Solid-Phase Extraction at High pH as a Promising Tool for Targeted Isolation of Biologically Active Fractions of Humic Acids

A search for novel sources of biologically active compounds is at the top of the agenda for biomedical technologies. Natural humic substances (HSs) contain a large variety of different chemotypes, such as condensed tannins, hydrolyzable tannins, terpenoids, lignins, etc. The goal of this work was to develop an efficient separation technique based on solid-phase extraction (SPE) for the isolation of narrow fractions of HS with higher biological activity compared to the initial material. We used lignite humic acid as the parent humic material, which showed moderate inhibition activity toward beta-lactamase TEM 1 and antioxidant activity. We applied two different SPE techniques: the first one was based on a gradient elution with water/methanol mixtures of the humic material sorbed at pH 2, and the second one implied separation by a difference in the pKa value by the use of sequential sorption of HS at pH from 8 to 3. SPE cartridges Bond Elute PPL (Agilent) were used in the fractionation experiments. The first and second techniques yielded 9 and 7 fractions, respectively. All fractions were characterized using high-resolution mass spectrometry and biological assays, including the determination of beta-lactamase (TEM 1) inhibition activity and antioxidant activity. The acidity-based separation technique demonstrated substantial advantages: it enabled the isolation of components, outcompeting the initial material at the first step of separation (sorption at pH 8). It showed moderate orthogonality in separation with regard to the polarity-based technique. Good perspectives are shown for developing a 2D separation scheme using a combination of polarity and acidity-based approaches to reduce structural heterogeneity of the narrow fractions of HS.

1,2-Bis(triazolyl)tetraphenyldigermanes: Synthesis, Structure and Properties

Using the [3+2] cycloaddition reaction of [HC≡C-GePh2 -]2 (1) and a number of RCH2 N3 , this work described the synthesis of a series of novel heterocyclic digermanes, bitriazoles [1,4-C2 HN3 (CH2 R)GePh2 -]2 , 2-12 (R=Ph, p-Tol, p-C6 H4 NMe2 , p-C6 H4 OMe, p-C6 H4 Br, m-C6 H4 NO2 , 2-Naphth, CH2 -p-OC6 H4 CHO, CH2 -p-OC6 H4 COOMe, CH2 P(O)(OEt)2 , COOEt), difficult to produce by other methods. The structural peculiarities of these compounds were studied in detail by NMR spectroscopy and by XRD analysis (for 6, 9 and 10). The properties of 1-12 were studied by UV/vis and luminescence emission spectroscopy, electrochemistry and DFT calculations, indicating an effective conjugation in their molecules.

Structural Motifs in Aryl Organogermanium Ge-O Derivatives for Material Design

The aim of this work was to understand the main structural features and ways of formation of Ge-O bonds in organogermanium compounds under the conditions of ArnGeHal4-n (Hal = halide) hydrolysis. The structural types of these compounds were considered, providing 11 blocks (A-K). The molecular structures of the novel compounds [(p-FC6H4)3Ge]2O (1), [(p-F3CC6H4)3Ge]2O (2), and cyclo-[(p-F3CC6H4)2GeO]4 (3) were studied through XRD (X-ray diffraction) analysis. The molecular structure of [(p-F3CC6H4)3GeO]4Ge (4), representing a novel structural type, was also investigated. The data presented in this study will be important in the design of materials with useful properties based on group 14 element derivatives with element-oxygen bonding.

Comparative Analysis of Stress-Protective Activity and Prevention of Fatigue during Physical Load of Standardized Humic Acids from Peat and Officinal Preparations of Succinic Acid in Experiment

The effect of humic acids and substances with similar action - derivatives of succinic acid (ethylmethylhydroxypyridine succinate) and combined agent consisting of succinic acid, nicotinamide, riboflavin, and riboxin on the performance and stress resistance of experimental rats was studied. Performance was assessed in the test of exhaustive forced swimming with a load, stress resistance was evaluated by the serum level of corticosterone and open field behavior, and the state of anaerobic metabolism was estimated by the serum level of lactate after swimming test. Humic acids from peat showed anti-stress activity comparable to that of the officinal preparation and preventive effect on fatigue during physical exercise. They can be recommended as a component for the development of drugs that increase human performance and stress resistance.

