Di­methyl­phenyl­sulfonium tri­fluoro­methane­sulfonate and methyl­di­phenyl­sulfonium tri­fluoro­methane­sulfonate

The bonding geometry of sulfur in the cations of the title compounds, C₈H₁₁S⁺·CF₃SO₃^? and C₁₃H₁₃S⁺·CF₃SO₃^?, respectively, is similar and is independent of the ratio of the Me/Ph substituents. As expected, in both cations, the S—Ph bonds are somewhat shorter than the S—Me bonds. In both crystal structures, the interaction between cations and anions is similar.     

2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.     

Glass formation in the CaO-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>-B<Subscript>2</Subscript>O<Subscript>3</Subscript> and SrO-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>-B<Subscript>2</Subscript>O<Subscript>3</Subscript> systems

A physicochemical study of glasses based on the MO-Bi₂O₃-B₂O₃ and SrO-Bi₂O₃-B₂O₃ systems was performed. Glass formation regions were found. The structural and optical properties, as well as the thermal behavior of the glasses, were studied.     

3,3,10,10‐Tetra­methyl‐1,2‐di­thia‐5,8‐di­aza­cyclo­deca‐4,8‐diene

The title compound, C₁₀H₁₈N₂S₂, acts as an important precursor for the synthesis of the pharmaceutically important di­amine­di­thiol ligand system. The mol­ecule has a local twofold axis and the arrangement of the S₂N₂ donor atoms in the macrocycle is anticlinal.     

4‐Hydro­xy‐3‐methoxy­benz­aldehyde 4,5‐di­azafluoren‐9‐yl­idene­hydrazone

The whole mol­ecule of the title compound, C₁₉H₁₄N₄O₂, is essentially planar, with a highly conjugated π system. In the crystal, the mol­ecules are packed as chains along the [011] direction connected by O—H?N intermolecular hydrogen bonds.     

Preparation and characterization of Pb<Subscript>0.56</Subscript>Sr<Subscript>0.44</Subscript>Zr<Subscript>0.52</Subscript>Ti<Subscript>0.48</Subscript>O<Subscript>3</Subscript> inverse opal

Pb_0.56Sr_0.44Zr_0.52Ti_0.48O₃ (PSZT) inverse opal photonic crystals (PCs) have been synthesized by a process of self-assembly in combination with a sol–gel procedure. PSZT inverse opals show pure perovskite structure with good orders in three dimensions. The evident photonic band gaps have been observed in the transmittance spectra with a blue-shift phenomenon due to the decrease of opal template periods. PSZT inverse opals also exhibit the reflection peaks in basic agreement with the calculated results. This three-dimensional (3D) ordered PSZT inverse opals have shown interesting optical characteristics and potential applications in optoelectronic and photonic devices.     

Methyl­tri­phenyl­stibonium tetra­fluoro­borate

In the title compound, [Sb(CH₃)(C₆H₅)₃]BF₄, there are four independent cations and anions in the asymmetric unit. The geometry around the Sb atom is distorted tetrahedral, with Sb—C distances in the range 2.077 (4)–2.099 (10) Å and angles at the Sb atom in the range 103.3 (3)–119.0 (4)°.     

2,4,6‐Tri­chloro­phenyl­iso­nitrile and 2,4,6‐tri­chloro­benzo­nitrile

The molecular structures of the title compounds, 2,4,6‐tri­chloro­phenyl­iso­nitrile (IUPAC name: 2,4,6‐tri­chloro­phenyl isocyanide), C₇H₂Cl₃N, and 2,4,6‐tri­chloro­benzo­nitrile, C₇H₂Cl₃N, are normal. The two structures are not isomorphous, but do contain similar two‐dimensional layers in which pairs of mol­ecules are held together by pairs of Cl?CN [3.245 (3) Å] or Cl?NC [3.153 (2) Å] interactions. The two‐dimensional isomorphism is lost through different layer‐stacking modes.     

4,5‐Propyl­enedi­thio‐1,3‐di­thiole‐2‐thione and 4,5‐propyl­enedi­thio‐1,3‐di­thiol‐2‐one

4,5‐Propyl­ene­di­thio‐1,3‐di­thiole‐2‐thione, C₆H₆S₅, (I), crystallizes in the centrosymmetric space group P2₁/c. The molecular packing is characterized by pairs of S⋯S intermolecular contacts between neighbouring mol­ecules, which may account for the rather high thermal stablity of the crystal. 4,5‐Propyl­ene­di­thio‐1,3‐di­thiol‐2‐one, C₆H₆OS₄, (II), in which an O atom replaces the terminal S atom of (I), crystallizes in the non‐centrosymmetric polar space group Cc. The packing pattern of (II) indicates that the macropolarization direction is along [101]. Although the packing patterns are qualitatively significantly different, the molecular structures of (I) and (II) are similar, each exhibiting a chair conformation.     

