Ресурсный центр «Магнитно-резонансные методы исследования»

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

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.

A.V. Artem’ev, E.P. Doronina, M.I. Rakhmanova, A.O. Sutyrina, I.Yu. Bagryanskaya, P.M. Tolstoy, A.L. Gushchin, A.S. Mazur, N.K. Gusarova, B.A. Trofimov

“Luminescent CuI thiocyanate complexes based on tris(2-pyridyl)phosphine and its oxide: from mono-, di- and trinuclear species to coordination polymer”

New J. Chem., 2016, 40, 10028-10040
DOI:10.1039/C6NJ02087A

Tris(2-pyridyl)phosphine oxide reacts with CuSCN to form a variety of luminescent complexes, depending on the specified metal-to-ligand ratio and the solvent used, viz. mononuclear [Cu(N,N′,N′′-Py3P=O)(NCS)], dinuclear (N,N′-Py3P=O)Cu(SCN NCS)Cu[(N,N′-Py3P=O)], their co-crystal (2 : 1, correspondingly) and trinuclear {Cu(NCS)[SCNCu(N,N′,N′′-Py3P=O)]2}. In the solid state, these complexes feature red-orange emission upon UV photoexcitation. The reaction of tris(2-pyridyl)phosphine with CuSCN quantitatively produces an almost insoluble coordination polymer, [Cu(Py3P)NCS]n, which exhibits bright green emission. The synthesized compounds are the first members of the hitherto unknown family of Cu(I) thiocyanate complexes supported by tripodal ligands.

В рамках Конгресса Университета Арктики (12-16.09.2016, Санкт-Петербург; http://www.uarctic.spbu.ru/) П.М. Толстой выступил с докладом о работе Научного парка СПбГУ на примере РЦ «Магнитно-резонансные методы исследования». Был организован телемост с ресурсным центром, во время которого специалисты А.С. Мазур и М.А. Вовк отвечали на вопросы о текущей работе и выполняемых проектах.

A.A. Osipov, V.E. Eremyashev, A.S. Mazur, P.M. Tolstoi, L.M. Osipova

“Coordination State of Aluminum and Boron in Barium Aluminoborate Glass”

Glass Physics and Chemistry, 2016, 42(3), 230–237
DOI:10.1134/S1087659616030111

This paper considers the coordination state of boron and aluminum ions in barium aluminoborate glass with a constant ratio of BaO : B₂O₃ = 0.5 and a variable ratio of Al₂O₃ : BaO = 0–3. The dependence of the concentrations of boron and aluminum atoms with a variable coordination number on the Al₂O₃ content was estimated by IR, ¹¹B and ²⁷Al NMR spectroscopy. The nonlinear nature of the obtained dependences was attributed to variations in the aluminum oxide properties. At a content of less than 30 mol % Al₂O₃ serves primarily as a network former, while an increase in the Al₂O₃ concentration results in its higher modifying role in the studied glass.

Доклад нашего коллеги Антона Мазура на конференции Spinus 2015 “Применение метода ЯМР для исследования свойств магнито-упорядоченных веществ”. Видео версию доклада можно посмотреть тут.

А. В. Бутлак, Ю. В. Кондратьев, А. С. Мазур, А. Ю. Тимошкин

“Термическое разложение амминборана при 357 К”

Журнал общей химии, 2015, 85(вып.11), 1761-1764

Калориметрическим методом определены тепловые эффекты разложения амминборана при 357 K и атмосферном давлении в стеклянных и медных кюветах. Энтальпия термического разложения BH₃NH₃ в стеклянных ампулах составляет –24.8±2.3 кДж/моль, эта величина включает структурную перестройку в диаммониат диборана –4.0±2.8 кДж/моль и тепловой эффект разложения до полиамидоборана –20.8±1.6 кДж/моль. В случае опытов в медных кюветах наблюдается существенно больший (–47.6±8.3 кДж/моль) экзотермический эффект. Анализ образцов после калориметрических опытов методом твердотельного ЯМР на ядрах ¹⁵N и ¹¹B показал, что в ходе опытов в медных кюветах происходит частичное окисление с образованием борной кислоты.