Germanium Complexes with ONO Tridentate Ligands: O-H Bond Activation Control According to DFT Calculations

Polydentate ligands are used for thermodynamic stabilization of tetrylenes-low-valent derivatives of Group 14 elements (E = Si, Ge, Sn, Pb). This work shows by DFT calculations how the structure (the presence or absence of substituents) and type (alcoholic, Alk, or phenolic, Ar) of tridentate ligands 2,6-pyridinobis(1,2-ethanols) [^AlkONO^R]H₂ and 2,6-pyridinobis(1,2-phenols) [^ArONO^R]H₂ (R = H, Me) may affect the reactivity or stabilization of tetrylene, indicating the unprecedented behavior of Main Group elements. This enables the unique control of the type of the occurring reaction. We found that unhindered [ONO^H]H₂ ligands predominantly led to hypercoordinated bis-liganded {[ONO^H]}₂Ge complexes, where an E(+2) intermediate was inserted into the ArO-H bond with subsequent H₂ evolution. In contrast, substituted [ONO^Me]H₂ ligands gave [ONO^Me]Ge: germylenes, which may be regarded as kinetic stabilized products; their transformation into E(+4) species is also thermodynamically favorable. The latter reaction is more probable for phenolic [^ArONO]H₂ ligands than for alcoholic [^AlkONO]H₂. The thermodynamics and possible intermediates of the reactions were also investigated.

Aluminum Salen Complexes Modified with Unsaturated Alcohol: Synthesis, Characterization, and Their Activity towards Ring-Opening Polymerization of ε-Caprolactone and D,L-Lactide

A highly efficient one-step approach to the macromonomer synthesis using modified aluminum complexes as catalysts of ring-opening polymerization (ROP) of ε-caprolactone and D,L-lactide was developed. The syntheses, structures, and catalytic activities of a wide range of aluminum salen complexes, 3a-c, functionalized with unsaturated alcohol (HO(CH₂)₄OCH=CH₂) are reported. X-Ray diffraction studies revealed a tetragonal pyramidal structure for 3c. Among the complexes 3a-c, the highest activity in bulk ROP of ε-caprolactone and D,L-lactide was displayed by 3b, affording polyesters with controlled molecular weights at low monomer to initiator ratios (M_n up to 15,000 g mol^-1), relatively high polydispersities (Ð~1.8) and high number-average functionalities (F_n up to 85%).

Formation of Azaphilone Pigments and Monasnicotinic Acid by the Fungus Aspergillus cavernicola

Due to the ever-increasing demand for healthy and safe food, much attention has been gained by natural food colorants. This study showed the culture fluid extract of the fungus Aspergillus cavernicola VKM F-906 to contain red pigment and monasnicotinic acid (MNA) in predominant amounts. The structure of the pigment corresponded to cis-cavernamine (red pigment, RP). Two tautomers, NH and OH forms, in rapid equilibrium were present in a solution of RP. The critical factors for RP to form were the presence of NH₄⁺ salt and pH 6.3-6.5. In vitro experiments showed that MNA was synthesized from RP as a result of chemical transformations without the participation of enzymes. In this case, the main influence on the reaction rate is exerted by the pH of the medium, which is associated with the keto-enol tautomerism of RP in solution. The culture broth extract and MNA exhibited antifungal activity against Fusarium fungi.

Oligoorganogermanes: Interplay between Aryl and Trimethylsilyl Substituents

Derivatives of main group elements containing element-element bonds are characterized by unique properties due to σ-conjugation, which is an attractive subject for investigation. A novel series of digermanes, Ar₃Ge-Ge(SiMe₃)₃, containing aryl (Ar = p-C₆H₄Me (1), p-C₆H₄F (2), C₆F₅ (3)) and trimethylsilyl substituents, was synthesized by the reaction of germyl potassium salt, [(Me₃Si)₃GeK*THF], with triarylchlorogermanes, Ar₃GeCl. The optical and electronic properties of such substituted oligoorganogermanes were investigated spectroscopically by UV/vis absorption spectroscopy and theoretically by DFT calculations. The molecular structures of compounds 1 and 2 were studied by XRD analysis. Conjugation between all structural fragments (Ge-Ge, Ge-Si, Ge-Ar, where Ar is an electron-donating or withdrawing group) was found to affect the properties.

