Modern society is faced with a pack of interconnected energy and environmental challenges, including rapid fossil fuel exhaustion accompanied by rise of greenhouse gases emissions and contamination of water resources by industrial waste and pharmaceuticals. All of this is aggravated by constantly increasing worldwide energy consumption that makes it economically unfeasible to invest into solving aforementioned problems by traditional means. In such context environmentally safe photocatalytic technologies that rely on sunlight energy are seen as a promising solution. Special attention is paid to composite photocatalysts with synergetic effects such as MXene/g-C3N4. These systems have an enhanced photocatalytic activity due to the combination of unique properties of the component: graphitic carbon nitride's excellent visible light absorption and MXene's high electric conductivity and tunable surface properties. The key advantage is formation of an effective 2D-2D interface with improved charge transfer and separation to improve reaction kinetics and charge carrier lifetime. Modern researches are usually aimed at optimization of morphology to achieve close contact between components and to maximize the availability of active sites. This review examines synthetic approaches to creating composite photocatalysts based on g-C3N4 and MXene and summarizes data on photocatalyst activity in processes such as hydrogen production, carbon dioxide reduction, and degradation of organic pollutants under light irradiation.
Boron-dipyrromethene (BODIPY) fluorophores are well-known for their high fluorescence quantum yields, chemical stability, and tunable optical properties, which make them excellent candidates for sensing applications. This work focuses on the transition from BODIPY-based fluorescent solutions to solid-state materials, specifically cellulose and fabric matrices, designed for hydrogen sulfide (H2S) detection. The study demonstrates how immobilization of BODIPY dyes into cellulose-derived or textile substrates preserves, or even enhances, their photophysical characteristics while providing mechanical robustness and practical usability. Spectroscopic analysis revealed that the micro-environment within the matrix affects fluorescence intensity and spectral shifts, influencing the dye's sensitivity to gaseous H2S. The prepared hybrid materials show rapid, visible, and reversible fluorescence responses under ambient conditions, highlighting their potential for environmental and industrial gas sensing. These results establish a foundation for developing cost-effective, flexible, and reusable optical sensors based on BODIPY-doped natural matrices.
The interaction of pheophytin-a with ethanolamine under various conditions was studied. It was shown that the action of ethanolamine on pheophytin-a in a chloroform medium results in opening of the exocycle with the formation of the corresponding 13-amide derivative of chlorin e(6). Subsequent removal of chloroform and continuation of the reaction with ethanolamine without a solvent leads to chemoselective amidation of the phytylpropionate substituent with the formation of the corresponding 13-,17-diamide derivative of chlorin e(6). Based on the results obtained, a method for obtaining hydrophilized chlorin e(6 )derivatives with two and three ethanolamine fragments on the periphery of the macrocycle directly from pheophytin-a "in one flask" was proposed.
This study presents a conformational analysis of pyrazine-fused aza-dipyrromethenes (aza-DIPYs) using quantum chemical calculations. The influence of various substituents (-H, -Et, -Ph, -O-Ph, -O-tBu, -O-2,6-iPr(2)Ph) on the preferred configurations of the aza-DIPY backbone was systematically investigated. Intramolecular hydrogen bonding between the NH group in one pyrrolo[3,4-b]pyrazine fragment and nitrogen atom in the pyrrolenine or pyrazine ring in another determines Z,Z and Z,E configurations of the aza bridge. Conformational analysis was performed with CREST, followed by DFT optimization. The results reveal that substituents inducing steric hindrance near the pyrazine nitrogen atoms (e.g., -O-Ph, -O-tBu, -O-2,6-iPr(2)Ph) strongly favor and stabilize the Z,Z conformation. In contrast, unsubstituted and phenyl-substituted derivatives exhibit a significant population of the Z,E conformer. These findings provide insights into the structural preferences of pyrazine-annulated aza-dipyrromethenes and offer guidance for the rational design of corresponding aza-BODIPY dyes with tailored conformational stability.
