Dye Complex Research Articles

In-Depth Photocatalytic Degradation Mechanism of the Extensively Used Dyes Malachite Green, Methylene Blue, Congo Red, and Rhodamine B via Covalent Organic Framework-Based Photocatalysts

Photocatalytic degradation technology has received much attention from researchers in the last few decades, due to its easy and cost-effective nature. A lot of review articles have been published on dyes via photocatalytic degradation, but most of the review articles lack a detailed and in-depth photocatalytic degradation mechanism of dyes. Numerous review articles are available on photocatalysis. Here, in this review article, we are mainly focused on the complete and in-depth photocatalytic degradation mechanism of four commonly used dyes such as Malachite Green, Methylene Blue, Congo Red and Rhodamine B, which will be highly useful for the new researchers that work on dyes’ photocatalytic degradation. Initially, various aspects of dyes have been included in this review article, comprehensively. The main focus was on the covalent organic framework-based photocatalysts for dyes’ photocatalytic degradation, due to their porous nature and various unique properties. Various synthesis routes and the photocatalytic performance of covalent organic frameworks and composite of covalent organic frameworks have been highlighted in this review article. In the last section of this review article, the main stimulus was the four mentioned dyes’ properties, uses, and toxicity, and the photocatalytic degradation mechanism through various paths into environmentally friendly and less-harmful compounds in the presence of photocatalysts. Factors effecting the photocatalytic degradation, economic cost, challenges and future aspects of photocatalytic technology were also included in this review article. This review article will be highly useful for those researchers that work on the photocatalytic degradation of various dyes and search for the complete degradation of complex dye molecules.

Study of reactive dyes and their hydrolyzed forms in a real trichromatic dyeing process by capillary electrophoresis with UV detection.

Detecting the concentration of reactive dyes and their hydrolyzed products is essential for controlling the dyeing process and is an important guide for upgrading and improving textile dyeing technology. In this study, capillary electrophoresis (CE) with UV detection was for the first time applied in a real trichromatic dyeing process to provide qualitative and quantitative determination of reactive dyes and their hydrolyzed forms. Here, three original reactive dyes (SES-Cl-red-195, SES-Cl-yellow-145, and SES-Cl-blue-194), their vinyl sulfone forms (VS-Cl-red-195, VS-Cl-yellow-145, and VS-Cl-blue-194), and complete hydrolyzed forms (HES-OH-red-195, HES-OH-yellow-145, and HES-OH-blue-194) could be baseline separated in our developed BGE comprised of 10.0 mol/L Na2B4O7, 15% (V/V) ACN at pH 8.50 that adjusted by 0.50 mol/L H3BO3. The LODs (S/N = 3) of nine analytes ranged from 0.3 to 1.3 mg/L, and high sensitivities were achieved with UV detection. The RSDs of peak area and migration time were in the ranges of 1.4-3.8% and 0.39-1.29%, which indicated the CE methods were reliable for studying different dye forms in complex dye baths, and for evaluating dyeing process quality. Thus, the percentage of dye-uptake in single and trichromatic combination dyes was calculated based on the concentration of the original and their vinyl sulfone and hydrolyzed forms, and the result was consistent with the traditional UV-Vis method.

Methylene blue (MB) removal from aqueous solution by alum; catalytic ozonation process

Textile wastewater is among the most polluted types of industrial waste. Wastewater treatment in the textile industry is notoriously difficult because of the use of complex chemicals and dyes in the textile production steps, and conventional methods are not enough to treat these. Textile wastewater, known for its high pollution levels, poses challenges for treatment due to complex chemicals and dyes. A comparative study was conducted on simple ozonation and catalytic ozonation (CO) using alum to degrade methylene blue (MB). The authors analyzed various factors like time, pH, catalyst loading and ozone dosages during the study. Results showed that catalytic activity in ozonation depends on pH and ozone flow. The maximum MB elimination was achieved at pH 6.6 and 200 V ozone flow. Scanning electron microscopy (SEM) was used to characterize the surface morphology of the catalyst, Fourier transform infrared spectroscopy (FTIR) was used to identify the important functional groups, and energy dispersive X-ray spectroscopy (EDS) was used to characterize the catalyst's elemental composition. Compared to simple ozonation, CO showed higher removal in the initial phase. Real textile wastewater analysis confirmed the effectiveness of alum catalysts in achieving significant removal of MB (87%) through this novel cost-efficient process.Graphical

