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Halide perovskites belong to an important family of semiconducting materials with unique electronic properties that enable a myriad of applications, especially in photovoltaics and optoelectronics. Their optical properties, including photoluminescence quantum yield, are affected and notably enhanced at crystal imperfections where the symmetry is broken and the density of states increases. These lattice distortions can be introduced through structural phase transitions, allowing charge gradients to appear near the interfaces between phase structures. In this work, we demonstrate controlled multi-phase structuring in a single perovskite crystal. The concept uses cesium lead bromine (CsPbBr3) placed on a thermoplasmonic TiN/Si metasurface and enables single, double and triple phase structures to form on demand above the room temperature. This approach opens up application horizons of dynamically controlled heterostructures with distinctive electronic and enhanced optical properties.

It is known that four peptide fragments of predominant protein in human semen Semenogelin 1 (SEM1) (SEM1(86–107), SEM1(68–107), SEM1(49–107) and SEM1(45–107)) are involved in fertilization and amyloid formation processes. In this work, the structure and dynamic behavior of SEM1(45–107) and SEM1(49–107) peptides and their N-domains were described. According to ThT fluorescence spectroscopy data, it was shown that the amyloid formation of SEM1(45–107) starts immediately after purification, which is not observed for SEM1(49–107). Seeing that the peptide amino acid sequence of SEM1(45–107) differs from SEM1(49–107) only by the presence of four additional amino acid residues in the N domain, these domains of both peptides were obtained via solid-phase synthesis and the difference in their dynamics and structure was investigated. SEM1(45–67) and SEM1(49–67) showed no principal difference in dynamic behavior in water solution. Furthermore, we obtained mostly disordered structures of SEM1(45–67) and SEM1(49–67). However, SEM1(45–67) contains a helix (E58-K60) and helix-like (S49-Q51) fragments. These helical fragments may rearrange into β-strands during amyloid formation process. Thus, the difference in full-length peptides’ (SEM1(45–107) and SEM1(49–107)) amyloid-forming behavior may be explained by the presence of a structured helix at the SEM1(45–107) N-terminus, which contributes to an increased rate of amyloid formation.

Chiral crystals remain one of the probable sources of first minute chiral symmetry breaking, a trigger that potentially causes an as-yet unknown type of asymmetric autocatalysis during the formation of chiral biopolymers under the conditions of the Archean Earth. Therefore, studying adsorption processes on the surface of such crystals may help improve the understanding of the nature of the initial chiral shift. The adsorptive activity of non-porous crystals with respect to the majority of organic molecules essentially depends on the ability of a crystal surface to engage in specific intermolecular interactions. In this work, the enantioselectivity provided by hippuric acid and phloroglucinol crystals, obtained under Viedma ripening conditions, was studied by the adsorption of menthol enantiomers from solutions and the adsorption of limonene and α-pinene enantiomers from vapors. To establish the reliability of chiral recognition, the experimental adsorption isotherms on chiral crystals were compared with the isotherms on achiral (racemic mixtures) crystals, obtained under similar conditions. The data obtained were confirmed using CD spectra, XRD patterns and SEM images. A

The first evidence of native cyclodextrins fusion was registered using fast scanning calorimetry (FSC) with heating rates up to 40,000 K s−1. The endothermal effects, detected at low heating rates, correspond to the decomposition processes. Upon the increase of the heating rate the onset of these effects shifts to higher temperatures, reaching a limiting value at high heating rates. The limiting temperatures were identified as the melting points of α-, β- and γ-cyclodextrins, as the decomposition processes are suppressed at high heating rates. For γ-cyclodextrin the fusion enthalpy was measured. The activation energies of thermal decomposition of cyclodextrins were determined by dependence of the observed thermal effects on heating rates from 4 K min−1 in conventional differential scanning calorimetry to 40,000 K s−1 in FSC. The lower thermal stability and activation energy of decomposition of β-cyclodextrin than for the other two cyclodextrins were found, which may be explained by preliminary phase transition and chemical reaction without mass loss. The obtained values of fusion parameters of cyclodextrins are needed in theoretical models widely used for prediction of solubility and solution rates and in preparation of cyclodextrin inclusion compounds involving heating.

Dantrolene represents yet another interesting example of abundant molecular crystal polymorphism existing in at least six different neat polymorphs, three of which can be obtained via crystallizati...

