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Geosciences, 2017, 7, 24

A. Lupachev, E. Abakumov, S. Gubin

“The Influence of Cryogenic Mass Exchange on the Composition and Stabilization Rate of Soil Organic Matter in Cryosols of the Kolyma Lowland (North Yakutia, Russia)”

Geosciences, 2017, 7, 24
DOI:10.3390/geosciences7020024

Источник: http://www.mdpi.com/2076-3263/7/2/24

Soil organic matter (SOM) was studied in different types of organo-mineral material (from surface horizons and partially isolated materials—cryoturbated or buried horizons) sampled from the surface horizons, the central parts of the Cryosol profiles, and the lower active layer. We found that the humic acids (HAs) of the cryoturbated and buried horizons showed an increased degree of oxidation and an increment of alkylaromatic and protonized aromatic fraction content. In contrast, the HAs of the surface horizons showed increased values of alkylic carbon components. The content of free radicals was essentially higher in the surface layers than in the cryoturbated and buried layers. While the bulk soil organic matter composition (total organic carbon, total nitrogen, and aromatic/aliphatic values) was not essentially different between surface, cryoturbated, and buried horizons, there were essential differences in elemental composition, carbon species, and free radical content. This indicates that the degree of humification in cryoturbated and buried organo-mineral material is higher than in surface horizons and that partial isolation results in relative stabilization of such material in soil profiles.

 

Оптика и Спектроскопия, 2017,122(3), 436-444

Е.А. Катленок, С.Н. Смирнов, А.Ю. Иванов, С.В. Макаренко, К.П. Балашев

“Влияние донорно-акцепторных свойств лигандов на спектроскопические и электрохимические характеристики смешанно-лигандных циклометаллированных комплексов Pt(II) и Ir(III) 2-фенилбензотиазола”

Оптика и Спектроскопия, 2017,122(3), 436-444
DOI:10.7868/S0030403417030126
Приведены результаты спектроскопических ЯМР 1Н, 13C, 195Pt, ИК, оптических и вольтамперометрических характеристик смешанно-лигандных комплексов Pt(II) и Ir(III) с металлированным 2-фенилбензотиазолом и трет-бутилизоцианидом (tBuNC), ацетонитрилом (AN), этилендиамином(En), О-этилдитиокарбонат- (Exn–) и диэтилдитиокарбонат-ионами (Dtc–). Показано, что изменение донорно-акцепторного взаимодействия с металлом лигандов tBuNC, AN, En, Exn–, Dtc– приводит к повышению энергии высшей заполненной молекулярной орбитали комплексов и сопровождается катодным смещением потенциала металл-центрированного окисления, батохромным смещением спин-разрешенного и спин-запрещенного оптических переходов переноса заряда металл-циклометаллированный лиганд и увеличением степени смешивания 1ПЗМЛ- и триплетного внутрилигандного состояния, ответственного за фосфоресценцию комплексов.

 

J. Wood Chem. Technol, 2017

E.I. Evstigneyev, A.V. Kalugina, A.Yu. Ivanov, A.V. Vasilyev

“Contents of α-o-4 and β-o-4 bonds in native lignin and isolated lignin preparations”

J. Wood Chem. Technol, 2017,accepted
DOI:10.1080/02773813.2017.1297832

An analytical calculation method for the estimation of the contents of alkyl aryl ether bonds (α-O-4 and β-O-4) in lignin was developed. In the framework of the method, Alkyl–O–Aryl type bonds are described as coupled phenolic hydroxyls (OHphen). The method is based on the balance equation including the free and coupled OHphen contents in dissolved and residual lignins, on the one hand, and their respective contents in native lignin, on the other. The free OHphen content is calculated on the basis of the OHphen contents of dissolved and residual lignin, determined by the aminolysis method in the course of kraft cooking of softwood. The calculation results for soluble lignin preparations are in good agreement with the 13C NMR (nuclear magnetic resonance) spectral data for the solutions. The content of Alkyl–O–Aryl bonds in native softwood (pine, spruce) lignin was estimated at 79/100 PPU (phenylpropane unit). In isolated lignin preparations, the contents of these bonds decrease in the sequence: Freudenberg lignin (71/100 PPU)> Bjorkman lignin (61/100 PPU)> Pepper lignin (44/100 PPU). Dissolved alkaline lignin still contains small amounts of Alkyl–O–Aryl bonds (36/100 PPU in soda lignin and an average of 23/100 PPU in soda-AQ lignin, kraft lignin, and kraft-AQ lignin). Residual lignin which represents the fraction of native lignin with inter-unit bonds resistant to kraft pulping contains 66/100 PPU of such bonds. A relatively high content of Alkyl–O–Aryl bonds (61/100 PPU) is preserved in technical hydrolysis lignins.