The development of highly sensitive and selective room-temperature ammonia sensors remains a critical challenge for environmental and biomedical applications. We report chemiresistive sensors based on hybrid materials formed by non-covalent functionalization of pristine and carboxylated single-walled carbon nanotubes (SWCNTs and SWCNT-COOH) with chlorinated zinc phthalocyanines, specifically, tetra-(ZnPcCl4) and octa-chloro (ZnPcCl8) derivatives and unsubstituted ZnPc for comparative purposes. Comprehensive characterization by FTIR, Raman spectroscopy and ICP-AES confirmed successful hybrid formation and revealed that oxidation of SWCNTs significantly enhances phthalocyanine loading via additional hydrogen-bonding interactions. All hybrid layers demonstrated reversible chemiresistive sensor response to NH3 (1-50 ppm), with the highest performance observed for the hybrids with ZnPcCl4. Notably, SWCNT-COOH/ZnPcCl4 exhibited a 2-3-fold higher sensor response and a lower limit of detection (0.3 ppm) compared to the hybrids with pristine SWCNT (0.5 ppm), attributable to greater phthalocyanine coverage. Humidity and selectivity studies have revealed the following features: while SWCNT-COOH-based hybrids exhibit excellent sensitivity under dry conditions, their performance is affected by signal bias at high relative humidity (>40%). In contrast, SWCNT/ZnPcCl4 maintains stable characteristics. These findings highlight the impact of phthalocyanine substitution and carbon nanotube type on sensor performance, providing a foundation for designing effective ammonia sensors.
Nowadays, lithium is a critical element essential for the production of lithium-ion batteries, as well as for use in glass and ceramics manufacturing, lubricants, metallurgy, and the nuclear industry. The continuously growing industrial demand for lithium drives the development of efficient techniques for its extraction from a wide range of sources - from natural salines to industrial wastes. Since the global lithium reserves are mostly dispersed in seawater in vanishing concentrations, the extraction is the most promising technique for its isolation. In turn, crown ethers provide opportunities for the precise tuning of their physical-chemical properties, allowing to control coordination properties, solubility and selectivity for particular metal ions through chemical modification. Despite the relatively little reported studies, crown ethers of 14-crown-4 type can be considered as a promising platform for the development of selective extractants of lithium for further development of industrial extraction processes. The present review is aimed to systematically analyze the existing data concerning the aspects of synthesis and application of 14-crown-4 derivatives for the detection and extraction of lithium.
A series of chlorin e6 derivatives bearing galactose fragments at the periphery of the macrocycle and exhibited good water solubility were studied for the in vivo toxicity. Preliminary results obtained on adult male white outbred mice shows that, in general, conjugates of chlorin e(6) with galactose exhibit significantly lower toxicity than chlorin e6 itself. The most toxic of the studied compounds has an LD50 equal to 772 +/- 11 mg/kg that is at least three times greater than that of chlorin e(6), despite the fact that all studied compounds are significantly more soluble in water and therefore more bioavailable, than chlorin e(6). The primary structural factor influencing toxicity is the number of galactose fragments on the periphery of the macrocycle: the greater the number of galactose fragments in the molecule, the higher the compound's toxicity. It can be expected that such derivatives will exhibit relatively low toxicity and thus may serve as a basis for further synthetic modifications in the development of new photosensitizers.
Supramolecular complexes based on 5,10,15,20-tetraphenylporphyrin (TPP) and beta-cyclodextrin beta-CD), and its dimeric derivative-di-6,6'-dideoxy-6,6'-(hexane-1,3-diyl diamine)-beta-cyclodextrin iodide (HD beta-CD), were synthesized using the drop-titration method in an aqua-organic medium. N,N-Dimethylformamide was used as the organic solvent. Complex formation was confirmed and comparatively studied using absorption and fluorescence spectroscopy. The stability of the obtained supramolecular complexes and the binding capacity of the system components were assessed. The role of the structural features of beta-CD and HD beta-CD during their interaction with TPP was investigated.
