Dyes In Solvents Research Articles

Novel lacmoid-based deep eutectic solvent dye as writing ink

A novel lacmoid-based deep eutectic solvent was prepared by mixing of choline chloride as hydrogen bond acceptor and lacmoid as hydrogen bond donor. The mixture of both components was heated until a stable purplish blue homogenous liquid DES dye was formed at 25 °C temperature. The physical and chemical properties of the DES dye ink were studied at 25 °C temperature and characterized by FT-IR, TLC, TGA, 1H-NMR and DSC techniques. The DES dye ink was applied as writing ink and it revealed interesting characteristics for writing without feathering, fading, and penetrating the reverse side of paper and drying by adsorption within few seconds. Moreover, The DES dye ink showed high stability in water for 72 h due to the absorption of DES dye ink by cellulose paper. The green DES dye ink exhibited an effective ability to replacement of pigments and organic compounds used in making writing ink.

Separation of Some Anionic Dyes Using Reverse Micelles of CTAB and SDS as Efficient Surfactants Adsorbents from Aqueous Medium

Extractive removal of anionic dyes, namely, Color Index (CI) Reactive Blue 222 and Reactive Yellow 145, using reverse micelles based on liquid-liquid extraction (LLE) was carried out from aqueous solutions using different anionic and cationic surfactants (e.g., sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), resp.), which dissolved in ethyl acetate as solvent. The reverse micelle principal acts on the dye encapsulated in the solvent in an aqueous micropool. The experiments were carried out by mixing in a simple mixer a given amount of dyes and surfactants dissolved in a solvent in an aqueous process. Due to gravity, the dye is separated from water after the solvent phase is separated from the aqueous phase, including dye encapsulated in reverse micelles. Under various experimental conditions, extraction efficiency was studied, including solution pH, extraction time, initial dye concentration, extractant concentration, temperature, stripping agent, and solvent reusability. Dyes extracted were stripped quantitatively with NaOH solution. Recovery of the solvent and the reuse of dyes and surfactants after extraction of dye molecules from reverse micelles surfactant core considered are very important from an economic point of view. The optimized conditions were 7 ± 0.2 solution pH, 9 × 10−2 mol/L extractant concentration, 1M NaOH stripping agent concentration, 60 min extraction time, 6 × 10−5 mol/L dye concentration, and 1 : 1 aqueous to organic (A/O) ratio. 87–93% of dyes were extracted at experimental optimum conditions.

The effects of polar solvents on structural, electronic, and optical properties of organic dyes

AbstractThis study reports first principles investigations on effects of polar solvents acetonitrile, acetone, water, ethanol, and methanol on the structural, electronic, and optical properties of organic dyes named D1, D1A, D1B, and D1C. The solute‐solvent interaction studied via conductor like screening model revealed changes in structural parameters whereas dipole moment of all the dyes increased after immersing in the solvents. The relaxation of dyes structures in the solvents caused stabilization or destabilization of molecular orbitals which is responsible for spectral shifts in UV–visible absorption spectra. The absorbance and light harvesting efficiency of majority of dyes increased upon solvation which shows their suitability to use as sensitizer. The findings suggested that water is not a suitable solvent for the simulated dyes. The efficiency of solvated dyes D1, D1B, and D1C increased but that of D1B is decreased.

Linked Rotaxane Structure Restricts Local Molecular Motions in Solution to Enhance Fluorescence Properties of Tetraphenylethylene.

The restriction of local molecular motions is critical for improving the fluorescence quantum yields (FQYs) and the photostability of fluorescent dyes. Herein, we report a supramolecular approach to enhance the performance of fluorescent dyes by incorporating a linked rotaxane structure with permethylated α-cyclodextrins. Tetraphenylethylene (TPE) derivatives generally exhibit low FQYs in solution due to the molecular motions in the excited state. We show that TPE with linked rotaxane structures on two sides displays up to 15-fold higher FQYs. Detailed investigations with variable temperature 1 H NMR, UV-Vis, and photoluminescence spectroscopy revealed that the linked rotaxane structure rigidifies the TPE moiety and thus suppresses the local molecular motions and non-radiative decay. Moreover, the linked rotaxane structure enhances the FQY of the dye in various solvents, including aqueous solutions, and improves the photostability through the inhibition of local molecular motions in the excited TPE.

