Porphyrins constitute a versatile platform for designing photocatalysts, and the growing interest in photocatalysis for organic synthesis and sustainable technologies underscores the need for strategies that improve their efficiency. The synthesis of the target pyrazinoporphyrins was carried out following previously developed methodologies, which involve the reduction of 2-nitro-3-aminoporphyrin to the corresponding 2,3-diamino derivative followed by condensation with aromatic carbonyl compounds. A synthetic approach enabling the introduction of phosphoryl groups on the periphery of diaryl-substituted and phenanthrene-appended pyrazinoporphyrins was established via phosphorylation of brominated precursors. This strategy afforded a series of photoactive compounds, including the free bases and the Zn(II) and In(III) complexes bearing various meso-substituents.

To assess the effect of these structural modifications on the stability of pyrazinoporphyrins, the kinetics of photodegradation were analyzed. The introduction of diethylphosphoryl groups was found to markedly enhance photostability. Indium(III) complexation further decreased the photodegradation rate by nearly 20-fold, whereas zinc(II) coordination had the opposite effect.

The introduction of phosphoryl substituents and indium(III) ions into the macrocycle also resulted in a systematic enhancement in photocatalytic activity in the photooxidation of thioanisole. At 0.0005 mol% loading, functionalized free bases and In(III) complexes achieved 78–100% conversion, whereas non-functionalized pyrazinoporphyrins produced only 66–72% even at higher loadings (0.001 mol%).

Kinetics studies of thioanisole photooxidation in acetic acid revealed that in both series of pyrazinoporphyrins, the In(III) complexes outperform the corresponding free bases. At the lowest tested loading (0.00001 mol%), an exceptional TON of 9900000 and a TOF of 309000 h^-1 were obtained, highlighting the outstanding catalytic performance of these systems. The high efficiency of the catalysts was further demonstrated in the selective oxidation of a wide range of sulfides. Overall, the new photosensitizers outperformed previously reported porphyrin systems.

This work was supported by the Russian Science Foundation (grant № 24-73-00168).

Extensive efforts have been devoted towards the development of methods for the direct conversion of methane (CH₄), ethane (CH₃CH₃), or other abundant natural gasses into useful products, such as the corresponding alcohols, aldehydes, ketones, and carboxylic acids, liquid fuels, and precursors of chemical and pharmaceutical products. Selective aerobic oxygenation of CH₄ into liquid products without the concomitant formation of CO₂ and CO has served as an elusive target reaction. The selective oxygenation of CH₄ to CH₃OH with molecular oxygen (O₂) has been unknown because the oxidation of oxygenated products, CH₃OH and formic acid (HCOOH) is much easier than that of CH₄, leading to over-oxidation products such as CO and CO₂. Here, we report that oxygenation of methane photochemically occurred in the presence of ClO₂^•. The yields of methanol and formic acid as products were 17% and 82%, respectively, with a methane conversion of 99% in a two-phase system comprising perfluorohexane and water under ambient conditions. The reaction occurred by the efficient radical chain process.^[1–3]

UV light irradiation of chlorine dioxide radical results in the excited state of one-electron reduction potential to be E_red^* = +3.22 V vs. SCE. The highly oxidative power of chlorine dioxide at the excited state allowed electron-transfer oxidation of benzene and cyclohexane as hydrocarbon substrates to yield the corresponding oxygenated products. The reaction is initiated by the formation of the photoexcited state of ClO₂^•. Electron transfer from benzene (Eox = 2.48 V vs SCE) to the excited state of ClO₂^• occurs to form a radical ion pair composed of a benzene radical cation and ClO₂^–. Phenol, as a final product, is formed from the reaction between benzene radical cation and H₂O.

[1] K. Ohkubo, K. Hirose, T. Shibata, T. Takamori, S. Fukuzumi, J. Phys. Org. Chem. 2017, 30, e3619.

[2] K. Ohkubo, K. Hirose, Angew. Chem. Int. Ed. 2018, 57, 2126.

[3] Y. Itabashi, H, Asahara, K, Ohkubo, Chem. Commun. 2023, 59, 7506.