Increase in the Two-Photon Absorption Cross Section of Styryl Dye in Supramolecular Complexes with Cucurbiturils

Increase in the Two-Photon Absorption Cross Section of Styryl Dye in Supramolecular Complexes with Cucurbiturils

PVDF-Halloysite-Ceria multifunctional membrane for one-step treatment to industrial effluent

Industrial wastewater, containing diverse pollutants like dyes and oils, poses detrimental environmental challenges. Membrane technology addresses this complexity well but requires tailored nanofiller modifications that enhance hydrophilicity, oleophobicity, and antifouling potential for efficient separation. In this context, our work focuses on the development of mixed matrix membranes (PV-H-C) – PVDF, halloysite nanotubes (HNTs), and ceria nanoparticles – for effective dye and oil-water emulsion separation, enabling high flux recovery. The tubular structure of HNTs, with a lumen, enables the encapsulation and controlled distribution of ceria nanoparticles, preventing their agglomeration and leading to more uniform dispersion within the membrane matrix. HNTs porous structure, high surface area, and numerous adsorption sites within its nanotubes excel in rapid dye adsorption and ceria’s inherent hydrophobic properties along with low surface energy, forms a barrier against oil adhesion and spreading. Optimal results were achieved by loading 2% HNT and 1% ceria in the PVDF matrix, ensuring improved membrane performance. HNTs enhanced hydrophilicity and achieved pure water permeate flux of 1698 L/m2.h.bar. Developed membranes are super-oleophobic with an underwater contact angle of 132° + 3° and show a 100% increase in dyes and oils separation efficiency as compared to the pristine PVDF membranes. This unique integration of ceria with halloysite nanotubes in PV-H-C membranes is pivotal, bestowing exceptional anti-fouling characteristics and reusability, while providing a one-step, comprehensive solution for the effective treatment of complex industrial wastewater that encompasses both oil and complex dyes.

A synergistic polyelectrolytes-Zr-MOF hydrated construction graphene oxide nanofiltration with enhanced dye wastewater remediation

In recent years, developing an efficient nanofiltration membrane had been a thorny challenge for dye/salt wastewater purification. In this study, a novel graphene oxide-based nanofiltration membrane (GO/UiO@S-GO-8) was constructed by intercalating the synergistic polyelectrolytes-Zr-MOF hydrated construction (UiO@S-GO) into GO nanosheets. Here, combining the hydrophilic high-density anionic sulfonic groups (SO3-) with cationic amino groups (-NH2), GO-based nanofiltration membrane demonstrated outstanding separation ability, anti-pollution performance and structure stability. Compared to pure GO membrane, benefiting by effective expansion of graphene layer spacing from intercalation effect of UiO@S-GO, the water permeance of GO/UiO@S-GO-8 membrane increased to 8 times (about 66.3 ± 1.5 L m−2 h−1 bar−1). Importantly, the permeances of various dyes wastewater also reached up to 65.1 ± 1.8 L m−2 h−1 bar−1 at the high removal rate (exceeding 99.4%). Furthermore, strong hydratability of polyelectrolytes and hard porous crystal constructed the robust anti-fouling micro/nano rough structures onto the membrane surface, which made flux recovery rate (FRR) of GO/UiO@S-GO-8 enhanced to 96.7 ± 1.3%. Remarkably, the salt-resistant behavior of the polyelectrolytes and porous MOF could maintain the stability of the membrane filtration channels, the GO/UiO@S-GO-8 membrane could realize efficient removal rate of dyes (over 98%) faced the complex dye wastewater with different salt concentrations. Meanwhile, the GO/UiO@S-GO-8 membrane also could maintain the high permeance (46.7 ± 1.5 L m−2 h−1 bar−1) as well as excellent removal rate (97.2 ± 1.4%) after 10 cycle experiments. Hence, the GO/UiO@S-GO-8 nanofiltration membrane with Polyelectrolytes-Zr-MOF hydrated construction possessed a broad application inspiration in the purification of high-salt/dye wastewater.

