Presence Of Molecular Oxygen Research Articles

Bioenergetic suppression by redox-active metabolites promotes antibiotic tolerance in Pseudomonas aeruginosa

The proton-motive force (PMF), consisting of a pH gradient and a membrane potential (ΔΨ) underpins many processes essential to bacterial growth and/or survival. Yet bacteria often enter a bioenergetically diminished state characterized by a low PMF. Consequently, they have increased tolerance for diverse stressors, including clinical antibiotics. Despite the ubiquity of low metabolic rates in the environment, the extent to which bacteria have agency over entry into such a low-bioenergetic state has received relatively little attention. Here, we tested the hypothesis that production of redox-active metabolites (RAMs) could drive such a physiological transition. Pseudomonas aeruginosa is an opportunistic pathogen that produces phenazines, model RAMs that are highly toxic in the presence of molecular oxygen (O2). Under oxic conditions, the phenazines pyocyanin and phenazine-1-carboximide, as well as toxoflavin-a RAM produced by Burkholderia species-suppress the ΔΨ in distinct ways across distributions of single cells, reduce the efficiency of proton pumping, and lower cellular adenosine-triphosphate (ATP) levels. In planktonic culture, the degree and rate by which each RAM lowers the ΔΨ correlates with the protection it confers against antibiotics that strongly impact cellular energy flux. This bioenergetic suppression requires the RAM's presence and corresponds to its cellular reduction rate and abiotic oxidation rate by O2; it can be reversed by increasing the ΔΨ with nigericin. RAMs similarly impact the bioenergetic state of cells in (hyp)oxic biofilm aggregates. Collectively, these findings demonstrate that bacteria can suppress their bioenergetic state by the production of endogenous toxins in a manner that bolsters stress resilience.

Porphyrinoid macrocycles as potential photosensitizers for photodynamic inhibition of biofilm formation in household water storage systems

AbstractThe issue of biofilm formation by microorganisms in household water storage systems is a problem that lowers the efficiency of disinfectants. Antimicrobial photodynamic inactivation (aPDI) is a potential alternative to the current water disinfection methods. It employs a photosensitizer agent that inactivates microbes by absorbing light of a specific wavelength in the presence of molecular oxygen. Although aPDI has been proven in literature to have a wide spectrum of action, effective against resistant microbes and biofilms, it has not been approved for real-life applications yet. Therefore, there is an ongoing search for ideal photosensitizers that can produce sufficient reactive oxygen species for efficient inactivation of microbes and disruption of biofilms in household water storage systems. This review summarises the developments that have been made so far with porphyrin-, expanded porphyrin-, corrole-, and boron dipyrromethene-based photosensitizers. First, the issues with the current water disinfection methods are described, and then aPDI is also described as a possible alternative to the current methods. Emphasis is put on the antimicrobial activities and the solid support materials that the porphyrinoid family members have been incorporated into for potential application in the disinfection of household water and limitation of biofilm formation in water storage systems.

Nrf2-Mediated Antioxidant Response and Drug Efflux Transporters Upregulation as Possible Mechanisms of Resistance in Photodynamic Therapy of Cancers.

Photodynamic therapy (PDT) is a groundbreaking approach involving the induction of cytotoxic reactive oxygen species (ROS) within tumors through visible light activation of photosensitizers (PS) in the presence of molecular oxygen. This innovative therapy has demonstrated success in treating various cancers. While PDT proves highly effective in most solid tumors, there are indications that certain cancers exhibit resistance, and some initially responsive cancers may develop intrinsic or acquired resistance to PDT. The molecular mechanisms underlying this resistance are not fully understood. Recent evidence suggests that, akin to other traditional cancer treatments, the activation of survival pathways, such as the KEAP1/Nrf2 signaling pathway, is emerging as an important mechanism of post-PDT resistance in many cancers. This article explores the dual role of Nrf2, highlighting evidence linking aberrant Nrf2 expression to treatment resistance across a range of cancers. Additionally, it delves into the specific role of Nrf2 in the context of photodynamic therapy for cancers, emphasizing evidence that suggests Nrf2-mediated upregulation of antioxidant responses and induction of drug efflux transporters are potential mechanisms of resistance to PDT in diverse cancer types. Therefore, understanding the specific role(s) of Nrf2 in PDT resistance may pave the way for the development of more effective cancer treatments using PDT.

