The iron(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with the lithium cation Li[FeIII(thpy)2]·3H2O (1) has been synthesized and characterized by FTIR spectroscopy, powder and single crystal X-ray diffraction, direct current magnetic susceptibility measurements, and 57Fe Mössbauer spectroscopy. Moreover, the molecular structure of the [Fe(thpy)2]- anion has been determined for the first time. The [Fe(thpy)2]- units in the triclinic P1̄ lattice of 1 are assembled into layers parallel to the bc plane. The Li+ cations and water molecules are located between the layers and the structure is stabilized by hydrogen bonding. The [Fe(thpy)2]- anions form interconnected dimer pairs through hydrogen bonds and short contacts with Fe⋯Fe separation of 6.7861(4) Å. According to dc magnetic measurements, compound 1 demonstrates an incipient spin-crossover transition from the LS (S = 1/2) to the HS (S = 5/2) state above 250 K. The Bleaney-Bowers equation for a model of an isolated LS dimer with a mean-field correction was applied to fit the experimental data of magnetic susceptibility dependence on temperature in the temperature range of 2-250 K. The intra-dimer J1 = -1.79(1) K and inter-dimer J2 = -0.24(3) K antiferromagnetic coupling constants were defined. The analysis of the 57Fe Mössbauer spectra at 80 K and 296 K confirms the presence of the shortened distances between the iron nuclei. Moreover, the influence of the lithium cation on the stabilization of the LS state was shown for the [Fe(thpy)2]- anion. BS-DFT calculations for the optimized structure of two isolated [Fe(thpy)2]- anions also correctly predict a weak exchange J1(calc) = -0.92 K. DFT calculations revealed the OPBE (GGA-type) functional that correctly predicts the spin-crossover transition for the iron(III) thpy compounds. Besides, the effect of the N2O4, N2S2O2, and N2Se2O2 coordination environments on the energy stabilization of the LS state of iron(III) anionic thpy complexes was noted as well.

As a result of the electrochemical oxidation process, the [Fe-III(5Cl-thsa)(2)] spin-crossover (SCO) anion with N2S2O2 coordination sphere transforms into N4O2-coordinated Fe-III SCO neutral binuclear complex 2 with twist of two disulfide bridges. Each dimeric complex is a binuclear double-stranded helicate with similar chirality of both Fe centers. The crystal structure of the complex 2 center dot 3H(2)O at 100 K has a monoclinic C2/c space group and contains large cavities (about 21.5% of the unit cell volume) half-filled by 3 water molecules per one dimer. The N4O2 coordination of iron(III) with two oxygen atoms ( O) of phenoxy groups, two imine-type (-N-im-) nitrogen atoms of azomethine groups, one amidrazone-type (=NamidH) nitrogen atom and one ionized terminal group (-NionizH) of nitrogen has not been observed in CCDC so far. The oxidation state of the iron atoms in the dimeric complex was confirmed by Fe-57 Mossbauer spectroscopy on 90% enriched Fe-57 sample. Mossbauer spectra and dc magnetic measurements demonstrated the partial HS-HS!LS-LS SCO in the 185-225 K temperature range. The details of the structure of complex 2 and the features of its magnetic properties were refined by theoretical analysis based on DFT calculations. The B3LYP* functional correctly predicting the energy of the spin-crossover process was revealed.

The nonlinear optical responses of perovskite films CsPbI2Br, MAPbI3 + 1% PVC, MA0.15FA0.75Cs0.1PbI2.85Br0.15, and MA0.15FA0.75Cs0.1PbI3, irradiated by femtosecond laser pulses with wavelengths of 1064 and 532 nm, are investigated using z-scan measurements. Nonlinear absorption is found to occur in perovskite films irradiated at a wavelength of 1064 nm; the nonlinear absorption coefficient in thin films (45 – 65 nm) greatly exceeds that in thick ones (120 – 350 nm): 524 – 928 and 38 – 50 cm GW−1, respectively. It is shown that the nonlinear absorption saturation intensity for perovskite films depends on the pump pulse duration and increases with pulse shortening. It is also established that the nonlinear absorption coefficient of organometallic perovskite films exceeds that of a film of inorganic perovskite CsPbI2Br. Bleaching of film samples during z-scanning at a wavelength of 532 nm is related to the irreversible photochemical degradation of films exposed to intense light. The kinetics of photochemical bleaching of the films is detected at a wavelength of 532 nm.