Access to clean water is essential for human health, yet the persistent and poorly degradable nature of synthetic dyes continues to threaten aquatic environments. This challenge underscores the need for efficient nanoscale photocatalysts capable of enhancing pollutant degradation. In this study, an eco-friendly, simple, and cost-effective pulse laser ablation in liquid (PLAL) technique was employed to synthesize high-purity chromium nanoparticles (CrNPs) without the use of surfactants or chemical precursors. CrNPs were produced at various laser energies and evaluated for their potential in dye-degradation applications. The nanoparticles were characterized using ultraviolet–visible (UV–Vis) spectroscopy, fluorescence (FL) spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy to elucidate their optical and chemical properties. UV–Vis and FL analyses showed that laser energy significantly influences NP size distribution and optical behavior, while bandgap analysis revealed a slight shift with increasing laser energy. FTIR spectra confirmed the presence of Cr–O and O–H functional groups, which are known to contribute to photocatalytic activity. The absorption spectra of methylene blue (MB) decreased gradually with irradiation time. Photocatalytic degradation experiments under visible light demonstrated that CrNPs exhibit strong photodegradation efficiency. Overall, these findings highlight the potential of surfactant-free, PLAL-synthesized CrNPs as promising photocatalysts for the remediation of pharmaceutical pollutants and heavy-metal-contaminated wastewater.

Synthetic dyes, such as methylene blue (MB) and methyl orange (MO), are widely released from textile industries and pose a serious global health concern due to their carcinogenic and mutagenic properties, threatening public health and disrupting natural ecosystems. In this study, titanium-nickel nanocomposites (Ti-Ni NCs) were synthesized using the pulse laser ablation in liquid (PLAL) method for efficient dye removal applications. The optical and chemical properties of TiO₂ NPs, NiO NPs, and Ti-Ni NCs were characterized using ultraviolet-visible (UV-Vis), fluorescence (FL), and Fourier-transform infrared (FTIR) spectroscopy. The UV-Vis spectra exhibited a prominent absorption peak at ~361 nm in the UV region, while Tauc plot analysis showed a significant bandgap blue shift upon incorporation of NiO into TiO₂ NPs. FTIR spectra showed the presence of Ti-O, Ni-O, and Ti-O-Ni vibrational bands, proving the interfacial interaction between TiO₂ and NiO upon mixing. The Ti-Ni NCs revealed enhanced photocatalytic activity, achieving up to 97.1% degradation of MB and 89.6% MO removal within 45 minutes, showing advanced photocatalytic properties under UV light irradiation. This enhancement is attributed to the synergistic effect between TiO₂ and NiO, which forms a p-n heterojunction, effectively improving charge separation efficiency. These findings proposed the potential of high-purity PLAL-synthesized Ti-Ni NCs as advanced photocatalysts for wastewater remediation.

Titanium dioxide (TiO₂) is one of the most widely studied photoactive metal oxides, with applications that span self-cleaning windows, air-purifying surfaces, and a range of photocatalytic technologies aimed at improving urban environmental quality. At the nanoscale, titanium-oxo clusters provide a precise and well-defined bridge between molecular systems and bulk materials, offering precise control over both structure and electronic behaviour. Such tunability makes these clusters particularly attractive for photocatalytic applications, where their properties can be tuned more directly than those of extended solids.

In this work, we investigate the electronic structure and photochemical response of a series of Ti₆-oxo clusters and assess how these features shape their broader photocatalytic potential. Through time-dependent density functional theory (TD-DFT), we show that the energies and distributions of the frontier orbitals are strongly influenced by the ligands coordinated to the metal-oxo core. This ligand-controlled modulation closely parallels bandgap-engineering strategies commonly applied to nanoscale semiconductor materials.

Our findings reveal that adjusting the ligand environment, including the use of extended π-conjugated ligands, can optimise photocatalytic behaviour by deliberately tuning the underlying electronic landscape. These insights broaden the understanding of photoactivity in titanium-oxo clusters and highlight new routes for their use in sustainable energy conversion, environmental remediation, and chemical synthesis.

