Synthesis of some derivatives of 3-amino-3-desoxyerythrose and 3-amino-3-desoxy-D-3-erythrose

The synthesis of derivatives of 3-amino-3-deoxy-L-erythrose by LAH or LAD reduction of the oxime of 1,2-O-isopropylidene α-L -glycero-tetros-3-ulofuranose is described.     

Synthesis of γγγ-trifluorocarbonyl compounds

γγγ-Trifluorocarbonyl compounds are easily obtained in a good yield by introduction of the 1,1,1-trifluoroethyl moiety (CF₃-CH₂-) on the -methylene group of a ketone.     

Freezing the polarization of CH3NH3PbI3 and CH3NH3PbI3-xClx perovskite films

Thin films of methylammonium lead halides, CH₃NH₃PbI₃ and CH₃NH₃PbI_3-xCl_x, were deposited onto symmetrical microstructured electrode arrays of gold or platinum on Si/SiO₂ wafers. Polarization studies were carried out on perovskite films under vacuum in the dark. For poling, a constant voltage was applied to the samples while the temperature was cycled between 295 K and 4 K. The measured current densities depending on the temperature showed distinct characteristics relating strongly to the crystal phase and the dielectric properties of the perovskite films. Voltage sweeps were carried out at different scan rates at specific temperature intervals after poling. The polarization of the films due to the migration of iodide vacancies in direction of the blocking perovskite/metal interface was frozen almost up to room temperature. Charge carriers were only able to cross the blocking barrier and contribute to the current where the ions have accumulated during poling. All J-V curves showed hysteresis: inverted and regular hysteresis at room temperature and below, respectively. Inverted hysteresis originates from the slow accumulation of ions at the blocking barrier, while regular hysteresis arises from a distortion in the adjacent crystals which will be discussed.     

钙钛矿CH3NH3PbI3晶体的电化学

电化学方波伏安及循环伏安测量表明,钙钛矿CH₃NH₃PbI₃晶体在有机电解质中的氧化还原过程伴随着化学降解。该化学降解源于CH₃NH₃PbI₃晶体中铅离子的还原以及碘离子的氧化。通过电化学伏安法可以测定晶体的能带。     

Non-Isothermal Kinetics of the Decomposition Reaction of Cluster [Ag3WS3Br]（PPh3）3 and [Cu3WS3Br]（PPh3）3

The thermal behaviors of clusters [Ag3WS3Br](PPh3)3 and [Cu3WS3Br](PPh3)3 (PPh3=triphenyl phosphine) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC and EDS techniques. The results showed that the evolution of PPh3 generally proceeded before the release of the other moiety in one or two step-mode. The mechanisms, the kinetic and the thermodynamic parameters for decomposition of PPh3 of both clusters were determined and calculated by jointly using several methods, which showed that its evolution was controlled by Avrami-Erofeev equation. The results also showed that there was no new stable phase composed of W-Ag(Cu)-S-Br after release of organic moiety PPh3 and that CVD method was not applicable to their further processing.     

Synthesis of 3-functionalized 3-methylazetidines

1-t-Butyl- and 1-(4-methylbenzyl)-3-bromo-3-methylazetidines were prepared from the corresponding N-(2,3-dibromo-2-methylpropylidene)alkylamines and their propensity to undergo nucleophilic substitution at the 3-position by different nucleophiles was assessed, providing a convenient access to novel 3-alkoxy-, 3-aryloxy-, 3-hydroxy-, 3-cyano-, 3-carboxy-, 3-(aminomethyl)- and 3-(hydroxymethyl)azetidines.     

Addition of NH3 to Al3O3-

Recent computational studies on the addition of ammonia (NH3) to the Al3O3- cluster anion [A. Guevara-Garcia, A. Martinez, and J. V. Ortiz, J. Chem. Phys. 122, 214309 (2005)] have motivated experimental and additional computational studies, reported here. Al3O3- is observed to react with a single NH3 molecule to form the Al3O3NH3- ion in mass spectrometric studies. This is in contrast to similarly performed studies with water, in which the Al3O5H4- product was highly favored. However, the anion PE spectrum of the ammoniated species is very similar to that of Al3O4H2-. The adiabatic electron affinity of Al3O3NH3 is determined to be 2.35(5) eV. Based on comparison between the spectra and calculated electron affinities, it appears that NH3 adds dissociatively to Al3O3-, suggesting that the time for the Al3O3-NH3 complex to either overcome or tunnel through the barrier to proton transfer (which is higher for NH3 than for water) is short relative to the time for collisional cooling in the experiment.     

