Thermal stability of In2(MoO4)3 and phase equilibria in the MoO3–In2O3 system

Thermal stability of a compound forming in a binary system MoO₃?CIn₂O₃ was investigated by DTA/TG, XRD and SEM methods in this study. For the first time, the diagram of phase equilibria established in the whole range of concentrations of this system's components has been constructed. The temperature and concentration ranges of the components of MoO₃?CIn₂O₃ system in which the compound In₂(MoO₄)₃ co-exists in solid state with MoO₃ or In₂O₃ or with the liquid were determined. The composition and melting point of the eutectic mixture consisting of In₂(MoO₄)₃ and MoO₃ were found.     

High-pressure synthesis and local structure of corundum-type In(2-2x)Zn(x)Sn(x)O(3) (x ≤ 0.7)

The corundum-type In(2-2x)Zn(x)Sn(x)O(3) solid solution (cor-ZITO, x ≤ 0.7) was synthesized at 1000 °C under a high pressure of 70 kbar. cor-ZITO is a high-pressure polymorph of the transparent conducting oxide bixbyite-In(2-2x)Zn(x)Sn(x)O(3) (x ≤ 0.4). Analysis of the extended X-ray absorption fine structure suggests that significant face-sharing of Zn and Sn octahedra occurs, as expected for the corundum structure type. In contrast to the ideal corundum structure, however, Zn and Sn are displaced and form oxygen bonds with lengths that are similar to those observed in high-pressure ZnSnO(3). Powder X-ray diffraction patterns of cor-ZITO showed the expected unit cell contraction with increased cosubstitution, but no evidence for ilmenite-type ordering of the substituted Zn and Sn. A qualitative second harmonic generation measurement, for the solid solution x = 0.6 and using 1064 nm radiation, showed that Zn and Sn adopt a polar LiNbO(3)-type arrangement.     

The layer crystal structure of [In2(C2O4)3(H2O)3]·7H2O and microstructure of nanocrystalline In2O3 obtained from thermal decomposition

A new indium oxalate, [In₂(C₂O₄)₃(H₂O)₃]·7H₂O, with a layered structure has been synthesised from precipitation methods at room temperature. It crystallises with a monoclinic symmetry, space group P2₁/c (No. 14), a=8.7456(1) Å, b=11.1479(2) Å, c=21.9376(4) Å, β=112.1(1)°, V=1979.98(6) ų and Z=4. The structure is built from neutral [In₂(C₂O₄)₃(H₂O)₃] corrugated layers, between which water molecules are intercalated. The layers are built from chains with two different sequences of indium atoms and bichelating oxalate groups. Two independent indium atoms are present in the structure with two coordination polyhedra, i.e., InO₈ as a distorted square-based antiprism and InO₇ as a nearly regular pentagonal-based bipyramid. The thermal decomposition has been studied in situ by temperature dependent X-ray diffraction and thermogravimety. The final product is nanocrystalline indium oxide. The microstructure of the oxide has been characterised with both the Voigt/Langford method based on the integral breadth and the whole pattern fitting approach. The size of the isotropic crystallites increases from 322 to 924 Å, while microstrains decrease, in the annealing temperature range 500–750 °C.     

LC-DAD and LC–MS–MS Analysis of Piperidine Alkaloids of Lobelia inflata L. (In Vitro and In Vivo)