The past three decades have witnessed the rapid development of fast scanning calorimetry (FSC), a novel calorimetric technique that employs micromachined sensors. The key advances of this technique are the ultrahigh scanning rate, which can be as high as 106 K s–1, and the ultrahigh sensitivity, with a heat capacity resolution typically better than 1 nJ K–1. Nanocalorimetry has attracted much attention in materials science, where it is applied to perform quantitative analysis of rapid phase transitions, particularly on fast cooling. Another emerging area of application of FSC is physical chemistry, with a focus on the thermophysical properties of thermally labile compounds. Quantities like fusion temperature, fusion enthalpy, sublimation, and vaporization pressures and enthalpies of such molecules became available. This paper shortly reviews the development of FSC and summarizes its applications to various materials ranging from polymers (including proteins) to pharmaceuticals. Several of them are based on results from the laboratory of fast scanning calorimetry at Kazan Federal University, where applications of FSC, especially for biopolymers and low-molecular-mass organic compounds, were developed. Furthermore, FSC, coupled with structural characterization techniques, such as polarized optical (POM) and atomic force (AFM) microscopy, as well as infrared spectroscopy (IR), is presented. Finally, current challenges and future outlooks are discussed. Given the unique attributes of the technique, nanocalorimetry is expected to attract increasing attention, especially concerning the characterization of fast phase transitions and evaluation of thermally labile compounds.

A lot of processes, which are of great industrial importance, proceed according to the following schemes: A→P and A+B→C. Therefore, it is necessary to predict the course of such processes in a wide range of temperatures. A wide range of possible A→P (I) and A+B→C (II) type reactions between liquid reagents of various organic compound classes is considered. The effect of temperature on the volume change of such reactions is analyzed. The equations were derived allowing to calculate volume changes of isopolar reactions of I- and II-type at temperature range 230-390 K using the values of the volume change of reaction at T=298.15 K: ∆VT(I)= =∆V0(I)[1+(3.21±0.25)∙10-3(T−T0)]; ∆VT(II) = ∆V0(II)[1+(4.82±0.33)∙10-3(T−T0)].

The specific features of crystal nucleation widely determine the morphology of the evolving crystalline material. Crystal nucleation is, as a rule, not accessible by direct observation of the nuclei, which develop with time. This limitation is caused by the small size (nanometer scale) of the critical nuclei and the stochastic nature of their formation. We describe an experimental approach to the determination of specific features of the cluster size distribution employing fast scanning calorimetry at scanning rates up to 10 000 K s−1. The surviving cluster fraction is determined by selectively melting/dissolving clusters smaller than the critical size corresponding to the highest temperature of a short spike positioned between the nucleation and the development stage in Tammann’s two-stage method. This approach allows for estimating the time evolution of the radius of the largest detectable clusters in the distribution. Knowing this radius as a function of nucleation time allows for determining a radial growth rate. In the example of poly(l-lactic acid) (PLLA), the order of magnitude estimate of radial growth rates of clusters of about 2–5 nm yields values between 10−5 and 10−3 nm s−1. The radial growth rate of micrometer-sized spherulites is available from optical microscopy. The corresponding values are about three orders of magnitude higher than the values for the nanometer-sized clusters. This difference is explainable by stochastic effects, transient features, and the size dependence of the growth processes on the nanometer scale. The experimental and (order of magnitude) classical nucleation theory estimates agree well.

A convenient method for the synthesis of the first generation PAMAM dendrimers based on the thiacalix[4]arene has been developed for the first time. Three new PAMAM-calix-dendrimers with the macrocyclic core in cone, partial cone, and 1,3-alternate conformations were obtained with high yields. The interaction of the obtained compounds with salmon sperm DNA resulted in the formation of the associates of the size up to 200 nm, as shown by the UV-Vis spectroscopy, DLS, and TEM. It was demonstrated by the CD method that the structure of the DNA did not undergo significant changes upon binding. The PAMAM-calix-dendrimer based on the macrocycle in cone conformation stabilized DNA and prevented its degradation.

The crystal nucleation and overall crystallization kinetics of cross-linked poly(ε-caprolactone) was studied experimentally by fast scanning calorimetry in a wide temperature range. With an increasing degree of cross-linking, both the nucleation and crystallization half-times increase. Concurrently, the glass transition range shifts to higher temperatures. In contrast, the temperatures of the maximum nucleation and the overall crystallization rates remain the same independent of the degree of cross-linking. The cold crystallization peak temperature generally increases as a function of heating rate, reaching an asymptotic value near the temperature of the maximum growth rate. A theoretical interpretation of these results is given in terms of classical nucleation theory. In addition, it is shown that the average distance between the nearest cross-links is smaller than the estimated lamellae thickness, which indicates the inclusion of cross-links in the crystalline phase of the polymer.