Temperature effects and molecular insights towards the optimization of polyvinyl alcohol as adsorbent of organic pollutants from aqueous solution

One of the easier methods of wastewater treatment is adsorption due to its simplicity in implementation, environmental friendliness, and economic feasibility. Polyvinyl alcohol (PVA) looks promising as an adsorbent due to its biocompatible, non-toxic, water-soluble and eco-friendly nature. The investigation of PVA for its potential in the adsorption of pollutants has been reported in many studies but the mechanistic understanding of the adsorption is poor. The present study used a theoretical approach through density functional theory and Monte Carlo with molecular dynamics simulations to investigate the adsorption mechanism behaviors of model organic molecules (bromothymol blue (BTB), methylene blue (MB), metronidazole (MNZ) and tetracycline (TC)) on PVA surface. The quantum chemical calculations result showed that with the increase in PVA chains (2, 4, 8, 16, and 32 units), the zero-point energy decreases (from −308.79 to −4922.93 kcal/mol) while the dipole moment increases (from 4.37 to 87.52 Debye). Temperature effect on the PVA chain structures showed the same trends for all the chain units and with the increase in temperature (50–600 K), there are no appreciable changes in zero-point energy, enthalpy energy increases while Gibbs free energy decreases. Considering PVA-pollutant complexes, the effects of temperature on the structures showed that there are no appreciable changes in the zero-point energy, Gibbs free and thermal energies increase with an increase in temperature while the kinetic rate of reactions decreases with an increase in temperature. The enthalpy of the reaction showed different trends with antibiotic and dye complexes. In all the thermodynamic properties investigated and the rate of reaction, the order of affinity of the pollutants with PVA followed TC > MNZ > MB > BTB. Monte Carlo simulation was used to investigate the adsorption behavior of the pollutants on the surface of PVA. The negative adsorption energies (−366.56 to −2266.81 kcal/mol) in terms of affinity towards the pollutants on the surface of PVA followed the sequence TC > MNZ > BTB > MB and the molecular dynamic simulation results followed the same order. The obtained results give valuable insights into the mechanism and performance of PVA as an adsorbent. Most of these computational observations are in good agreement with the available experimental results.

Dyeing of Cotton and Wool Fibers with the Aqueous Extract of Alnus glutinosa: Evaluation of Their Ultraviolet Protection Factor, Their Color fastness and the Antioxidant Activity of the Aqueous Extract

The aim of the present study is to evaluate the dyeing properties and behavior of the aqueous extract of Alnus glutinosa leaves when applied on cotton and wool fibers. The antioxidant activity and the total phenolic content of the aqueous extract were calculated. The colorfastness of the dyed samples such as washing, acid and alkali perspiration, wet and dry fastness and light fastness was performed. The ultraviolet protection factor (UPF) which is a measurement of the protection offered by the dyed fabric substrates against ultraviolet radiation was also assessed. It was found that Alnus glutinosa aqueous extract shows exceptionally high antioxidant activity and high phenolic content. The dyed samples showed astonishingly high light fastness approaching the light fastness of synthetic dyes such as the vat dyes or metal complex dyes. The conferred protection of the dyed samples against the distractive ultraviolet radiation is exceptionally high as this is demonstrated by the high UPF measurements of the dyed samples.

Comparison of electrochemical advanced oxidation processes for the treatment of complex synthetic dye mixtures

Many industries use complex synthetic organic dye mixtures in their dyeing processes, producing wastewater effluents with complex dye mixtures. In this study, electrochemical advanced oxidation processes like electrochemical oxidation (ECO), ECO with electrogenerated H2O2 (ECO-H2O2), electro-Fenton (EF), and photo electro-Fenton (PEF) with UVC irradiation were compared to discolor and mineralize a mixture of Methyl Orange, Methyl Red, and Toluidine Blue O with a boron-doped diamond anode and a gas-diffusion cathode. While ECO and ECO-H2O2 required long times to achieve a complete discoloration, the dyes were quickly degraded by EF and PEF due to the oxidation with ∙OH formed from Fenton’s reaction. Almost complete mineralization was rapidly achieved by PEF for a solution with 424 mg O2 L−1 of chemical oxygen demand (COD) at a current density of 66.6 mA cm−2 due to the synergistic action of the UVC irradiation. Additionally, the treated effluent was evaluated using the DFZ (Deutsche Farb Zah) parameter for water condition, offering a new perspective and distinguishing this work from previous studies focused on electrified technologies for dye removal. The same behavior has been found for the mixture of such dyes in an industrial effluent upon PEF treatment, even showing faster discoloration and COD reduction as result of the additional removal with active chlorine formed from Cl− oxidation. Ion-exclusion HPLC analysis of the treated synthetic effluent revealed the formation of final carboxylic acids like malic, acetic, oxalic, and formic. Released nitrate, ammonia, and nitrite were detected as nitrogenated by-products from the initial N of the dyes.