An LC-DAD method was developed for determination of lobeline from in vitro and in vivo cultures of Lobelia inflata. Samples were extracted with 0.1 N HCl–acetonitrile (1:1, v/v), and purified by solid-phase extraction. Optimized conditions resulted in high recovery. LC separations were performed on an Eurosphere C8 reversed-phase column using 30:70 (v/v) acetonitrile–0.1% trifluoroacetic acid as a mobile phase. Quantitative determination of lobeline was performed by external standard method at 250 nm, in the range of 2.4–80 μg mL⁻¹. Validation studies proved that the repeatability of the method was good and the recovery was satisfactory. In vitro organized cultures contained considerable amount of lobeline (herb: 175 μg g⁻¹, root: 100 μg g⁻¹). When these cultures were transplanted into the open field, the lobeline content increased significantly (herb: 323 μg g⁻¹, root: 833 μg g⁻¹). Plants obtained from seed propagation contained 382 μg g⁻¹ lobeline in the herb. For direct characterization of di-substituted piperidine alkaloids in extracts of L. inflata, tandem mass spectrometric method was developed using electrospray ionization. Analysis was performed in the positive ion mode on a triple quadropole LC–MS system. LC separations were achieved on Eurosphere C8 column with a modified mobile phase (acetonitrile–30 mM ammonium formate, pH 2.80) to ensure proper molecular ionization. The identification and structural elucidation of the alkaloids were performed by comparing their changes in molecular mass (ΔM), full-scan MS–MS spectra with those of lobeline, norlobelanine and lobelanidine. These alkaloids and ten other derivatives were identified in the plant extracts. Three piperidine alkaloids were reported in L. inflata for the first time.

     

Raman spectra of crystals of some β-diketonates Al(III), Ga(III) and In(III)

Raman spectra of crystals of some metal β-diketonates of the third group have been obtained in the region of 10–3100 cm⁻¹. The polarized spectra of oriented crystals and solutions of chelates in chloroform have been measured. The factor group analysis, polarized spectra and results of deuteration of the chelates showed that all the spectra were divided into two regions: low-frequency 10–100 cm⁻¹ (external vibrations) and high-frequency 100–3100 cm⁻¹ (internal vibrations). In their turn the external modes were divided into translational and librational. The common analysis of the internal vibration behaviour in a series of metals and ligands has been carried out. The torsional vibrations of methyl groups have been interpreted.     

In silico screening for agonists and blockers of the β(2) adrenergic receptor: implications of inactive and activated state structures

Ten crystal structures of the β(2) adrenergic receptor have been published, reflecting different signaling states. Here, through controlled-docking experiments, we examined the implications of using inactive or activated structures on the in silico screening for agonists and blockers of the receptor. Specifically, we targeted the crystal structures solved in complex with carazolol (2RH1), the neutral antagonist alprenalol, the irreversible agonist FAUC50 (3PDS), and the full agonist BI-167017 (3P0G). Our results indicate that activated structures favor agonists over blockers, whereas inactive structures favor blockers over agonists. This tendency is more marked for activated than for inactive structures. Additionally, agonists tend to receive more favorable docking scores when docked at activated rather than inactive structures, while blockers do the opposite. Hence, the difference between the docking scores attained with an activated and an inactive structure is an excellent means for the classification of ligands into agonists and blockers as we determined through receiver operating characteristic curves and linear discriminant analysis. With respect to virtual screening, all structures prioritized well agonists and blockers over nonbinders. However, inactive structures worked better for blockers and activated structures worked better for agonists, respectively. Notably, the combination of individual docking experiments through receptor ensemble docking resulted in an excellent performance in the retrieval of both agonists and blockers. Finally, we demonstrated that the induced-fit docking of agonists is a viable way of modifying an inactive crystal structure and bias it toward the in silico recognition of agonists rather than blockers.     

Synthesis and chemistry of tris(2-pyridyl)phosphine and bis(2-pyridyl)phenylphosphine complexes of mercury(II) X (X = Br,Cl) and X-ray crystal structural determination of [HgBr2(PPh(2-py)2)2]

Mercury(II) halide complexes [HgX₂(P(2-py)₃)₂] (X?=?Br (1), Cl (2)) and [HgX₂(PPh(2-py)₂)₂] (X?=?Br (3), Cl (4)) containing P(2-py)₃ and PPh(2-py)₂ ligands (P(2-py)₃ is tris(2-pyridyl)phosphine and PPh(2-py)₂ is bis(2-pyridyl)phenylphosphine) were synthesized in nearly quantitative yield by reaction of corresponding mercury(II) halide and appropriate ligands. The synthesized complexes are fully characterized by elemental analysis, melting point determination, IR, ¹H, and ³¹P-NMR spectroscopies. Furthermore, the crystal structure of [HgBr₂(PPh(2-py)₂)₂] determined by X-ray diffraction is also reported.     

