A one-pot synthesis of superparamagnetic nanocomposites via polycondensation of phenylenediamine isomers and 1,1 '-diacetylferrocene in the melt is described. Obtained nanocomposites were characterized by IR spectroscopy, XPS, XRD, EPR, SEM, TGA/DTA, and magnetization curves. The formation of oligomeric azomethines in the melt was accompanied by side hydrothermolysis of 1,1 '-diacetylferrocene, even at 140 degrees C under an argon atmosphere. According to XRD and IR spectroscopy, hydrothermolysis of 1,1 '-diacetylferrocene led to the formation of magnetite nanoparticles with an average size of around 10 nm, and a mixture of diacetyldicyclopentadiene isomers, presumably acting as crosslinking agents via reaction with terminal groups of oligomeric azomethines. XPS and IR spectroscopy demonstrated the formation of C=N bonds with retention of a fraction of unreacted keto and amino groups. The possibility of C=N bond formation was established in experiments on low-molecular-weight model compounds, and the synthesized monoimines and diimines of 1,1 '-diacetylferrocene and aniline were characterized by NMR, IR spectroscopy, and X-ray diffraction. XPS revealed the presence of Fe3+ on the surface of the nanocomposites, which, according to EPR spectroscopy and magnetization curves, exhibit superparamagnetism. The obtained nanocomposites are promising materials for cores of high-frequency inductors, as well as other devices requiring magnetization without energy dissipation due to hysteresis.

Organometallic and metal-organic compounds are widely used in different fields of chemistry and allied disciplines, including bioinorganic and medicinal chemistry. Of particular interest is the development of novel potential anticancer agents based on palladium(II) complexes of the so-called pincer-type ligands, featuring a specific monoanionic tridentate framework. In this work, hybrid imine-thiocarbamate ligands are shown to readily undergo direct cyclopalladation in solution and under solvent-free conditions, in particular upon mechanochemical activation, yielding a series of Pd(II) pincer complexes. The latter exhibit promising cytotoxic activity against several solid and hematopoietic cancer cell lines.

The creation of new potential metal-based therapeutics largely relies on the development of useful ligand scaffolds. In recent years, our research group has introduced thiophosphoryl-functionalized carboxamides as a convenient framework for obtaining biologically active cyclopalladated derivatives. In continuation of these studies, β-(aminoalkyl)phosphine sulfides bearing additional substituents in the ethylene backbone were synthesized for the first time and reacted with picolinic acid to afford a series of new functionalized amide ligands. The latter readily underwent direct cyclopalladation under the action of PdCl2(NCPh)2 under mild reaction conditions. The resulting S,N,N-complexes were studied for in vitro cytotoxicity against several solid and hematopoietic cancer cell lines, as well apoptosis induction and DNA damage ability, which showed their promising anticancer properties. In addition, moderate antibacterial activity was observed for a representative palladocycle of the β-thiophosphorylated derivatives.

The development of new, more effective, and selective anticancer agents is one of the most important tasks of modern medicinal chemistry. Recently, we have found that non-classical Pd(II) pincer complexes derived from thiophosphoryl-appended picolinamides exhibit promising cytotoxic properties. In this work, the potential of this class of metal-based derivatives was studied on an extended family of Pd(II) complexes with a deprotonated amide core featuring thiophosphoryl pendant arms, readily obtained by the direct cyclopalladation of new functionalized amide ligands upon interaction with PdCl2(NCPh)2 under mild conditions. The ligands, in turn, were obtained by conventional amide coupling methods using (aminobenzyl)- and (aminomethyl)diphenylphosphine sulfides as the key precursors and different N- and S-donor-substituted carboxylic acids. The effect of an acid component and carbon chirality in the ligand framework on the bioactivity of the resulting Pd(II) pincer complexes was elucidated by evaluating their cytotoxicity against different solid and blood cancer cell lines, apoptosis induction ability, and P-glycoprotein (P-gp) affinity, which revealed the high anticancer potential of some of them, and in particular, the potential to overcome drug resistance associated with P-gp overexpression. The representative palladocycle was also shown to possess moderate antibacterial activity.