[Experimental study of the features of post-stress recovery of psychophysiological functions using balneological treatments during the solstice]

The development of new programs and methods of rehabilitation after the action of various stress factors on the body continues to be an actual problem. There are post-stress recovery programs include both standard pharmacotherapy and physical therapies. However, when prescribing certain types of physiotherapy procedures, the season of the year is not taken into account.

OBJECTIVE

During the summer and winter solstices to study the features of post-stress recovery of psychophysiological functions of laboratory rats after light or dark deprivation, followed by physical exertion and rehabilitation procedures in the form of water and antler baths.

MATERIAL AND METHODS

The experiment was carried out on 160 male Wistar rats. The animals were divided into 8 groups of 10 individuals at each solstice period (winter, summer). Group 1 was not exposed to any impact. Group 2 was presented with physical activity (swimming test). These two groups were in natural light conditions. Groups 3-8 underwent light desynchronosis (light or dark deprivation) followed by physical activity. After the above-mentioned influences, procedures were carried out in the form of water baths (groups 4 and 7) and baths with a preparation based on pantogematogen «Pantovanna» (groups 5 and 8). Behavioral responses were assessed using the open field test. The content of corticosterone was determined by enzyme immunoassay.

RESULTS

During the periods of the winter solstice, dark or light deprivation increased the resistance of animals to the stress of subsequent physical activity, i.e. showed a training effect, while during the summer solstice the studied stress factors led to depletion of serum corticosterone levels, although the structure of behavior did not undergo significant changes. Post-stress recovery in the form of water and antler baths for 10 days was determined by the nature of desynchronosis and the solstice period. Pantobaths were effective in summer and winter only under TT conditions. However, in winter, after the CC-regime, the antlers intensified the stressful effect of physical activity on the animals' organism.

CONCLUSION

The experiment carried out indicates the need to take into account the season of the year and the direction of the transmeridian flight to balneological resorts. Using the example of solstices in experimental conditions on rats, we have shown that balneological procedures will perform best the restorative functions when expanding as a result of such a movement of the light phase of the day, but not the dark one. It is possible that this feature can also persist for a person, since a more rapid adaptation to new light-dark conditions has been established also with the expansion of the light phase, but not the dark one.

[Speciality of restoring the psychophysiological parameters of laboratory rats with the help of balneological procedures during the periods of equinox]

Currently methods development for restoring physiological functions and increasing the adaptive capabilities of the body after prolonged stress exposure of various genesis is an urgent problem in the field of balneology and physiotherapy. It is known that the adaptive potential of the organism is not the same in different seasons of the year. In this regard, it becomes necessary to take into account the seasonality factor when carrying out recreational activities.

PURPOSE OF THE STUDY

To perform a comparative study of balneotherapeutic procedures effectiveness in the form of water and antler baths in relation to the restoration of the psychophysiological parameters of laboratory rats after a consistent stressful effect of light desynchronosis and physical activity to a state of complete fatigue during autumn and spring equinoxes.

MATERIAL AND METHODS

The experiment was carried out during the periods of the spring and autumn equinoxes on 160 male Wistar rats weighing 220-250 g. In each season, the animals were divided into 8 groups of 10 individuals. Two groups were in natural lighting conditions. Animals of the 1st group (intact) were not exposed to experimental influences; rats of the 2nd group were exposed to physical activity in the form of a swimming test until complete fatigue for 5 days in a row in the morning; animals of groups 3-8 were exposed to stress loads in the form of 10-day light desynchronosis (light or dark deprivation) followed by physical activity. In the 4-th, 5-th, 7-th and 8-th groups, post-experimental post-stress recovery programs were carried out using water baths (groups 4 and 7) and baths with drug «Pantovanna» (groups 5 and 8). After the completion of exposures, the animals were tested in the «open field» according to the standard method. The level of corticosterone in the blood serum was determined by ELISA.

RESULTS

It was found that in laboratory rats sensitivity to stressful influences - light desynchronosis followed by physical activity to the point of fatigue, as well as active post-stress recovery were determined by the nature of desynchronosis and the season of the year. The stress load was accompanied by a phase of exhaustion during the spring equinox and by a phase of anxiety during the autumn equinox. In the spring, antler baths as a procedure for active post-stress recovery were ineffective; in autumn, they had a normalizing effect on the level of corticosterone and behavior only after dark deprivation.

