ChemInform Abstract: All-Electron Molecular Dirac-Hartree-Fock Calculations: The Group IV Tetrahydrides CH4, SiH4, GeH4, SnH4, and PbH4

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Synthesis of 4-Bromo-1,1′:4′,1″-terphenyl and 4-Methyl-1,1′:4′,1″-terphenyl

Russian Journal of Organic Chemistry - Possible synthetic routes to 4-bromo-1,1′:4′,1″-terphenyl and 4-methyl-1,1′:4′,1″-terphenyl have been studied. Stevens...     

Zur Oktaederstreckung an A2BO4-Verbindungen: SrNdMnO4 und SrNdCrO4

About the Octahedra Elongation on A₂BO₄ Compounds: SrNdMnO₄ and SrNdCrO₄ Single crystals of SrNdMnO₄ (I) and SrNdCrO₄ (II) were prepared. The X-ray investigation of (I) and (II) lead to the tetragonal space group D? I4/mmm; lattice constants: (I) a = 377.7; c = 1296 pm; (II) a = 384.2; c = 1233.8 pm. The elongation of the oxygen octahedra surrounding Mn³⁺ and Cr³⁺ are discussed.     

Zintlphasen mit isolierten SiAs4- bzw. GeAs4-Anionen: Darstellung und Struktur von Ba4SiAs4 und Ba4GeAs4 sowie Sr4SiAs4 und Sr4GeAs4

Die erstmals dargestellten isotypen Verbindungen Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄ und Sr₄GeAs₄ kristallisieren kubisch, Raumgruppe P4 3n, mit 8 Formeleinheiten in der Elementarzelle: In den Strukturen liegen isolierte, d.h. nur von Ba-Ionen umgebene SiAs - bzw. GeAs -Tetraeder vor. Die Verbindungen sind die bisher eindrucksvollsten Beispiele für Zintlphasen mit komplexen Anionen. Zintl Phases with Isolated SiAs₄ or GeAs₄ Anions: Preparation and Structure of Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄, and Sr₄GeAs₄ The new compounds Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄, and Sr₄GeAs₄ have been prepared and their structures determined. They crystallize in the cubic system, P4 3n, with axes: data see “Inhaltsübersicht”. There are isolated SiAs or GeAs tetrahedra in the structures. The compounds can be interpreted as Zintl phases with complex anions.     

A New azacyanocarbon,C4N4: tricyanomethanimine

- 2,2-Dichloroethylene-1,1-dicarbonitrile reacted with sodium azide to give 2,2- diazidoethylene-1,1-dicarbonitrile, which underwent thermolysis to give tricyanomethanimine, C₄N₄. The latter is as reactive as TCNE toward electron-rich molecules.     

(CuI)P4Se4: An Adduct of Polymeric P4Se4 with CuI

Pure yellow (CuI)P₄Se₄ was prepared by reaction of stoichiometric amounts of CuI, red P, and gray Se in evacuated silica ampoules. The crystal structure was determined from single crystals at room temperature. (CuI)P₄Se₄ crystallizes in the orthorhombic system, space group Cmca with a = 14.770 (1) Å, b = 12.029 (1) Å, c = 12.449 (1) Å, V = 2211.9(6) ų, and Z = 8. The structure refinement converged to R = 0.0190 (wR = 0.0272) for 1020 independent reflections and 51 parameters. A prominent feature of the crystal structure are neutral polymeric P₄Se₄ strands which are connected by copper iodide. These strands consist of norbornane analogous P₄Se₃ cages which are linked by selenium bridges. The polymers are achiral since a mirror plane exists perpendicular to the strands. The single polymers are connected by [Cu₂I₂] units to form layers. These layers are stacked along the b axis and are connected by van der Waals-interactions only. Raman spectra of (CuI)P₄Se₄ differ significantly from Raman spectra of (CuI)₃P₄Se₄ and catena-(P₄Se₄)_x.     

2-Trif luoromethyl-4H-thiochromen-4-one and 2-trif luoromethyl-4H-thiochromene-4-thione: Synthesis and reactivities

2-Trifluoromethyl-4H-thiochromene-4-thione obtained from 2-trifluoromethyl-4H-thiochromen-4-one and P₂S₅ reacts with aromatic amines, hydrazine hydrate, phenylhydrazine, and hydroxylamine at the C(4) atom of the chromene ring to give the corresponding anils, azine, hydrazones, and oxime of thiochromone. 2-Trifluoromethyl-4H-thiochromen-4-one is oxidized by hydrogen peroxide in AcOH into 4-oxo-2-trifluoromethyl-4H-thiochromene 1,1-dioxide and reduced by NaBH₄ to 2-trifluoromethyl-4H-thiochromen-4-ol or cis-2-(trifluoromethyl)thiochroman-4-ol. When treated with hydrazine hydrate, thiochromen-4-one gives 3(5)-(2-mercaptophenyl)-5(3)-trifluoromethylpyrazole. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 504–509, March, 2006.     

