific community in several areas such as food, cosmetics, biomedical, and energy due to their physical-chemical features. This review presents an overview of the chemistry of these compounds including their synthesis procedures, formation mechanisms, physical-chemical characterization, spectroscopic properties, and interactions studies with macromolecules. Gathering all the insights about these pigments will allow exploring and investigating their potential technological applications such as dyes, colorants, photosensitizers, pH-sensors, and antioxidants, as well as in the development of emergent materials and devices from intelligent (bio)materials to organic electronics. [Display omitted] • Pyranoflavylium dyes are either obtained from plant-based foods or by synthesis. • Pyranoflavylium-based dyes present important stimuli-responsive properties. • Their physicochemical properties could be tuned for a specific application. • Potential technological applications in foods, cosmetics, energy, biomedical areas. [ABSTRACT FROM AUTHOR]

A family of new highly substituted and symmetrical BOPHYs with modulated optoelectronic properties was synthetized. The strategy consisted in the formation of pyrroles substituted with electron-donor or -withdrawing groups through the cycloaddition reaction between Fischer carbene and oxazolones. The absorption spectra of all compounds present a main peak due to the HOMO-LUMO electronic transition, as supported by the theoretical study. The maximum has large absorption coefficient ε (∼104 M−1cm−1) and is in the green region from 514 to 531 nm, red shifted with respect to unsubstituted BOPHY. The dihedral angle between the two bridged rings in the BOPHY core affects the degree of puckering, depending on the chemical modulation. The fluorescence spectra present excitonic features and pure color according to the CIE coordinates, from green, orange to almost red. Inside the family, the Stokes shift (Δν) follows the same trend as the maxima, and inversely with the fluorescence quantum yield (φ), being the most fluorescent (φ = 85%) the BOPHY with the lowest Stokes shift (Δν) (R1 = phenyl and R2 = methyl). BOPHYs are more difficult to oxidize and reduce than BODIPYs, displaying a shift in the anodic and cathodic potentials in regard to BODIPYs. The delocalization of charges in BOPHYs does not extend with an additional = N–BF 2 nucleus, thus BOPHYs rather present a higher band gap reveling that are less conjugated molecules than mononucleous = N–BF 2. [Display omitted] • Synthesis of new highly substituted BOPHYs with modulated optoelectronic properties. • Absorption and emission maxima are between 514-531 nm and 543–604 nm, respectively. • The molecules are electrochemically active, even after successive cycles. • The molecules may be considered as electron acceptors in organic solar cells. • Electron Donor groups increase HOMO but not LUMO, which is in the BOPHY core. [ABSTRACT FROM AUTHOR]

Man has always used writing to be able to communicate, express, and disseminate his thoughts. In time, many different coloured extracts of plant and animal origin have been used to produce inks; after the development of synthetic chemistry, artificial and synthetic dyes started to be widely exploited. The end of the 19th century marked great technological and industrial innovations in commercial production of artists' materials. To reveal ink formulations and build a database of red inks by different producers, we developed a multi-analytical approach and investigated a collection of writing inks produced in France in the late 19th – early 20th century. The materials used as binders, additives, dyes, and pigments have been investigated by high performance liquid chromatography coupled with diode array and tandem mass spectrometric detectors (HPLC-DAD-MS2), in situ derivatisation pyrolysis coupled with gas chromatography-mass spectrometry (Py(HMDS)-GC/MS), surface enhanced Raman (SERS, TLC-SERS) and X-Ray Fluorescence spectroscopies. Several dyes and pigments were detected, showing that the French ink's formulations of the early days of synthetic dye industry were based on rhodamine B and 6G , eosin Y , rose Bengal and methyl or crystal violet. Instead, as binder and additives only gum Arabic and shellac resin have been identified, respectively. Mass spectrometry also allowed us to detect possible by-products of the synthesis of ink's dyes and even early degradation products, that can be used for ink identification in historical writings and drawings. Our studies can pave the way to investigate inks in historical samples by introducing ultra-sensitive chromatographic and mass spectrometric methods in the array of analytical tools available to the chemist. [Display omitted] • We applied a multianalytical method to the analysis of historical red inks. • We applied Raman spectroscopy and TLC-SERS to study mixtures of organic pigments. • We investigated secondary components by HPLC-DAD-MS2. • We characterized binders and additives by Py(HMDS)-GC/MS. • We revealed a trend in French ink formulations from late 19th – early 20th cent. [ABSTRACT FROM AUTHOR]

Environment-sensitive fluorescent dyes are widely used in biomedical research, clinical diagnostics, molecular and cellular biology, analytical and bioanalytical chemistry. Many sensing dyes in the series of cyanines, styryls, BODIPY, squaraines, fluoresceins, and rhodamines among others have been developed and employed for these applications. Meanwhile, push-pull hemisquaraine dyes have been only moderately explored as the environment sensors. Herein, we developed a series of hemisquaraine dyes containing methylamino (MeH), dimethylamino (MeMe), phenylamino (PhH), phenylmethylamino (PhMe), and diphenylamino (PhPh) groups. These substituents were found to strongly affect sensitivity of the dyes towards H -bond formation, polarity, pH, viscosity, and the presence of bovine serum albumin (BSA), which aids the development of sensors for particular applications. [Display omitted] • A series of new monosquaraine dyes with substituted amino groups was synthesized. • These substituents affect independent sensitivity of the dyes to medium parameters. • Methylamino and phenylamino derivatives are sensitive to H -bonding and acidity. • Dimethylamino and diphenylamino derivatives are sensitive to polarity and viscosity. • Phenylmethylamino derivative is sensitive towards the presence of albumin (BSA). [ABSTRACT FROM AUTHOR]

Developing fluoran dyes for fluorescent material is significant but challenging because they are notorious for terrible luminescent efficiency. In this manuscript, two fluoran dyes (F3 and F4) were synthesized by the introduction of thiazole and indazole into the fluoran skeleton, which showed colored and fluorescent spirolactone opening form in a wide pH range (F3 : 1–10, F4 : 1–13). In addition, the absorption and emission spectra of methyl esterification products F3Me and F4Me showed large Stokes shifts (over 75 nm) in water and achieved an improved fluorescence quantum yield of 30.1% in CHCl 3. Based on the dye F4Me, a new fluorescent probe F4HP was developed, which showed high selectivity and high sensitivity (LOD of 2.0 nM) to copper ions in H 2 O/CH 3 CN (v/v, 3/2) system. Moreover, the sensing experiment was allowed in the pH range of 4.0–7.5. Furthermore, the F4HP exhibits suitable cell cytotoxicity and can be applied for imaging intracellular copper ions by confocal fluorescence imaging technology. Thiazole and indazole functionalized fluoran dyes were prepared with improved fluorescence and application in the construction of a novel copper-selective and sensitive fluorescent probe. [Display omitted] • Two modified fluoran dyes were prepared with stable fluorescence in water. • F4Me achieved a fluorescence quantum yield of 30.1% in CHCl 3. • A novel probe F4HP for Cu2+ was prepared with high selectivity and sensitivity. • F4HP could be employed as a tool for imaging intracellular Cu2+. [ABSTRACT FROM AUTHOR]