Porous highly cross-linked polymer (PIP) was synthesized by a polycondensation reaction between hexachlorocyclotriphosphazene and piperazine. The obtained polymer has a surface area of 76.9 m2/g and a mesoporous structure. After carbonization, the obtained product (PIP-C) has a surface area of 177 m2/g. The obtained carbon product contained nitrogen and phosphorus heteroatoms, which leads to a higher specific capacitance (155.6 F/g) and catalytical activity in the electroreduction of oxygen (15.9 A/g). This work shows the possibility of the use of such porous phosphazene polymers as precursors for heteroatom-doped carbon materials, which might be used in electrochemical devices like electrodes for supercapacitors or metal-free electrocatalysts in fuel cells.

Exploration of new ways for the direct preparation of cross-linked structures is a significant problem in terms of materials for biomedical applications, lithium batteries electrolytes, toughening of thermosets (epoxy, benzoxazine, etc.) with interpenetrating polymer network, etc. The possibility to utilize hydrosilylation and Piers–Rubinsztajn reactions to obtain cross-linked model phosphazene compounds containing eugenoxy and guaiacoxy groups has been studied. It was shown that Piers–Rubinsztajn reaction cannot be used to prepare phosphazene-based tailored polymer matrix due to the catalyst deactivation by nitrogen atoms of main chain units. Utilizing the hydrosilylation reaction, a series of cross-linked materials were obtained, and their properties were studied by NMR spectroscopy, FTIR, DSC, and TGA. Rheological characterizations of the prepared tailored matrices were conducted. This work showed a perspective of using eugenoxy functional groups for the preparation of three-dimensional hybrid phosphazene/siloxane-based materials for various applications.

The redox-isomeric transitions in Langmuir monolayers of sandwich europium and samarium bisphthalocyaninates have been studied using simultaneous in situ measurements by UV-visible reflectionabsorption spectroscopy and XANES spectra. The inducing role of X-ray irradiation in such transitions has been revealed for the first time. The studied switches are related to the intramolecular electron transfer between metal and ligand in the investigated complexes in 2D systems under the influence of external factors such as pressure and X-ray irradiation ([Ln3+(R4Pc2-)(R4Pc center dot-)]0 <-> [Ln2+(R4Pc center dot-)2]0). Such switches are particularly interesting due to the fact that they can change a number of physicochemical properties of the investigated ultrathin films, such as their optical properties, electrical conductivity, and magnetic behavior. It was found that, for both complexes, the UV-Vis spectra underwent reversible changes that are typical of redox-isomeric switching upon surface pressure changes in the monolayer, but no change in the position of the white line of the metal center absorption edge, which was expected for intramolecular electron transfer, was registered. Studies of Langmuir-Blodgett films (LBF) of europium and samarium bis-phthalocyaninates on solid substrates by X-ray photoelectron spectroscopy confirmed the capability of both of the above-mentioned factors to cause tautomeric transitions in the 2D systems considered. In the spectra of the films transferred onto glass substrates at different surface pressures, differences in the electronic structure of the phthalocyanine ligands were registered. They were assigned to the change in the molecular orbital structure upon electron transfer from the ligand to the metal center (i.e., upon intramolecular oxidation of the ligand). At the same time, the cations of both metals also showed a rapid transition to the Ln3+ state under the influence of X-ray irradiation. The connection of the mechanism of X-ray induced lanthanide complexes redox isomerization with photoionization upon reaching the metal center (Sm or Eu) absorption edge was demonstrated. Thus, in this work we have obtained direct evidence for the possibility of controlling the redox isomeric state of lanthanide bis-phthalocyaninates in 2D systems by changing the monolayer surface pressure, and also revealed one more governing factor for such molecular switches - X-ray irradiation near the metal center absorption edge.

Coatings with low surface energy can be promising in various fields of science and technology. It is well known that to achieve low surface energy, it is usually enough to form thin layer or even monolayer of hydrophobic compound on the surface of the coating. On the other hand, to increase stability, such monolayers should be covalently bonded with the surface. In this work, we have shown the possibility of the use of Piers–Rubinsztajn reaction for grafting of oligoorganosiloxane hydrophobic monolayer on the surface of phenol-formaldehyde, alkyd, and epoxy coating, most used in the paint and varnish industry. The organosilicon monolayers were studied by XPS, ellipsometry, and contact angle measurements. Additionally, coatings with grafted organosilicon monolayers were studied for the static effects of water. It was shown that the formed organosilicon monolayers exhibit good hydrophobic efficiency, with an increase in contact angle from 75° to 116° for phenol-formaldehyde coatings, from 82° to 107° for alkyd coatings, and from 84° to 100° for epoxy coatings.