Boosting piezo-photocatalytic activity in CuBi2O4/NaNbO3 by coupling it with PVDF for organic pollutant degradation

This work reports a piezo-photocatalytic film, which is easily synthesised and retrievable from water with an environmentally friendly composition exhibiting higher reaction kinetics for degradation of dye using polyvinylidene-fluoride (PVDF), copper bismuth oxide (CuBi2O4) and sodium niobate (NaNbO3). XRD confirmed the structure of CuBi2O4 and NaNbO3, and FTIR was used to confirm β-PVDF, while HR-SEM was used to study morphology. The prepared film displays excellent stability in piezo-photocatalytic conditions. It degrades rhodamine B (RhB) with 98 % efficiency within 30 min in piezo-photocatalysis mode and 113 times faster than CuBi2O4/NaNbO3. This enhanced performance is due to the synergistic piezocatalytic effect of PVDF and NaNbO3. Further, to understand the catalytic nature of the ultrasonic-induced piezo-photocatalytic effect for dye degradation, scavenger studies were performed to identify the radicals generation. Reusability tests revealed no loss in efficiency for five consecutive runs. The strategy outlined here can be used to treat industrial effluents containing various complex dyes.

Enzymatic coloration of polyamide fabrics and its comparison with conventional dyeing

AbstractAmong the textile wet processes, the colouring process is the process step that causes the most environmental pollution. New approaches that support sustainable production instead of environmentally harmful processes are extensively researched in the literature. When considering substitution of chemical processes with environmentally friendly methods, one of the issues that comes to mind is enzymatic processes. It is noteworthy that in recent years, interesting and promising studies on the use of laccase enzymes in textile dyeing have been published in the literature. However, studies on enzymatic colouring are still very limited and sufficient success has not been achieved especially on polyamide. The aim of this study is to develop an environmentally friendly enzymatic dyeing method, which can be an alternative to dyeing polyamide knitted fabrics with 1:2 metal complex dyes according to the exhaustion method. For this purpose, various phenol and amine compounds, and their mixtures were used as precursor, and the colours that can be obtained by enzymatic colouring have been determined. In addition, optimisation of enzymatic colouring conditions (enzyme concentration, temperature and time) was carried out for the precursors that gave the best results in terms of colour and fastness. Furthermore, enzymatic dyeing was compared with conventional 1:2 metal complex dyeing in terms of technical and economic aspects. The reaction pathways in enzymatic coloration with laccase enzyme by using various precursors were also explained by Fourier‐transform infrared (FTIR) analysis.

Unraveling the formation of enhanced long-term durability chromate-phosphate conversion coatings with a Cr(III) complex dye

The role of additives in surface treatments is pivotal for enhancing the functionality and performance of coatings. While the impact of additives on the functionality and performance of various types of coatings has been mechanistically investigated, the specific influence of additives on the durability of chromate-phosphate conversion coatings remains less understood. This study introduces a novel Cr(III) complex dye, which significantly improves the long-term durability of such coatings. Through comprehensive experimentation, it is demonstrated that the application of this dye markedly influences the morphology, chemical composition, element distribution, and modulus of the conversion film, with negligible effects on the film thickness. The paramount effectiveness of the dye is predominantly realized through the mitigation of bound water in the conversion film and the formation of a more stable structure via interaction with phosphate ions. This work contributes to the nuanced understanding of additive-coating interactions, highlighting the potential of specific chemical agents in advancing the durability of protective coatings.