Synthesis and Magnetic Properties of Fe(II) and Nd(III) Complexes of Poly(N-2-thiazolylacrylamide)

In recent years,the organic ferromagnets have drawn growing attention due to their characteristics of structural diversities,low density,and readily processing1-3.Design and synthesis of magnetic polymers are one of great challenges in today′s magnetic material research,and some significant achievements have been made in this field4,5.In this article,we describe the synthesis of acrylamide-type polymer with pendent thiazolyl groups(Scheme1).The as-prepared polymer exhibited better solubility …     

Changes of decay rates of radioactive ~(111)In and ~(32)P induced by mechanic motion

The changes of decay rates of radionuclide 111In(electron capture) and 32P(β decay) induced by exter-nal mechanic motion are studied. The results indicate that,in the external circular rotation in clockwise and anticlockwise centrifuge on Northern Hemisphere(radius 8 cm,2000 r/min) ,the half life of 111In compared with the referred(2.83 d) is decreased at 2.83% and increased at 1.77%,respectively;the half life of 32P compared with the referred(14.29 d) is decreased at 3.78% and increased at 1.75%,respec-tively. When the clockwise and anticlockwise rotations increase to 4000 r/min,the half life of 111In is decreased at 11.31% and increased at 6.36%,respectively;the half life of 32P is decreased at 10.08% and increased at 4.34%,respectively. When the circular rotation is removed,the decay rates of 111In and 32P return back to the referred,respectively. It is found that the external circular rotations in clockwise and anticlockwise centrifuge selectively increased and decreased the decay rates of 111In and 32P,respec-tively,and the effects are strongly dependent on the strength of circular rotation. It is suggested that these effects may be caused by the chiral interaction.     

Synthesis, structure and reactivity of binuclear metal-metal bonded molybdenum(V) and tungsten(V) thioselenohalides: Molecular structure of Mo2(μ-S2)2Cl6(SeCl2)2 and W2(μ-S2)2Cl6(SeCl2)2

Thioselenohalide complexes Mo₂(μ-S₂)₂Cl₆(SeCl₂)₂ (I), Mo₂(μ-S₂)₂Br₆(SeBr₂)₂ (II), and W₂(μ-S₂)₂Br₆(SeBr₂)₂ (III) were synthesized by the reactions of corresponding metal halides or carbonyls or molybdenum metal with excesses of S₂ X ₂+Se₂ X ₂ mixtures. The complex W₂(μ-S₂)₂Cl₆(SeCl₂)₂ (IV) was obtained by an exchange reaction between (III) and excess of Se₂Cl₂. Coordination of the neutral SeX ₂ ligands to thiohalidesM ₂(μ-S₂)₂ X ₆ results in higher thermal stability, and suggests the possibility to synthesize SeX ₂ complexes of the unstable parent tungsten thiohalides. An unusual oxidative addition reaction of (I) was detected: {fx27-1} Both (I) and (IV) were characterized by X-ray crystal structure analysis. They are isostructural and form discrete molecules. Bridging S ₂ ^2? ligands are coordinated perpendicularly to the metal-metal bond;d(M?M)=2.8066 Å and 2.793 Å for I and IV, respectively. Nonequivalence of chlorine atoms which are bound to the metal atom, relate to nonequivalence of halogen atoms in the complexesM ₂(μ?S₂)₂ X ₈ ^2? . Chlorine atomstrans to SeCl₂ ligands form short bonds with the metal; the corresponding³⁵Cl NQR frequency is increased. The selenium dichloride ligand is ambidentate. The selenium atom binds as a donor to the metal and as an acceptor to two chlorine atoms which are also bound covalently to the same metal atom.     