The modern concept of green chemistry calls for the development of more environmentally benign synthetic protocols and a reduction in the use of auxiliary substances, including solvents. In this work the effect of a thiophosphoryl pendant arm on the cyclopalladation features of both symmetrical and unsymmetrical thiocarbamate pincer ligands was explored. The ligands were 1,3-bis(thio-carbamoyloxy)-5-(diphenylthiophosphoryl)-or 1-thio-carbamoyloxy-3-(diphenylthiophosphoryl)benzenes, the palladium source was (PhCN)2PdCl2.

The reactions of a-(aminoalkyl)diphenylphosphine sulfides with pyrazine-2-carbonyl chloride hydrochloride afforded two novel representatives of non-classical amide-based pincer ligands. The latter were shown to furnish PdII complexes with either bi-or tridentate coordination modes of the ligands, depending on the reaction conditions. The cytotoxicity assays revealed remarkable activity of one of the resulting cyclopalladated derivatives, especially, towards hematopoietic cancer cell lines.

A convenient synthetic route to b-and g-thiophosphorylated alkylamines is suggested based on the nucleophilic substitution between the w-bromoalkylamines and Ph2PK followed by the addition of elemental sulfur. These functionalized phosphine sulfides are shown to serve as useful synthons for the new non-classical picolinamide-based pincer ligands. The cyclopalladated derivatives of the latter exhibit promising cytotoxic properties, which strongly depend on the length of the thiophosphoryl pendant arm.

A new representative of hybrid pincer ligands has been synthesized by the thiocarbamoylation of a potassium salt of 3-(quinoxalin-2-yl)phenol with ClC(S)NMe2 to probe its cyclopalladation features in solution and under solvent-free conditions. The compound obtained is shown to readily undergo cyclometalation under the action of PdCl2(NCPh)2 upon heating in benzonitrile and, more importantly, in the absence of an added solvent, using the preliminary ground mixture of reactants as the starting material, which provides a powerful and green alternative to the conventional solution-based synthesis. The course and outcome of the solid-phase reaction were analyzed by IR spectroscopy, elemental and SEM/EDS analysis. The possibility to scale up the solid-phase synthesis using a simple thermoreactor was demonstrated for the first time. The resulting palladacycle exhibited high cytotoxic activity against several solid and hematopoietic cancer cell lines.

Different mechanochemical tools continue to encompass new fields of synthetic chemistry, often suggesting yield and rate enhancement along with the reduced waste production and simplified product isolation. In this communication, the cyclopalladation of a range of symmetrical and unsymmetrical pincer ligands is shown to readily proceed under conditions of liquid-assisted grinding upon interaction with a simple Pd(II) salt (PdCl2) used as a metalating agent in the presence of DMSO as a green liquid additive. The suggested approach represents a highly efficient and ecologically friendly alternative to the conventional methods for synthesis of Pd(II) pincer complexes in solution.

A simple method of obtaining composites based on fullerene and silver nanoparticles (AgNPs) has been proposed. Non-covalent water-dispersible composites were prepared by mixing a water solution of polymer-stabilized AgNPs and a solution of pristine fullerene C60 in N-methylpyrrolidone (NMP), followed by exhaustive dialysis against water. Alternating copolymers of dicarboxylic acid were used as stabilizing copolymers in the complexes of AgNPs: poly(styrene-alt-maleic acid) - SM, poly(N-vinyl-2-pyrrolidone-alt-maleic acid) - VM or poly(ethylene-alt-maleic acid) - EM. A 5-6-fold molar excess of copolymer/AgNP complexes SM/Ag0 or VM/Ag0 and approximately 10-fold excess of EM/Ag0 were used relative to C60 (moles of copolymers corresponded to AgNPs containing dimer units of copolymers). The volume of the aqueous phase when preparing composites was correlated with the organic phase as 1 to 1-1.3. The physical and optical properties of the preparations were characterized by UV-vis and FTIR spectroscopy, DLS, TGA, TEM and XPS. It has been shown that fullerene is included in the composites in solvated form. The AgNP content in the composites was 22-34, and that of C60 is 20-28 wt%. The dry composites were found to be dispersible in water, but were practically insoluble and did not dissociate in nonpolar solvents and NMP. It has been shown that C60 significantly inhibits the oxidative degradation of AgNPs in the composites and increases the antifungal activity of the preparations against Candida albicans.

