Structure determination of KScS2, RbScS2 and KLnS2 (Ln = Nd,Sm, Tb,Dy, Ho,Er, Tm and Yb) and crystal–chemical discussion

The title structures of KScS₂ (potassium scandium sulfide), RbScS₂ (rubidium scandium sulfide) and KLnS₂ [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS₂, RbScS₂ and KTbS₂) or redetermined. All of them belong to the α‐NaFeO₂ structure type in agreement with the ratio of the ionic radii r³⁺/r⁺. KScS₂, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S—S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S²⁻) and the bond‐valence sums.     

Fluoride-assisted trifluoromethylation of aromatic thiones with (trifluoromethyl)trimethylsilane

In the presence of a stoichiometric amount of Bu₄NF·3H₂O, (trifluoromethyl)trimethylsilane reacts with aromatic thiones in both thiophilic and carbophilic ways to deliver, in medium yield, a mixture of (trifluoromethylthio)diarylmethane and 1,1-diaryl-2,2,2-trifluoroethanethiol, the former product being the major one.     

Synthesis and properties of noncoplanar rigid‐rod aromatic polyhydrazides and poly(1,3,4‐oxadiazole)s containing phenyl or naphthyl substituents

Two new phenyl‐ and naphthyl‐substituted rigid‐rod aromatic dicarboxylic acid monomers, 2,2′‐diphenylbiphenyl‐4,4′‐dicarboxylic acid ( 4 ) and 2,2′‐di(1‐naphthyl)biphenyl‐4,4′‐dicarboxylic acid ( 5 ), were synthesized by the Suzuki coupling reaction of 2,2′‐diiodobiphenyl‐4,4′‐dicarboxylic acid dimethyl ester with benzeneboronic acid and naphthaleneboronic acid, respectively, followed by alkaline hydrolysis of the ester groups. Four new polyhydrazides were prepared from the dicarboxylic acids 4 and 5 with terephthalic dihydrazide (TPH) and isophthalic dihydrazide (IPH), respectively, via the Yamazaki phosphorylation reaction. These polyhydrazides were amorphous and readily soluble in many organic solvents. Differential scanning calorimetry (DSC) indicated that these hydrazide polymers had glass transition temperatures in the range of 187–234 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300–400 °C. The resulting poly(1,3,4‐oxadiazole)s exhibited T_g's in the range of 252–283 °C, 10% weight‐loss temperature in excess of 470 °C, and char yield at 800 °C in nitrogen higher than 54%. These organo‐soluble polyhydrazides and poly(1,3,4‐oxadiazole)s exhibited UV–Vis absorption maximum at 262–296 and 264–342 nm in NMP solution, and their photoluminescence spectra showed maximum bands around 414–445 and 404–453 nm, respectively, with quantum yield up to 38%. The electron‐transporting properties were examined by electrochemical methods. Cyclic voltammograms of the poly(1,3,4‐oxadiazole) films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited reversible reduction redox with E_onset at ?1.37 to ?1.57 V versus Ag/AgCl in dry N,N‐dimethylformamide solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6466–6483, 2006     

Preparation and evaluation of nickelmesogen for micropacked gas chromatography

The preparation and mesomorphic properties of a substituted bis(dithiolene)nickel complex derived from 4, 4'-dimethoxybenzil are reported. The phase transition temperatures were based on data obtained by polarized light microscopy and differential scanning calorimetry. The mesogenic phase existed over the temperature range from 77 to 175 degrees C. A novel micropacked column (1.5 or 3 m x 1 mm i.d.) prepared from the slurry of bis[1,2-bis(4-n-undecyloxyphenyl)ethane-1,2-dithiolene] nickel(II) (5%, w/w), coated on Chromosorb W was applied for the separation of dialkyl sulfides. The non-linearity (discontinuity) of Van't Hoff plots suggests that the liquid crystal property existed even in the coated phase. Factors affecting the retention and the sample selectivity on the prepared column were examined by using a flame photometric detector (FPD). The separation might be based on the mechanism of ligand exchange, shape selectivity and polarity interaction besides the vapor pressure. LOD for the determination of dialkyl sulfides was below 1 ng for most of the analytes.     

