The reaction of benzonorbornadiene and related compounds with iron carbonyls

1974 ◽  
Vol 27 (1) ◽  
pp. 143 ◽  
Author(s):  
L Lombardo ◽  
D Wege ◽  
SP Wilkinson
Keyword(s):  
Room Temperature ◽  
Iron Carbonyls ◽  
Related Compounds

Reaction of benzonorbornadiene, 7-isopropylidenebenzonorbornadiene (1,4-dihydro-9-isopropylidene-1,4-methanonaphthalene) and 1,4-dihydro-1,4-epoxynaphthalene (7-oxabenzonorbornadiene) with dicarbonyldinitrosyliron, Fe(CO)2(NO)2, gave in good yields the corresponding dimers having the exo-trans-exo configuration. Treatment of a mixture of benzonorbornadiene and norbornadiene with Fe(CO)2(NO)2 gave a 'crossed dimer', in addition to the dimers derived from benzonorbornadiene and norbornadiene. The reaction of benzonorbornadiene with pentacarbonyliron at 100� gave the exo-trans-exo dimer and a ketone derived by dimerization and carbonyl insertion. This ketone, and the analogous ketone obtained from 7-isopropylidenebenzonorbornadiene, have been assigned the exo-trans-exo configuration. Reaction of 1,4-dihydro-1,4-epoxynaphthalene with enneacarbonyldiiron, Fe2(CO)9, at room temperature gave tetracarbonyl(l,4-dihydro-l,4-epoxynaphthalene)iron(0), in which the olefinic ח-bond is bonded to the metal. In solution at 63� this complex gave naphthalene.

Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

2019 ◽  
Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  
Keyword(s):  
First Principles ◽  
Room Temperature ◽  
Stokes Shift ◽  
Green Luminescence ◽  
Counter Ions ◽  
Self Consistent ◽  
Deep Ultraviolet ◽  
Halide Perovskite ◽  
Related Compounds ◽  
Level Analysis

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>

Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

2019 ◽  
Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  
Keyword(s):  
First Principles ◽  
Room Temperature ◽  
Stokes Shift ◽  
Green Luminescence ◽  
Counter Ions ◽  
Self Consistent ◽  
Deep Ultraviolet ◽  
Halide Perovskite ◽  
Related Compounds ◽  
Level Analysis

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>

Polydentate Ligands Containing Phosphorus, III [1]. Synthesis and Nuclear Magnetic Resonance Studies of Some Unsymmetrical Potentially Tridentate Phosphine Chalcogenide Ligands

1980 ◽  
Vol 35 (7) ◽  
pp. 832-837 ◽  
Author(s):  
Samuel O. Grim ◽  
Larry C. Satek ◽  
J. Dale Mitchell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Room Temperature ◽  
Electron Pair ◽  
Nmr Spectrum ◽  
Magnetic Resonance Studies ◽  
Polydentate Ligands ◽  
Nmr Data ◽  
Type C ◽  
Related Compounds ◽  
Reduced Temperature

The synthesis via the useful lithium reagent intermediate, (C6H5)2P(S)CH2Li, is reported for eight compounds of the type [(C6H5)2P(X)][R2P(X)]2CH, where R is methyl or phenyl and X is an electron pair, oxygen, or sulfur in various combinations. Two related compounds with three and four phosphorus atoms, respectively, per molecule have also been prepared from the same lithium reagent. Tris(diphenylthiophosphoryl)methane has three equivalent phosphorus atoms as indicated by the room temperature phosphorus-31 NMR spectrum, but at reduced temperature a favored conformation exists which has two equivalent phosphorus atoms and a unique one. Other phosphorus-31 and proton NMR data are reported

scholarly journals Sintering Behavior of BST Nanoparticles at Low Temperature and Electrical Properties of their Ceramics

2020 ◽  
Author(s):  
Jianquan Qi ◽  
Yan Li ◽  
Mengyin Li ◽  
Jiahui Xie ◽  
Tianchi Yu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Dielectric Constant ◽  
Alkaline Earth ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Sintering Aids ◽  
Bst Ceramics ◽  
Related Compounds ◽  
Alkaline Earth Cations

Abstract The powders of the Ba0.75Sr0.25TiO3 (BST) nanoparticles were directly synthesized by milling of Ba(OH)2·8H2O, Sr(OH)2·8H2O and Ti(BuO)4 in ethanol at room temperature. They have homogenous grains of ~15 nm and the high sintering activity. The dense ceramics with the density >90% can be obtained at a sintering temperature of ≤950 oC by them with adding 3 wt% sintering aids of Bi2O3 and Li2CO3. The sintering behavior of the BST nanoparticles by adding the aids of Bi2O3 and Li2CO3 is studied carefully. Several Bi-related compounds are involved in the sintering procedure at a different temperature. They enhance the mass transfer and promote the sintering densification. These compounds such as Ba2BiO4 and SrBiO4 appear at 800 oC, LiBa4Bi3O11 and Sr1.2Bi0.8O3 appear over 830 oC, and Bi8.11Ba0.89O13.05 appears at 950 oC. The cation Bi in the ceramics has mixture valences of 3+ and 5+. It makes the ceramics as semiconducting state with the dark gray color and decreases the ceramics resistivities. With the sintering temperature increase, especially at 950 oC, the cation Bi tends back to single valence of +3 in the ceramics. The most of alkaline earth cations in Bi-related compounds will release and resorb into the lattice of BST and drive the densification of the nanoparticles. The BST ceramics can have a peak dielectric constant >6500 at 53 oC, loss <0.025, and resistivity >1012 W·cm when sintered at a temperature of ≥900 oC with 3 wt% sintering aids. They have a potential application for multiple layer ceramic capacitors (MLCC) with silver inner-electrodes.