Performance Enhancement of Dye-Sensitized Solar Cells: Solvation Model

A solubility model for Merocyanine-540 dye together with the interface's electron transfer kinetics of MC-540/TiO2 has been investigated (Merocyanine 540-based dye has been used effectively in dye-sensitized solar cells). The highest absorption peaks were recorded at 489 nm and 493 nm in Water and Ethanol solvent, versus the vacuum phase which yielded 495 nm (associated with a modest electron injection-free energy value (ΔGinj) of -2.34 eV for both Water and Ethanol solvents). The time-dependent density functional theory (TD-DFT) method approach has been applied in this simulation. Additionally, the electronic structure and simulated UV-Vis spectra of the dye in different solvents have been determined, and the alignment with the solar spectrum has been discussed to a certain extent. The energy level diagrams and electron density of the primary molecular orbitals are shown, and the major issues that have an impact on our new interface's performance are examined. It is concluded that the proposed Solvation Model (SM) can improve the performance of Dye-Sensitized Solar Cells.

Multi-fidelity prediction of molecular optical peaks with deep learning.

Optical properties are central to molecular design for many applications, including solar cells and biomedical imaging. A variety of ab initio and statistical methods have been developed for their prediction, each with a trade-off between accuracy, generality, and cost. Existing theoretical methods such as time-dependent density functional theory (TD-DFT) are generalizable across chemical space because of their robust physics-based foundations but still exhibit random and systematic errors with respect to experiment despite their high computational cost. Statistical methods can achieve high accuracy at a lower cost, but data sparsity and unoptimized molecule and solvent representations often limit their ability to generalize. Here, we utilize directed message passing neural networks (D-MPNNs) to represent both dye molecules and solvents for predictions of molecular absorption peaks in solution. Additionally, we demonstrate a multi-fidelity approach based on an auxiliary model trained on over 28 000 TD-DFT calculations that further improves accuracy and generalizability, as shown through rigorous splitting strategies. Combining several openly-available experimental datasets, we benchmark these methods against a state-of-the-art regression tree algorithm and compare the D-MPNN solvent representation to several alternatives. Finally, we explore the interpretability of the learned representations using dimensionality reduction and evaluate the use of ensemble variance as an estimator of the epistemic uncertainty in our predictions of molecular peak absorption in solution. The prediction methods proposed herein can be integrated with active learning, generative modeling, and experimental workflows to enable the more rapid design of molecules with targeted optical properties.

Enhancing Intersystem Crossing by Intermolecular Dimer-Stacking of Cyanine as Photosensitizer for Cancer Therapy

Enhancing Intersystem Crossing by Intermolecular Dimer-Stacking of Cyanine as Photosensitizer for Cancer Therapy

Ultrafast proton transfer dynamics of 2-(2′-hydroxyphenyl)benzoxazole dye in different solvents

The excited-state intramolecular proton transfer of 2-(2′-hydroxyphenyl)benzoxazole dye in different solvents is investigated using ultrafast femtosecond transient absorption spectroscopy combined with quantum chemical calculations. Conformational conversion from the syn-enol configuration to the keto configuration is proposed as the mechanism of excited-state intramolecular proton transfer. The duration of excited-state intramolecular proton transfer is measured to range from 50 fs to 200 fs in different solvents. This time is strongly dependent on the calculated energy gap between the N-S0 and T-S1 structures in the S1 state. Along the proton transfer reaction coordinate, the vibrational relaxation process on the S1 state potential surface is observed. The duration of the vibrational relaxation process is determined to be from 8.7 ps to 35 ps dependent on the excess vibrational energy.

Effect of Solvent on Third-Order Nonlinear Optical Behavior of Reactive Blue 19 Dye.

The present work focuses the study of effectof solvent on third-order nonlinear optical (NLO) properties of reactive blue 19 dye dissolved in various polar solvents, namely ethanol, DMF and DMSO, respectively. Fourier Transform Infrared Spectroscopy (FT-IR) was used to find the functional groups present in reactive blue 19 dye. Third-order NLO features of reactive blue 19 dye was examined by a low power continuous wave laser of 650nm wavelength. Reactive blue 19 dye exhibit negative nonlinear index of refraction of the power of 10-7 cm2/W and the nonlinear coefficient of absorption of the order of 10-3cm/W. Both positive and negative nonlinear absorption coefficient of reactive blue 19 dye in different polar solvents is due to the characteristic behavior of saturable and reverse saturable absorption. Third-order NLO susceptibility of reactive blue 19 dye in polar solvents was determined to be the power of 10-6 esu. The experimental results reveal that the dye samplereactive blue 19 is a potential material for nonlinear optical applications.