Baeyer-Villiger oxidation of cyclohexanone catalyzed by bifunctional Mg2Fe layered double hydroxide

Mg2Fe layered double hydroxide was prepared by the coprecipitation method and was used as an efficient catalyst for the Baeyer–Villiger oxidation of cyclohexanone to caprolactone in the presence of molecular oxygen and benzaldehyde. The obtained catalyst was characterized by XRD, FTIR, SEM, TG, XPS, and Hammett indicator method. The effects of solvent, benzaldehyde dosage. reaction temperature, O2 flow rate, catalyst dosage, and reaction time on the reaction were examined. Mg2Fe-LDH catalyst shows good catalytic results in the catalytic process which could also selectively convert a variety of cyclic ketone derivatives to their corresponding lactone with high yields. A series of controlled experiments were conducted to reveal the reaction mechanism. The results imply that the catalyst is bifunctional, possessing both alkalinity and redox properties. The alkalinity of Mg2Fe-LDH catalyzes the oxygen transfer from perbenzoic acid to cyclohexanone, iron with its highest oxidation state could catalyze the autoxidation of benzaldehyde to perbenzoic acid. In addition, the catalysts can be reused at least five times without significant decrease in catalytic activity.

Aerobic mechanochemical reversible-deactivation radical polymerization

Polymer materials suffer mechano-oxidative deterioration or degradation in the presence of molecular oxygen and mechanical forces. In contrast, aerobic biological activities combined with mechanical stimulus promote tissue regeneration and repair in various organs. A synthetic approach in which molecular oxygen and mechanical energy synergistically initiate polymerization will afford similar robustness in polymeric materials. Herein, aerobic mechanochemical reversible-deactivation radical polymerization was developed by the design of an organic mechano-labile initiator which converts oxygen into activators in response to ball milling, enabling the reaction to proceed in the air with low-energy input, operative simplicity, and the avoidance of potentially harmful organic solvents. In addition, this approach not only complements the existing methods to access well-defined polymers but also has been successfully employed for the controlled polymerization of (meth)acrylates, styrenic monomers and solid acrylamides as well as the synthesis of polymer/perovskite hybrids without solvent at room temperature which are inaccessible by other means.

Molecular and Evolution In Silico Studies Unlock the h4-HPPD C-Terminal Tail Gating Mechanism

The enzyme 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) is involved in the catabolism of the amino acid tyrosine in organisms such as bacteria, plants, and animals. It catalyzes the conversion of 4-hydroxyphenylpyruvate to a homogenisate in the presence of molecular oxygen and Fe(II) as a cofactor. This enzyme represents a key step in the biosynthesis of important compounds, and its activity deficiency leads to severe, rare autosomal recessive disorders, like tyrosinemia type III and hawkinsinuria, for which no cure is currently available. The 4-HPPD C-terminal tail plays a crucial role in the enzyme catalysis/gating mechanism, ensuring the integrity of the active site for catalysis through fine regulation of the C-terminal tail conformation. However, despite growing interest in the 4-HPPD catalytic mechanism and structure, the gating mechanism remains unclear. Furthermore, the absence of the whole 3D structure makes the bioinformatic approach the only possible study to define the enzyme structure/molecular mechanism. Here, wild-type 4-HPPD and its mutants were deeply dissected by applying a comprehensive bioinformatics/evolution study, and we showed for the first time the entire molecular mechanism and regulation of the enzyme gating process, proposing the full-length 3D structure of human 4-HPPD and two novel key residues involved in the 4-HPPD C-terminal tail conformational change.

Cyclotriphosphazene‐Based Photocatalysts containing Orthogonal BODIPY Moieties for Chemical Transformations

AbstractMolecular organic photocatalysts developed for use in chemical transformation reactions have gained momentum in recent years. In this study, six new triplet photosensitizers were prepared to determine their photocatalyst capabilities and chemical transformation abilities. The chemical structures of the synthesized orthogonal BODIPYs and their cyclotriphosphazene derivatives were analyzed and then their photophysical characteristics including the UV‐Vis absorption spectra, fluorescence emission spectra, fluorescence quantum yields, were investigated. The quantitative singlet oxygen formation was determined by chemical trapping using DPBF (diphenylisobenzofuran). In particular, cyclotriphosphazene derivative 12 having three BODIPY moieties showed efficient singlet oxygen production with high photostability and good molar extinction coefficient. The photo‐oxidation ratio constant of 1,5‐dihydroxynaphthalene (DHN) was calculated as 28.7×10−3 min−1 for compound 12 and at the end of 22.5 min., DHN converted to juglone with 100 % efficiency. In addition, the ability of the compounds to convert 1,3‐cyclohexadiene into peroxides in the presence of molecular oxygen and light was investigated and the conversion efficiency was determined by NMR technique. All compounds have been presented as photocatalysts for use in different synthetic photochemistry applications.