The widespread use of phenylurea herbicides (PUHs) such as chlorotoluron (CHL) has caused important environmental and human health concerns due to their persistence, bioaccumulation and resistance to conventional wastewater treatments. Until now, the degradation and transformation of PUHs have been the subject of numerous research. Adsorption, microbial degradation, chemical oxidation, biodegradation, and radical-based advanced oxidation processes (AOPs) have all been shown to be effective in the removal of PUHs. These methods do have some serious disadvantages, though, including poor kinetics, the production of hazardous byproducts, and high costs of treatment. On the other hand, ARPs could be an effective alternate to degrade impurities and yield non-harmful byproducts unlike AOPs and other approaches.

In this paper, we have studied the degradation of a phenylurea herbicide (CHL) contaminant in an aqueous environment by the first highly effective process based on UV based sulfite (S), palladium on activated carbon (Pd-C), and hydrogen gas (H₂) (UV/S/Pd-C/H₂) using an ARP approach. The developed process provides CHL's complete reduction within 1 hour of treatment along with >90% dechlorination at ambient temperature. Also, we observed excellent resistance of the reaction system to the presence of inorganic anions, and the system performed well across a wide pH range.

Funding informationThe authors gratefully acknowledge financial support from the National Science Centre, Warsaw, Poland, for project OPUS nr UMO-2021/41/B/ST8/01575.

Water-based sol–gel synthesis of TiO₂ is increasingly relevant for sustainable photocatalytic materials, but its strong temperature-sensitive hydrolysis–condensation behaviour often leads to poor viscosity control, unpredictable gelation, and non-uniform coatings. These rheological instabilities limit catalyst loading and reduce photocatalytic efficiency, particularly in gas-phase VOC degradation. This work investigates the viscoelastic evolution, thermoreversibility, and structural transitions of fully aqueous TTIP–acetic acid TiO₂ sols to establish processing conditions that yield uniform, high-performance coatings.

TiO₂ sols were aged at ambient temperature (Ta), thermally incubated at 50 °C (Ti), and subsequently cold stored at 4 °C (Tc). Viscosity was monitored using vibro-viscometry, while microstructural viscoelasticity was evaluated through DLS microrheology with 40 nm and 100 nm Au probes. Coatings prepared by dip-coating were examined via FE-SEM, profilometry, XRD, and UV-Vis spectroscopy. Gas-phase formaldehyde (10 ppm) degradation under UV-A irradiation (300–700 mL/min) was used to assess photocatalytic performance.

Ta sols remained weakly condensed (48–60 nm particles; ~1.8 mPa·s viscosity), producing thin, non-uniform coatings with low catalyst loading (0.016 mg/cm²) and poor HCHO degradation (<30%). Thermal incubation induced controlled condensation, optimized viscosity (~8 mPa·s), and generated subdiffusive microrheological behaviour, enabling uniform coatings with 0.106 mg/cm² loading and crystallite size ~7 nm. These coatings achieved 100%, 97%, and 78% HCHO degradation under UV-A irradiation at 300, 500, and 700 mL/min, respectively. Cold storage partially reversed the incubation effects, reducing viscosity, thickness, and photocatalytic activity.

Thermally modulated aqueous sol–gel processing enables precise control of TiO₂ sol viscoelasticity and thermoreversibility, allowing the formation of stable, uniform, nanocrystalline coatings with high gas-phase photocatalytic efficiency. This study establishes a rheology-guided pathway for designing sustainable, high-performance water-based TiO₂ photocatalytic materials.