In the article we assess the possibility of application of k-means clustering method towards unsupervised analysis of electronic absorption spectra of BODIPY dye during compression on an air - water interface. Using investigated dye as an example case, we provide rationales for selection of the number of clusters for analysis and demonstrate how introduction of additional dimension (molecular area) with subsequent normalization provides meaningful results. From analysis in the proposed technique, we were able to extract previously unavailable data on efficiency of heteromolecular interactions between BODIPY dye and three co-surfactants of choice (Palmitic acid, Cetyl alcohol, Triton X-100). Ultimately, we suggest the developed technique for fast and in-depth analysis of spectral data for dyes on an air - water interface during compression, as well as for any similar dataset, involving large corpus of high-dimensional measurements, obtained along with time-series properties.

Reactions between the model compound N-1,4,5-trimethyl-1H-imidazole-3-oxide and electron-deficient olefins including 2-(4-methoxybenzylidene)malononitrile, (E)-ethyl-2-cyano-3-(4-methoxyphenyl)acrylate, 2-benzoyl-3-(4-methoxyphenyl)acrylonitrile, and 5-(4-methoxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione were theoretically studied in terms of the density functional theory. It was demonstrated that the reactions can proceed either by the 1,3-dipolar cycloaddition mechanism or by the Michael addition mechanism depending on the type of electron-withdrawing substituents in the olefin molecule. The reaction pathways were calculated and the intermediate structures were determined.

The radiation thermal stability of extraction mixtures based on methyltrioctylammonium (MTOA) carbonate was studied. The volumes and maximum rate of release of gaseous products at atmospheric and elevated pressures were determined. No exothermic processes were shown to occur in the studied mixtures under experimental conditions. Irradiation up to a dose of 1 MGy has little effect on the density, viscosity, and surface tension of mixtures, but significantly reduces the phase separation rate. The distribution coefficients of Am(III) in the system of 50% MTOA carbonate in toluene are practically independent of the absorbed dose; however, irradiation can significantly affect the composition of the extractable americium complexes. The results of the study of extraction systems showed their high radiation thermal stability.

A three-component condensation of 2-unsubstituted imidazole N-oxides, 3-ketonitriles, and aldehydes is described. The reaction proceeds via sequential Knoevenagel condensation/Michael addition under mild, catalyst-free conditions with various substrates. Furthermore, the corresponding 2-functionalized imidazole N-oxides can be further dehydrated to (Z)-2-aroyl-3-(1H-imidazol-2-yl)-acrylonitriles, which may also be directly prepared by changing the reaction conditions as a cascade of Knoevenagel condensation/Michael addition/dehydration.

The time-dependent density functional theory (TD-DFT) method was used for the first time to calculate electronic transitions of amphiphilic spiro compounds. It is shown that it gives a fundamentally correct electron density distribution, corresponding to the results obtained using the CASSCF method, and allows one to predict the nature of the electronic transition of the merocyanine form. For negative photochromes, the possibility of the existence of conical intersections of the potential energy surfaces of the ground and excited electronic states has been discovered, which may be the reason for the slow photochromism of these compounds. The fundamental possibility of using TD-DFT to predict the optical characteristics of long-chain spiropyrans is demonstrated, provided that scaling regressions are used. For the first time, linear regressions have been developed for such compounds, taking into account a set of physical parameters of the solvent in explicit form. This made it possible to obtain a unified empirical correction that takes into account the solvatochromic effect. The results obtained can be used as a basis for developing a main concept that takes into account the effect of the solvent on the spectral properties of spiro compounds and for constructing a unified regression model covering various types of solvato- and photochromism.

A novel porous hydrolytically degradable cross-linked polymer was obtained via polycondensation reaction between hexaphenoxycyclotriphosphazene and octa(tetramethylammonium)silicate. The synthesized polymer was characterized by solid NMR, FTIR, nitrogen adsorption etc. This polymer showed perspectives in the use as container for loading and releasing of drug, which was shown with the use of Rhodamine-6G (Rh6G) as model compound. It was shown that due to the presence of hydrolytically unstable P-O-Si fragments the obtained porous polymer can load Rhodamine-6G and release it with various rates, depending on pH value of the medium.

The results of a study of the physicochemical and photomechanical properties of mixed Langmuir monolayers based on palmitoyloleoylphosphatidylcholine (POPC), dipalmitoylphosphatidylcholine (DPPC) and amphiphillic spirocompounds are presented. For the first time mixed monolayers based on POPC, DPPC, spiropyran 1',3'-dihydro-1'-hexadecyl-3'3'-dimethyl-6-nitrospiro[2H-benzopyran-2,2'-(2H)indole] and spironaphtoxazine 3,3-dimethyl-1-hexadecyl-1,3-dihydrospiro[indoline-2,3'-naphtho[2,1-b][1,4]oxazine]-9'-ol were formed in various combinations and ratios, and their comparative study was carried out. It has been established that binary mixture of phospholipids and spirocompounds form stable monolayers in which phase transitions can be controlled by UV-light. It has been shown that irradiation of monomolecular phosphatidylcholine films containing small amounts of photosensitive compounds (up to 10

Associative behavior of geometrically anisotropic meso-(4-octadecyloxy-phenyl)-boron-dipyrrin (BODIPY) studied spectroscopically in binary solvent mixtures and upon compression in Langmuir floating layers. Different steady and excited state species were found upon monolayer compression and facilitated aggregation in water/ acetonitrile systems. This discrepancy points to a big concern in possibility of commonly applied generalizations across different aggregating systems. Broad range of decay fitting models were examined to reveal their benefits and pitfalls specific to examination of dye aggregates. Radiative constant gamma-distribution approach and free form fluorescence lifetime distribution with maximum entropy method (MEM) outperformed multiple common techniques for analysis of complex fluorescence decays. MEM could be recommended for analysis of systems where complicated lifetime distributions appear over time or upon external stimuli. Findings and protocols could be utilized as tools in studies of steady and excited-state photophysics of BODIPY aggregates.