Influence of dissolved oxygen in the environment on toxicity indices obtained by various bio-testing methods

RELEVANCE of the study comes from the understanding of the necessity of continuous development of toxicological analysis. Since The simplest organisms are used in toxicological analysis as bioindicators, the reactions of which to the presence of certain pollutants will always differ, the only way to assess the usefulness of a bioindicators as a tool is to study its behavior under specific tasks. Biondicators differ in their metabolic properties, in particular, in the ways of obtaining energy from the presence of molecular oxygen in the environment. However, it is assumed that the presence of different concentrations of oxygen in the environment affects the behavior of the simplest organisms, which, in its turn, can affect the results of toxicological analysis. Previously, this effect has not been studied. THE PURPOSE. The research of the effect of dissolved oxygen on toxicity indices obtained using of bacteria Escherichia coli (Migula) Castellani and Chalmers and ciliates Paramecium caudatum Ehrenberg, METHODS. Obtaining indices of toxicity is given with different concentrations of dissolved oxygen in the environment, which are distilled water and Bonaqua brand water, by the bioluminescent reaction of bacteria and chemotactic reaction of ciliates. RESULTS. With an increase in the concentration of dissolved oxygen in the environment, the bioluminescence of bacteria increases, therefore, the toxicity index decreases. No effect on ciliates is observed. CONCLUSION. It can be concluded that dissolved oxygen does not affect the biotest analysis using ciliates. When using bacteria as a test organism, an error occurs in the toxicity index.

Impact of PVC microplastics in photodynamic inactivation of Staphylococcus aureus and MRSA.

Photodynamic processes have found widespread application in therapies. These processes involve photosensitizers (PSs) that, when excited by specific light wavelengths and in the presence of molecular oxygen, generate reactive oxygen species (ROS), that target cells leading to inactivation. Photodynamic action has gained notable attention in environmental applications, particularly against pathogens and antibiotic-resistant bacteria (ARB) that pose a significant challenge to public health. However, environmental matrices frequently encompass additional contaminants and interferents, including microplastics (MPs), which are pollutants of current concern. Their presence in water and effluents has been extensively documented, highlighting their impact on conventional treatment methods, but this information remains scarce in the context of photodynamic inactivation (PDI) setups. Here, we described the effects of polyvinyl chloride (PVC) microparticles in PDI targeting Staphylococcus aureus and its methicillin-resistant strain (MRSA), using curcumin as a PS under blue light. The presence of PVC microparticles does not hinder ROS formation; however, depending on its concentration, it can impact bacterial inactivation. Our results underscore that PDI remains a potent method for reducing bacterial concentrations in water and wastewater containing ARB, even in highly contaminated scenarios with MPs.

Avoiding Oxygen Removal for Photochemical Reactions – towards Water as the Solvent

AbstractOxygen removing protocols have long been the standard approach to perform photoreactions. By encapsulating photosensitizers and reactants in tailored supramolecular assemblies, preservation of photoreactivity even in the presence of molecular oxygen can be observed. Herein, we showcase some of the solutions that could render time‐consuming oxygen removal redundant in photochemical synthesis. A focus has been dedicated to aqueous solutions of supramolecular assemblies as potential reaction media. They present an attractive solution possibly useful not only for synthetic photochemical transformations, but also for water purification, bio‐applications or biocatalysis. The included media are membranes, hydrogels, deep eutectic solvents and peptide assemblies.

Hypoxia Modulates Radiosensitivity and Response to Different Radiation Qualities in A549 Non-Small Cell Lung Cancer (NSCLC) Cells.