CONCLUSION

The conducted experiment indicates the need to take into account the season of the year and the direction of the transmeridian flight to sanatorium-and-spa treatment with balneotherapy procedures. Using the example of equinoxes under experimental conditions on laboratory rats, it has been shown that balneological procedures will more effectively perform rehabilitative functions when the light phase of the day expands as a result of such a shift, but not the dark one.

[An effect of mexidol on the level of corsticosteron in the blood serum and beam zone cells in rats with light desynhronizes and physical loads]

OBJECTIVE

In order to develop methods and means of maintaining normal human functioning under conditions of desynchronizes, the effect of mexidol on the level of corticosterone in the blood serum and the state of the cells of the beam zone of the adrenal cortex of rats after light or dark deprivation and physical activity to a state of fatigue.

MATERIALS AND METHODS

The experiments were performed on 7 groups of rats (10 animals each) in the spring. The model of physical activity is the method of forced swimming of rats until exhaustion in its own modification. For the induction of experimental desynchronizes, the animals of the experimental groups were kept around the clock for 10 days with artificial bright light of 150 LX or a complete darkening of 2-3 LX. Mexidol was administered intramuscularly at a dose of 10 mg/kg animal 30 minutes before the swimming test. Control animals under similar conditions were administered 0.9% sodium chloride solution. The level of corticosterone in the serum was determined using enzyme immunoassay. The measurements were carried out on a programmable photometer for STAR FAX 303 PLUS microsamples (USA). Histological analysis of the adrenal glands was carried out according to standard methods. Microscopy of preparations, imaging and measurements were carried out using an Axio Lab A1 microscope, an AxioCamERc 5s camera and ZEN 2012 software («Carl Zeiss Microscopy», Germany). Statistical processing of the results was carried out using standard parametric and non-parametric methods, depending on the nature of the distributions.

RESULTS AND CONCLUSION

Mexidol under combined successive stress loads - desynchronizes and physical activity - demonstrated anti-stress properties not only at the level of corticosterone in the blood serum of rats, but also at the level of adrenal glands. The severity of this effect of the drug depended on the number of stress loads (isolated physical or shown in conditions of desynchronizes), the phase of stress and the nature of deprivation. Under natural lighting conditions and after light deprivation, when animals were in the anxiety phase of varying severity, the drug worked more reliably than after dark deprivation in conditions of developing depletion. Nevertheless, even in the latter case, he showed himself as a means of preventing exhaustion in animals and the breakdown of adaptation.

Optical Properties of Soil Dissolved Organic Matter Are Related to Acidic Functions of Its Components as Revealed by Fractionation, Selective Deuteromethylation, and Ultrahigh Resolution Mass Spectrometry

The goal of this study was to establish a relationship between the optical properties of soil dissolved organic matter (DOM) and acidic functions carried out by its individual constituents. We obtained 12 fractions of DOM samples using sequential solid phase extraction on nonionic sorbent at steadily lowered pH values: 7, 5, 3, 2, which correspond to low bounds of pK_a values of phenols, aliphatic, and aromatic carboxylic acids, and ketoacids. The structural studies were conducted with the use of NMR and selective deuteromethylation of isolated fractions coupled to ultrahigh resolution mass spectrometry. First, a gradual shift of molecular compositions was observed from reduced components to aromatic oxidized compounds isolated at pH 7 and 2, respectively. Changes in molecular compositions were accompanied by a red shift of fluorescence spectra. Further application of deuteromethylation enabled us to distinguish DOM constituents with different amounts of carboxylic groups. Moreover, identification of structural isomers in a single DOM sample was achieved. Statistical analysis revealed that red shift of fluorescence is facilitated by the increase of a contribution of aromatic poly(carboxylic acid)s with high conjugation lengths. Additionally, analysis of the labeled fractionated permafrost thaw DOM directly showed carboxyl-rich alicyclic molecules, while the same components from lower-latitude DOM were assigned to lignin-like species.

[Effect of mexidol on physical working capacity and level of lactate in the blood of rats in conditions of light deprivation]

AIM

To study an effect of mexidol on the performance of rats after light or dark deprivations in the swimming test with a load and to evaluate the state of glycolytic processes under these conditions.

MATERIAL AND METHODS

The experiment was carried out in the spring on 70 Wistar male rats. Three groups (30 animals) were in natural light conditions. One of them was not affected. The other two groups were subjected to exercise and 30 minutes before it either saline or mexidol was administered intramuscularly. Four other groups (40 animals) for 10 days were under conditions of dark or light deprivation prior to the presentation of physical activity and received either saline or mexidol before the test after deprivation was canceled. A forced swimming test with an additional load, which was presented to animals every day at 10-11 am for five days in a row, was used as a model of physical activity. The level of lactate was determined by colorimetric method.

