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Alexander V Virovets

Publications and source records attributed to Alexander V Virovets.

10 recordsLinked to original sources
PubMed2005

Bis[N-(2-hydroxyethyl)-beta-alaninato]copper(II).

The Cu(II) ion in the title complex, [Cu(C5H10NO3)2] or [Cu(He-ala)2] [He-ala = N-(2-hydroxyethyl)-beta-alaninate], resides at the inversion centre of a square bipyramid comprised of two facially arranged tridentate He-ala ligands. Each He-ala ligand binds to a Cu(II) ion by forming one six-membered beta-alaninate chelate ring in a twist conformation and one five-membered ethanolamine ring in an envelope conformation, with Cu-N = 2.017 (2) angstroms, Cu-O(COO) = 1.968 (1) angstroms and Cu-O(OH) = 2.473 (2) angstroms. The [Cu(He-ala)2] molecules are involved in a network of O-H...O and N-H...O hydrogen bonds, forming layers parallel to the (10-1) plane. The layers are connected into a three-dimensional structure by van der Waals interactions, so that the molecular centres form pseudo-face-centered close packing.

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PubMed2005

Synthesis and reactivity of W3Te74+ clusters and chalcogen exchange in the M3Q7 (M = Mo, W; Q = S, Se, Te) cluster family.

Heating WTe(2), Te, and Br(2) at 390 degrees C followed by extraction with KCN gives [W(3)Te(7)(CN)(6)](2-). Crystal structures of double salts Cs(3.5)K{[W(3)Te(7)(CN)(6)]Br}Br(1.5).4.5H(2)O (1), Cs(2)K(4){[W(3)Te(7)(CN)(6)](2)Cl}Cl.5H(2)O (2), and (Ph(4)P)(3){[W(3)Te(7)(CN)(6)]Br}.H(2)O (3) reveal short Te(2)...X (X = Cl, Br) contacts. Reaction of polymeric Mo(3)Se(7)Br(4) with KNCSe melt gives [Mo(3)Se(7)(CN)(6)](2-). Reactions of polymeric Mo(3)S(7)Br(4) and Mo(3)Te(7)I(4) with KNCSe melt (200-220 degrees C) all give as final product [Mo(3)Se(7)(CN)(6)](2)(-) via intermediate formation of [Mo(3)S(4)Se(3)(CN)(6)](2-)/[Mo(3)SSe(6)(CN)(6)](2-) and of [Mo(3)Te(4)Se(3)(CN)(6)](2-), respectively, as was shown by ESI-MS. (NH(4))(1.5)K(3){[Mo(3)Se(7)(CN)(6)]I}I(1.5).4.5H(2)O (4) was isolated and structurally characterized. Reactions of W(3)Q(7)Br(4) (Q = S, Se) with KNCSe lead to [W(3)Q(4)(CN)(9)](5-). Heating W(3)Te(7)Br(4) in KCNSe melt gives a complicated mixture of W(3)Q(7) and W(3)Q(4) derivatives, as was shown by ESI-MS, from which E(3)[W(3)(mu(3)-Te)(mu-TeSe)(3)(CN)(6)]Br.6H(2)O (5) and K(5)[W(3)(mu(3)-Te)(mu-Se)(3)(CN)(9)] (6) were isolated. X-ray analysis of 5 reveals the presence of a new TeSe(2-) ligand. The complexes were characterized by IR, Raman, electronic, and (77)Se and (125)Te NMR spectra and by ESI mass spectrometry.

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PubMed2005

Three differently coloured concomitant polymorphs: synthesis, structure and packing analysis of (4-(3',5'-dimethyl-1H-pyrazol-1'-yl)-6-methyl-2-phenylpyrimidine)dichlorocopper(II).

A novel pyrazolylpyrimidine ligand (L) and its complex CuLCl(2) were prepared and structurally characterized. The simultaneous crystallization of three polymorphs of CuLCl(2), green (G), emerald green (EG) and orange (O), was discovered. The molecular structures vary only slightly between the three forms. The Cu atom forms four coordinate bonds with the two N and two Cl atoms, and a shortened Cu...H contact with an H atom of the phenyl ring in L. The structural difference between polymorphs was analyzed with the boundary surfaces of molecular Voronoi-Dirichlet polyhedra. The difference in colour of the polymorphs is likely to be due to the different pi-pi stackings. There is no stacking in the G modification, but EG and O polymorphs demonstrate face-to-face and slipped stacking, resulting in dimers and infinite chains, respectively. The EG and O polymorphs are packed according to the hexagonal close-packing motif, while in G no special topology is found.

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PubMed2004

[[Ba2(C2O4)(H2O)6](NCS)2]n: a layered mixed-anion barium oxalate.

We present the first example of a compound containing Ba2+, C2O42-, water and some additional halide or pseudo-halide anions, viz. hexa-mu2-aqua-mu6-oxalato-dibarium(II) diisothiocyanate, [[Ba2(C2O4)(H2O)6](NCS)2]n. The structure consists of positively charged planar covalent layers of Ba2+ cations, oxalate anions and water molecules. The first coordination sphere of the Ba2+ cation contains six water molecules and four O atoms from two planar oxalate anions. The oxalate anion lies on an inversion centre and is coordinated to six Ba2+ cations, each donor O atom being bonded to two cations. Pairs of water molecules are coordinated by two Ba2+ cations. The layers are interspersed with non-coordinated NCS- anions.

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PubMed2003

Synthesis of inorganic fullerene-like molecules.

The reaction of [Cp*Fe(eta5-P5)] with Cu(I)Cl in solvent mixtures of CH2Cl2/CH3CN leads to the formation of entirely inorganic fullerene-like molecules of the formula [[Cp*Fe(eta5:eta1:eta1:eta1:eta1:eta1-P5)]12[CuCl]10[Cu2Cl3]5[Cu(CH3CN)2]5] (1) possessing 90 inorganic core atoms. This compound represents a structural motif similar to that of C60: cyclo-P5 rings of [Cp*Fe(eta5-P5)] molecules are surrounded by six-membered P4Cu2 rings that result from the coordination of each of the phosphorus lone pairs to CuCl metal centers, which are further coordinated by P atoms of other cyclo-P5 rings. Thus, five- and six-membered rings alternate in a manner comparable to that observed in the fullerene molecules. The so-formed half shells are joined by [Cu2Cl3]- as well as by [Cu(CH3CN)2]+ units. The spherical body has an inside diameter of 1.25 nanometers and an outside diameter of 2.13 nanometers, which is about three times as large as that of C60.

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PubMed2002

Preparation and properties of the aqua ions [W(4)S(4)(H(2)O)(12)](n+) (n = 5, 6) and crystal structure of (Me(2)NH(2))(6)[W(4)S(4)(NCS)(12)].0.5H(2)O.

The [3 + 1] reaction of [W(3)S(4)(H(2)O)(9)](4+) with [W(CO)(6)] in 2 M HCl under hydrothermal conditions (130 degrees C) gives the [W(4)S(4)(H(2)O)(12)](6+) cuboidal cluster, reduction potential 35 mV vs NHE (6+/5+ couple). The reduced form is obtained by controlled potential electrolysis. X-ray crystal structure was determined for (Me(2)NH(2))(6)[W(4)S(4)(NCS)(12)].0.5H(2)O. The W-W and W-S bond lengths are 2.840 and 2.379 A, respectively.

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