Hypoxia-induced radioresistance reduces the efficacy of radiotherapy for solid malignancies, including non-small cell lung cancer (NSCLC). Cellular hypoxia can confer radioresistance through cellular and tumor micro-environment adaptations. Until recently, studies evaluating radioresistance secondary to hypoxia were designed to maintain cellular hypoxia only before and during irradiation, while any handling of post-irradiated cells was carried out in standard oxic conditions due to the unavailability of hypoxia workstations. This limited the possibility of simulating in vivo or clinical conditions in vitro. The presence of molecular oxygen is more important for the radiotoxicity of low-linear energy transfer (LET) radiation (e.g., X-rays) than that of high-LET carbon (12C) ions. The mechanisms responsible for 12C ions' potential to overcome hypoxia-induced radioresistance are currently not fully understood. Therefore, the radioresistance of hypoxic A549 NSCLC cells following exposure to X-rays or 12C ions was investigated along with cell cycle progression and gene expression by maintaining hypoxia before, during and after irradiation. A549 cells were incubated under normoxia (20% O2) or hypoxia (1% O2) for 48 h and then irradiated with X-rays (200 kV) or 12C ions (35 MeV/n, LET ~75 keV/µm). Cell survival was evaluated using colony-forming ability (CFA) assays immediately or 24 h after irradiation (late plating). DNA double-strand breaks (DSBs) were analyzed using γH2AX immunofluorescence microscopy. Cell cycle progression was determined by flow cytometry of 4',6-diamidino-2-phenylindole-stained cells. The global transcription profile post-irradiation was evaluated by RNA sequencing. When hypoxia was maintained before, during and after irradiation, hypoxia-induced radioresistance was observed only in late plating CFA experiments. The killing efficiency of 12C ions was much higher than that of X-rays. Cell survival under hypoxia was affected more strongly by the timepoint of plating in the case of X-rays compared to 12C ions. Cell cycle arrest following irradiation under hypoxia was less pronounced but more prolonged. DSB induction and resolution following irradiation were not significantly different under normoxia and hypoxia. Gene expression response to irradiation primarily comprised cell cycle regulation for both radiation qualities and oxygen conditions. Several PI3K target genes involved in cell migration and cell motility were differentially upregulated in hypoxic cells. Hypoxia-induced radioresistance may be linked to altered cell cycle response to irradiation and PI3K-mediated changes in cell motility and migration in A549 cells rather than less DNA damage or faster repair.

Featuring long-lifetime deep-red emitting iridiumIII complexes with high colour purity: insights into the excited state dynamics from spectroscopic and theoretical perspectives.

The significant attention drawn to IrIII-complexes in recent years has boosted the development of new compounds with advantageous photophysical features. However, obtaining IrIII deep-red-emitting complexes with long lived excited state, high colour purity and high quantum yield (Φ) remains a challenging task. To address this issue, this study reports the synthesis and photophysical investigation of three novel zwitterionic complexes, [Ir(C^N)2bqdc] (C^N = ppy, phq, and bzq), with ppy = 2-phenylpyridine (Ir-pb), phq = 2-phenylquinoline (Ir-qb), bzq = benzo[h]quinoline (Ir-bb), and bqdc = potassium 2,2'-biquinoline-4,4'-dicarboxylate. These complexes exhibit high quantum yields and long emission lifetimes with high colour purity in the deep-red region. The structural characterisation carried out by usual spectroscopic measurements supports the proposed structures, while the photophysical study unveiled the high contribution of the 3MLCT state to the hybrid emitter state, as endorsed by theoretical investigations. The desired correspondence between the calculations and the experimental data set affirmed the accuracy of the theoretical analysis, which enabled us to establish a relationship between the ground-to-excited-state geometry distortion and the lifetime through the nonradiative decay (knr). Furthermore, these newly synthesized complexes exhibit quenching in the presence of molecular oxygen. In deoxygenated DMSO solution the knr values halve, increasing the quantum yields (34.0, 10.6, and 26.6%) and the lifetimes (1.13, 1.11, and 1.72 μs), while leading to quite pure deep-red emission - CIE coordinates: (0.67, 0.33), (0.60, 0.40;), (0.65, 0.35) for Ir-pb, Ir-qb, and Ir-bb, respectively. These complexes display considerable potential for a wide range of applications, such as photodynamic therapy, due to their attractive photophysical properties, and are among the deep-red-emitting complexes reported in the literature with longer lifetimes and higher Φ.

Gold standard assessment of immunogenic cell death induced by photodynamic therapy: From in vitro to tumor mouse models and anti-cancer vaccination strategies.

