A series of antimicrobial protonated diallylammonium polymers, poly(diallylammonium trifluoroacetate) (PDAATFA), were synthesized by classical polymerization, using an especially elaborated method for preparation of polymers with low molecular weight (MW), and by RAFT polymerization, with different end groups in a range of MW values of (8–43) × 103 g∙mol−1. Cytotoxicity relative to eukaryotic cells (epithelioid lines A-549 and MA-104) and bactericidal activity of the polymers (relative to Pseudomonas aeruginosa and Staphylococcus aureus) are investigated. The effect of the end groups and MW on toxicity and bactericidal activity is shown. Dependence of the activity and, most of all, cytotoxicity on MW is preserved even at a small difference in MW values in the MW range of (18–40) × 103 g·mol−1. A clear dependence of the studied properties on the nature of the terminal group is revealed. Sulfate -O-S(=O)2-O¯ end group has a noticeable effect on the bactericidal efficiency and smaller influence on toxicity, while dithiocarbonyl end group -S-C(=S)-O-CH2-CH3 has a significant effect on efficiency and especially toxicity, drastically increasing the latter. Overall, based on the results obtained, polymers PDAATFA of low MW are considered promising antimicrobial agents for the creation of new transdermal drugs.

In the present study, the macromolecular chain composition of copolymers prepared by the reactive blending of poly(ethylene terephthalate) (PET) and bisphenol A polycarbonate (PC) in the presence of Ti(OBu)(4) catalyst was tested using H-1 and C-13 NMR spectroscopy. The NMR spectra were meticulously analyzed across all regions, revealing unexpected results that provide new insights into the transreaction mechanism occurring between these two polymers in the melt phase. It was found that only two primary reactions occurred: the formation of a bisphenol A terephthalate bond accompanied by the release of ethylene carbonate and the formation of an aliphatic-aromatic ether bond with the release of CO2. The release of ethylene carbonate during the PET-PC blending led to a loss of ethylene glycol (EG). The kinetics of EG loss and ether bond formation were examined. A new transreaction mechanism for PET-PC reactive blending is proposed. (c) 2024 Society of Chemical Industry.

— Metathesis poly(5-perfluorobutyl-2-norbornene) has been synthesized for the first time with a high yield of 85–98% and a variable cis / trans ratio of double bonds over first- and third-generation Grubbs’ Ru catalysts in solution. The conditions for preparing the parent monomer 5-perfluorobutyl-2-norbornene with a yield of up to 98% have been selected. The study of the gas separation properties of the final polymer showed that the introduction of a perfluorobutyl substituent into the repeating unit of polynorbornene increases the permeability for noncondensable gases due to an increase in their diffusion coefficients. The ideal selectivity for gas pairs containing methane increases or remains almost unchanged as a result of an increase in the difference between the solubility coefficients of these gases. The reasons for the observed changes in the gas separation and other properties of polynorbornene can be associated with a rigid conformation and weak interaction of fluoroalkyl substituents, which affects the free volume of the polymer and the energy of interaction of macromolecules with each other and with penetrant molecules. The study expands the understanding of gas separation and other properties of the class of fluorinated polynorbornenes.

The reaction of 1,3,5,7-cyclooctatetraene with silicon-substituted ethylenes has been studied for the first time. It is shown that vinyltrimethylsilane is inactive in the reaction, and vinyltrichlorosilane forms 7-trichlorosilyltricyclo[4.2.2.02,5]deca-3,9-diene in up to 12% yield. A new silicon-substituted monomer 7‑trimethylsilyltricyclo[4.2.2.02,5]deca-3,9-diene containing 92% of the endo-isomer has been synthesized by methylation of the chloroadduct. The metathesis polymerization of the final monomer mediated by the Grubbs Ru catalysts of the first and second generations is studied. A new poly(7-trimethylsilyltricyclo[4.2.2.02,5]deca-3,9-diene) containing a bulky bicyclic fragment and predominantly trans-double bonds in the main chain (up to 94%) is obtained in 90–96% yields. The polymer is characterized by the highest glass transition point (187°C) in the series of monotrimethylsilyl-substituted polynorbornenes. The double bonds present in the monomer unit open up prospects for further modification.

A series of novel copolyesters based on polyethylene terephthalate (PET) and 4′-hydroxy-biphenyl-4-carboxylic acid (HBCA) was obtained by melt polycondensation of bis(2-hydroxyethyl) terephthalate and 4′-acetoxybiphenyl-4-carboxylic acid (ABCA) as co-monomers with Sb2O3 as a catalyst. Using this synthetic procedure, a set of copolymers containing 20–80 mol% of HBCA units was prepared. According to NMR spectroscopy, the copolymers were of random composition. Copolyesters comprising 60–80 mol% of HBCA possessed increased heat resistance and formed nematic melts at 270 °C and higher. The liquid crystal (LC) phase formation was accompanied by transition to non-Newtonian characteristics of the melt flow, as well as an equalization of storage and loss moduli values. According to XRD and polarizing microscopy, the LC glassy phase of the copolyesters coexists with crystalline regions of poly-(4′-hydroxy-4-biphenylcarboxylate), non-melting up to 400 °C and above. The mechanical characteristics of these LC copolyesters showed similar or better values than those of well-known LC polymers. These novel copolyesters can be useful in obtaining heat-resistant materials with an ordered structure and, as a consequence, improved performance.