Chemotherapy with anthracycline antibiotics is a common method of treating tumors of various etiologies. To create more highly effective cytostatics based on daunorubicin, we used the method of reductive amination using polyalkoxybenzaldehydes. The obtained derivatives of the anthracycline structure have much greater cytotoxicity compared to daunorubicin due to increased affinity for DNA, the ability to disrupt the cell cycle, and their inhibition of the glycolysis process, which is confirmed by data from extensive biological studies and the results of molecular modeling.

New polysiloxane–butylene oxide–urethane–ureas based on α,ω-bis[(3-aminopropyl)diethoxy]oligodimethylsiloxane, oligobutylene oxide, and fractions of dicyclohexylmethane 4,4'-diisocyanate (H12-MDI) with different contents of a trans-trans isomer have been synthesized. The mechanical properties of the films have been tested. It is established that the strength and relative elongation at break increase with the increasing content of the trans-trans isomer.

Abstract Chemotherapy with anthracycline antibiotics is a common treatment of tumours of various etiologies. Creation of highly effective cytostatics based on daunorubicin is possible by applying the method of reductive amination using polyalkoxybenzaldehydes. The obtained derivatives of anthracycline structure are up to 500 times more potent compared with daunorubicin due to the increased affinity to DNA, which is confirmed by the data of extensive biological assays and the results of molecular modeling.

In this study, we report an easy approach for the production of aqueous dispersions of C60 fullerene with good stability. Maleic acid copolymers, poly(styrene-alt-maleic acid) (SM), poly(N-vinyl-2-pyrrolidone-alt-maleic acid) (VM) and poly(ethylene-alt-maleic acid) (EM) were used to stabilize C60 fullerene molecules in an aqueous environment by forming non-covalent complexes. Polymer conjugates were prepared by mixing a solution of fullerene in N-methylpyrrolidone (NMP) with an aqueous solution of the copolymer, followed by exhaustive dialysis against water. The molar ratios of maleic acid residues in the copolymer and C60 were 5/1 for SM and VM and 10/1 for EM. The volume ratio of NMP and water used was 1:1.2–1.6. Water-soluble complexes (composites) dried lyophilically retained solubility in NMP and water but were practically insoluble in non-polar solvents. The optical and physical properties of the preparations were characterized by UV-Vis spectroscopy, FTIR, DLS, TGA and XPS. The average diameter of the composites in water was 120–200 nm, and the ξ-potential ranged from −16 to −20 mV. The bactericidal properties of the obtained nanostructures were studied. Toxic reagents and time-consuming procedures were not used in the preparation of water-soluble C60 nanocomposites stabilized by the proposed copolymers.

A series of three closely related unsymmetrical pincer ligands featuring thione sulfur donors have been derived from m-thiophosphorylated phenyl isothiocyanate to probe the effect of a spectator heteroatom in the flanking ring on their direct cyclopalladation. The reaction efficiency is shown to drastically increase on passing from a thionated thiazolidinone derivative to its oxazolidinone analog, and further to an imidazolidinone ligand. The investigations by IR and NMR spectroscopy as well as X-ray diffraction confirmed the realization of S,C,S'-type pincer coordination but did not reveal considerable differences in the molecular structures of the Pd(II) com-plexes obtained; however, the results of DFT calculations provided some valuable insights into the peculiarities of their formation. In addition, the possibility of solid-phase synthesis of the target pincer complexes upon ther-mally induced CH activation has been demonstrated. This methodology does not afford a significant yield enhancement over the conventional solution-based technique but appears to be highly advantageous in terms of the absence of a solvent at the synthesis step and reaction time.

New network poly(siloxane–propylene oxide–urethane–ureas) based on α,ω-bis[(3-aminopropyl)diethoxy]oligodimethylsiloxanes, oligo(propylene oxide), and cycloaliphatic diisocyanates are synthesized. The resulting polymers are studied by differential scanning calorimetry and thermogravimetric analysis; their stress–strain characteristics are elucidated. These polymers are found to feature microphase separation and, consequently, two glass transition temperatures, defined by the chemical structures of the microphases. It is shown that an increase in the molecular weight and mass content of siloxane blocks leads to a decrease in the elastic modulus and tensile strength.