Qualitative and Quantitative Analysis of Siderophore Production from Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) is known for its production of a diverse range of virulence factors to establish infections in the host. One such mechanism is the scavenging of iron through siderophore production. P. aeruginosa produces two different siderophores: pyochelin, which has lower iron-chelating affinity, and pyoverdine, which has higher iron-chelating affinity. This report demonstrates that pyoverdine can be directly quantified from bacterial supernatants, while pyochelin needs to be extracted from supernatants before quantification. The primary method for qualitatively analyzing siderophore production is the Chrome Azurol Sulfonate (CAS) agar plate assay. In this assay, the release of CAS dye from the Fe3+-Dye complex leads to a color change from blue to orange, indicating siderophore production. For the quantification of total siderophores, bacterial supernatants were mixed in equal proportions with CAS dye in a microtiter plate, followed by spectrophotometric analysis at 630 nm. Pyoverdine was directly quantified from the bacterial supernatant by mixing it in equal proportions with 50 mM Tris-HCl, followed by spectrophotometric analysis. A peak at 380 nm confirmed the presence of pyoverdine. As for Pyochelin, direct quantification from the bacterial supernatant was not possible, so it had to be extracted first. Subsequent spectrophotometric analysis revealed the presence of pyochelin, with a peak at 313 nm.

Design and Exploration by Quantum Chemical Analysis of Photosensitizers Having [D-π-π-A]- and [D-D-triad-A]-Type Molecular Structure Models for DSSC.

Density functional theory (DFT) calculations are performed on the newly developed and designed photosensitizers having [D-D-triad-A]- and [D-π-π-A]-type structural models for near-infrared absorption dye-sensitized solar cells (DSSCs). For this purpose, three novel molecules are designed, which are named as follows: [naphthalene-anthracene-thiophene-furan-benzonitrile] as dye S1, [coronene-anthracene-thiophene-furan-benzonitrile] as dye S2, and [fluorene-thiophene-furan-benzonitrile] as dye S3. In all three systems, benzonitrile is the acceptor moiety, while thiophene and furan are bridging moieties. Naphthalene and anthracene are donor moieties in S1, whereas coronene and anthracene are donor moieties in S2, and fluorene is the only single donor moiety used for designing the dye complex S3. All three dye complexes are optimized under the DFT framework by using the B3LYP hybrid functional with 6-31G(d,p) basis set on Gaussian 16W software. The absorption spectra are calculated utilizing time-dependent density functional theory (TD-DFT) with the CAM-B3LYP/6-31G(d,p) basis set. The calculated absorption maxima of S1 and S2 are 749.45 and 750.04 nm, respectively, while for S3, it is reported to be at 337.35 nm, which suggests that the designed molecular structure having a double-donor moiety is suitable for high absorption wavelength. Further, the analysis of frontier molecular orbital energy gap suggests that the molecular systems S1, S2, and S3 have values 2.17, 2.13, and 3.618 eV, respectively, which lie in the semiconducting region. The other parameters calculated for the photovoltaic performance are exciton binding energy, change in free energy of charge regeneration, change in free energy of charge injection, oscillator strength, light harvesting efficiency, and open-circuit voltage.

Bioinformatics analysis and molecular dynamics simulations of azoreductases (AzrBmH2) from Bacillus megaterium H2 for the decolorization of commercial dyes