 

Известия РАН. Серия физическая, 2017, том 81, 344–348

Т. Н. Тарасенко, З. Ф. Кравченко, В. В. Бурховецкий, А. С. Мазур, В. И. Каменев, А. И. Линник

“Синтез, микроструктура, сложный характер магнитного состояния слаболегированного висмутом манганита лантана”

Известия РАН. Серия физическая, 2017, том 81, № 3, с. 344–348
DOI:10.7868/S036767651703036X

Проведены структурные, магнитные и резонансные исследования манганитов BixLa1 – xMnO3. Золь–гель-методом получены нанопорошки слаболегированных составов (x = 0.0–0.1) с размером частиц ≤40 нм. При спекании в одинаковых условиях средний размер гранул резко растет с ростом содержания Bi. Спектры ЯМР манганитов твердофазного синтеза 55Mn отвечают условию быстрого обмена Mn4+ ↔ Mn3+. Измерение магнитной восприимчивости обнаружило неоднородность магнитного состояния системы BixLa1 – xMnO3.

 

New J. Chem., 2017, 41, 316-325

Elena V. Andrusenko, Evgeniy V. Kabin, Alexander S. Novikov, Nadezhda A. Bokach, Galina L. Starova and Vadim Yu. Kukushkin

“Metal-mediated generation of triazapentadienate-terminated di- and trinuclear μ2-pyrazolate NiII species and control of their nuclearity”

New J. Chem., 2017, 41, 316-325
DOI:10.1039/C6NJ02962K
источник: http://pubs.rsc.org/

1,3,5-Triazapentadienate-terminated di- and trinuclear nickel(II) complexes featuring bridging azolate ligands, [Ni2(μ2-azolate)2(TAP)2] (TAP = H[N with combining low line][double bond, length as m-dash]C(OMe)NC(OMe)[double bond, length as m-dash][N with combining low line]H; azole = 3,5-Me2pyrazole 2, 3,5-Ph2pyrazole 3) and [Ni3(μ2-azolate)4(TAP)2] (azole = 3,5-Me2pyrazole 4, indazole 5), were obtained from systems Ni2+/NCNR2/azole systems in MeOH. The terminal TAP ligands in the [Ni2(μ2-azolate)2(TAP)2] and [Ni3(μ2-azolate)4(TAP)2] species originate from the previously unreported cascade NiII-mediated and chelation-driven reaction between cyanamides and methanol. The oligomeric species and also [Ni(TAP)2] (1) are subject to interconversions that depend on the reactants involved and the reaction conditions. The control of the nuclearity of the complexes can be achieved by changing the amount of azoles or by their protonation, alteration of the steric hindrance of the substituents in the heterocycles, and by changing the reaction temperature. Complexes 1–4 were characterized using elemental (C, H, N) analyses, 1H, 13C{1H} NMR, FTIR, HRESI-MS, TG-DTA, X-ray crystallography, and 5 was characterized using HRESI-MS and X-ray crystallography. Unconventional metallophilic contacts NiII⋯NiII were observed in dimer 3 in the solid state (the distance for Ni⋯Ni is 2.99 Å, whereas the double Bondi’s vdW radius for Ni is 3.26 Å) and the reality of these interactions was confirmed theoretically by the topological analysis of the electron density distribution (AIM method). The estimated energy for these non-covalent Ni⋯Ni interactions (ca. 4 kcal mol−1) fills the gap in the reported energies of the metal⋯metal interactions in a series comprising of NiII⋯NiII (this work), PdII⋯PdII (4.3–6.0 kcal mol−1), and PtII⋯PtII (3.9–11.7 kcal mol−1).