The discovery of the concept of immunogenic cell death (ICD) is a cornerstone in the development of novel anti-cancer immunotherapeutic approaches. Induction of the ICD pathway by specific anti-cancer therapeutic regimens can eliminate cancer cells by directly killing them during therapy and by activation of strong and specific anti-cancer immunity, leading to a long-lasting immunological memory that prevents cancer recurrence. ICD encompasses different forms of regulated cell death and can be triggered by many anti-cancer treatment modalities, including photodynamic therapy (PDT). PDT is a multistep procedure involving the accumulation of a light-sensitive dye known as a photosensitizer (PS) in tumor cells, followed by its activation by irradiation with a light of an appropriate wavelength. In the presence of molecular oxygen, the irradiated PS leads to the generation of cytotoxic reactive oxygen species, which can lead to ICD induction in the cancer cells. Here, we first describe in vitro methods to help optimize the PDT procedure for a specific PS. We also provide a collection of protocols and techniques for assessing ICD in vitro, including analysis of the emission of damage associated molecular patterns (DAMPs), efferocytosis, and the maturation and activation state of antigen presenting cells. Next, we describe in detail protocols for diverse tumor mouse models for assessing and characterizing ICD in vivo, such as murine tumor vaccination models. Finally, as an immunotherapeutic vaccine, we suggest using either PDT-induced dead cancer cells, preferably undergoing ICD, or dendritic cells loaded with lysates of PDT-induced cancer cells in a syngeneic orthotopic glioma model. Overall, this methodological article provides a quantitative, comprehensive set of validated tools that can be successfully used, with some adaptations, to identify, optimize and validate novel PSs in vitro and in vivo for the efficient induction of ICD during photodynamic treatment.

Fluorescent probe to quantify lipid-derived electrophiles in edible oils.

In the presence of molecular oxygen, edible oils can be oxidized to form a multitude of α,β-unsaturated carbonyl products collectively called 'lipid-derived electrophiles'. These molecules affect the taste of fat-containing foods but also act as electrophiles by covalently binding to protein amines/thiols and DNA nucleotides. The chemical modification of proteins by lipid-derived electrophiles appears to play an important role in human health, but the quantification of this diverse class of compounds remains a challenge. In this study, we describe a method capable of measuring the relative content of α,β-unsaturated carbonyls in food containing edible oils by using a "turn-on" fluorescent probe. The detection of electrophiles is based on a pre-fluorescent probe, 7-mercapto-4-methyl-coumarin (C-SH). The fluorescence of C-SH increases after nucleophilic addition to electrophilic lipid oxidation products. Since different lipid-derived electrophiles will react at a different rate with our fluorescent probe, we expressed the probe's response against a standard electrophile: trans-2-nonenal. In this assay, electrophiles which react more quickly will have a more dominant weight in the measurements carried out. Using this analytical technique, we can compare electrophilic content in French fries from several restaurants, and find they have lower amounts of lipid-derived electrophiles versus frozen fries baked at home. We also demonstrate that potato chips sealed in a reduced oxygen atmosphere will have a low 'electrophilic content' that increases over time, whereas chips in oxygen-permeable packaging initially have a higher 'electrophilic content' that does not increase as much over time. The relative ease of fluorescence measurements using microplate readers coupled with a simple oil extraction protocol should allow this method to quantify 'electrophilic content' in several food sources.

Copper-catalyzed intramolecular dearomative aza-Wacker reaction of indole.

Herein, we describe a copper-catalyzed intramolecular dearomative amination of indoles via a formal aza-Wacker reaction. This protocol provides an efficient method to access aza-polycyclic indoline molecules bearing exocyclic CC bonds in moderate to excellent yields in the presence of molecular oxygen as an oxidant. It is worth noting that indolin-3-ones are achieved when employing C3-non-substituted indoles as substrates.

Hydrogen peroxide preoxidation as a strategy for enhanced antimicrobial photodynamic action against methicillin-resistant Staphylococcus aureus.

Antimicrobial photodynamic treatment (aPDT) is a photooxidative process based on the excitation of a photosensitizer (PS) in the presence of molecular oxygen, under specific wavelengths of light. It is a promising method for advanced treatment of water and wastewater, particularly targeting disinfection challenges, such as antibiotic-resistant bacteria (ARB). Research in improved aPDT has been exploring new PS materials, and additives in general. Hydrogen peroxide (H2O2) a widely applied disinfectant, mostly in the food industry and clinical settings, present environmentally negligible residuals at the usually applied concentrations, making it friendly for the water and wastewater sectors. Here, we explored the effects of preoxidation with H2O2 followed by blue light-mediated (450 nm) aPDT using curcumin (a natural-based PS) against methicillin-resistant Staphylococcus aureus (MRSA). Results of the sequential treatment pointed to a slight hampering in aPDT efficiency at very low H2O2 concentrations, followed by an increasing cooperative effect up to a deleterious point (≥7 log10 inactivation in CFU mL-1), suggesting a synergistic interaction of preoxidation and aPDT. The increased performance in H2O2-pretreated aPDT encourages studies of optimal operational conditions for the assisted technology and describes potentials for using the described strategy to tackle the issue of ARB spread.