The present study aimed to investigate the decolorization of various commercial dyes by azoreductases (AzrBmH21, AzrBmH22/3, and AzrBmH24/5) through bioinformatics means, comprising molecular docking, molecular dynamics simulation, and molecular mechanics Poisson–Boltzmann surface area (MM-PBSA). Therefore, four commercial dyes, namely acid orange 7, cresol red, methylene blue, and malachite green, were selected as potential targets for degradation by the above said azoreductases derived from Bacillus megaterium H2. The prediction of ligand binding or catalytic sites for AzrBmH21, AzrBmH22/3, and AzrBmH24/5 were performed using a machine learning algorithm based on the Prank Web and DeepSite chemoinformatic tool. This analysis revealed that several amino acids of AzrBmH2 interacted with the tested dyes, indicating the presence of distinct ligand-binding sites for AzrBmH2-dye complexes. Likewise, the binding affinity for AzrBmH21, AzrBmH22/3, and AzrBmH24/5 ranged from − 9.4 to − 5.5 kcal/mol, − 9.2 to − 5.4 kcal/mol, and − 9.0 to − 5.4 kcal/mol, respectively, with each complex stabilized at a minimum of 0–5 hydrogen bonds. MD simulations revealed stable AzrBmH2-dye complexes with RMSD and RMSF values ranging from 0.15 to 0.42 nm and 0.05 to 0.48 nm, respectively, with Rg values between 1.75 and 1.88 nm. MM-PBSA calculations indicated that the AzrBmH2–dye complexes, except for AzrBmH2–malachite green, exhibited the lowest binding energy (− 191.05 ± 7.08 to 314.19 ± 6.88 kcal/mol), with prevalent hydrophobic interactions (− 268.25 ± 12.25 to − 418.92 ± 29.45 kcal/mol) through van der Waals forces. Therefore, this study was able to highlight the potential role of enzymes, specifically azoreductases from Bacillus megaterium H2, in predicting the decolorization of commercial dyes. These findings could contribute to our understanding of the azoreductases’ mechanisms in bioremediation and for biotechnological applications.

Facile Preparation of TICT@MOF Solids with Unprecedented PL Quantum Yields

AbstractLuminescent solids exhibit unique optical and electronic properties, and it is important to develop a simple experimental procedure to reduce the mass of weakly emissive hybrid inorganic–organic solids. The instant mixing of (1‐cyano‐2‐[α‐terthiophen‐2‐yl]‐vinyl)carboxylic acid (3TCC) and a metal–organic framework (MOF‐177; ZnO4(BTB)2; BTB = 1,3,5‐benzenetribenzoate) in an organic solvent, followed by evaporation of the solvent, produces solids with distinct photoluminescence (PL) properties, turning over the PL quantum yields (PLQY) of the generated 3TCC@MOF‐177 solids by 2‐ to 40‐fold compared to the 3TCC solution is demonstrated. The new solids are characterized by various methods and optical measurements. Contrarily to the trend in the photophysical results of 3TCC solutions, the anisotropic rotational times of 3TCC@MOF‐177 solids inversely correlate with the corresponding PLQY values depending on the protic solvent used in the initial preparation step in the following order: methanol>ethanol>butanol. This behavior is attributed to the complexation of 3TCC dye with metal clusters within the pores of MOF‐177 and hydrogen bonding of the CN group in the dye with the OH group in the linkers. These factors interplay with the kinetics of dye twisting. These observations reflect the potential of new solid luminescent architectures with remarkable PLQY that can be easily manufactured.

Host-Guest Chemosensor Ensembles based on Water-Soluble Sulfonated Calix[n]arenes and a Pyranoflavylium Dye for the Optical Detection of Biogenic Amines.

Biogenic amines (BAs) are biologically active nitrogen-containing compounds formed during the food spoilage process and are often related as key markers of food quality, safety, and freshness. Because their presence in foods at high levels can cause significant health problems, researchers have been focused on developing novel strategies and methods for early detection and capture of these analytes. Herein, water-soluble sulfonated calix[n]arene macrocycles (SC4, SC6, and SC8) and a pH-sensitive dye (4'-hydroxy-10-methylpyranoflavylium) were investigated as host-guest systems for BA sensing. The hosts were able to bind the flavylium cation of the dye with association constants of 103 to 104 M-1. The dye complexation also allowed tuning its pKa from 6.72 (free) toward high values: 7.68 (SC4), 7.79 (SC6), and 8.45 (SC8). These data were crucial to optimize the host-guest complexes as optical sensing systems for putrescine/tyramine (pH 7.2-7.6), yielding a colorimetric redshift from yellow to red. The BA sensing was also demonstrated by fluorescence quenching for the calix[n]arene/dye complexes and fluorescence recovery after the addition of BAs. 1H NMR spectroscopy was used to demonstrate the interaction mode, confirming an encapsulation-driven mechanism. Overall, these host-guest systems demonstrated great potential for the detection of BAs, one of the main key markers of food spoilage.