Complete separation of colorants from polymeric materials for cost-effective recycling of waste textiles

Currently, only 1% of waste textiles, mainly whites, are recycled because dyes on fibers caused various problems. Unseparated colors might sublime during the fiber regeneration process and pollute the working environment. More seriously, final color quality of regenerated fibers is uncontrollable. Technologies for complete color removal from waste textiles either by dye-destruction or extraction have major challenges impeding their industrialization. Dye-destruction damages polymers, changes dyeability of regenerated textiles, and pollutes the environment. Since the differences in solubility parameters between polymers and dyes are large, and dye extractions focuses on finding solvents with high dye solubility, dye-extraction fails to remove all dyes from textiles. Finding solvents is almost impossible to lower the chemical potential of dyes in solutions than that in fibers where dyes are accessible, and polymers are tightly arranged. Lessening fiber density substantially disrupts physical interactions between dyes and fibers, and thus raises chemical potential of dyes in all parts of fibers higher than that in solutions, although reducing fiber density might increase the chemical potential of dyes in solvents. Here we demonstrate that minimization of fiber density by solvents and temperatures completely removes disperse dyes, acid dyes and direct dyes from polyethylene terephthalate, nylon and cotton fibers, respectively. The chemical structures of dyes and average molecular weight polymers did not change after dye removal.

Study of Third-order Nonlinear Optical Properties of Basic Violet 3 Dye in Polar Protic and Aprotic Solvents.

The present work aims to study of third-order nonlinear optical (TONLO) behavior of basic violet 3 dye dissolved in polar protic and aprotic solvents, namely, ethanol, 1-propanol, acetone and dimethyl sulfonate (DMSO), respectively. The polarity of the solvent used to have a substantial impact on the linear and TONLO properties of the dye sample. The dye exhibits self-defocusing nonlinearity due to thermally induced nonlinear refractive index and nonlinear absorption coefficient reveals the character of both saturable and reverse saturable absorption (RSA). The order of magnitude of nonlinear refractive index (n2) and nonlinear coefficient of absorption (β) of dye sample was determined to be 10-7 cm2/W and 10-3cm/W, respectively. The real and imaginary factors of the TONLO susceptibility of basic violet 3 dye were measured to be the power of 10-5 esu. The obtained results reveal that the dye sample seems to have the potential candidate for use in various photonics and optoelectronics applications.

Waterless leather dyeing with dense carbon dioxide as solvent for dyes

Conventional leather dyeing consumes high amounts of dyes and increases pollution of tannery wastewater. We have focused on the reduction of dyestuff and the avoidance of water and additional chemicals for the colorization of leather. Waterless leather dyeing with supercritical CO2 as solvent for the dye 1-(methylamino)anthraquinone was performed in a technical scale autoclave. The intensity and uniformity of the dyed leathers was assessed using spectroscopic color measurements. The rub fastness was assessed according to DIN EN ISO 11640. In the result, waterless dyeing at 100 bar and 40 °C leads to uniform, intensive colorizations of the leather surface at a usage of 0.1 g of dye per square foot of leather. The dyed leathers achieve the highest rub fastness grades. The exhaustion of dyestuff is almost 100%. The waterless dyeing process offers potential to save significant amounts of dyestuff and reduce wastewater emissions by 100%.

Study of the Effect of Solvent Polarity on Transitions of Absorption and Fluorescence Spectrum of a Erythrosine Dye

In this paper, the absorption and fluorescence spectra of Erythrosine dye laser liquid solution dissolved with acetone and ethanol solution were studied in different concentrations (10-3, 10-4, 10-4 M). The results showed an increase in absorption and fluorescence intensity by increasing polarity of the solvent. Some of the linear optical properties of the prepared models were also studied. The results showed an increase in the absorbance, linear refractive index, and linear absorption coefficient with an increase in solvent polarity and the molar concentration against a decrease in the permeability value, as well as the quantitative production efficiency was calculated based on the results of the absorption spectra and fluoridation. The Purpose of the search Study the effect of solvent polarity on both absorption and fluorescence spectra, and on linear and electrical optical properties. Keywords: Erythrosine Laser dye, absorption, fluorescence spectra and Polar solvents (acetone and ethanol).