RESULTS AND CONCLUSION

Mexidol increased the performance of rats in the swimming test, both under natural lighting conditions and with light desynchronization, contributed to the formation of cross adaptation to physical activity under natural lighting conditions and prolonged this state under conditions of light deprivation, did not change the content of lactate in the blood of rats after exercise in natural lighting conditions and dark deprivation and prevented its rise after light deprivation.

Hypercoordinated Oligosilanes Based on Aminotrisphenols

The hypercoordinated silicon chlorides ClSi[(o-OC₆H₄)₃N] (3) and ClSi[(OC₆H₂Me₂CH₂)₃N] (5) were used for the synthesis of catenated derivatives (Me₃Si)₃SiSi[(o-OC₆H₄)₃N] (9), (Me₃Si)₃SiSiMe₂SiMe₂Si(SiMe₃)₂Si[(o-OC₆H₄)₃N] (11), and (Me₃Si)₃SiSi[(OC₆H₂Me₂CH₂)₃N] (13) in reactions with (Me₃Si)₃SiK·THF (7) or (Me₃Si)₃SiK·[18-crown-6] (8). It was found that the nature of the (Me₃Si)₃SiK solvate determines the product of interaction, resulting in the formation of (Me₃Si)₃Si(CH₂)₄OSi[(OC₆H₂Me₂CH₂)₃N] (12) or 13. Compounds obtained were characterized using multinuclear NMR and UV-vis spectroscopy and mass spectrometry. The molecular structures of 3, 9, and 11-13 were investigated by single-crystal X-ray analysis, featuring hypercoordinated Si atoms in a trigonal-bipyramidal coordination environment with O atoms in the equatorial plane. The structure of the side product [N(CH₂C₆H₂Me₂O)₃Si]₂O (6) was also studied, indicating highly tetrahedrally distorted trigonal-bipyramidal environment at the Si atoms, which was confirmed by crystal density functional theory calculations indicating the very weak Si ← N interaction. The Si···N interatomic distances span a broad range (2.23-2.78 Å). The dependence of structural and NMR parameters for hypercoordinated catenated compounds from the type of the ligand was established.

Oligothienyl catenated germanes and silanes: synthesis, structure, and properties

The synthesis of two new groups of oligothienyl catenated silanes and germanes, Me5M2Thn (1a-b), Me5M2ThnM2Me5 (2a-c) (terminal), and ThnM2Me4Thn (3a-d) (internal) (M = Si, Ge; n = 2, 3; Th = 2- or 2,5-thienyl), is reported. The study of their structural parameters as well as of their spectral (NMR), electrochemical (CV) and optical (UV/vis absorbance, luminescence) properties has been performed in detail; in addition, the unexpected compound [Th2Si2Me4Th]2 (3a') is also studied. Theoretical investigations have been performed for model compounds in order to establish structure-property relationships. The molecular structures of 2a (Me5Si2Th2Si2Me5), 2b (Me5Ge2Th2Ge2Me5), 3a (Th2Si2Me4Th2) and 3b (Th2Ge2Me4Th2) have been investigated by X-ray diffraction analysis. An effective conjugation with flattening of both Th planes in terminal 2a and 2b was observed. The main trends in the dependence of the optical and electrochemical properties on the structural parameters have been established. All of the compounds studied exhibit a strong emission within the 378-563 nm range, and the maximal quantum yield (up to 77%) is observed for the Si derivative 3a'. For the majority of the compounds, the quantum yields (20-30%) are significantly larger than for 2,2'-bi- and 2,2':5',5''-terthiophenes. Due to their good emission properties, these compounds could be used to develop new materials with specific spectral properties.

Synthesis of carboxylated styrene polymer for internal calibration of Fourier transform ion cyclotron resonance mass-spectrometry of humic substances

We report synthesis and application of the novel carboxylated styrene for internal calibration of Fourier transform ion cyclotron resonance mass-spectra of humic substances. The calibrant was synthesized in five steps from acetylsalicylic acid (aspirin) followed by spontaneous polymerization of vinyl salicylic acid. Aromatic nature of the prepared polymer enabled its simultaneous analysis in the presence of the Suwannee River fulvic acid without using dual-spray approach. The major advantage of the calibrant proposed in this study is a lack of suppression of humic substances signals and maintenance of peak intensity distribution. The appropriate calibration resulted in an increased number of unambiguous identification in Suwannee River fulvic acid. Thanks to the higher mass accuracy, it was also possible to refine attribution of the CHOS species to hydrolysable tannins as opposed to the erroneous previous assignment to the condensed tannins.

