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Novel approach to methyl 2-aryl-2-(arylhydrazono) acetates via methanolysis of dichlorodiazabutadienes was developed. Hydrogen bonding in methyl Z-2-phenyl-2-(phenyl-hydrazono) acetate was explored by DFT calculations and topological analysis of the electron density distribution within the framework of Bader’s theory (QTAIM method).

The pyridoxal derivatives of chitosan with various degrees of substitution (DS) were synthesized from low-, moderate- and high-molecular-weight chitosans by their reaction with pyridoxal followed by treatment with NaBH4. The derivative of moderate molecular weight and high DS demonstrated a maximum antibacterial activity against S. aureus and E. coli. The nanoparticles of this derivative obtained by ionic gelation are nontoxic, and they exhibit a high in vitro antibacterial effect, which slightly exceeds that of ampicillin and gentamicin.

The metal-assisted nitrone-nitrile cycloaddition reaction is apply to empower chitosan chemistry. The ultrasonic irradiation has proven to efficiently accelerate the cycloaddition affording new heterocyclic (1,2,4-oxadiazoline) chitosan derivatives and avoiding ultrasonic degradation of the chitosan macromolecules. By varying the nitrone nature, both water- and toluene-soluble chitosan derivatives were successfully synthesized. Relying on the ionic gelation approach nanoparticles of heterocyclic chitosan derivatives were prepared. Water-soluble chitosan derivative demonstrated a high antibacterial activity coupled with low toxicity. The toxicity of the synthesized heterocyclic chitosan derivatives and their based nanoparticles are comparable with those of the starting chitosan, while their antibacterial activity is superior. Toluene-soluble derivatives are shown to be efficient homogeneous catalysts towards monoglyceride synthesis via the epoxide ring opening. They efficiently catalyze selective conversion of fatty acids and glycidol into corresponding monoglycerides allowing one to simplify significantly the procedure for separating the reaction product from the catalyst for its recovery and reusage.

In this work, we demonstrate that the thiol-yne click reaction could be efficiently mediated by ultrasonic irradiation and implement the ultrasound-assisted thiol-yne click reaction to chitosan chemistry as a polymer-analogous transformation. We optimize power and frequency of ultrasound to preserve selectivity of the click reaction and avoid ultrasonic degradation of the chitosan polymer chain. Thus, we obtain a new water-soluble betaine. Using ionic gelation of the obtained betaine derivatives of chitosan, we prepare nanoparticles with a unimodal size distribution. Furthermore, we present results of antibacterial and transfection activity tests for the chitosan derivatives and their based nanoparticles. The derivative with a medium molecular weight and a high degree of substitution demonstrated the best antibacterial effect. It derived nanoparticles with a size of ca. 100 nm and ζ-potential of ca. +69 mV revealed even higher antibacterial activity, slightly superior to commercial antibiotics ampicillin and gentamicin. On the contrary, the obtained polymers possess a much more pronounced transfection activity as compared with their based nanoparticles and species with a low degree of substitution acts as the most efficient transfecting agent. Moreover, the obtained betaine chitosan derivatives as well as their derived nanoparticles are non-toxic.

1-Aryl-3-(4-bromophenyl)-4,4-dichloro-1,2-diazabuta-1,3- dienes were synthesized via copper-catalyzed reaction of 4-bromobenzaldehyde arylhydrazones with CCl4. X-ray diffraction analysis revealed non-covalent Cl···Br interactions in the crystalline state and formation of 3D supramolecular framework; DFT calculations and topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method) confirmed these observations. Theoretical calculations showed that highly polarizable dichlorodiazadiene unit is capable of acting as a relatively strong halogen bond donor.

A synthesis of the PdII and PtII N,N-diaryldiazabutadiene complexes and their self-assembly into infinite 1-dimensional chains in the solid state via rare C (sp2)–H … Hal hydrogen bonding is reported. All the new compounds were characterized using elemental analyses (C, H, N), ESI-MS, IR, 1H and 13C NMR techniques and X-ray diffraction analysis. The nature and energies of intermolecular non-covalent interactions, which are responsible for the supramolecular polymerization, were studied theoretically using DFT calculations and topological analysis of the electron density distribution within the formalism of Bader's theory (QTAIM method). While chloro-complexes, which feature a relatively stronger C (sp2)–H … Hal hydrogen bonding, form supramolecular polymers, the iodo-derivative does not self-assemble into 1-D chains due to the dominance of other crystal packing forces over the potential H⋯I contacts. Thus, the C (sp2)–H … Hal HB can dictate a packing preference in the solid state and serve as a useful tool for supramolecular engineers.