Dy3+在Ba3La(BO3)3 中的光致发光

研究了Ba3La(BO3)3 基质中Dy3 的光致发光特性; 探讨了RE3 的电荷半径比(z/r)和Ce3 , Dy3 含量对Dy3 发光强度及发光颜色的影响; 分析了Ba3La(BO3)3 中Ce3 对Dy3 发光的敏化作用; 确定了Dy3 的 4F9/2→6H15/2及4F9/2→6H13/2跃迁发射的浓度猝灭机制均为电偶极-电四极相互作用.     

Synthesis of 3-Bromo-3-nitroacrylates

Russian Journal of Organic Chemistry -     

3-(3＇-乙酰基-5＇-芳基-1＇,3＇,4＇-二氢噁二唑-2＇-)色酮的微波促进合成

将微波应用于促进有机合成是近年来兴起的新技术,已受到极大注意,我们采用简单的微波反应装置,成功地合成了3－杂环基取代的色酮,杂环基取代的色酮因其显著的生理活性,而成为近年来的研究特点,以3－甲酰基色酮为原料,与芳酰肼反应得到相应的芳酰腙,再用乙酸酐关环,合成了一系列3位为1,3,4－二氢恶二唑基取代的色酮（3）,为在合适的母体上引入杂环提供了一系新思路,合成路线如下。     

Syntheses and Crystal Structures of the Novel Ternary Thioborates Na3BS3, K3BS3, and Rb3BS3

The orthothioborates Na₃BS₃, K₃BS₃ and Rb₃BS₃ were prepared from the metal sulfides, amorphous boron and sulfur in solid state reactions at temperatures between 923 and 973 K. In a systematic study on the structural cation influence on this type of ternary compounds, the crystal structures were determined by single crystal X‐ray diffraction experiments. Na₃BS₃ crystallizes in the monoclinic space group C2/c (No. 15) with a = 11.853(14) Å, b = 6.664(10) Å, c = 8.406(10) Å, β = 118.18(2)° and Z = 4. K₃BS₃ and Rb₃BS₃ are monoclinic, space group P2₁/c (No. 14) with a = 10.061(3) Å, b = 6.210(2) Å, c = 12.538(3) Å, β = 112.97(2) and a = 10.215(3) Å, b = 6.407(1) Å, c = 13.069(6) Å, β = 103.64(5)°, Z = 4. The potassium and rubidium compounds are not isotypic. All three compounds contain isolated [BS₃]^3– anions with boron in a trigonal‐planar coordination. The sodium cations in Na₃BS₃ are located between layers of orthothioborate anions, in the case of K₃BS₃ and Rb₃BS₃ stacks of [BS₃]^3– entities are connected via the corresponding cations. X‐ray powder patterns were measured and compared to calculated ones obtained from single crystal X‐ray structure determinations.     

Beam-foil lifetime data for 3s 3p 3 and 3s 2 3p 3d levels of Si-like Ni14+

In the EUV spectrum of foil-excited 24 MeV Ni ions the decays of the 3s 3p ³ and 3s ² 3p 3d levels to the 3s ² 3p ² levels of the ground configuration have been observed. For most of the levels decay curves have been obtained. The lifetime results compare well with predictions from semi-empirically scaled HXR calculations. Some problems with cascade repopulations will be discussed.     

ChemInform Abstract: Theoretical Study of Structural and Vibrational Properties of Al3N3, Ga3N3, and In3N3.

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.     

Syntheses and Crystal Structures of BaAgTbS3, BaCuGdTe3, BaCuTbTe3, BaAgTbTe3, and CsAgUTe3

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS₃, BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃, were synthesized by the reactions of the elements at 1173–1273 K. For CsAgUTe₃ CsCl flux was used. Their crystal structures were determined by single‐crystal X‐ray diffraction studies. The sulfide BaAgTbS₃ crystallizes in the BaAgErS₃ structure type in the monoclinic space group C³,_2h‐C2/m, whereas the tellurides BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃ crystallize in the KCuZrS₃ structure type in the orthorhombic space group D¹_,2⁷_,h‐Cmcm. The BaAgTbS₃ structure consists of edge‐sharing [TbS₆^9–] octahedra and [AgS₅^9–] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features ²_∞[MLnTe₃^2–] layers for BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and ²_∞[AgUTe₃^1–] layers for CsAgUTe₃. These layers comprise [MTe₄] tetrahedra and [LnTe₆] or [UTe₆] octahedra. Ba or Cs atoms separate these layers. As there are no short Q ··· Q (Q = S or Te) interactions these compounds achieve charge balance as Ba²⁺M⁺Ln³⁺(Q^2–)₃ (Q = S and Te) and Cs⁺Ag⁺U⁴⁺(Te^2–)₃.