Vadim A. Platonov

The remote detection of nitro compounds typically requires complex analytical procedures and expensive instrumentation, often resulting in prolonged analysis times. Fluorescence-based methods, which exploit the quenching of organic fluorophores in the presence of nitro analytes, offer a more practical and efficient alternative. Particularly promising is the use of excimer emission generated by bis-pyrene species (bis-Pyr), formed either through supramolecular interactions or covalent linkages. Regarding the latter, the integration of covalently linked bis-Pyr sensors onto polymer backbones, such as commercially available polyvinyl chloride (PVC), represents a highly attractive strategy. In this manuscript, we wish to report our recent findings on the mechanosynthesis of bis-pyrene-based PVC-supported chemosensors, and on studies of its fluorescence response towards common nitro-compound/explosive components, such as 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), taggant 2,3-dimethyl-2,3-dinitrobutane (DMDNB), pentaerythritol tetranitrate (PETN) and 2,4,6-trinitrophenol (picric acid, PA). For DNT, a selective fluorescence “turn-off” response was observed with a Stern–Volmer quenching constant as high as 1.15 × 10⁴ M⁻¹.

Lawsone and its derivatives have a variety of applications in the field of pharmaceutical research: as drug candidates, reagents for the chelation and recognition of metal cations (including those for catalytic applications), chemosensors for anions, and materials for energy storage applications. Moreover, there are some reports on the application of lawsone and its derivatives in the forensic science field. One of the most attractive features of lawsones is their bright color and well-pronounced fluorescence, which can be altered due to covalent or non-covalent interactions with various species. In this work, we endeavor to present our recent findings on the fluorescence response of lawsone and its methyl ester to nitro compounds and explosives components, such as 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenole (picric acid, PA), 2-nitromesitylene (2-NM), 4-nitrophenol (NP) as well as Fe3+ (FeCl3). In all the cases a dramatic fluorescence turn-off response was observed with up to 104 M-1 quenching constants. To explore the practical application of lawsone derivatives a mechanochemical modification of polyvinyl chloride (PVC) with lawsone residues was carried out, and thus obtained polymer was found to exhibit a pronounced fluorescence turn-off response to the both nitro-compounds and Fe3+ with as high as 104 M–1 quenching constants.

A method for the mechanochemical CuAAC click reaction (Cu⁺-promoted azido–alkyne cycloaddition) in the presence of bronze powder/copper beads without the use of a pre-introduced catalyst and ligands with greener prospect is presented. A new type of tri-, tetra-, and penta-ethylene glycols (PEGs) α,ω-disubstituted with 4-(PAH)-1H-1,2,3-triazole moieties has been synthesized by means of solvent-free click reaction in the planetary ball-milling in absence of a pre-introduced Cu(I) catalyst. The reaction afforded the above-mentioned compounds at room temperature in as short as 3 h in up to 96% yields and with E-factor values as low as 0.38. For the comparison, some of the key compounds were obtained by the conventional click synthesis in DMF solution. The compounds obtained were synthesized for the first time and can be considered as representative examples of bola-type chemosensors for the detection of electron-deficient species. This work presents a method for catalyzing a click reaction using bronze microparticles that are formed in situ during powder milling. This heterophase catalyst has been shown to be efficient and inexpensive and is suitable for green chemistry methods under solvent-free ball-milling conditions.

The research into quorum sensing inhibitors is mainly directed towards fighting pathogenic bacteria resistant to therapy with antimicrobial drugs. Natural quorum sensing inhibitors may serve as an effective alternative to antibiotics, since they are less likely to cause the development of drug resistance of pathogenic microbiota. Currently, the search for effective inhibitor molecules and analysis of structure–activity relationships among natural compounds is considered to be the most obvious strategy towards solution of the antibiotic resistance problem. Since plants have co-evolved with the microbial environment and have been constantly exposed to bacterial infections, they successfully developed chemical mechanisms to fight external pathogens, in particular the quorum sensing inhibition. The review considers the secondary metabolites of various classes of plants such as terpenes, quinones, coumarins, stilbenes, alkaloids, curcuminoids, flavonoids, phenolic compounds, and their derivatives and analogues that possess quorum quenching activity. Some aspects of the structure–activity relationships for the described compounds are highlighted for the first time. The bibliography includes 139 references.