Molecular Oligogermanes and Related Compounds: Structure, Optical and Semiconductor Properties

The optical (UV/Vis absorbance, fluorescence in the solid state and in solution) and semiconducting properties of a number of di- and trigermanes as well as related silicon- and tin-containing germanes, 1-6 ((p-Tol)₃ GeGeMe₃ (1), Ph₃ SnGe(SiMe₃ )₃ (2), (C₆ F₅ )₃ GeGePh₃ (3), (p-Tol)₃ GeSiMe₂ SiMe₃ (4), (p-Tol)₃ GeGeMe₂ Ge(p-Tol)₃ (5), (p-Tol)₃ GeSiMe₂ SiMe₂ Ge(p-Tol)₃ (6)) were investigated. Molecular structures of 5 and 6 were studied by X-ray diffraction analysis. All compounds displayed luminescence properties. In addition, a band gap (of about 3.3 eV) was measured for compounds 1-6 showing that those molecules display semiconductor properties.

Enumeration of carboxyl groups carried on individual components of humic systems using deuteromethylation and Fourier transform mass spectrometry

Here, we report a novel approach to enumeration of carboxylic groups carried by individual molecules of humic substances using selective chemical modification and isotopic labeling (deuteromethylation) and high-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR MS). Esterification was conducted with a use of thionyl chloride-deuteromethanol reagent under mild conditions to avoid transesterification. The deuteromethylated products were subjected to solid phase extraction using PPL Bond Elute cartridges prior to FTICR MS analysis. An amount of carboxyl groups in the individual molecular component was estimated from the length of identified deuteromethylation series. The method allowed for discerning between compounds with close elemental compositions possessing different protolytic properties. We found that different carboxylic moieties occupy distinct regions in molecular space of humic substances (HS) projected onto Van Krevelen diagram. These locations do not depend on the source of the humic material and can be assigned to carboxyl-rich alicyclic molecules (5 to 6 COOH), hydrolyzable tannins (3-4 COOH), lignins (1 to 2 COOH), condensed tannins and lignans (0 to 1 COOH), and carbohydrates (0 COOH). At the same time, the alignment pattern of these carboxylated species along the structural evolution lines in Van Krevelen diagrams was characteristic to the specific transformation processes undergone by the humic materials in the different environments. The obtained data enable mapping of molecular ensemble of HS with regards to their specific acidic compartments and might be used for directed fractionation of HS. Graphical abstract Selective isotopic labeling followed by FTICR MS enables discerning between humic molecules with close elemental compositions carrying different numbers of carboxylic groups.

[SEASONAL FEATURES OF SEROTONIN IN BLOOD SERUM OF RATS AFTER PHYSICAL OVERWORK UNDER DESYNCHRONOSIS]

The content of serotonin in the blood serum of rats with light desynchronizes and physical fatigue in different seasons was investigated ву enzyme immunoassay. It was found that long-term light deprivation and exercise to complete depletion lowered levels of serotonin in the blood serum of rats in the winter and increased that of the spring season. At the same time, a dark deprivation and physical activity had no effect on this indicator.

Synthesis of model humic substances: a mechanistic study using controllable H/D exchange and Fourier transform ion cyclotron resonance mass spectrometry