2‐Iso­propyl‐4‐methyl‐4‐phenyl‐1,2,3,4‐tetra­hydro­iso­quinoline‐1‐thione

The title compound, C₁₉H₂₁NS, is the photoproduct obtained from N‐iso­propyl‐N‐[(E)‐2‐phenyl­propenyl]­thio­benz­amide. Recrystallization showed a spontaneous resolution.     

{[(N‐Methyl‐p‐toluidino)­di­phenyl­phospho­ranyl­idene]­methyl}(N‐methyl‐p‐toluidino)­di­phenyl­phospho­nium iodide

The cationic part of the homodifunctional amino­phospho­ranyl ligand, C₄₁H₄₁N₂P₂⁺·I^?, shows interesting features associated with the N—P—C—P—N skeleton. The P—C(H) bond distances [1.696 (3) and 1.697 (3) Å] possess partial double‐bond characteristics. The nature of the P—C(H) and P—N bonds suggests that the positive charge is only distributed around the P—C—P atoms. The structure has near twofold symmetry through the central methyl­ide‐C atom.     

Bis(μ‐hexa­methyl­enetetr­amine)­bis(aqua­di­bromo­cadmium)­di­aqua­di­bromo­cadmium dihydrate

The title compound, poly­[[di­aqua­di­bromo­cadmium‐μ‐(1,3,5,7‐tetra­aza­tri­cyclo[3.3.1.1^3,7]decane‐N¹:N⁵)‐aqua­cad­mium‐di‐μ‐bromo‐aqua­cadmium‐μ‐(1,3,5,7‐tetra­aza­tri­cyclo[3.3.1.1^3,7]decane‐N¹:N⁵)‐di‐μ‐bromo] dihydrate], [Cd₃­Br₆­(C₆­H₁₂­N₄)₂­(H₂O)₄]·­2H₂O, is made up of two‐dimensional neutral rectangular coordination layers. Each rectangular subunit is enclosed by a pair of Cd₃(μ₂‐Br)₆(H₂O)₃ fragments and a pair of (μ₂‐hmt)Cd(H₂O)₂Br₂(μ₂‐hmt) fragments as sides (hmt is hexa­methyl­enetetr­amine). The unique Cd^II atom in the Cd₂Br₂ ring in the Cd₃(μ₂‐Br)₆(H₂O)₃ fragment is in a slightly distorted octahedral CdNOBr₄ geometry, surrounded by one hmt ligand [2.433 (5) Å], one aqua ligand [2.273 (4) Å] and four Br atoms [2.6409 (11)–3.0270 (14) Å]. The Cd^II atom in the (μ₂‐hmt)Cd(H₂O)₂Br₂(μ₂‐hmt) fragment lies on an inversion center and is in a highly distorted octahedral CdN₂O₂Br₂ geometry, surrounded by two trans‐related N atoms of two hmt ligands [2.479 (5) Å], two trans‐related aqua ligands [2.294 (4) Å] and two trans‐related Br atoms [2.6755 (12) Å]. Adjacent two‐dimensional coordination sheets are connected into a three‐dimensional network by hydrogen bonds involving lattice water mol­ecules, and the aqua, bromo and hmt ligands belonging to different layers.     

Specific heat on Sr<Subscript>2</Subscript>Nb<Subscript>2</Subscript>O<Subscript>7</Subscript> and Sr<Subscript>2</Subscript>Ta<Subscript>2</Subscript>O<Subscript>7</Subscript>

Summary Specific heats on the single crystals of Sr₂Nb₂O₇, Sr₂Ta₂O₇ and (Sr_1-xBa_x)₂Nb₂O₇ were measured in a wide temperature range of 2-600 K. Heat anomalies of a λ-type were observed at the incommensurate phase transition of T_INC (=495 K) on Sr₂Nb₂O₇ and at the super-lattice phase transition of T_SL (=443 K) on Sr₂Ta₂O₇; the transition enthalpies and the transition entropies were estimated. Furthermore, a small heat anomaly was observed at the low temperature ferroelectric phase transition of T_LOW (=95 K) on Sr₂Nb₂O₇. The transition temperature T_LOW decreases with increasing Ba content x and it vanishes for samples of x>2%.     