As a result of bright complexation properties, easy functionalization and the ability to self-organize in an aqueous solution, amphiphilic supramolecular macrocycles are being actively studied for their application in nanomedicine (drug delivery systems, therapeutic and theranostic agents, and others). In this regard, it is important to study their potential toxic effects. Here, the synthesis of amphiphilic calix[4]resorcinarene carboxybetaines and their esters and the study of a number of their microbiological properties are presented: cytotoxic effect on normal and tumor cells and effect on cellular and non-cellular components of blood (hemotoxicity, anti-platelet effect, and anticoagulant activity). Additionally, the interaction of macrocycles with bovine serum albumin as a model plasma protein is estimated by various methods (fluorescence spectroscopy, synchronous fluorescence spectroscopy, circular dichroic spectroscopy, and dynamic light scattering). The results demonstrate the low toxicity of the macrocycles, their anti-platelet effects at the level of acetylsalicylic acid, and weak anticoagulant activity. The study of BSA–macrocycle interactions demonstrates the dependence on macrocycle hydrophilic/hydrophobic group structure; in the case of carboxybetaines, the formation of complexes prevents self-aggregation of BSA molecules in solution. The present study demonstrates new data on potential drug delivery nanosystems based on amphiphilic calix[4]resorcinarenes for their cytotoxicity and effects on blood components.

The solution calorimetry approach for determination of the fusion enthalpy at 298.15 K of aromatic compounds not capable of self-association was extended to those forming intermolecular hydrogen bonds. Two groups of such compounds, namely phenol and aniline derivatives, were investigated. From the solution enthalpies at 298.15 K of phenols in anisole and aromatic amines in aniline the fusion enthalpies at 298.15 K can be derived. Validity of the solution calorimetry approach was checked using differential scanning calorimetry and fast scanning calorimetry. The solution enthalpies of 12 compounds in anisole and aniline at 298.15 K and the fusion enthalpies at the melting temperature of 9 compounds were measured. Resorcinol, 1,6-dihydroxynaphthalene, and 1,3-diaminobenzene were additionally studied using fast scanning calorimetry. The molar heat capacities of crystalline 1,6-dihydroxynaphthalene and liquid 1,3-diaminobenzene were measured by conventional DSC in the wide temperature range.

Significant deviations were found between the solution enthalpy in benzene at 298.15 K and the fusion enthalpy at the melting temperature of 1,2,3,4-tetraphenylnaphthalene (3.9 ± 0.5 kJ mol−1 and 23.6 ± 0.6 kJ mol−1 (470.8 K), respectively) and 1,3,5-triphenylbenzene (20.1 ± 0.2 kJ mol−1 and 32.4 ± 1.2 kJ mol−1 (447.3 K)). These aromatic compounds are structurally related to benzene and their solution enthalpies in hypothetical liquid state at 298.15 K in benzene should be close to zero, so the differences between the solution enthalpy of crystal and the fusion enthalpy at the melting temperature should be attributed to the temperature dependence of the fusion enthalpy. Direct adjustment of the fusion enthalpy to 298.15 K requires knowledge of the supercooled liquid state heat capacity, which is hardly attainable by conventional methods due to fast crystallization. The heat capacities of 1,2,3,4-tetraphenylnaphthalene and 1,3,5-triphenylbenzene in liquid, deeply supercooled liquid, glassy and crystalline states were obtained for the first time by using fast scanning calorimetry in wide temperature ranges. Crystalline 1,2,3,4-tetraphenylnaphthalene heat capacity was measured over the temperature range from 323 to 410 K by conventional DSC. The temperature dependences of the heat capacities of the studied compounds in supercooled liquid state were fitted with the linear equations. The experimental results obtained by fast scanning calorimetry are in excellent agreement with the data obtained by solution calorimetry and conventional DSC.