Facile Synthesis and Catalytic Properties of β-Co(OH)2 and Mg(OH)2 Nanoplates

β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach. The different conditions of preparation and catalytic properties of the products were studied and discussed. The products were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, selected area electron diffraction(SAED), and gas chromatograph.     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

Preparation and reaction of platinum(II) complexes of N,N-bis(dicyclohexylphosphinomethyl)aminomethane. Crystal structures of (Cy2PCH2)2NMe (Cy = cyclohexyl) and [PtX2{(Cy2PCH2)2NMe}], (X = Cl and I)

Treatment of [Cy₂P(CH₂OH)₂]Cl with MeNH₂ in the presence of Et₃N affords a high yield of the phosphine (Cy₂PCH₂)₂NMe (1) (dcpam) which has been characterised by a single crystal X-ray structure. Treatment of [PtX₂(COD)], (COD=cyclo-octa-1,5-diene, X= Cl or I) with (1) affords the platinum complexes [PtX₂{(Cy₂PCH₂)₂NMe}] (2). The chloride complex, (2a), reacts with t-BuNC to afford [PtCl(t-BuNC)-{(Cy₂PCH₂)₂NMe}]Cl (3) and treatment of (2a) with 2-mercapto-1-methylimidazole affords [Pt{SCN(Me)CHCH=N(Me)}{Cy₂PCH₂)₂NMe}]Cl (5). The reaction of (2a) with 2-acetamidoacrylic acid in the presence of silver(I) oxide affords the carbon bonded isomer (8a) only whereas a similar reaction using [PtCl₂{Ph₂P-(CH₂)₃PPh₂}] affords a mixture of the azaallyl complex (7) and the carbon bonded isomer (8b) which can be separated by fractional crystallisation. The crystal structures of PtX₂{(Cy₂PCH₂)₂NMe}] are also reported.     

In Situ Study of the Solid-State Formation of U(1-x)Am(x)O(2±δ) Solid Solution

In order to reduce the nuclear waste inventory and radiotoxicity, U(1-x)Am(x)O(2±δ) materials are promising fuels for heterogeneous transmutation. In this context, they are generally fabricated from UO(2+δ) and AmO(2-δ) dioxide powders. In the subsequent solid solution, americium is assumed to be trivalent whereas uranium exhibits a mixed-valence (+IV/+V) state. However, no formation mechanisms were ever evidenced and, more particularly, it was not possible to know whether the reduction of Am(IV) to Am(III) occurs before the solid-solution formation, or only once it is established. In this study, we used high-temperature X-ray diffraction on a UO(2±δ)/AmO(2-δ) (15 mol?%) mixture to observe in situ the formation of the U(1-x)Am(x)O(2±δ) solid solution. We show that UO(2+δ) is, at relatively low temperature (<700 K), oxidized to U(4)O(9-δ), which is likely to be caused by oxygen release from the simultaneous AmO(2-δ) reduction to cubic Am(2)O(3±δ). Cubic Am(2)O(3+δ) then transforms to hexagonal Am(2)O(3) at 1300 K. Thus, the initial Am(IV) is fully reduced to Am(III) before the solid solution starts forming at 1740 K. The UO(2) fluorite phase vanishes after 4 h at 1970 K, indicating that the formation of the solid solution is completed, which proves that this solid solution is formed after the complete reduction of Am(IV) to Am(III).     