The products of the oxidative coupling of phenols are frequently used as synthetic analogues to natural humic substances (HS) for biomedical research. However, their molecular compositions and exact structures remain largely unknown. The objective of this study was to develop a novel approach for the molecular-level analysis of phenolic polymerisates that is capable of inventorying molecular constituents and resolving their distinct structural formulas. For this purpose, we have synthesized the model HS using the oxidative coupling of a specifically designed phenylpropanoic monomer, 3-(4-hydroxy-3-methoxyphenyl)-3-oxopropionic acid, to hydroquinone. We have characterized the synthesized model HS using high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS), (1)H NMR spectroscopy, and controllable hydrogen/deuterium (H/D) exchange. We succeeded in the molecular inventory of the model HS. The assigned molecular formulas occupied the substantial space of CHO compositions in the Van Krevelen diagram with a maximum density found in the regions of tannins and lignins, resembling those of natural HS. To identify the exact structural formulas of the individual constituents in the model HS, we have applied selective H/D exchange of non-labile backbone protons by a choice of basic or acidic catalytic conditions followed by FTICR MS. The determined formulas allowed us to verify the proposed pathways of hydroxylation and carboxylation in the course of the phenolic coupling and to identify the acetylation of aromatic rings as an important side reaction. We conclude that the proposed analytical approach may be used to identify the molecular carriers of biological activity within the phenolic polymerisates and eventually within natural HS.

IMMUNOPHENOTYPICAL CHARACTERISTICS OF CELLULAR COMPOSITION IN BREAST MILK

The morphology and immunophenotype of female colostrum adherent cells with the help of CD3, CD31, CD34, CD45, CD68, vimentin, and osteocalcin antibodies panel was studied in short-term (6—7 days) culture in vitro. Approximately equal (1 : 1) ratio of fibroblast-like and rounded cells was observed in 20 % of cultural flasks. The cells with regular shape mixed with single fibroblasts were noted in 80 % of cultural flasks. The diameter of spreaded cells varied within 10—100 mm. All cells adhered to plastics did not express CD3 and interacted slightly (sl) with antibodies to CD31, CD34, and CD45. At the same time, adherent cells with intensive CD68, vimentin and osteocalcin staining have been revealed. Literature data allows to interpret CD68+CD3–CD31slCD34slCD45sl immunophenotype of significant part of mother colostrum adherent cells as belonging to monocyte-macrophage lineage. Marked expression of stromal antigens (vimentin, osteocalcin) in 40—45 % adherent cells in cultural medium without osteogenic supplements (beta-glycerophosphate, ascorbic acid, dexamethasone) proposes an existence of osteoblasts fraction differentiated in colostrum from mesenchymal stem cells under an action of breast milk humoral factors.

Crystal structure of (tert-butyldimethylsilyl)triphenylgermane, Ph3Ge-SiMe2(t-Bu)

In the title compound, Ph₃Ge-SiMe₂(t-Bu) or C₂₄H₃₀GeSi, the Si and Ge atoms both possess a tetra­hedral coordination environment with C—E—C (E = Si, Ge) angles in the range 104.47 (5)–114.67 (5)°. The mol­ecule adopts an eclipsed conformation, with three torsion angles less than 29.5°. In the crystal, neighbouring mol­ecules are combined to dimers by six T-shaped C—H⋯π inter­actions, forming sixfold phenyl embraces (6PE).

Crystal structure of 2,6-bis(2-hydroxy-5-methylphenyl)-4-phenylpyridinium bromide dichloromethane hemisolvate hemihydrate

The asymmetric unit in the structure of the title compound, C₂₅H₂₂NO₂⁺·Br ⁻·0.5CH₂Cl₂·0.5H₂O, comprises two pseudosymmetry-related cations, two bromide anions, a di­chloro­methane molecule and a water mol­ecule of solvation. The two independent cations are conformationally similar with the comparative dihedral angles between the central pyridine ring and the three benzene substituent rings being 3.0 (2), 36.4 (1) and 24.2 (1)°, and 3.7 (2), 36.5 (1) and 24.8 (1)°, respectively. In the crystal, the cations, anions and water mol­ecules are linked through O—H⋯O and O—H⋯Br hydrogen bonds, forming an insular unit. Within the cations there are also intra­molecular N—H⋯O hydrogen bonds. Adjacent centrosymmetrically related aggregates are linked by π–π stacking inter­actions between the pyridine ring and a benzene ring in both cations [ring-centroid separations = 3.525 (3) and 3.668 (3) Å], forming chains extending across the ac diagonal. Voids between these chains are filled by dichloromethane molecules.