Equol (4',7-isoflavandiol) is a metabolite of isoflavandiol estrogen daidzein, which is found in soybeans and other plant sources. In this manuscript we wish to report the first mechanochemical approach to equol-based polymers, such as polycarbonate and polyester. Our approach involves the polycondensation reaction between 4',7-isoflavandiol (rac-equol) and triphosgene or oxalyl chloride under ball-milling conditions. The obtained polymers were characterized by means of 1H NMR- and IR-spectroscopy. To explore the possibility of practical application of the abovementioned polymers, the fluorescence “turn-off” response of the equol-based polycarbonate towards some common nitroanalytes (2,4-dinitrotioluene (DNT) and 2,4,6-trinitrophenol (picric acid, PA)) was investigated, and up to 1o5 M–1 Stern-Volmer constants were observed.

Iptycenes are common building blocks for the small-molecules or polymer-based chemosensors and fluorophores. In addition, iptycene derivatives are widely presented in polymers of intrinsic microporosity (PIMs) as materials for the separation and purification technologies. In this manuscript we wish to report a mechanochemical approach to pentiptycene-based polyesters and polycarbonates as, possibly, new representatives of PIMs. Our approach involves the polycondensation reaction between 5,7,12,14-tetrahydro-5,14:7,12-bis([1,2]benzeno)pentacene-6,13-diol (pentiptycene-6,13-diol) and triphosgene or oxalyl chloride under ball-milling conditions. The obtained polymers were characterized by means of 1H NMR- and IR-spectroscopy. As the last step, the fluorescence “turn-off” response of pentiptycene-6,13-diol and two pentiptycene-based polymers towards nitroanalytes (2,4-dinitrotioluene (DNT) and 2,4,6-trinitrophenole (picric acid, PA)) was investigated, and Stern-Volmer constants as high as 1o4 M–1 were observed.

Polyvinyl chloride (PVC) plays an important role in industry; however, due to its uncontrolled accumulation in the environment, the methods for its utilization are of high demand. Herein we wish to report an approach for the utilization of PVC via its use as a carrier for some azole-based drugs, such as 2-mercaptobenzothiazole (multi-activity drug), 4-oxo-1,4-dihydropyrazolo[5,1-c]-1,2,4-triazine-3,8-dicarboxylic acid diethyl ester (antidiabetic drug) and 5-methyl-6-nitro-7-oxo-1,2,4-triazolo[1,5-a]pyrimidinide (antiviral drug). The abovementioned approach involves the reaction between PVC and potassium or sodium salts of these azole-based drugs either in solution or under ball-milling conditions. The as-obtained PVCs modified with azole-based drugs were isolated for the first time and characterized by means of 1H NMR-spectroscopy as well as gel-permeation chromatography (GPC).

1,4-Bis(5-phenyl-2-oxazolyl)benzene (POPOP) is a common scintillation fluorescent laser dye. In this manuscript, the synthesis of 2-Ar-5-(4-(4-Ar’-1H-1,2,3-triazol-1-yl)phenyl)-1,3,4-oxadiazoles (Ar, Ar’ = Ph, naphtalenyl-2, pyrenyl-1, triphenilenyl-2), as PAH-based aza-analogues of POPOP, by means of Cu-catalyzed click reaction between 2-(4-azidophenyl)-5-Ar-1,3,4-oxadiazole and terminal ethynyl-substituted PAHs is reported. An investigation of the photophysical properties of the obtained products was carried out, and their sensory response to nitroanalytes was evaluated. In the case of pyrenyl-1-substituted aza-POPOP, dramatic fluorescence quenching by nitroanalytes was observed.

Mechanochemically induced methods are commonly used for the depolymerization of polymers, including plastic and agricultural wastes. So far, these methods have rarely been used for polymer synthesis. Compared to conventional polymerization in solutions, mechanochemical polymerization offers numerous advantages such as less or no solvent consumption, the accessibility of novel structures, the inclusion of co-polymers and post-modified polymers, and, most importantly, the avoidance of problems posed by low monomer/oligomer solubility and fast precipitation during polymerization. Consequently, the development of new functional polymers and materials, including those based on mechanochemically synthesized polymers, has drawn much interest, particularly from the perspective of green chemistry. In this review, we tried to highlight the most representative examples of transition-metal (TM)-free and TM-catalyzed mechanosynthesis of some functional polymers, such as semiconductive polymers, porous polymeric materials, sensory materials, materials for photovoltaics, etc.

In this small note we explicit the relation between Ito and Stratonovich integrals when conditional measure flow components are present in the integrands. The `correction' term involves Lions-type measure derivatives and clarifies which cross-correlations need to be taken into account. We cast the framework in relation to SDEs of mean-field type depending on conditional flows of measure. The result being trivial under full flows of measure.