Study of cis–trans stereochemistry of 2-(2-chlorobenzylideneamino)phenol and 2-(2-chlorophenyl imino)methyl)phenol (Schiff bases) by GC and GC-MS spectrometry

Cis–trans stereochemistry of 2-(2-chlorobenzylideneamino)phenol (1) and 2-(2-chlorophenyl imino)methyl)phenol (2) (Schiff bases) was studied by GC-MS spectrometry, and cis–trans conversion of the two compounds in solution was investigated by GC. Thus, 2 exists as a sole trans configuration and its conversion to cis was unsuccessful in any circumstance, while compound 1 exists as a mixture of two configurations in solution, occurrence of which were dependent on the temperature, heating time, solvent, and acid catalyst. X-ray crystallography of solid 1 presented a sole trans configuration.     

Enzymatic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol and (±)-cis- and (±)-trans-2-aminoindan-1-ol

Pseudomonas cepacia lipase (PSL) efficiently catalyses the kinetic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol through the O-acylation reaction of the corresponding N-benzyloxycarbonyl derivative using vinyl acetate as the acyl donor. In a similar way, cis-N-Cbz-2-aminoindan-1-ol is resolved when isopropenyl acetate is used as the acylating agent. The enantioselectivity of the reaction was lower for (±)-trans-N-Cbz-2-aminoindan-1-ol due to the different steric requirements for the two conformers of this substrate.     

Simultaneous determination of In(III) and Cd(II) by differential pulse polarography in the presence of poly β-cyclodextrin

The difference in the peak potentials of In(III) and Cd(II), whose reduction potentials are very close to each other, becomes large in the presence of poly beta-cyclodextrin in sodium perchlorate medium. The relationships between the peak currents for these two ions and their concentrations are linear, suggesting that the simultaneous determination of the ions is possible in the presence of this reagent.     

In situ Raman and UV-vis spectroscopic studies of polypyrrole and poly(pyrrole-2,6-dimethyl-β-cyclodextrin)

Polypyrrole (PPy) and poly(pyrrole-2,6-dimethyl-β-cyclodextrin) [P(Py-β-DMCD)] films prepared by potential cycling in aqueous acidic solutions on indium tin oxide (ITO)-coated glass and gold electrodes were studied by in situ UV-vis and Raman spectroscopy. Characteristic UV-vis and Raman bands were identified and their dependencies on the electrode potential have been discussed. Spectroelectrochemical results reveal differences both in the position of the spectral bands and their potential dependence for PPy and P(Py-β-DMCD) films indicating interactions between polymer chains and CDs during electropolymerization process. The films were also characterized by cyclic voltammetry and FT-IR spectroscopy.     

Preparation and Raman spectra of Ca(NO2)2·H2O,Ca(NO2)2 and Mg(NO2)2·H2O

The above named salts have been prepared from aqueous solutions of the pure nitrates. Distinct compounds Ca(NO₂)₂·H₂O and Ca(NO₂)₂ which are free of nitrate impurity have been characterized by their Raman spectra. The hydrated salt appears to contain four crystallographically non-equivalent nitrate groups. A distinct hydrate of magnesium formulated as Mg(NO₂)₂·H₂O can also be prepared and characterized by Raman spectroscopy but this sample always contained significant nitrate impurity.     

Chemical and enzymatic synthesis of 2-(2-carbamoylethyl)- and 2-(2-carboxyethyl)aziridines and their conversion into δ-lactams and γ-lactones

Treatment of 1-arylmethyl-2-(2-cyanoethyl)aziridines with a nitrile hydratase afforded the corresponding 2-(2-carbamoylethyl)aziridines, which underwent rearrangement into 5-hydroxypiperidin-2-ones upon heating under microwave irradiation. In addition, treatment of 2-(2-cyanoethyl)aziridines with a nitrilase selectively afforded 5-hydroxypiperidin-2-ones in good yields. On the other hand, chemical hydrolysis of 2-(2-cyanoethyl)aziridines using KOH in EtOH/H(2)O furnished the corresponding potassium 3-(aziridin-2-yl)propanoates, which, upon acidification with acetic acid, smoothly rearranged into 4-(aminomethyl)butyrolactones.