 

Inorganica Chimica Acta, 2017, 455, 607–612

Mikhail A. Kinzhalov, Galina L. Starova, Vadim P. Boyarskiy

“Interaction of benzene-1,2-diamines with isocyanide complexes of palladium(II): Insight into the mechanism”

Inorganica Chimica Acta, 2017, 455, 607–612
DOI:10.1016/j.ica.2016.05.014
источник: http://www.sciencedirect.com/science/article/pii/S0020169316302432

Reactivity of 4-toluidine (2) and 4,5-dimethylbenzene-1,2-diamine (3) were compared in coupling with the palladium-bis(isocyanide) complex cis-[PdCl2(CNXyl)2] (Xyl = 2,6-Me2C6H3, 1), mixed isocyanide/diaminocarbene species cis-[PdCl2(CNXyl){C(NHXyl)double bond; length as m-dashNH(4-C6H4CH3)}] (4), and cis-[PdCl(CNXyl){C(NHXyl)double bond; length as m-dashNHC6H2(Me)2NH2}]Cl (5). In these Pd(II)-mediated reactions, 4,5-dimethylbenzene-1,2-diamine (3) was significantly more reactive than 4-toluidine (2), leading to the first mixed bis(diaminocarbene) complex cis-[PdCl{C(NHR)double bond; length as m-dashNHC6H2X2NH2}{C(NHXyl)double bond; length as m-dashNH(4-C6H4CH3)}]Cl (6) containing two different diaminocarbene ligands. Complex 6 was isolated and characterized by elemental analyses (C, H, N), HRESI+-MS, IR, 1H and 13C{1H} NMR spectroscopies, and single-crystal X-ray diffraction.

 

Glass Phys Chem, 2017, 43, 70–74

V.V. Tomaev, A.S. Mazur, A.S. Grevtsev

“A study of the process of thermal oxidation of lead selenide by the NMR and XRD methods”

Glass Phys. Chem., 2017, 43, 70–74
DOI:10.1134/S1087659617010163

Studies of the process of oxidation of powder samples of lead selenide in a dry air atmosphere have been performed. As shown by the methods of X-ray diffraction and scanning electron microscopy, the process of thermal treatment of samples resulted in the formation of the PbSeO3 phase, aside from the initial PbSe phase. Studies by the method of nuclear magnetic response (NMR) allowed revealing the dynamics of changes in the spectrum under the changed thermal treatment conditions.

 

Eur. J. Mineral., 2016, 28, 931–941

T.L. Panikorovskii, S.V. Krivovichev, E.V. Galuskin, V.V. Shilovskikh, A.S. Mazur, A.V. Bazai

“Si-deficient, OH-substituted, boron-bearing vesuvianite from Sakha-Yakutia, Russia: a combined single-crystal, 1H MAS-NMR and IR spectroscopic study”

Eur. J. Mineral., 2016, 28, 931–941
DOI:10.1127/ejm/2016/0028-2570

источник: http://www.ingentaconnect.com/content/schweiz/ejm/2016/00000028/00000005/art00006