In the present work, the thermochemistry of solution, solvation, and hydrogen bonding of cyclic amides in proton acceptor (B) and proton donor (RXH) solvents were studied. The infinite dilution solution enthalpies of δ-valerolactam, N-methylvalerolactam, ε-caprolactam, and N-methylcaprolactam were measured at 298.15 K. The solvation enthalpies of cyclic amides were calculated based on the measured solution enthalpies and sublimation/vaporization enthalpies from literature. The enthalpies of hydrogen bonding between cyclic amides and proton acceptor and donor solvents were then calculated as a difference between the total solvation enthalpy and the non-specific contribution. The latter was estimated via two different approaches in proton donor and proton accepting solvents. The effect of the cycle size on the strength of hydrogen bonding of the cyclic amides in solution is discussed.

Synthetic organic 2D materials are attracting careful attention of researchers due to their excellent functionality in various applications, including storage batteries, catalysis, thermoelectricity, advanced electronics, superconductors, optoelectronics, etc. In this work, thiacalix[4]arene derivatives functionalized by geranyl fragments at the lower rim in cone and 1,3-alternate conformations, that are capable of controlled self-assembly in a 2D nanostructures were synthesized. X-ray diffraction analysis showed the formation of 2D monomolecular-layer nanosheets from synthesized thiacalix[4]arenes, the distance between which depends on the stereoisomer used. It was established by DSC, FSC, and PXRD methods that the obtained macrocycles are capable of forming different crystalline polymorphs, moreover dimethyl sulphoxide (DMSO) is contributing to the formation of a more stable polymorph for cone stereoisomer. The obtained crystalline 2D materials based on synthesized thiacalix[4]arenes can find application in material science and medicine for the development of modern pharmaceuticals and new generation materials.

The use of the amorphous forms of drugs is a modern approach for the enhancement of bioavailability. At the same time, the high cooling rate needed to obtain the metastable amorphous state often prevents its investigation using conventional laboratory methods such as differential scanning calorimetry, X-ray powder diffractometry. One of the ways to overcome this problem may be the application of Fast Scanning Calorimetry. This method allows direct determination of the critical cooling rate of the melt and kinetic parameters of the crystallization for bad glass formers. In the present work, the amorphous states of dopamine hydrochloride and atenolol were created using Fast Scanning Calorimetry for the first time. Critical cooling rates and glass transition temperatures of these drugs were determined. Based on the values of the kinetic fragility parameter, dopamine hydrochloride glass can be considered strong, while atenolol glass is moderately strong. Both model-based and model-free approaches were employed to determine the kinetic parameters of cold crystallization of dopamine and atenolol. The results were compared with the data from isothermal crystallization experiments. The Nakamura crystallization model provides the best description of the crystallization process and can be used to predict the long term stability of the amorphous forms of the drugs. The presented approaches may find applications in predicting the storage time and choosing the optimal storage conditions of the amorphous drugs prone to crystallization.

Novel water-soluble multifunctional pillar[5]arenes containing amide-ammonium-amino acid moiety were synthesized. The compounds demonstrated a superior ability to bind (1S)-(+)-10-camphorsulfonic acid (S-CSA) and methyl orange dye depending on the nature of the substituent, resulting in the formation one-to-one complexes with both guests. The formation of host-guest complexes was confirmed by ultraviolet (UV), circular dichroism (CD) and 1H NMR spectroscopy. This work demonstrates the first case of using S-CSA as a chiral template for the non-covalent self-assembly of architectures based on pillar[5]arenes. It was shown that pillar[5]arenes with glycine or L-alanine fragments formed aggregates with average hydrodynamic diameters (d) of 165 and 238 nm, respectively. It was established that the addition of S-CSA to the L-alanine-containing derivative led to the formation of micron-sized aggregates with d of 713 nm. This study may advance the design novel stereoselective catalysts and transmembrane amino acid channels.

The present work represents interactions between the core-shell nanoparticles and different proteins, exemplified by lysozyme (LSZ), pepsin, bovine serum albumin (BSA), thioredoxin (TRX) and yellow fluorescent protein (YFP). The core-shell morphology derives from the non-covalent deposition of polyethyleneimine (PEI) onto nanoprecipitated luminescent complex (AuCl)2L (L is cyclic PNNP ligand). Analysis of the data obtained by DLS, CD spectroscopy, luminescence derived from both (AuCl)2L and YFP reveal the electrostatically driven interaction of negatively charged proteins with the shell of PEI-(AuCl)2L. The fluorescence of YFP enables to reveal the inclusion of the protein molecules into the shell. The lack of any luminescent response of PEI-(AuCl)2L on TRX conforms its electrostatically driven interactions with the shell which, in turn, excludes a binding of the exposed thiol moieties with (AuCl)2L. The negatively charged surface of pepsin provides the greatest recharging of the PEI-based shell versus the other proteins, which is followed by the enhanced luminescence of (AuCl)2L. The significant effect of PEI-(AuCl)2L on the CD spectra of LSZ followed by the decreased intensity of (AuCl)2L-based luminescence points to specific interaction mode of PEI-(AuCl)2L with LSZ. The flow cytometry and fluorescent microscopy measurements revealed efficient internalization of PEI-(AuCl)2L into the Wi-38 cell samples resulting in the efficient staining of all cell organelles. The concentration dependent cytotoxicity of PEI-(AuCl)2L is detectably enhanced by LSZ, which is correlated with its interaction mode with the nanoparticles.