Enhancing Near-Infrared Absorption in Terpyridyl Ru/Os Complexes with Ancillary Ligands to Activate Spin-Forbidden Transitions in Dye-Sensitized Solar Cells: A TDDFT Investigation.

Dye sensitizers with wideband absorption covering the near-IR region have long been of interest because they potentially harvest a wide range of solar energies essential to promote photocurrent power conversion efficiencies. In this study, we used time-dependent density functional theory with spin-orbit (SO) interactions to theoretically explore the long-wavelength absorptions and spin-forbidden triplet transitions activated by SO interactions for terpyridyl ruthenium/osmium complex dyes. These dyes feature a Ru(II) sensitizer coordinated with a phosphine ligand and are exemplified by DX1, denoted as [trans-dichloro-(phenyldimethoxyphosphine)(2,2';6',2″-terpyridyl-4,4',4″-tricarboxylic)Ru]. We found that ancillary ligands significantly affected the longest wavelength spin-allowed absorption, with NCS- ligands yielding longer wavelength S1 transitions than halides. High atomic number halide ligands caused blue shifts in the S1 transition. Os complexes consistently exhibited longer wavelength S1 transitions than Ru complexes with identical ligands. In Ru/Os complexes, ancillary ligands with higher atomic numbers have a more pronounced effect in activating spin-forbidden triplet transitions through spin-orbit coupling (SOC) than those with lower atomic numbers. The absorption wavelength of the SOC-activated transition primarily depended on the energy of lower lying triplet states. Some complexes exhibited T1 states activated by SOC, leading to longer wavelength absorption than that of SOC-activated T2 states. Our study revealed the significance of ancillary ligands and SOC interactions in Ru/Os complexes, offering insights for optimizing materials with enhanced long-wavelength absorption properties, particularly in the near-IR range, for photovoltaic and optoelectronic applications.

Spectroscopic and electrochemical characterizations of copper complexes with thionine, azure C and azure A

Structures held together by secondary interactions such as intramolecular or intermolecular hydrogen bonding, electrostatic and π–π interaction without covalent bonds can exhibit new properties such as high orientation, optoelectronics, biocompatibility and reversibility (self‐renewal). Recently, interest has been growing surrounding novel molecules fashioned through non‐covalent interactions. These molecules have garnered attention due to their significant roles in both physical and chemical applications. However, the formation of complexes between cationic phenothiazine derivative dyes, commonly employed in electrochemical studies, and diverse metal groups presents a challenge. Therefore, the existing literature contains only a scant number of studies concerning the formation of phenothiazine complexes with metal salts. In this study, metal complexes of thionine, azure C and azure A with copper(II) chloride were prepared using two steps: dissolving and then slow evaporation of dyes‐copper(II) chloride in acetonitrile. Besides the theoretical computations, thermal, spectral, electrochemical and fluorescence techniques were performed to determine the characteristics of the monoclinic crystals of Cu–dyes complexes. Cl− ion in the dyes and copper(II) chloride conjugated to form [CuCl3]−, then this anion electrostatically bound to cationic phenothiazine ring bond to be phenothiazine+[CuCl3]−. Cu–dye complexes showed interestingly high electron transportation. In addition, prepared Cu–dye complexes have a great potential to be used in optical and spectral applications with extraordinary behaviour of their spectral and fluorescence features.

The copolymerized sulfur coordination-metal complex dye sensitizer exhibiting the highest power conversion efficiency (PCE) 11.78% in dye sensitized solar cells

Polymeric metal complex dyes have been recognized as a significant class of dye sensitizer for optoelectronic applications due to their unique properties. In order to improve the light absorption and photovoltaic performance and to decrease costs, five novel D-A-π-A motif copolymerized sulfur coordination-metal complexes (BDTT-BBT-Ni, BDTT-BBT-Cu, BDTT-BBT-Zn, BDTT-BBT-Cd and BDTT-BBT-Hg) have been designed and synthesized for being used as dye sensitizer. And the photovolataic performance test results show that the highest PCE of the copolymer complex BDTT-BBT-Hg of five copolymers has reached 11.78% and the copolymer dye sensitizers are simple and inexpensive to synthesize and have good solubility. These results provide a new way to develop stable and efficient metal complexes with sulfur coordination dye sensitizers in the future.