Optimization of the synthesis conditions for graphitic carbon nitride (g-C3N4) is a practical challenge aimed at maximizing product yield. The primary issues stem from the fact that the synthesis involves thermal polycondensation at temperatures of 500-600 degrees C, accompanied by precursor sublimation and oxidation, which significantly reduce the yield of the final product. In this study, the synthesis conditions of g-C3N4 were optimized using melamine and melamine-cyanurate under various atmospheric conditions and reactor configurations. It was established that synthesis in an open crucible in an oxygen-containing environment is the least effective, whereas conducting the process in a nitrogen atmosphere increases the yield. The best result was achieved using a semi-closed crucible without the need for a specialized atmosphere, which minimized the effects of sublimation and oxidation while offering a rational approach in terms of process efficiency.
Nowadays, coordination compounds capable of redox isomeric transformations are intensively discussed by researchers around the world due to the promise of creating efficient molecular switches based on them. In this work, the redox isomerization of ytterbium bis-phthalocyaninates with different peripheral substitutions in Langmuir mono-layers and Langmuir-Blodgett films was discovered and studied. We show the possibility of control over the tautomeric equilibrium established in ytterbium bis-phthalocyaninates at the air/water interface by varying the peripheral substituents in the studied complexes. In particular, photoinduced redox isomerization of homoleptic crown-substituted ytterbium bis-phthalocyaninate in ultrathin films on solid and liquid substrates has been demonstrated. It was found that the impact of certain substituents in the peripheral positions of phthalocyanine macrocycles on the tendency of the studied complexes to redox isomerization depends on the physical nature of inducing stimulus.
A combination of computational modeling and experimental techniques was used to study metal-porphyrin complexes containing in crude oil (petroporphyrins). The TDDFT method was applied to calculate the electronic absorption spectra of vanadyl and nickel petroporphyrin complexes. A correlation was established between the ligand structure and the characteristics of B- and Q-absorption bands. The permanent electric dipole moments of the petroporphyrin complexes were shown to differ from each other by a factor of six. The simulated spectrum of the vanadyl-porphyrin mixture was found to closely match the experimental spectrum of the sample solution isolated from the asphaltene fraction of crude oil, enabling prediction of the electronic absorption spectra of mixtures with a known ligand composition. The sublimation of the petroporphyrin mixture under high vacuum conditions was experimentally investigated by two methods: evaporation from a Knudsen cell with in-situ mass spectrometric detection and sublimation from a quartz crucible with ex-situ recording of the sublimate absorption spectra. In both cases, the composition of the vapor above the analyzed petroporphyrin mixture depended on the process time and temperature. This result opens up new opportunities for separating petroleum porphyrin mixtures into their individual components and producing thin films with controlled properties.
Based on acyldichloride of 1,10-phenanthroline-2,9-dicarboxilic acid and alkylenediamines a set of new macrocyclic 1,10-phenanthroline-2,9-dicarboxamides has been prepared. The size of macrocyclic cavity in these compounds ranges from 14 to 24 atoms. The structure of 24-membered macrocycle consists of two phenanthroline moieties which are linked together by two alkylenediamine spacers. The structure of all the obtained compounds was confirmed by a combination of spectral analysis methods, including NMR, IR spectroscopy, and mass spectrometry. The structure of two macrocycles was unambiguously confirmed by single-crystal X-ray diffraction analysis. Using the quantum chemical calculations, we studied the potential ability of the obtained macrocycles to effectively bind anions of various nature and geometry. The computations were carried out both in the gas phase approximation and considering the specific solvation for the F-and HF2-anions. The calculations indicate that the macrocycle 5 is capable of acting as a receptor for F-and HF2-anions in both organic and aqueous media.