Controlling the self-assembly of polyfunctional compounds in interpolyelectrolyte aggregates is an extremely challenging task. The use of macrocyclic compounds offers new opportunities in design of a new generation of mixed nanoparticles. This approach allows creating aggregates with multivalent molecular recognition, improved binding efficiency and selectivity. In this paper, we reported a straightforward approach to the synthesis of interpolyelectrolytes by co-assembling of the thiacalix[4]arene with four negatively charged functional groups on the one side of macrocycle, and pillar[5]arene with 10 ammonium groups located on both sides. Nanostructured polyelectrolyte complexes show effective packaging of high-molecular DNA from calf thymus. The interaction of co-interpolyelectrolytes with the DNA is completely different from the interaction of the pillar[5]arene with the DNA. Two different complexes with DNA, i.e., micelleplex- and polyplex-type, were formed. The DNA in both cases preserved its secondary structure in native B form without distorting helicity. The presented approach provides important advantage for the design of effective biomolecular gene delivery systems.

Fusion enthalpy temperature dependence is related to the difference in heat capacity of the liquid and solid. Below the melting temperature, it is hard to measure the liquid heat capacity using conventional methods due to fast crystallization. Based on an indirect solution calorimetry approach, we previously concluded that the temperature dependence of heat capacities below the melting temperature is the extrapolation of the linear function above it. In this study, we employed a fast scanning calorimetry technique to test the validity of this conclusion. Three compounds were studied: two organic glass formers, benzophenone and o-terphenyl, for which the liquid and supercooled liquid heat capacities were known to be accurately described by a linear function of temperature, and m-terphenyl, which had never been studied in the supercooled liquid state. The results were in good agreement with the literature for liquid benzophenone and o-terphenyl heat capacities above and below the melting temperature. The heat capacity of the supercooled liquid and glassy m-terphenyl was obtained for the first time. The measured molar heat capacity of supercooled liquid m-terphenyl was the linear extrapolation of the temperature dependence of the heat capacity of the melt found in the literature. The molar heat capacity of the solid, the enthalpy and fusion temperature of m-terphenyl were determined by conventional DSC. Kirchhoff’s integral, calculated from the measured molar heat capacities of solid and liquid m-terphenyl, was in accordance with the fusion and solution thermochemistry data.

Background Protein denaturation is often studied using differential scanning calorimetry (DSC). However, conventional instruments are limited in the temperature scanning rate available. Fast scanning calorimetry (FSC) provides an ability to study processes at much higher rates while using extremely small sample masses [ng]. This makes it a very interesting technique for protein investigation. Methods A combination of conventional DSC and fast scanning calorimeters was used to study denaturation of lysozyme dissolved in glycerol. Glycerol was chosen as a solvent to prevent evaporation from the micro-sized samples of the fast scanning calorimeter. Results The lysozyme denaturation temperatures in the range of scanning rates from 5 K/min to ca. 500,000 K/min follow the Arrhenius law. The experimental results for FSC and conventional DSC fall into two distinct clusters in a Kissinger plot, which are well approximated by two parallel straight lines. Conclusions The transition temperatures for the unfolding process measured on fast scanning calorimetry sensor are significantly lower than what could be expected from the results of conventional DSC using extrapolation to high scanning rates. Evidence for the influence of the relative surface area on the unfolding temperature was found. General significance For the first time, fast scanning calorimetry was employed to study protein denaturation with a range of temperature scanning rates of 5 orders of magnitude. Decreased thermal stability of the micro-sized samples on the fast scanning calorimeter raise caution over using bulk solution thermal stability data of proteins for applications where micro-sized dispersed protein solutions are used, e.g., spray drying.