The multi‐magnetic salt [Fe(3‐OMe‐Sal2trien)][Fe(tdas)2]·CH3CN (1) has been prepared and fully characterized by a variety of methods. The crystal structure of 1, determined at 150, 297 and 350 K, consists of alternating layers composed by a parallel arrangement of the chains of isolated π–π coupled cation pairs of [Fe(3‐OMe‐Sal2trien)]+ and anion pairs of [Fe(tdas)2]–. The complex magnetic behavior of this salt is consistent with the sum of the contributions from spin‐crossover (SCO) cations and strong antiferromagnetically (AFM) coupled dimeric [Fe(tdas)2]22– anions. The observed gradual thermally induced spin transition (T1/2 = 195 K) is relatable to the cation exhibiting disordering of ethylene (–CH2–CH2–) groups between two conformers with a narrow thermal hysteresis of 6 K. The dc magnetization measurements and 57Fe Mössbauer spectroscopy at room temperature are in excellent agreement between γHS(%) value and ratio of disordering of ethylene groups obtained from X‐ray analysis. Mössbauer spectra at 80 K and 296 K indicate a spin transition between S = 1/2 and S = 5/2 for the iron(III) saltrien‐cation and confirms S = 3/2 for the [FeIII(tdas)2]– anion. The experimental results are supplemented with a theoretical Density Functional Theory (DFT) analysis.

Polytetrafluoroethylene-based aerogel has been synthesized for the first time. Graphene oxide has been used as a binder. After reduction with hydrazine and annealing at 370°C, the aerogel surface has been found to become superhydrophobic (the contact angle of water is 162°). Superhydrophobic aerogel with a specific gravity of 30 mg/cm 3 has been characterized by IR spectroscopy and X-ray photoelectron spectroscopy.

Aerogel is obtained from graphene oxide reduced by a mixture of H 3 PO 2 and I 2 . The porous structure of an aerogel has been studied at room temperature using the method of standard contact porosimetry. Both water and octane were used as working fluids, which allowed us to study the pore size distributions of hydrophilic and hydrophobic pores separately. It was found that very small pores, with the radius < 2.5 nm, and very large pores, with the radius more than 100 nm, were mostly hydrophobic, while the intermediate pores were hydrophilic.

The optical nonlinear absorption and bleaching of aqueous suspensions of multilayer MoS2 sheets (structural modification 2H) under excitation by a 400-fs pulse at a wavelength of 514 nm is investigated using longitudinal scanning. The sample exhibits nonlinear absorption at intensities up to 15 GW cm−2, while a further increase in intensity to 70 GW cm−2 causes nonlinear bleaching with a relative change in transmission to 14 %. The dynamics of interband transitions in the picosecond range is studied by femtosecond laser photolysis. The relaxation time of photoexcited excitons is measured to be 20 ± 2 ps. The transition dynamics is calculated in the three-level approximation, and the absorption cross sections of photoinduced electron transitions from the valence band to the conduction band and from the first to the second conduction band are estimated. It is shown that the optical nonlinear properties of suspensions of multilayer 2H MoS2 sheets are mainly determined by the dynamics of single-photon interband transitions.

This work is dedicated to low-molecular hydrogels based on biodegradable sodium deoxycholate (SDC) and lysine hydrochloride (lys × HCl) with magnesium octa-[(4'-benzo-15-crown-5)-oxy]phthalocyaninate (Mgcr 8 Pc) as the active component, namely, their synthesis, spectral properties of gel-solubilized Mgcr 8 Pc, its release from the gel etc. Addition of Mgcr 8 Pc occurs both via the mixing of the components and via its diffusion from the aqueous solution into the phase of the formed SDC/lys × HCl gel. Mgcr 8 Pc-containing hydrogels are thermoreversible. The state of Mgcr 8 Pc in the SDC/lys × HCl/NaCl gel at the room temperature and in the melt is studied using spectral methods. Gel melting releases Mgcr 8 Pc in the form of a micelle-bound monomer. The presence of the Mgcr 8 Pc monomer phase in the phthalocyanine-carrying supramolecular hydrogel causes fluorescent activity of the latter.