The reaction of 1,3,5,7-cyclooctatetraene with silicon-substituted ethylenes has been studied for the first time. It is shown that vinyltrimethylsilane is inactive in the reaction, and vinyltrichlorosilane forms 7-trichlorosilyltricyclo[4.2.2.0 2,5 ]deca-3,9-diene in up to 12% yield. A new silicon-substituted monomer 7‑trimethylsilyltricyclo[4.2.2.0 2,5 ]deca-3,9-diene containing 92% of the endo -isomer has been synthesized by methylation of the chloroadduct. The metathesis polymerization of the final monomer mediated by the Grubbs Ru catalysts of the first and second generations is studied. A new poly(7-trimethylsilyltricyclo[4.2.2.0 2,5 ]deca-3,9-diene) containing a bulky bicyclic fragment and predominantly trans -double bonds in the main chain (up to 94%) is obtained in 90–96% yields. The polymer is characterized by the highest glass transition point (187°C) in the series of monotrimethylsilyl-substituted polynorbornenes. The double bonds present in the monomer unit open up prospects for further modification.

We have studied applicability of reversible addition-fragmentation chain transfer/macromolecular design via the interchange of xanthate (RAFT/MADIX) method to radical cyclopolymerization of protonated diallylammonium monomer, namely diallylammonium trifluoroacetate (DAATFA), occurring with efficient chain transfer to monomer reaction. The latter drives to a significant extent polymerization, noticeably setting molecular weight, MW, of polymers and their polydispersity (polydispersity index (PDI) = 2.8-3.0). For the first time, upon DAATFA polymerization in presence of RAFT ethylxanthogenacetic acid (xanthate) in aqueous solutions at 70 degrees C, the side chain transfer reaction was inhibited and control of the polydispersity was achieved, the PDI = 1.2-1.3. The structural characteristic of poly(diallylammonium trifluoroacetate) (PDAATFA) polymers was analyzed via H-1 and C-13 NMR and IFS FTIR (ATR) spectroscopy. It was proved that the structure of polymers obtained by RAFT polymerization fully corresponds to the polymers PDAATFA containing cationic pyrrolidinium links and trifluoroacetate-counterions. At the optimal xanthate concentrations, the main products are polymers with the end dithiocarbonate group, i.e. macro-RAFT PDAATFA. Static/dynamic light scattering, viscometry and ultracentrifugation were used for polymers characterization. Molecular weight was determined by two independent methods: static light scattering (M-w) and hydrodynamic parameters analysis (M-Dn). The PDI M-w/M-n was calculated on the basis of Fujita approach, using the determined distributions of sedimentation coefficients. The experimental number average molecular weights, M-n grow with polymerization time, 6700 g mol(-1) < M-n < 10500 g mol(-1), but did not correspond to the theoretical one. The rate of polymerization mediated by xanthate was shown to increase approximately twice in comparison to free-radical process that distinguishes DAATFA RAFT polymerization from other processes mediated by RAFT agent.

New copolymers of norbornene and 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane containing flexible siloxane and rigid norbornene fragments in the main chain are synthesized. Synthesis is carried out using three types of olefin metathesis reactions: the ring-opening metathesis polymerization of norbornene, the metathesis of nonconjugated diene 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane, and the interchain macromolecular cross-metathesis between polynorbornene and siloxane-containing polyene. The latter reaction is studied for the first time. With its help, new statistical multiblock copolymers of norbornene and 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane with different average block lengths are obtained and characterized by 1H and 13C NMR and IR spectroscopy. The effect of the copolymer structure on their thermal properties is investigated.

The polymerization of commercial strained cycloalkene, 5-ethylidene-2-norbornene, in the presence of Pd– N -heterocyclic carbene complexes (two of which are synthesized for the first time) containing phosphine or pyridine ligands is studied. Upon activation with borate Na + [B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 )] – , the studied Pd complexes catalyze the polymerization of 5-ethylidene-2-norbornene according to the addition scheme. Polymerization proceeds selectively and involves only the endocyclic (norbornene) double bond of the monomer, while the exocyclic (ethylidene) double bond remains unaffected. Pd– N -heterocyclic carbene complexes with phosphine ligands are inactive in polymerization, while similar complexes with 3-chloropyridine ligands show a higher activity. Two new Pd complexes are synthesized.

The solid-phase synthesis and purification of the 1-40 sequence of the human beta-amyloid were optimized, resulting in a preparation of a product with a high yield and homogeneity more than 95%. The synthetic peptide is capable of forming oligomers. This fact was confirmed by electrophoresis in the polyacrylamide gel with a subsequent immunoblotting and fluorescence spectrophotometry using the thioflavin T dye. An available method for a production of the highly specific anti-beta-amyloid antibodies with a high titer was developed. These antibodies recognized both monomeric and oligomeric forms of the 1-40 peptide of beta-amyloid under the immunoblotting conditions.