This work is devoted to the quantitative study of hydrogen bond formation of N-alkyl substituted ionic liquids with proton acceptor and proton donor organic solvents. 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM][NTf2], 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO], 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], triethylsulfonium bis(trifluoromethylsulfonyl)imide [Et3S][NTf2], 1-butyl-3-methylimidazolium tricyanomethanide [BMIM][TCM], 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF4] were investigated by solution calorimetry and FTIR-spectroscopy techniques. The stretching vibration region of C O group of 2-pentanone in mixture with N-alkyl substituted ionic liquid in inert solvent carbon tetrachloride was analyzed at different concentrations of components for the estimation of proton donor ability of ionic liquids. Also, the stretching vibration region of the OH-group of methanol was studied in a ternary system carbon tetrachloride (inert solvent), methanol (proton donor) and N-alkyl substituted ionic liquid for the estimation of proton acceptor ability of ionic liquids. The hydrogen bond enthalpy of methanol in ionic liquids was calculated using data of measured solution enthalpies and data extracted from the literature. The frequency shifts of the OH-group of methanol induced by intermolecular interactions within ionic liquids in a carbon tetrachloride solution were compared with the hydrogen bonding enthalpies of methanol with ionic liquids. A linear relationship between the frequency shifts of the OH-groups and hydrogen binding enthalpies of methanol in ionic liquids were found. According to measured FTIR-spectroscopy data, the N-alkyl substituted ionic liquids analyzed in this work possess weak proton donor properties, and at the same time their proton acceptor ability (basicity) is much higher and shows dependency on anion structure.

The present work introduces an impact of polyelectrolyte-based hydrophilic shell on magnetic relaxivity and luminescence of hard cores built from isostructural complexes of Tb(III) and Gd(III) in the core-shell aqueous colloids. Microscopic and scattering techniques reveal "plum pudding" morphology of the colloids, where polyelectrolyte-coated ultrasmall (5nm) hard cores form aggregates in aqueous solutions. Interaction of bovine serum albumin (BSA) with the colloids provides a tool to modify the polyelectrolyte-based shell, which is the reason for the improvement in both aggregation behavior of the colloids and their relaxivity. The modification of the hydrophilic polyelectrolyte-based shell enables to tune the longitudinal relaxivity from 5.9 to 23.3mM

For the first time thiacalix[4]arene derivatives in 1,3-alternate conformation simultaneously containing amide, carboxyl and hydroxyl groups capable of forming 1 : 1 stoichiometry complexes with dopamine hydrochloride were obtained. The efficiency of dopamine hydrochloride binding was evaluated by a number of spectral methods. Using the methods of fluorescent, UV-Vis and NMR spectroscopy, the mechanism of interaction of the synthesized macrocycles with dopamine has been studied. It was shown that quenching of dopamine fluorescence by the studied macrocycles is carried out through a static mechanism.

In this work, we adapted a procedure for vapor pressures determination utilizing a fast scanning chip calorimeter to the case of a stagnant gas phase. The validity of the developed procedure was checked by comparing the vapor pressures determined in this work for several polyaromatic, heteroaromatic, and long-chain compounds with reliable vapor pressure data available in the literature. The results of the comparison show that the commercial Flash DSC 1 and the Flash DSC 2+ (Mettler Toledo, Switzerland) can be used for a reliable appraisal of the vapor pressures in a wide temperature range, which allows using these devices without additional technical changes as a source of comprehensive and internally consistent information about the energy of phase transitions.

In this work, we have studied the thermochemistry of the hydrogen bond formation between ionic liquids and solute molecules. The solution enthalpies of several organic compounds (benzene, acetone, 3-picoline dimethylsulfoxide, formamide, N-methylformamide, acetamide, N-methylacetamide) in the series of ionic liquids with common anion bis(trifluoromethanesulfonyl)imide and different cations (1-butyl-3-methylimidazolium [BMIM][NTf2], 1-butyl-1-methylpyrrolidinium [BMPYR][NTf2], 1-butylpyridinium [BPY][NTf2], 1-butyl-1-methylpiperidinium [BMPIP][NTf2], trimethylpropylammonium [TMPAm][NTf2]) were measured by solution calorimetry at infinite dilution. The enthalpies of hydrogen bond between solutes and ionic liquids were determined by the previously proposed approach. The hydrogen bond enthalpies were correlated with the proton acceptor ability of ionic liquids from the Kamlet-Abboud-Taft equation and the proton donor ability of amides from the Abraham model. The proton donor ability and hydrogen bond reorganization of studied ionic liquids was analyzed. The formation of the hydrogen bond complexes of linear amides with ionic liquids with different compositions was shown. The effect of the ionic liquid structure on the strength of the hydrogen bond of linear amides with ionic liquids has been established.