Crystal structure of 4,8-di-tert-butyl-6,6-dichloro-13-ethyl-2,10-dimethyl-13,14-dihydro-12H-dibenzo[d,i][1,3,7,2]dioxazasilecine toluene 0.25-solvate

The coordination polyhedron at the silicon atom in the title compound, C26H37Cl2NO2Si·0.25C7H8, is typical for pentacoordinated silicon derivatives and represents a slightly distorted trigonal bipyramid with an N atom and a Cl atom in the apical positions and the two O atoms and the other Cl atom occupying the equatorial sites. There are two independent molecules in the asymmetric unit. The N–Si–Cl fragment in each is close to linear [178.24 (5) and 178.71 (5)°], in good agreement with 4e–3ctheory, as is the elongation of the apical bond lengths [Si—Cl = 2.1663 (7) and 2.1797 (7) Å] in comparison with the equatorial bonds [Si—Cl = 2.0784 (7) and 2.0748 (7) Å]. Orthogonal least-squares fitting of the two independent molecules resulted in r.m.s. deviation of 0.017 Å. The conformations of the two molecules are almost the same, with corresponding torsion angles differing by less than 5.5°. The toluene solvent molecule is disordered about an inversion centre.

Aluminum complexes based on pyridine substituted alcohols: synthesis, structure, and catalytic application in ROP

2,6-Bis(hydroxyalkyl)pyridines were used in the synthesis of Al complexes. The structure of the ligand determines the complex nature. Compounds were used as initiators of lactone ROP.

Crystal structure of 2,2,3,3-tetra-methyl-1,1,1,4,4,4-hexa-phenyl-tetra-germane

The mol­ecule of the title compound, C₄₀H₄₂Ge₄, lies with its central Ge—Ge bond on an inversion centre giving rise to a zigzag backbone of four tetra­hedrally coordinated Ge atoms. The symmetrically independent Ge—Ge bonds are slightly shorter than in other organo­tetra­germanes whereas the Ge—C_Ph (Ph = phen­yl) and Ge—C_Me (Me = meth­yl) distances have their usual values. In the crystal, (010) layers of Ph₆Me₄Ge₄ mol­ecules with a parallel orientation of the Ge₄ backbone exist, held together by van der Waals forces only. Main bond lengths in organo-substituted oligogermanes are compared.

Crystal structure of a mixed-valence μ-oxide Sn12 cluster

The mixed-valence μ-oxide Sn12 cluster, deca-carbonyl-tetra-μ4-oxido-hexa-μ3-oxido-tetra-kis-[μ-2,2'-(pyridine-2,6-di-yl)bis(1,1-di-phenyl-ethano-lato)]deca-tin(II)ditin(IV)dimolyb-denum(O)(2 Mo-Sn) toluene hepta-solvate, [Mo2Sn12(C33H27NO2)4O10(CO)10]·7C7H8, has a crystallographically imposed inversion centre. The asymmetric unit also contains three and a half toluene solvent mol-ecules, one of which is disordered about a centre of symmetry. The complex mol-ecule comprises six distinct Sn atom species with four different coordination numbers, namely 3, 4, 5, and 6. The Sn(II) atoms forming the central Sn10O10 core adopt distorted trigonal-pyramidal, square-pyramidal and octa-hedral coordination geometries provided by the μ-oxide atoms and by the O- and N-donor atoms of two pyridinedi-ethano-late ligands. The terminal Sn(IV) atoms have distorted trigonal-bipyramidal coordination geometries, with a μ4-oxide atom and the N atom of a pyridinedi-ethano-late ligand occupying the axial positions, and the Mo atom of a Mo(CO)5 group and the alk-oxy O atoms of a ligand forming the equatorial plane. In the crystal, weak intra- and inter-molecular C-H⋯O hydrogen bonds are observed.

New oligogermane with a five coordinate germanium atom: the preparation of 1-germylgermatrane

The first example of a hypercoordinate oligogermane was prepared and characterized.

{2,2'-[Ethane-1,2-diylbis(nitrilo-methan-yl-yl-idene)]diphenolato}(iso-propano-lato)aluminium di-chloro-methane hemisolvate

In the title compound, [Al(C16H14N2O2)(C3H7O)]·0.5CH2Cl2, the salen complex is monomeric and the dichlormethane solvent mol-ecule lies on a crystallographic twofold axis. The central Al atom is fivefold coordinated and possesses a square-based pyramidal environment. The Al-OAlk( (i) prop-yl) bond [1.7404 (14) Å] is much shorter than the Al-OAr(salen) bond lengths [1.7974 (15) and 1.8094 (14) Å]. The iso-propyl-oxo group forms an intra-molecular C-H⋯N hydrogen bond. In the crystal, the complex mol-ecules are linked by weak C-H⋯O inter-actions.