Preparatory to the 90th anniversary of the birth of Corresponding Member of the Russian Academy of Sciences, Professor Georgy Nikolaevich Vorozhtsov, who made a significant contribution to the development of the cubogens class of and methods for their use in various dyeing and printing processes, obtained water-soluble dyes and, based on them, developed ultra-thin selective polaroids and insulating coatings, and was involved in the synthesis of semiproducts, we cannot help but remember his grandfather, N.N. Vorozhtsov (Sr.), who devoted his entire scientific career to the development of organic dye chemistry. The Department of Fine Organic Synthesis Technology at ISUCT, whose scientific foundations were laid back in the 1920s under the leadership of N.N. Vorozhtsov (Sr.) continues to develop research not only in the field of macroheterocyclic compounds chemistry capable of exhibiting various biologically active, electrochemical, and catalytic properties, but also, together with industrial partners, successfully works in the field of organic pigments chemistry with the aim of improving their coloristic characteristics and optimizing the their synthesis process.
For the first time, p-tert-butyl-thiacalixarene derivatives bearing imidazolium and fluorescein groups on one side and alkyl fragments on the other side of the macrocyclic platform were synthesized. The physicochemical properties of these amphiphilic fluorescein conjugates were thoroughly investigated, revealing the formation of stable aggregates for the octyl-substituted derivative with an average size of approximately 170 nm and a low polydispersity index (0.16). Critical micelle concentrations (CMC) and relative quantum yields were determined using UV-visible absorption and fluorescence spectroscopy. These compounds demonstrated high catalytic activity as photocatalysts in the cross-coupling reaction between N-phenyl-1,2,3,4-tetrahydroisoquinoline and malonic ester in DMF-water solutions. Analysis by gas chromatography-mass spectrometry (GC-MS) and 1H NMR confirmed an exceptional conversion of the starting heterocycle exceeding 96%. The results underscore the potential of these multifunctional thiacalixarenes as highly efficient photocatalysts in aqueous-organic media.
In a solution of aqueous tert-butanol, t-BuOH:H2O = 80:20 (vol.%), the absorption of molecular oxygen by a threecomponent synergistic system of butyl glycidyl ether - hydroquinone - pyridine was volumetrically studied. In the absence of water, the system is not oxidized. With increasing concentration of water in the solution, the rate of oxygen absorption by three-component system increases, and the oxidation induction period decreases. The oxidation rate is directly proportional to the concentrations of butyl glycidyl ether and pyridine, the heterocyclic components of the system. Pyridine is not consumed during the reaction, i.e. it acts catalytically. The consumption of butyl glycidyl ether, hydroquinone and the accumulation of benzoquinone during the oxidation reaction reflect the complexity of the mechanism of butyl glycidyl ether epoxide conversion. As the concentration of hydroquinone decreases, the concenes. The rate of butyl glycidyl ether consumption is directly proportional to the concentration of butyl glycidyl ether.The rate of oxygen absorption is several times higher than the rate of epoxy consumption. To explain this, a mechanism involving the oxidation of the labile substituent C4H9OCH2 in the oxirane cycle of butyl glycidyl ether is proposed. The oxidation of the substituent presumably occurs as an intramolecular reaction.
The first synthesis of 4,5-dichlorophthalonitrile was reported in 1992. Since then, this compound has become an indispensable building block for chemists working in porphyrazine chemistry. This is clearly evidenced by the constantly growing number of annual publications devoted to 4,5-disubstituted phthalonitriles. This review summarizes the use of this substrate in the synthesis of a wide variety of phthalonitrile derivatives. The primary goal of this work is to systematize the achievements in using 4,5-dichlorophthalonitrile as a universal precursor for constructing an extensive library of symmetric and unsymmetric 4,5-disubstituted phthalonitriles. In particular, the synthetic potential of 4,5-dichlorophthalonitrile in activated aromatic nucleophilic substitution reactions with O-, S-, and N-nucleophiles of different nature and functionality is considered. Furthermore, the review presents information on the preparation of various heterocyclic ortho-dinitriles based on 4,5-dichlorophthalonitrile. These include linked and condensed systems with 5-, 6-, 7-, and 8-membered heterocycles. Analysis of the literature leads the authors to conclude that 4,5dichloro-phthalonitrile is a promising and multifunctional synthon. Its reactivity provides researchers with a tool for significantly expanding the range of phthalonitrile derivatives - key intermediates for the preparation of substituted phthalocyanines, subphthalocyanines, and other valuable macrocyclic structures. The presence of substituents enables fine-tuning of desired properties. The information compiled in this review is of high practical value, as it is designed to help chemists consciously choose the most efficient and selective synthetic methods to obtain target molecules with the desired architecture and, consequently, optimize their further application in materials science, medicine, catalysis, and other cutting-edge fields of science and technology.