Thermophysical properties in the melting range of cytosine, one of the five nucleobases of DNA and RNA, are hard to determine because of the low thermal stability of the compound and the high vapor pressure. As for other biomolecules fast heating rates allow melting of cytosine without detectable decomposition. By applying fast scanning calorimetry with the heating rate at 6000 K s−1 we succeeded to avoid decomposition and determine the melting temperature of cytosine (extrapolated to zero heating rate), as Tfus = (606 ± 4) K, the glass transition temperature of the supercooled liquid state as Tg = (388 ± 3) K, cold-crystallization temperature as Tcryst = (448 ± 8) K, and the liquid state molar heat capacity C p , m ° ( l ) = (272 ± 2) J mol−1 K−1 at 423 K. Taking into account the temperature dependent mass loss of the nanogram sized sample (up to 25% during the melting scan) we obtained the molar enthalpy of fusion of cytosine as Δ c r l H ( T f u s ) = (35 ± 4) kJ mol−1 in good agreement with the adjusted molar enthalpy of crystallization Δ l c r H ( T f u s ) = (34 ± 2) kJ mol−1.

New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86–134 nm in diameter in water at a concentration of 1 × 10−4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical) properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule.

The work introduces Tb(III)-centered luminescence of amino-modified silica nanoparticles doped with Tb(III) complexes for cellular imaging. For these purposes water-in-oil procedure was optimized for synthesis of 20 and 35nm luminescent nanoparticles with amino-groups embedded on the surface. The obtained results indicate an impact of the nanoparticle size in decoration, aggregation behavior and luminescent properties of the nanoparticles in protein-based buffer solutions. Formation of a protein-based corona on the nanoparticles surface was revealed through the effect of the nanoparticles on helical superstructure of BSA. This effect is evident from CD spectral data, while no any size impact on the adsorption of BSA onto aminomodified silica surface was observed. Cellular uptake of the nanoparticles studied by confocal and TEM microscopy methods indicates greater cellular uptake for the smaller nanoparticles. Cytotoxicity of the nanoparticles was found to agree well with their cellular uptake behavior, which in turn was found to be greater for the smaller nanoparticles.

A lot of pharmaceutical substances have a poor solubility that limits their absorption and distribution to the targeted sites to elicit the desired action without causing untoward effects on healthy cells or tissues. For such drugs, new modes of delivery have to be developed for efficient and effective delivery of the drug to the target site. Formation of magnetically active solid dispersion of such drugs could be a useful approach to addressing this problem because they combine targeted delivery and good solubility. In this work, the distribution of superparamagnetic nanoparticles in the solid dispersion of polyethylene glycol with average molecular weight 950–1050 g/mol and phenacetin was studied using atomic force and magnetic force microscopy. The distribution of nanoparticles was found to be uniform in studied composites. Magnetically active solid dispersions may find application in the production of the capsulated drug delivery systems with enhanced solubility parameters.

The thermal stability of proteins in the presence of organic solvents and the search for ways to increase this stability are important topics in industrial biocatalysis and protein engineering. The denaturation of hen egg-white lysozyme in mixtures of water with dimethyl sulfoxide (DMSO) with a broad range of compositions was studied using a combination of differential scanning calorimetry (DSC), circular dichroism (CD), and spectrofluorimetry techniques. In this study, for the first time, the kinetics of unfolding of lysozyme in DMSO&ndash, water mixtures was characterized. In the presence of DMSO, a sharp decrease in near-UV CD and an increase in the fluorescence signal were observed at lower temperatures than the DSC denaturation peak. It was found that differences in the temperatures of the CD and DSC signal changes increase as the content of DMSO increases. Changes in CD and fluorescence are triggered by a break of the tertiary contacts, leading to an intermediate state, while the DSC peak corresponds to a subsequent complete loss of the native structure. In this way, the commonly used two-state model was proven to be unsuitable to describe the unfolding of lysozyme in the presence of DMSO. In kinetic studies, it was found that even high concentrations of DMSO do not drastically change the activation energy of the initial stage of unfolding associated with a disruption of the tertiary structure, while the enthalpy of denaturation shows a significant dependence on DMSO content. This observation suggests that the structure of the transition state upon unfolding remains similar to the structure of the native state.