The error of the weak binary electrolyte dissociation degree calculations using the approximate formula $$\alpha = \sqrt {{{{{K}_{c}}} \mathord{\left/ {\vphantom {{{{K}_{c}}} c}} \right. \kern-0em} c}} $$ and by the Ostwald dilution law is analyzed. The expressions for the relative error are derived and the limits of application for the specified approximations are set up, in particular, when the solvent self-dissociation must be considered.

In this review, we present one of the main areas of the work of the Laboratory of Physical Chemistry of Supramolecular Systems, Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, devoted to studying monolayers and ultrathin films on liquid and solid surfaces. Numerous problems are discussed concerning the peculiarities of the supramolecular organization, behavior, and functional potential of these traditional colloidal systems. The article describes diverse examples of systems that form ultrathin organized films at different interfaces and the processes occurring in them, thereby reflecting the contemporary stage of the interconnection of related fields of science (colloid and supramolecular chemistry, nanotechnology, biomimetics, sensorics, etc.). Such a combination makes it possible to develop new intelligent nanostructured devices. Complexation in ultrathin layers of ligands on liquid and solid substrates is considered in connection with the use thereof as sensitive sensory elements in systems with reduced dimensionality. Substantial attention is focused on the aggregation behavior of diverse ligands and topochemical reactions in organized 2D ensembles, development of new methods for preparing two-dimensional organic networks, and creation of highly stable supramolecular devices based thereon. In the light of the features of 2D systems, several types of mechanochemical transformations occurring under the action of two-dimensional compression–expansion are considered: the phenomenon of redox isomerism in monolayers of lanthanide bis-phthalocyaninates, the phenomenon of forced axial coordination in tetrapyrrole complexes of nickel with a change in its spin number, and the phenomenon of the reversible formation of excimers. Especial attention is given to the problems concerning the behavior of organic photochromes at interfaces and the perspectives of developing molecular switches based on photosensitive compounds.

Cellular membrane is one of the main targets of photodynamic therapy. Its high complexity has led to the study of the efficiency of photosensitizers on artificial lipid systems mimicking membranes. However, the preliminary analysis of this efficiency remains limited due to difficulty of the model construction and/or implementation of the required measurement techniques. Hereby, we propose a quite simple way for the rapid comparative assessment of novel photosensitizers in terms of membrane photodegradation, based on simple and fast measurements, such as wetting angle and surface plasmon resonance spectroscopy. As a proof of concept, we applied this methodology to two bacteriopurpurinimide derivatives. We have shown in particular that such complementary techniques can be employed not only for the multiparametric monitoring of the kinetics of the photodegradation, but also for the comparison of the damaging efficiency of the photosensitizers in the lipid structures as well.

The work presents the results of a study of the negative photochromism and luminescent properties of 1',3'-dihydro-3',3'-dimethyl-6-nitro-1'-octadecyl-[1-benzopyran-2,2'-indole]-8-methyl pyridinium chloride (SP2) in solutions, Langmuir monolayers, and cast films. It has been demonstrated that the introduction of the pyridine substituent into the chromene part of the amphiphilic spiropyran leads to stabilization of the open form of the compound under dark conditions, both in the dissolved and in the ordered planar state. The kinetic characteristics of photoreactions occurring in organic solvents upon irradiation by visible light and during relaxation in darkness are determined. Negative solvatochromism of SP2, which consists in the hypsochromic shift of the maximum absorption of the merocyanine form of the compound upon increase of the solvent polarity, is revealed. The luminescent properties of solutions of negative spiropyran and its cast films are investigated. For the first time, SP2 monolayers are formed at the air/water interface and their properties are studied. It is established that SP2 retains its photochromic properties upon transition from solutions to a two-dimensional condensed state. The results obtained open up broad prospects for the development of switchable optoelectronic and information systems based on negative spiropyrans.

In the present work, we demonstrate that transversal conductivity and, consequently, electrochemical activity of ultrathin solid films of two structurally similar octa-butoxy and tetra-crown-ether substituted europium bisphthalocyaninates are quite different. It is shown that presence of the crown moieties allows excellent transfer of charge through monomolecular ultrathin films of respectively substituted complex. This enables their redox-multistability, which can be utilized in molecular logic and information storage devices. On the other hand, transversal charge transfer is inhibited in the films of octa-butoxy-substituted bisphthalocyaninate, which might be promising for organic field-effect transistor applications.