Chemical durability of MoO<Subscript>3</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> and K<Subscript>2</Subscript>O-MoO<Subscript>3</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Thermal and chemical durability studies of the phosphate glasses belonging to the binary MoO₃-P₂O₅ and the ternary K₂O-MoO₃-P₂O₅ systems are reported. The chemical resistant attack tests carried out on the free alkaline MoO₃-P₂O₅ glasses show that the glass associated with the P/Mo ratio 2 has the high chemical durability. It shows also a high glass transition temperature value. The above findings are interpreted in terms of the cross-link density of the glasses and the strength of the M-O bonds (M=P, Mo). The influence of K₂O addition on the properties (density, T _g, durability) of this binary high water resistant glass is studied. It is found that the chemical durability along with the other physical properties are reduced by the incroporation of K₂O in the glass matrix. The results were explained by assuming the formation of non-bridging oxygens and weak bonds. The mechanism of the dissolution of these glasses is proposed.     

Di­propyl 3,6‐di­phenyl‐1,2‐di­hydro‐1,2,4,5‐tetrazine‐1,2‐di­carboxyl­ate

The title compound, C₂₂H₂₄N₄O₄, was prepared from propyl chloro­formate and 3,6‐di­phenyl‐1,2‐di­hydro‐s‐tetrazine. This reaction yields the title compound rather than di­propyl 3,6‐di­phenyl‐1,4‐di­hydro‐s‐tetrazine‐1,4‐di­carboxyl­ate. The 2,3‐di­aza­buta­diene group in the central six‐membered ring is not planar; the C=N double‐bond length is 1.285 (2) Å, and the average N—N single‐bond length is 1.401 (3) Å, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie 0.3268 (17) Å from the plane of the ring. The mol­ecule has twofold crystallographic symmetry.     

Thermal synthesis of the CeO<Subscript>2</Subscript>-PrO<Subscript>2</Subscript>-Nd<Subscript>2</Subscript>O<Subscript>3</Subscript>pigments

Summary The synthesis of new compounds based on the CeO₂-PrO₂-Nd₂O₃system, which can be used as pigments for colouring of ceramic glazes, is investigated in our laboratory. The optimum conditions for the syntheses of these compounds have been estimated. The methods of thermal analysis provided first information about the temperature region of the formation of the pigments investigated. The synthesis of these compounds was followed by thermal analysis using STA 449/C Jupiter (Netzsch, Germany).     

Thermal analysis on C<Subscript>6</Subscript>H<Subscript>10</Subscript>Ge<Subscript>2</Subscript>O<Subscript>7</Subscript>-doped MgB<Subscript>2</Subscript>

Additives to MgB₂ can improve the superconducting functional characteristics, such as critical current density (J _c) and irreversibility field (H _irr). Recently, we have shown that repagermanium (C₆H₁₀Ge₂O₇) is an effective additive, enhancing both J _c and H _irr. To look into details of the processes taking place during the reactive sintering, a thermal analysis study (0.167 K s^?1, in Ar) is reported. We used differential scanning calorimetry between 298 and 863 K and simultaneous thermogravimetric—differential thermal analysis between 298 and 1233 K. Samples were mixtures of powders with composition 97 mol% MgB₂ and 3 mol% C₆H₁₀Ge₂O₇. Up to 863 K, repagermanium decomposes by multiple steps and forms amorphous phases. A reaction with MgB₂ is not observed. Above this temperature, partial decomposition of MgB₂ occurs. Crystalline Ge and MgO are detected before formation of Mg₂Ge and MgB₄, when temperature approaches the melting point of Ge (1211 K). Carbon substitution for boron in the crystal lattice of MgB₂ is observed for samples heated above 863 K. The amount of substitutional C does not significantly change with temperature.     

β‐1‐Acet­amido‐4‐O‐β‐d‐galacto­pyranosyl‐d‐gluco­pyran­ose dihydrate

The crystal structure of the title compound, C₁₄H₂₅NO₁₁·2H₂O, has been determined. The glucose and galactose residues are in a ⁴C₁ conformation. The N‐acetyl group has a Z‐anti conformation.     

Three-component systems LiBr-LiVO<Subscript>3</Subscript>-Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript> and LiBr-Li<Subscript>2</Subscript>SO<Subscript>4</Subscript>-Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript>

Phase equilibria in the three-component systems LiBr-LiVO₃-Li₂MoO₄ and LiBr-Li₂SO₄-Li₂MoO₄ have been studied using differential thermal analysis (DTA). Eutectic compositions have been determined (mol %): in the system LiBr-LiVO₃-Li₂MoO₄, 56.0 LiBr, 22.0 LiVO₃, and 22.0 Li₂MoO₄ with a melting temperature of 413°C; and in the system LiBr-Li₂SO₄-Li₂MoO₄, 65.0 LiBr, 14.0 Li₂SO₄, and 21.0 Li₂MoO₄ with a melting temperature of 421°C. Phase fields have been demarcated.