One of the main tasks of modern pharmaceutics is enhancing the solubility of drugs. The approaches for solving this problem include producing active pharmaceutical ingredients in the amorphous state. However, the use of amorphous drugs requires the determination of their kinetic stability. The latter is often assessed using isothermal techniques, which are time-consuming. Alternatively, non-isothermal methods can be employed, allowing to determine the kinetic triplet more rapidly. Also, such techniques can be used to develop predictive models for storage stability. The production of the amorphous state itself typically requires fast cooling rates, which may not be easily accessible. Fast scanning calorimetry is a promising tool for the investigation of amorphous drug systems. In the present work, the crystallization of the model drug dipyridamole was investigated using the fast scanning calorimetry method. The kinetic stability of the amorphous form of the drug was evaluated using both, isothermal and non-isothermal methods. The Nakamura crystallization model was found to be applicable for the prediction of the temporal stability of the amorphous drug forms. The obtained results may find applications in the investigation of the kinetic stability of amorphous drug systems.

Thermal treatment of short-chain oligopeptides is able to initiate the process of their self-assembly with the formation of organic nanostructures with unique properties. On the other hand, heating can lead to a chemical reaction with the formation of new substances with specific properties and ability to form structures with different morphology. Therefore, in order to have a desired process, researcher needs to find its temperature range. In the present work, cyclization of L -isoleucyl-L -alanine dipeptide in the solid state upon heating was studied. Kinetic parameters of this reaction were estimated within the approaches of the nonisothermal kinetics. The correlation between side chain structure of dipeptides and temperature of their cyclization in the solid state was found for the first time. This correlation may be used to predict the temperature, at which dipeptide self-assembly changes to chemical reaction. The differences in self-assembly of linear and cyclic dipeptides were demonstrated using atomic force microscopy. The effect of dipeptide concentration in a source solution and an organic solvent used on self-assembly of dipeptides was shown. The new information obtained on the thermal properties and self-assembly of linear and cyclic forms of L -isoleucyl-L -alanine may be useful for the design of new nanomaterials based on oligopeptides, as well as for the synthesis of cyclic oligopeptides.

A nanocarrier (p(6SRA-5B)) for glucose-controlled insulin delivery consists of sulfonated resorcinarenes (SRA) that are assembled into a spherical shell and are attached to each other with phenylboronate linkers. p(6SRA-5B) is stable in water and blood plasma at normal glucose concentrations. At high glucose levels (>5 mM), p(6SRA-5B) dissociates into SRA and phenylboronates through competitive interaction with excess glucose. Insulin was successfully encapsulated into the cavity of p(6SRA-5B) and its release was investigated in water and blood plasma by NMR, UV, CD, and fluorescence spectroscopy. The results show that the dissociation of the nanocarrier and the insulin release occurs with an increase in glucose concentration. At 5 mM glucose, the nanocarrier is stable, and the insulin release does not exceed 10 %. Increasing the glucose concentration to 7.5-10 mM results in a 40-100 % insulin release. p(6SRA-5B) is thus a promising insulin nanocarrier for the treatment of type 1 diabetes.

Thermal treatment of short-chain oligopeptides is able to initiate the process of their self-assembly with the formation of organic nanostructures with unique properties. On the other hand, heating can lead to a chemical reaction with the formation of new substances with specific properties and ability to form structures with different morphology. Therefore, in order to have a desired process, researcher needs to find its temperature range. In the present work, cyclization of

In this paper, we report two approaches for the synthesis of nanostructured materials using two polyfunctional α-aminophosphonic acid derivatives of the thiacalix[4]arene. There are (1) the metal-organic framework approach using bridging sulfur atoms of cyclophane and (2) interpolyelectrolyte approach using polyfunctional substituents on the lower rim of the macrocyclic platform. It was found that the preferred formation of the metal-organic framework between thiacalix[4]arene and Ag+ is due to the coordination of the Ag+ with sulfur atoms. The second approach based on the synthesis of interpolyelectrolyte nanoparticles produces new nanomaterials for biomedical application. We studied the interaction of two types of interpolyelectrolyte nanoparticles with model proteins (lysozyme, bovine serum albumin and hemoglobin). These polyelectrolyte nanoparticles are capable to selectively binding of the lysozyme while maintaining protein conformation. It can be used to develop supramolecular systems for medical diagnostics and therapeutic purposes.