Polysubstituted 4-piperidones and 4-piperidols: Synthesis and spatial configuration

Triacetonamine was used to synthesize a series of highly substituted 4-piperidones and 4-piperidols. The spatial configuration of these compounds was determined. The anionoid addition to the carbonyl group of these piperidones proceeds through highly stereoselective equatorial attack. The position of the chair-chair-twist conformational equilibrium was determined for the polysubstituted 4-piperidols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 486–496, February, 1991.     

Ein Oxid neuen Typs: Kli4[AlO4]

New Oxoaluminate KLi₄[AlO₄] Transparent and colourless single crystals of Kli₄[AlO₄] have been prepared for the first time by heating mixtures of Li₅AlO₄ and K₂O in the ratio 1:5 [Ni-tube, 950°C, 50 d]. The structure determination [four-circle diffractometer, MoKα, 1699 of 2427 I₀ (hkl), R = 7.41%, R_w = 4.3%] proves the monoclinic space group P2₁/c with a = 554.4(3), b = 1544.1(7), c = 1103.3(6) pm, β = 109.71(5)°, parameters see text. Characterizing are “isolated” AlO₄ groups with symmetry nearly T_d. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Ein Oxostannat neuen Strukturtyps: Cs4[SnO4]

An Oxostannate of a New Structure Type: Cs₄[SnO₄] In order to prepare Cs₃LiSnO₄ by heating of a well ground mixture of the binary oxides [CsO_0.67, Li₂O, SnO₂; Cs:Li:Sn = 3.3:1.0:1.0; 450°C; 28 d; Ni-tube] colourless, monoclinic single crystals of Cs₄[SnO₄] have been yielded for the first time: space group P2₁/c with a = 1180.8 pm. b = 728.2 pm, c = 1166,7 pm, β = 111.79°, Z = 4. The crystal structure was solved by fourcycle-diffractometer data [Siemens AED2, 2299 from 2708 I₀(hkl), R = 7.0%, R_w = 5.6%], parameters see text. Characteristic for the complicated structure are “isolated” [SnO₄]^4? tetrahedra. Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN and the Madelung Part of Lattice Energy, MAPLE, have been calculated.     

4-Silapiperidine and 4-silapiperidinium derivatives: syntheses and structural characterization

A series of novel 4-silapiperidine and 4-silapiperidinium derivatives, with two silicon-bound aryl groups and various N-organyl groups, have been synthesized and structurally characterized (solution ¹H, ¹³C, ¹⁹F, and ²⁹Si NMR spectroscopy; eight crystal structure analyses). These synthetic and structural investigations provide the basis for the development of novel silicon-based drugs containing a 4-silapiperidine or 4-silapiperidinium skeleton.     

4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones: biological isostere to 4-chloro-2-carbamoyl-4-isoxazolin-3-ones

4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones (4) were designed on the basis of biological isosterism and prepared in four steps. Some of these compounds showed sufficient pre-emergent herbicidal activities against various kinds of weeds. Among the synthesized compounds, 2-(N-(4-chlorophenyl)-N-isopropylcarbamoyl)-4-ethylthio-5-methyl-4 -isoxazolin-3-one (4cd) exhibited the most promising activity.     

Zur Kenntnis der Na5[GaO4]-Verwandtschaft: KNa4[GaO4] und CsK4[GaO4]

About the Na₅[GaO₄]-Relationship: KNa₄[GaO₄] and CsK₄[GaO₄] KNa₄[GaO₄] was newly prepared from binary oxides (powders) and also from KGaO₂/Na₂O/K₂O (colourless columnar single crystals) in a closed Ag-cylinder at 600 and 650°C. Space group Pbca with a = 1046.1(2), b = 596.3(1), c = 1871.1(3) pm, Z = 8 [Four-circle-diffractometer data, 1138 I₀(hkl), MoKα, R = 8.29, R_w = 6.76%, anisotropic refinement] (Parameter s. text). Colourless cubic single crystals of hitherto unknown CsK₄[GaO₄] are formed by reaction of K₂O, CsGaO₂, and Cs₂O (surplus) in a closed Au-tube at 580°C. Space group Pbca with a = 1154.7, b = 667.7, c = 2096.6 pm, Z = 8 [Four-circle-diffractometer data, 1798 I₀(hkl), MoKα, R = 7.62, R_w = 7.68%, anisotropic refinement] (Parameter s. text). Both crystal structures belong to the Na₅[GaO₄] type. Structural aspects, ECoN, and MAPLE of KNa₄[GaO₄] and CsK₄[GaO₄] in relation with Na₅[GaO₄] are discussed.