Graphitic Carbon Nitride Meets Molecular Oxygen: New Sustainable Photocatalytic Ways for the Oxidation of Organic Molecules

In recent years, organic chemists have taken a resolute step toward green photocatalytic synthesis. In this regard, the oxidation of organic compounds with molecular oxygen is one of the most important classes of transformations, as it increases molecular complexity while avoiding the use of toxic and harmful oxidants. To this aim, the development of new and efficient photocatalysts capable of driving valuable oxidative reactions in a sustainable manner is highly desirable. These novel photocatalytic systems need to be metal-free, easy-to-prepare, and potentially recyclable. Carbon nitride (CN) fulfils all these requirements because of its outstanding physicochemical properties, thus emerging as a promising heterogeneous photocatalytic platform. The growing popularity of this material is also substantiated by its fast and facile preparation from readily available and inexpensive molecular precursors. This Review aims at highlighting the recent advances in synthesis of carbon nitride-based materials and their applications in organic photocatalysis for the oxidation of organic molecules in presence of molecular oxygen. Lastly, forward-looking opportunities within this intriguing research field are mentioned.

The Internal Heavy Atom Effect on the Deactivation of Triplet States of Porphyrins in the Presence of Molecular Oxygen

The Internal Heavy Atom Effect on the Deactivation of Triplet States of Porphyrins in the Presence of Molecular Oxygen

An approach for the improved measurement of pyrolysis products

The composition of a fuel and the combustion environment are factors that impact pyrolysis processes. The pyrolysis of a natural polymer, timber, and the synthetic polymers, polymethylmethacrylate (PMMA) and polystyrene (PS), was performed at a constant mass loss rate (MLR) using a feedback control loop utilising the Fire Propagation Apparatus (FPA) under inert and oxidative environments. The controlled MLR (2 g s−1 m−2) enabled a representative means of monitoring emissions via a combination of spectroscopic techniques. Reported yields were calculated utilising adapted Fourier-transform infrared spectroscopy (FT-IR) data based upon the species detected via gas chromatography-mass spectrometry (GC-MS). The speciation offered by the GC-MS was used to adjust recorded FT-IR yields, facilitating an insight into the composition of pyrolysis emissions. The presence of molecular oxygen was not found to drastically influence the decomposition behaviours of the investigated synthetic polymers with the yields of primary monomers being relatively unaffected by the atmospheric environment. However, a difference was noted when using timber, as the generated char was visually different under the oxidative atmospheres. The presence of char oxidation was confirmed as a lower applied heat flux was required to sustain the desired mass loss rate. We conclude that the proposed combined analytical approach shows great potential for tracking and quantifying effluent emissions.

Synthesis of Soluble Quinacridone Photocatalysts for the Homogeneous Oxidation of Thioethers

AbstractEvaluation of quinacridone (QA) derivatives as homogeneous metal‐free photocatalysts is here presented. QA derivatives were synthetized and systematically characterized, measuring their ground state and excited state redox potentials in dichloromethane (DCM) and 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP), in order to understand how structural modifications influenced their photocatalytic properties. In particular, the effect of dicyanomethylene and nitro EWG groups was investigated, in order to develop a photocatalyst capable of promoting oxidative processes in the presence of molecular oxygen. Among the analyzed derivatives, 2,9‐dinitro‐N,N′‐dibutylquinacridone (DNDBQA) was the one with the highest excited state reduction potential (Ered*=1.60 V in HFIP vs SCE), while N,N’‐dibutylquinacridone (DBQA) showed valuable excited state redox potentials (Ered*=1.29 V; Eox*=−1.28 V in HFIP vs SCE), making it suitable for bimodal applications in oxidative and reductive photocatalytic processes. Afterwards, the synthetized QA derivatives were examined as photocatalysts to promote the selective aerobic oxidation of thioether to sulfoxide. Promising results in thioanisole oxidation were achieved with all the QA derivatives tested as photocatalysts, in terms of yield and selectivity. Remarkably, DBQA showed the best performances, catalyzing the reaction in only 20 minutes, using 0.5 % of the photocatalyst, and showing excellent performances in the oxidation of several thioether derivatives.