The activity of known and newly synthesized Ru-carbene catalysts in the metathesis polymerization of 1,5-cyclooctadiene and interchain cross-metathesis of synthesized polybutadiene with polynorbornenes is studied. First- and second-generation Grubbs Ru-complexes, second-generation Hoveyda–Grubbs complexes, and their modified analogs with asymmetric fluoro-containing ligands and unsaturated imidazolyl moieties are used as catalysts. It is shown that in the presence of the second-generation modified and nonmodified catalysts a partially crystalline polybutadiene is formed, in which blocks with trans -С=С bonds are about four times longer than blocks containing cis -С=С bonds. In the case of catalysts with bulkier ligands, the length of trans blocks is smaller and the melting temperature of the polymer is lower. The activities of the catalysts are compared by in situ 1 Н NMR monitoring. New norbornene-butadiene multiblock copolymers are prepared for the first time by cross-metathesis between polybutadiene and polynorbornene. The highest degree of blockiness of the copolymers is attained when using second-generation Grubbs and Hoveyda–Grubbs catalysts. The activity sequences for the studied catalysts are constructed. It is shown that macromolecular cross-metathesis occurs more intensively in the presence of the catalysts with less bulky ligands.

The membrane receptor for advanced glycation endproducts (RAGE) is involved in the development of a number of pathological conditions, including Alzheimer’s disease (AD), in which the receptor overexpression in brain cells and its increasing activity is observed. We have previously shown that the synthetic fragment RAGE (60–76), administered intranasally, could prevent the disturbance of the spatial memory of olfactory bulbectomized mice, that develop features of AD. We suggested that N-terminal amino function of the peptide protected with acetic group and C-terminal carboxyl group replaced with amide, would increase the stability of this peptide in in vivo experiments, and this protected peptide would show higher activity compared to the original free one. In the current study the protected peptide analog Ac-(60–76)-NH 2 was synthesized. The activity of the peptide (60–76) and its protected analog has studied in transgenic 5xFAD mice, which represent a generally accepted model of AD. The memory testing was performed in the Morris water maze. It was shown that intranasal administration of these peptides to transgenic 5xFAD mice for two months preserved the spatial memory of animals, and both peptides exhibited the same ability to prevent the spatial memory. The difference in the activity of the tested peptides was revealed 7 days after drug administration had been over, and only animals, previously received the modified peptide Ac-(60–76)-NH 2 , showed the ability to find the Morris water maze learning sector. The animals received the peptide (60–76) lost their ability to find the learning sector after 7 days and were completely disoriented. The data obtained allow us to conclude that the modified fragment (60–76) with protected N- and C-terminal functional groups has a more pronounced and long lasting protective effect compared to the free peptide (60–76). Thus, Ac-(60–76)-NH 2 is a promising candidate for development of the drug for the treatment of Alzheimer’s disease.

Unsupported palladium catalysts are synthesized by the ex-situ and in-situ reduction from emulsions of a precursor solution in cyclohexane. It is shown that the presence of the polymer—nitrile–butadiene rubber and butadiene–styrene rubber—in cyclohexane affects the morphology of catalyst particles. When synthesized in the presence of the polymer, the catalyst has a grapelike structure formed by ball-shaped agglomerates of palladium particles with a diameter of about 20 nm. Introduction of the polymer contributes to the integration and retention of palladium particles in the polymer network, hampers the agglomeration of particles, and facilitates their reduction. The catalytic properties of the obtained systems in the butadiene–styrene rubber hydrogenation are studied. The optimum catalyst concentration is 1 wt % Pd per polymer, and the optimum weight ratio palladium : nitrile–butadiene rubber in the synthesis stage is 1 : 10. It is advisable to perform the synthesis in situ. The catalytic activity persists during two cycles of use, after which regeneration is required. For comparison, the activity of the commercial palladium catalyst 2% palladium on activated carbon (PC) is estimated under the same conditions. It is demonstrated that in terms of activity the synthesized unsupported catalysts surpass PC. The thermal stability of the original and hydrogenated rubbers is studied by differential scanning calorimetry.

Hydrogenation of indene–coumarone resin on commercial palladium catalysts, including crusted catalysts, was studied. The process parameters were optimized to reach the maximal hydrogenation of aromatic fragments with minimal thermal degradation of the macromolecules. The optimum conditions are as follows: temperature 230°C, pressure 3 MPa, resin concentration in the solvent 10–25 wt %. Comparative analysis of the activity of the tested catalysts shows that palladium on activated carbon exhibits the highest activity. The use of indene–coumarone resin as an adhesive component of polymer hot-melt and pressure-sensitive adhesives was considered. The rheology of the initial resins and adhesives based on them, the phase state of the formulations, and their adhesiveness were compared. The advantage of using the hydrogenated resin for preparing polymer adhesives based on styrene–isoprene–styrene triblock copolymer was demonstrated.