Single crystals of Si-deficient vesuvianite with significant degree of hydrogarnet-type (SiO4)4−–(O4 H4)4− substitution occur as epitactic overgrowth on the surface of large wiluite crystals from the Wiluy River, Sakha–Yakutia, Russia. Electron-microprobe analysis revealed considerable Si-deficiency, Si ranging from 16.30 to 17.50 apfu. The crystal structure of the mineral has been refined in the P4/nnc space group, a = 15.5876(4), b = 11.8021(5) Å to R 1 = 0.028 for 1533 unique observed reflections. The refinement of the site-occupancy factors confirmed significant vacancy at the Z(1) and Z(2) sites (27% and 10%, respectively), with associated increase of the Z(1)–O and Z(2)–O bond lengths to 1.697 and 1.655 Å, respectively. The increased size of the Z(1) tetrahedra results in the compression of the X(1) polyhedra, while the expansion of the Z(2) tetrahedra is compensated by the compression of the X(4) polyhedra. As a result, the significant degree of the hydrogarnet-type substitutions does not have an essential influence upon the unit-cell parameters compared to the usual defect-free vesuvianite. Thermogravimetric (TGA) and differential scanning calorimetry (DSC) curves indicated two steps of the weight loss in the temperature ranges of 600–900°C (2.08 wt%) and 1014°C (2.22 wt%). The total weight loss is estimated as 4.30%, which is in good agreement with the total content of OH estimated as 13.72 apfu. The 1H solid state MAS-NMR demonstrates the presence of a strong additional line at 3.38 ppm compared to the usual vesuvianite, which is explained by the existence of the additional H(3) site. The infrared spectrum in the OH-stretching vibration region shows the additional (B′) absorption band at 3618 cm−1 typical for a hydrogarnet-type substitution.

 

Colloid Surface A, 2017, 518, 273-282

A.S. Koneva, E.A. Safonova, P.S. Kondrakhina, M.A. Vovk, A.A. Lezov, Yu.S. Chernyshev, N.A. Smirnova

“Effect of water content on structural and phase behavior ofwater-in-oil (n-decane) microemulsion system stabilized by mixednonionic surfactants SPAN 80/TWEEN 80”

Colloid Surface A, 2017, 518, 273-282
DOI:10.1016/j.colsurfa.2017.01.020
источник: http://www.sciencedirect.com/science/article/pii/S0927775717300201

For the search of effective microemulsion systems with the properties demanded for various applica-tions the knowledge of structural properties of the reverse microemulsions for various compositionsand temperatures is of high value. In the present study, the microstructure and diffusion of the compo-nents of water-in-n-decane Winsor IV microemulsions stabilized by a mixture of nonionic surfactantsSpan 80 (sorbitane monooleate, HLB 4.9) and Tween 80 (polyoxyethylene sorbitan monooleate, HLB15.0) at the weight ratios 49:51 (i.e. at the maximal ability to solubilize water) were investigatedby viscosimetry, PGSTE NMR and DLS. The system phase diagram obtained at 298.2 K includes theintermediate heterogeneous region between the reverse micelles region and the microemulsions. Thewater-to-surfactant molar ratio was changed up to 15.5 (13 wt.% of water) at the weight ratios n-decane:surfactants 65:35 and 85:15. The microemulsion droplets are spherical (that is corresponded also to thecryo-TEM data) and grow with the increase of water content. The temperature effect on the aggregatesdiffusion (and on the aggregates size) in the range 298.2–318.2 K is not pronounced. The bimodal distri-butions of the diffusion coefficients determined using both DLS and PGSTE NMR methods are specific for the system. The slower diffusion mode relates to the diffusion of mixed microemulsion droplets with theradii Rh ∼10–20 nm. The second stable form of nanoaggregates are “dry” micelles with Rh ∼ 1–2 nm. Thedata on the diffusion coefficients are of special interest in particular for the molecular dynamic simulationof the reverse micelles or of the microemulsion droplets.

 

Tetrahedron Letters, 2017, 58, 172–174

M.A. Kuznetsov, A.N. Shestakov, M. Zibinsky, M. Krasavin, C.T. Supuran, S. Kalinin, M. Tanç

“Synthesis, structure and properties of N-aminosaccharin – A selective inhibitor of human carbonic anhydrase I”

Tetrahedron Letters, 2017, 58, 172–174
DOI:10.1016/j.tetlet.2016.12.005

Previously unknown N-aminosaccharin was prepared in good yield via the one-step direct amination of saccharin sodium salt with hydroxylamine-O-mesitylenesulfonic acid (MSH) and its reactivity investigated. N-aminosaccharin and its derivatives were tested against hCA isoforms and the parent compound was identified to be a selective, low micromolar inhibitor (Ki = 8.8 lM) of hCA I. These findings provide a ligand-efficient starting point for the design of potent hCA I inhibitors – a promising drug target for retinal/cerebral edema treatment.