A suspension formed as a result of ultrasonication of a mixture of graphite with N,N-dimethylformamide has been studied by 1H NMR spectroscopy. The dependence of the width of the 1H NMR signal on the N,N-dimethylformamide content of the suspension has been determined.

At first, a granulated aerogel of graphene oxide was obtained, which was later reduced by hydrazine vapour. The reduced aerogel was characterized through elemental analysis, infrared (IR) and Raman spectroscopy, electron paramagnetic resonance (EPR), thermogravimetric analyses (TGA), voltammetry, and X-ray photoelectron spectroscopy (XPS). Furthermore, the reduced sample was found to contain approximately 3 wt.% of nitrogen, which was present in the aerogel in three states corresponding to the photoelectron peaks N1s with binding energies of 399.5, 401.3, and 403.6 eV. In the electroreduction of oxygen, an appreciable catalytic effect was observed for the sample under study, which resulted from reducing the overvoltage of the reaction by ~90 mV and changing the mechanism of reduction.

A graphene oxide aerogel synthesized from graphene oxide hydrogel and graphene aerogels have been synthesized using the sol−gel method by reducing a suspension of graphene oxide with various reducing agents: a mixture of hypophosphorous acid and iodine, L-ascorbic acid, sodium metabisulfite, and by hydrothermal treatment. The obtained aerogels have been studied by scanning electron microscopy, IR spectroscopy, Raman spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. Comparative studies of graphene aerogels have shown that their properties, namely density, specific surface area, reduction degree, surface morphology, defectiveness of graphene sheets, interlayer spacing, average sizes of coherent scattering regions, number of layers, and crystallite size in the basal plane in graphene crystallites depend on the method of synthesis.

It has been found that ultrasonic irradiation of graphite in N-methylpyrrolidone is accompanied by the formation of polymer nanoparticles. These particles form aggregates with n-layered graphene particles, the formation of which prevents graphene particles from precipitation during centrifugation.

In continuation of our previous studies, we explored the solubilization of crown-and sulfophthalocyanines in the presence of bile salts (BS), sodium deoxycholate, and sodium taurodeoxycholate. The formation of BS-based lowmolecular-weight hydrogels was observed and their modification with 15-crown-5-phthalocyanines was studied. Some characteristics of hybrid gels and xerogels are presented, and the process of prolonged release of active component from gel under the action of external stimuli was studied in detail.

Two materials have been derived from a composite of humic acid and graphene oxide (HA-GO). First material was obtained by high-temperature carbonization of the HA-GO composite in an inert atmosphere, and second material was produced by reduction of the HA-GO composite with hydrazine hydrate. The results of comparative studies of the materials using IR, Raman and XPS spectroscopies are presented. In IR spectra, no absorption due to stretching of vibrations O H is observed for both the materials. The XPS spectra of humic acids and its composite show sufficiently high content of carbon atoms, which are bonded with oxygen atoms, the Cls peak in the XPS spectra of both the materials under study show asymmetry inherent of graphite material, which confirms the outcomes of IR and Raman studies. This could be attributed to high conductivity of the materials. It has also been established that specific surface area SBET is equal to 36.2 and 6.5 m(2)/g for thermally treated composite and chemically treated composites materials, respectively. However, the values of specific surface area SKI; measured by the method of standard contact porosimetry with octane as a working liquid, is equal to 470 m(2)/g and 200 m(2)/g in the case of thermally treated composite and chemically treated composites materials, respectively. (C) 2017 Elsevier Inc. All rights reserved.

A technique is described for producing 2D-printing ink based on ultrasound exfoliated graphite (UEG). It has been established that the conductivity of a film obtained by microfiltration of such ink is 26.4 S/cm. Data on the morphology, composition, and IR spectra of UEG films are provided and compared with analogous data for reduced graphene-oxide films.