Effect of temperature and composition of mixed solvent media on the interaction of bromocresol Green dye with cetylpyridinium chloride

The study of dye-surfactant interaction is very important in achieving an optimal dyeing process in textile industries. Conductivity measurements of the cationic surfactant cetylpyridinium chloride (CPC) in the presence of bromocresol green dye (BCG) in various solvents were performed, in order to provide insight into the interaction between BCG and CPC. Three critical micelle concentrations (cmc) were observed over the studied CPC concentration range. The observed cmc values of the BCG + CPC system were found to change significantly as a function of BCG concentration. The cmc values of the BCG + CPC system showed U-shaped variation, with increasing temperature in aqueous and propanol media, while decreasing monotonically in ethanol media. The concentration of additives (ethanol, propanol, and propylene glycol) also affected the cmc values significantly. The values of counterion binding (β) were also found to be dependent on the temperature and concentration of additives. Different thermodynamic parameters, e.g. Gibbs free energy (), enthalpy (), and entropy () changes, as well as their transfer properties associated with micellization of the BCG + CPC system, were determined. The ΔH o m and ΔS o m values reveal the presence of hydrophobic, ion-dipole, or dipole-diploe interactions amongst employed constituents.

Reactive dyeing of synthetic fibers employing dyes containing a diazirine moiety

It is well-known that polypropylene (PP) or aramid fibers are challenging to dye by using conventional dyeing methods, which limits their further development in the textile and garment industry. Herein, we report a new methodology for deep dyeing synthetic fibers employing synthesized diazirine-containing dyestuffs. The combination of the diazirine moiety with a chromophore with heating at 150 °C produced the dye-forming carbene intermediate, which could covalently bond with the C–H bonds in the synthetic fibers. It was demonstrated that the diazirine dyes did not pose any explosive risk, although nitrogen molecules were generated along with the formation of carbene. Compared with the high-temperature–high-pressure dyeing and carrier dyeing-fixation methods, the non-aqueous solvent dyeing–fixation method was screened and certified to be suitable for the reactive dyeing of synthetic fibers. The diazirine-based dyes could efficiently react with poly (ethyleneterephthalate), nylon, PP, aramid, acrylic, and polyurethane (spandex) fibers with moderate to excellent fixation values. Particularly, the color yields of the PP, aramid, and acrylic fabrics were further improved significantly by repeating the non-aqueous solvent dyeing–fixation operation. Thereafter, the detailed dyeing and fixing mechanisms of the reactive dyeing method were proposed. Finally, the color fastness properties of these dyed fabrics were demonstrated to be excellent, thus making such a reactive dyeing method for synthetic fibers a very promising one for the future.

Effect of polar protic solvents on the photophysical properties of bis(BODIPY) dyes

In this paper, detailed comparative analysis of the spectral properties of bis(BODIPY) dyes in various organic solvents: saturated aromatic hydrocarbons, homologous series of alcohols (CnOH, n = 2–4, 8, 10) and mixture of ethanol-glycerol with different viscosity was carried out. In bis(BODIPY) dimeric molecules, the BODIPY chromophore domains are linked by a methylene spacer at the 2,2-, 2,3-, or 3,3-positions (1, 2, and 3 respectively). The absorption spectra of the bis(BODIPY)s exhibit exciton splitting of band maxima. We showed that bis(BODIPY)s are sensitive to the polarity and acidity of media due to its structural features. The mechanism of fluorescence quenching of 1–3 in the series of alcohols are explained in detail. It has been established that the fluorescence quenching efficiency of dimeric dyes in alcohols is determined by both universal and specific interactions. The fluorescence quantum yield of bis(BODIPY)s is minimal in ethanol and increases in the alcohols homologous series due to a reduction in medium polarity and the stability of the bis(BODIPY)(Solv)2 supramolecular structures. In viscous ethanol-glycerol mixtures, fluorescence of 1–3 increases because of the limitation of the dye molecules conformational mobility. The results of the study allow us to predict the possibility of practical application of 1–3 as alcohols fluorescent sensors in various media.

Dyeing Para-Aramid Textiles Pretreated with Soybean Oil and Nonthermal Plasma Using Cationic Dye.

The increasing use of functional aramids in a wide array of applications and the inert nature of aramids against conventional dye and print methods requires developing new dyeing methods. This study aims to use environmentally friendly method with a cationic dye as an alternative for dyeing para-aramid fabrics. Experiments used a multi-factorial design with functions of pretreatment, dye solvent (water and/or glycerol) and auxiliary chemical additives (swelling agent and surfactant) and a sequential experimentation methodology. The most effective dyeing procedures involved the following steps: (i) pretreatments of the fabrics with soybean oil and nonthermal plasma (NTP), (ii) using water at T = 100 °C as the dye solvent, and (iii) omitting other chemical additives. With a commercial cationic dye, these conditions achieved a color strength in K/S value of 2.28, compared to ~1 for untreated samples. FTIR analysis revealed that a functional network formed on the fibers and yarns of the fabrics by chemical reactions of excited plasma species with double bonds in the soybean oil molecules was responsible for significantly improving the color strength. These results extend the potential uses of a renewable material (soybean oil) and an environmentally friendly technology (NTP) to improve the dyeing of para-aramid textiles and reduce the use of harsh dye chemicals.