Preparation of novel triarylazoimidazole trichlorogold(III) complexes is described. The new compounds were characterized using C, H, N elemental analyses, IR, UV/Vis and X-ray diffraction analysis. Structural characterization revealed that the distances N(imidazolic)···Au (2.030 A (4) and 2.037 A (5)) are significantly shorter than N(azo group)···Au (2.853 A (4) and 2.899 A (5)) indicating that the azo group is rather weakly coordinated at the Au(III) metal center. Thus, triarylazoimidazole trichlorogold(III) complexes could be described as square planar gold(III) complexes with weakly binding to the gold(III) center azogroup. Non-covalent chlorine···chlorine interactions were detected for 5 in the solid state and studied by DFT calculations and topological analysis of the electron density distribution within the framework of Bader’s theory (QTAIM method). Theoretical studies demonstrated that short non-covalent Cl···Cl interactions (3.202 A) play crucial role in self-assembly of high-valent Au(III) chloride.

Carbon dots (CDs) is a novel promising class of nanomaterials with unique properties. Most of synthetic methods to obtain CDs employ hydrothermal synthesis, breaking down larger carbon materials by laser irradiation, arc discharge, ultrasonication or electrolysis. Here we describe a conceptually new bottom-up approach to nitrogen-rich carbonaceous nanoparticles via high intensity femtosecond laser irradiation of neat acetonitrile where the latter serves a source of the doping N atoms. Selected photophysical properties of the new material and mechanism of the photoluminescence (PL) are discussed.

Aromatic amidines 1a-e undergo facile reaction with one isocyanide in PdCl2(CNBut)2 giving carbene complexes 2b-d (Scheme 2) in high isolated yields (79–95%). The structures of 2b–d were confirmed by the 1H and 13C NMR spectroscopies, high resolution electrospray ionization mass spectrometry (HRESI-MS), IR, the elemental analyses (C, H, N), and X-ray diffraction analysis for 2c, which revealed that the carbene and unreacted isocyanide ligands were located in a mutually trans position. Such arrangement was unexpected since it did not fit trans effect rule. Stabilization of the unfavorable isomer was rationalized by intramolecular hydrogen bonding. The nature of the intramolecular non-covalent interactions, which were responsible for the stabilization of the trans-isomer, was studied theoretically using DFT calculations and topological analysis of the electron density distribution within the framework of Bader’s theory (QTAIM method).

Preparation of the novel PdII osazone complex and its self-assembly into lasagna-like arrays in the solid state via rare C(sp2)–H⋯Hal hydrogen bonding, as well as N–H⋯Ph weak contact is reported. The rare PdII osazone complex was characterized using elemental analyses (C, H, N), ESI-MS, IR, 1H and 13C NMR techniques and X-ray diffraction analysis. The intermolecular non-covalent interactions C–H⋯Cl and N–H⋯Ph responsible for the formation of 1D supramolecular polymeric chains in the crystal were detected and studied by DFT calculations and topological analysis of the electron density distribution within the framework of Bader’s theory (QTAIM method). Estimated strength of these non-covalent interactions is 1.3–1.6 kcal/mol.

The magnetic behavior of Ba–K–Bi–O single crystals below T c was investigated. The magnetic moment hysteresis loops were examined with the help of a small Hall detector. The complex analysis of the data on the temperature dependencies of the residual magnetic moment and H c1 , obtained from the magnetic experiments, and the resistive superconducting transition curves give rise to the following picture: at T c =30 K the transition to the continuous superconducting phase takes place, while at T * =17 K one more transition happens––to the spatially inhomogeneous superconductor–insulator state, that also could be destroyed either by temperature or by magnetic field.

The magnetic response of HTSC Ba–K–Bi–O single crystals in superconducting state was investigated with the help of a small Hall detector. The magnetic moment of the sample was measured as a function of the magnetic field up to 650 Oe and as a function of temperature while heating in the external magnetic field. Distinct paramagnetic response (PMR) was observed. In contrast to the other works where “paramagnetic Meissner effect” was noted these experiments were carried out on zero field cooled samples and the paramagnetic response was exhibited both at very low (

The method of frequency modulation of microwave radiation to observe Josephson behavior of multicircuit weak links system is suggested. The possibilities of the method are theoretically analyzed for the case of the system consisting of many Josephson contacts with random parameters. The technique was sampled on the example of polycrystalline high-T c Ba 0.6 K 0.4 BiO 3 .

The resistivity of single crystals of the cubic high temperature superconductor Ba0.6K0.4BiO3 with Tc=30 K has been measured in the temperature range from 4.2 to 300 K. The experimental curve is well approximated in the framework of the classical electron-phonon model of resistivity by the Gruneisen type dependence using the phonon spectrum in the form of an acoustical branch and a widely separated narrow optical peak.

Raman spectra of the YBa 2 Cu 3 O x films deposited by laser ablation were studied. It was shown that both phase composition and preferable orientation of films as well as optimal conditions for deposition can be found by means of Raman spectroscopy.