Amino-functionalized phosphoryl compounds are among the most useful molecular scaffolds in medicinal chemistry, while the potential of their thiophosphorylated analogs, especially those having an alkylamino moiety, is still uncovered. This is mainly due to the lack of convenient synthetic routes to these organophosphorus derivatives. To address this issue, we have suggested the facile approaches to α-(aminomethyl)- and substituted/unsubstituted α-(aminobenzyl)diphenylphosphine sulfides based on either the sequential transformations of (hydroxymethyl)diphenylphosphine sulfide, with the Staudinger reaction of an azide derivative as the key stage, or the addition of Ph2P(S)H to hydrobenzamides followed by the acid hydrolysis. The compounds obtained were reacted with picolinyl chloride to yield functionalized amides which readily underwent direct cyclopalladation, resulting in new representatives of non-classical N-metalated Pd(II) pincer complexes. The latter exhibit promising cytotoxic activity against several human cancer cell lines and apoptosis inducing ability along with the remarkable cytotoxic effects on doxorubicin-resistant cell sublines.

(E)-2-Сyano-5-phenylpent-2-en-4-ynoic acid esters and N-substituted amides were synthesized by the Knoevenagel condensation of 3-phenylpropiolaldehyde with the corresponding cyanoacetates or cyanoacetamides in the presence of basic alumina used as a catalyst. The IR and Raman spectra of the resulting compounds show strong absorption bands in the range of 1565–1580 cm–1 which are attributed to the vibrations of the C=C bond in the enyl moiety.

One-pot synthesis of colloidal Au/ZnO and Ag/ZnO nanohybrid structures was carried out. The copolymers of maleic acid—poly(N-vinyl-2-pyrrolidone-alt-maleic acid), poly(ethylene-alt-maleic acid), or poly(styrene-alt-maleic acid) were used as templates for the sorption of cations of metals-precursors and stabilization of the resulting nanoheterostructures. Simultaneous production of two types of nanoparticles has been implemented under mild conditions in an aqueous alkaline medium and without additional reagents. Equimolar ratios of the metal cations and appropriate load on all copolymers were used: molar ratio of maleic acid monomeric units of copolymer/gold (silver)cations/zinc cations was 1/0.15/0.23 (1/0.3/0.15). The process of obtaining the heterostructures was studied using UV-Vis spectroscopy. The kinetics of the formation of heterostructures was influenced by the nature of the maleic acid copolymer and noble metal cations used. A high reaction rate was observed in the case of using zinc and gold cations-precursors and a copolymer of maleic acid with N-vinylpyrrolidone as a stabilizer of nanoparticles. The structure of the synthesized polymer-stabilized heterostructures was studied using instrumental methods of analysis—XPS, FTIR, PXRD, and TEM. Under the conditions used, stable colloidal solutions of heterodimers were obtained, and such structure can be converted to a solid state and back without loss of properties.

The development of phosphorylated polybenzimidazoles (PBI) for high-temperature polymer–electrolyte membrane (HT-PEM) fuel cells is a challenge and can lead to a significant increase in the efficiency and long-term operability of fuel cells of this type. In this work, high molecular weight film-forming pre-polymers based on N1,N5-bis(3-methoxyphenyl)-1,2,4,5-benzenetetramine and [1,1′-biphenyl]-4,4′-dicarbonyl dichloride were obtained by polyamidation at room temperature for the first time. During thermal cyclization at 330–370 °C, such polyamides form N-methoxyphenyl substituted polybenzimidazoles for use as a proton-conducting membrane after doping by phosphoric acid for H2/air HT-PEM fuel cells. During operation in a membrane electrode assembly at 160–180 °C, PBI self-phosphorylation occurs due to the substitution of methoxy-groups. As a result, proton conductivity increases sharply, reaching 100 mS/cm. At the same time, the current-voltage characteristics of the fuel cell significantly exceed the power indicators of the commercial BASF Celtec® P1000 MEA. The achieved peak power is 680 mW/cm2 at 180 °C. The developed approach to the creation of effective self-phosphorylating PBI membranes can significantly reduce their cost and ensure the environmental friendliness of their production.