Direct conversion of tert-butyl 2-hydroxyalkyl sulfides to 1,3-oxathiolanes

tert-Butyl 2-hydroxyalkyl sulfides, prepared by reaction of epoxides with 2-methylpropane-2-thiol, are converted directly to 1,3-oxathiolanes upon treatment with pivalaldehyde and boron trifluoride diethyl etherate in the presence of thioanisole.     

Solid-state synthesis, structural variants and transformation of three-dimensional sulfides, AGaSnS4 (A=Na, K, Rb, Cs, Tl) and Na1.263Ga1.263Sn0.737S4

New cubic-AGaSnS₄ (A=Na, K, Rb, Cs, Tl) and orthorhombic-NaGaSnS₄ compounds were synthesized by solid-state reactions and characterized by X-ray diffraction and diffuse reflectance spectroscopy. Single crystals of orthorhombic-Na_1.263Ga_1.263Sn_0.737S₄ were obtained in the crystal growth attempts of sodium compound. All six new compounds have orthorhombic AgGaGeS₄ and cubic BaGa₂S₄ structures, as determined from single crystal X-ray structures of Na_1.263Ga_1.263Sn_0.737S₄ and cubic-AGaSnS₄ (A=Na, K, Rb). Orthorhombic-NaGaSnS₄ and known layered-KGaSnS₄ undergo structural transformation to thermodynamically stable cubic form.     

Regio- and stereoselective synthesis of vinyl sulfides via PhSeBr-catalyzed hydrothiolation of alkynes

We present here a simple and mild method of hydrothiolation of internal and terminal alkynes under PhSeBr-catalyzed reaction in the absence of solvent at room temperature. The reaction tolerates a wide variety of substituents on thiol, and provides the corresponding product in good yield and selectivity.     

Study of nitrogen- and sulfur-containing heterocycles. 54. Properties and conversions of pyrimido[4,5-<Emphasis Type="Italic">b</Emphasis>]-1,4-benzothiazepines. Synthesis of a novel heterocyclic system: Pyrimido[5,4-<Emphasis Type="Italic">c</Emphasis>]isoquinoline

We have studied some properties and conversions of pyrimido[4,5-b]-1,4-benzothiazepines: reduction, oxidation, reactions with nucleophilic reagents (methanol, hydrazine, hydroxylamine, o-methylhydroxylamine, and thiosemicarbazide). We have synthesized derivatives of a novel heterocyclic system: pyrimido[5,4-c]isoquinoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1863–1872, December, 2004.For Communication 53, see [1].     

过渡金属与二取代冠醚固态配合物的制备

由４＇，５＇－二碘苯并１５冠５，４＇，５＇－二溴苯并１５冠５，４＇－溴－５＇－硝基苯并１５冠５，四溴二苯并１８冠６与过渡全属Ｍｎ（Ⅱ）、Ｃｏ（Ⅱ）、Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）、Ａｇ（Ⅱ）、Ｃｄ（Ⅱ）的硝酸盐、高氯酸盐、气化物合成了１９个未见报道的固态配合物。用元素分析、红外光谱、摩尔电导和差热－热重分析等表征了它们的组成和性质。     

Stereochemistry of ketone olefination with methyl trimethylsilylacetate

High (Z)-stereoselectivity of olefination of methyl α-phenylthioalkyl and methyl α-phenylthioalkenyl ketones with methyl trimethylsilylacetate decreases in the case of ketones containing a higher alkyl-substituent in place of the methyl group. Dedicated to Corresponding Member of the Russian Academy of Sciences E. P. Serebryakov on the occasion of his 70th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1020–1021, April, 2005.