Photocatalysis is a highly promising approach to environmental pollution. However, the practical application of many photocatalysts is limited by the difficulties of efficently separating them from the reaction medium. Using magnetic materials is a viable solution to this problem. Nickel ferrite is a material that has proven to have high chemical stability and magnetic properties. Unfortunately, its application in photocatalysis is limited by the rapid process of charge recombination. The two primary mechanisms for separating charges are as follows: The first involves creating a contact between two semiconductors to form a solid-state heterojunction. The second is the addition of sacrificial agents in the liquid phase, which react irreversibly with charges from the semiconductor, thereby inhibiting rapid recombination. Therefore, the aim of this work is to synthesize and characterize nickel–ferrite-based materials and investigate their photocatalytic activity in the presence of sacrificial agents. NiFe2O4/Fe2O3 photocatalysts were prepared via co-precipitation of Fe(NO₃)₃ and Ni(NO₃)₂ using NaOH, followed by calcination at 650 °C for 3 hours. The synthesized materials were characterized by XRD, TEM, UV-Vis, and photoluminescence spectroscopy. Photocatalytic activity was evaluated via the degradation of an indigocarmine dye (20 mL, 4.0×10⁻⁵ mol·L⁻¹) under a13 W lamp with λmax =340 nm. Experiments to identify the most effective sacrificial agent (NaHCO₃, Na₂CO₃, sodium citrate, or H₂O₂) were conducted under the same conditions. The most promising photocatalyst was also tested for recyclability. The highest photocatalytic activity (73% degradation of indigocarmine under 340 nm irradiation for 45 minutes) was achieved using hydrogen peroxide (0,011 mol*L^-1 in the reaction medium) as a sacrificial agent. An indigocarmine degradation reaction mechanism is proposed.

Introduction. For photodynamic therapy (PDT), special attention is paid to photosensitizers (PS) based on chlorins and their derivatives, synthetic analogues of natural pigments that combine powerful photoactivity with the possibility of subtle chemical modification. The main advantages of chlorin photosensitizers are their intense absorption in the long-wavelength region of the spectrum (650–750 nm), providing deep penetration of light into biological tissues, high quantum yield of singlet oxygen generation and the ability to selectively accumulate in pathological foci. Reduced derivatives of chlorin imides are of particular interest in this context, as they have greater stability under physiological conditions.

Methods. N-hydroxy and N-methoxy derivatives of purpurinimide-18 methyl ester were selected as the starting compounds. The obtained derivatives were purified by means of preparative chromatography. The structures of the obtained compounds were confirmed using a complex of modern physico-chemical analysis methods: electron and fluorescence spectroscopy, mass spectrometry, and ¹H- and ¹³C NMR spectroscopy.

Results. In this work, strategies for the reduction of the “exocycle E” of N -methoxy purpurinimide-18 were developed. The resulting derivative had an absorption maximum in the long-wave region of the visible spectrum (656 nm), as well as a three-fold higher quantum yield of singlet oxygen generation compared to the original compound.

Conclusions. The resulting reduced imide derivative combines absorption in the therapeutic window (656 nm) and high photoactivity (compared to the parent compound). The reduction of carbonyl groups of exocycle E can lead to an improvement in pharmacokinetic parameters and a more effective modification of the nitrogen atom. This compound is a promising candidate for the development of new effective drugs for PDT.

The work was carried out with the support of the Ministry of Science and Higher Education of the Russian Federation (government assignment №075-00727-25-05 dated 20/03/2025; FSFZ-2024-0013).

With the rising cost of pharmaceutical drug synthesis, new ways of creating base molecules like sulfoxide are in high demand. The state-of-the-art methods for these oxidation reactions involve toxic heavy metals like chromium and vanadium as catalysts, which have long reaction times and require many purification steps. However, perylene-based compounds like perylenetetracarboxylicdianhydride (PTCDA) and perylene diimide (PDI) have shown very promising results when replacing these metals. These organic compounds are non-toxic and have the potential to be reusable when attached to different substrates, for instance, glass beads. When varying the catalytic load of the photocatalyst on the surface, the catalytic performance would, theoretically, be affected. Also, with varying concentrations, the color shade should also becomedarker with more concentrated solutions. Due to the correlation between color shade and concentration, we seek to relate the color shade to its photocatalytic performance, which has yet to be reported in the literture. Glass beads were etched utilizing a base bath followed by an acid bath. Then, the beads were refluxed in a toluene–PDI mixture for 48 hours to covalently attach the PDI photocatalyst. After washing, the beads were shown to retain a light pink color, proving that the attachment was successful. In the future, the beads will be characterized using colorimetry shade analysis and Fourier-Transform Infrared Spectroscopy . The photocatalytic performance of the photocatalyst-attached beads will be assessed by monitoring the rate of sulfide oxidation using Thin Layer Chromatography and Nuclear Magnetic Resonance.