Polymeric iron phthalocyanine (FePPC) and its composites with single-walled and multi-walled carbon nanotubes (FePPC@SWCNT and FePPC@MWCNT) were synthesized. The conductivity of FePPC and its composites was then studied and compared to pristine SWCNT, MWCNT and mononuclear iron phthalocyanine (FePC). Both FePPC and FePC exhibited semiconductor-like behavior with sub-eV activation energies; however, the polymer demonstrated significantly higher conductivity than its mononuclear counterpart. In the composites, the presence of the polymer substantially altered the conductivity. The charge transport in FePPC@CNT composites is of major importance for electrocatalytic systems based on carbon nanotubes and conductive polymers.
This work presents the results of a study on the chromatographic properties of the Chromaton N-AW adsorbent modified with isomers of copper tetra-4-(methoxy)phenoxyphthalocyanine. The modifiers employed were the ortho-, meta-, and para-isomers, differing in the spatial arrangement of substituents in the macrocycle. The aim of the study was to establish the influence of phthalocyanine isomer structure on retention and selectivity in the separation of various classes of organic compounds. To characterize the sorption properties of the columns, specific retention volumes (Vg) and selectivity factors (alpha) were determined for a range of nitrogen-containing heterocycles (lutidines, picolines), aromatic hydrocarbons (xylenes), and terpenes (limonene, alpha-pinene, menthol). In addition, a thermodynamic analysis of the sorption process was performed using the Van't Hoff equation, which allowed the calculation of standard enthalpies (Delta H degrees) and entropies (Delta S degrees) of sorption in the 50-140 degrees C range. It was shown that all sorption processes are exothermic (Delta H degrees < 0) and accompanied by negative entropy changes (Delta S degrees < 0), reflecting the ordering of molecules on the adsorbent surface. It was found that the column with the ortho-isomer exhibited the highest absolute Delta H degrees values, indicating strong enthalpic interactions; however, these were accompanied by significant entropy losses and reduced selectivity. The para-isomer was characterized by an optimal balance of enthalpic and entropic contributions, providing enhanced selectivity in the sorption of structural and chiral isomers. The meta-isomer demonstrated the lowest absolute values of Delta H degrees and Delta S degrees, indicative of weaker sorption and a more universal but less selective interaction profile. These findings highlight the key role of the spatial arrangement of substituents in the copper phthalocyanine macrocycle in shaping the chromatographic properties of modified columns. The practical significance of the study lies in the possibility of rational selection of phthalocyanine isomers for the design of selective stationary phases applicable to the separation of closely related compounds, including enantiomers and structural isomers.
Photosensitizer chlorin e6meets almost all the basic requirements for an optimal photosensitizer formulated by scientists and experts. This work is devoted to the theoretical and experimental study of chlorin e6 acid-base properties related directly to its interaction with transport proteins, lipid membrane and vesicle receptors along the entire path from the injection and entry into the bloodstream to reaching the target tumor and the specific key organelles. Generally, depending on the pH, the chlorin e6 molecule can undergo stepwise acid-base ionization at three peripheral carboxyl groups and one intracyclic nitrogen atom of the chlorin platform, forming a series of amphiphilic ions. Protonation of chlorin platform is accompanied by a clear optical response in the absorption and fluorescence spectra, associated with photosensitizer phototoxicity under photodynamic therapy conditions, as well as its aggregation and lipophilicity. The results obtained were consistent and consolidated with the published data on acid-base ionization of the three peripheral carboxyl groups of chlorin e6, and then were used to quantify the interfacial distribution coefficients between octanol-1 and phosphate-buffered saline. The study concluded that protonation of chlorin platform is likely the reason for the high selectivity ofphotosensitizer Fotoditazin (R) accumulation in tumor tissue.