Green preparation of thermal and solvent resistant poly (tetrafluoroethylene‐co‐perfluoropropylvinyl ether) hollow fiber membrane for organic solvent recycling

AbstractSo far, the organic solvent recycling still has great challenges. Herein, the thermal and solvent resistant poly (tetrafluoroethylene‐co‐perfluoropropylvinyl ether) (PFA) hollow fiber membranes (TS‐PFA HFMs) were continuously designed by on‐line compound technique for organic solvent recycling. The experiment results indicated that the increased sintering temperature brought about the porous surface and loose internal cavity structures. Importantly, the membrane exhibited the excellent thermal resistance at 70°C working condition. Furthermore, part of the poly (vinyl alcohol) was retained in the membrane which was competent to create synergistic effects, and endowed the membrane with not only favorable elasticity but also remarkable hot water resistance. Finally, the excellent organic solvent recycling ability of the membrane was demonstrated in simulated non‐aqueous solvent dyeing system. Specifically, no organic solvents or other hazardous substances were used during the fabrication process, which can realize the green preparation of the membrane.

Novel (Phenothiazinyl)Vinyl-Pyridinium Dyes and Their Potential Applications as Cellular Staining Agents.

We report here the synthesis and structural characterization of novel cationic (phenothiazinyl)vinyl-pyridinium (PVP) dyes, together with optical (absorption/emission) properties and their potential applicability as fluorescent labels. Convective heating, ultrasound irradiation and mechanochemical synthesis were considered as alternative synthetic methodologies proficient for overcoming drawbacks such as long reaction time, nonsatisfactory yields or solvent requirements in the synthesis of novel dye (E)-1-(3-chloropropyl)-4-(2-(10-methyl-10H-phenothiazin-3-yl)vinyl)pyridin-1-ium bromide 3d and its N-alkyl-2-methylpyridinium precursor 1c. The trans geometry of the newly synthesized (E)-4-(2-(7-bromo-10-ethyl-10H-phenothiazin-3-yl)vinyl)-1-methylpyridin-1-ium iodide 3b and (E)-1-methyl-4-(2-(10-methyl-10H-phenothiazin-3-yl)vinyl)pyridin-1-ium tetrafluoroborate 3a′ was confirmed by single crystal X-ray diffraction. A negative solvatochromism of the dyes in polar solvents was highlighted by UV-Vis spectroscopy and explanatory insights were supported by molecular modeling which suggested a better stabilization of the lowest unoccupied molecular orbitals (LUMO). The photostability of the dye 3b was investigated by irradiation at 365 nm in different solvents, while the steady-state and time-resolved fluorescence properties of dye 3b and 3a′ in solid state were evaluated under one-photon excitation at 485 nm. The in vitro cytotoxicity of the new PVP dyes on B16-F10 melanoma cells was evaluated by WST-1 assay, while their intracellular localization was assessed by epi-fluorescence conventional microscopy imaging as well as one- and two-photon excited confocal fluorescence lifetime imaging microscopy (FLIM). PVP dyes displayed low cytotoxicity, good internalization inside melanoma cells and intense fluorescence emission inside the B16-F10 murine melanoma cells, making them suitable staining agents for imaging applications.

Solvatochromic and pH Switch Properties of a D–π–A Dye with benzo[b]thiophene as Donor Moiety

A charge transfer dye with the D–[Formula: see text]–A structure was synthesized by Pd catalyzed Hartwig–Buchwald coupling and Knoevenagel condensation reaction, using N, N-dihexylbenzo[b]thiophen-6-amine as donor and 2-(3-cyano-4, 5, 5-trimethylfuran-2 (5H)-ylidene)malononitrile (TCF) as acceptor. The solvatochromic and pH switch properties of the as-synthesized dye were investigated through UV-vis absorption and fluorescence emission spectra. A positive solvatochromism of the dye in different polar solvents was observed along with a visible color change of the solution. By adding acid/base into the DMSO solution of the dye, the color as well as the absorption and emission spectra of the solution exhibited outstanding characteristics of pH switch.