Kinetics and Mechanism of the Reaction of 2-Mercaptobenzothiazole with N-(Cyclohexylthio)Phthalimide and Related Compounds

1972 ◽  
Vol 45 (6) ◽  
pp. 1513-1531 ◽  
Author(s):  
P. N. Son ◽  
K. E. Andrews ◽  
A. T. Schooley
Keyword(s):  
Thermal Instability ◽  
Room Temperature ◽  
Kinetic Studies ◽  
Kinetics And Mechanism ◽  
Related Compounds ◽  
Mechanism Of The Reaction

Abstract Kinetic studies show that 2-mercaptobenzothiazole (MBT) reacts faster with N-(cyclohexylthio)phthalimide (CPT) than with such accelerators as N-t-butyl-2-benzothiozolesulfenamide (BBTS) or 2-(4-morpholinothio)benzothiazole (OBTS). Furthermore, the reaction between N-(cyclohexylthio)-o-benzoic sulfimide (CTBS) and MBT is so fast that it reacts almost instantaneously even at room temperature. However, CTBS is not a good retarder due to its thermal instability.

Tunability of τf in perovskites and related compounds

2002 ◽  
Vol 17 (8) ◽  
pp. 2033-2040 ◽  
Author(s):  
P. L. Wise ◽  
I. M. Reaney ◽  
W. E. Lee ◽  
D. M. Iddles ◽  
D. S. Cannell ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Resonant Frequency ◽  
Room Temperature ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Ionic Polarizability ◽  
Microwave Dielectrics ◽  
Related Compounds ◽  
Range Of Values

Tuning the temperature coefficient of resonant frequency (τf) in microwave dielectrics has been attributed to two main mechanisms: (i) dilution of the average ionic polarizability; (ii) the onset of an octahedral tilt transition above room temperature. The contributions of each mechanism have been isolated using ceramics in the Srn+1TinO3n+1, SrxCa1−x)3Ti2O7, and (SrxCa1−x)TiO3 series. In the Srn+1TinO3n+1 series, relative permittivity (εr) and τf are linearly proportional over a broad range of values, 100–37 and 800–140 ppm/°C, n = 4 and 1, respectively. No structural phase transitions occur on cooling from the prototype symmetry, and the mechanism of tuning is attributed solely to dilution of the average ionic polarizability as the SrO:SrTiO3 ratio increases. Exchanging Ca for Sr in the (SrxCa1−x)3Ti2O7 series resulted in an 80% reduction in the magnitude of τf from +320 to +50 ppm/°C but only 21% in permittivity (58 to 46). The effect was nonlinear and attributed primarily to the onset of a phase transition involving rotations of the octahedra on cooling. Superlattice reflections associated with the octahedral tilt transition have been identified.

scholarly journals A DEVELOPMENT OF AN EFFECTIVE METHOD FOR THE SYNTHESIS OF 2-(5-OXO-4,5-DIHYDRO-1,2,4-OXADIAZOL-3-YL)BENZOIC ACID

2020 ◽  
pp. 51-54
Author(s):  
V. Tkachuk ◽  
T. Lyubchuk ◽  
T. Tkachuk ◽  
O. Hordiyenko
Keyword(s):  
Benzoic Acid ◽  
Room Temperature ◽  
Total Yield ◽  
Partial Hydrolysis ◽  
Diethyl Carbonate ◽  
Aromatic Acids ◽  
Sodium Ethylate ◽  
Anhydrous Ethyl Acetate ◽  
Naoh Solution ◽  
Related Compounds

2-(5-Oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was synthesized using a new effective method – thermal heterocyclization of 3-(hydroxyimino)isoindolin-1-one, which occurs as a result of its interaction with 1,1'-carbonyldiimidazole (CDI) and subsequent base-promoted cycleopening of the obtained intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione. Direct cyclization of 3-(hydroxyimino)isoindolin-1-one by the reaction with diethyl carbonate in the presence of sodium ethylate in ethanol at room temperature and under heating was unsuccessful. The same result was observed when using triphosgene in the presence of triethylamine in dichloromethane. Treating 3-(hydroxyimino)isoindolin-1-one with methyl chloroformate gave 3-(((methoxycarbonyl)oxy)-imino)isoindolin-1-one which was thermally stable and was not cyclized into the desired acid by boiling in toluene and o-xylene for 24 hours. The reflux of the excess of CDI with 3-(hydroxyimino)isoindolin-1-one in anhydrous ethyl acetate and subsequent alkaline hydrolysis gave the desired 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid in a total yield of 90%. An attempt to stop the process at the stage of formation of the intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione by carrying out the reaction in the absence of a base failed. Its partial hydrolysis took place during the reaction, and especially at the stage of isolation, and as a result a mixture of 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione and 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was formed in a ratio of about 2:3. The obtained substance after mixing with aqueousmethanolic NaOH solution and subsequent acidification with 1M HCl was quantitatively converted into the pure desired acid. The developed method allows the use of 3-(hydroxyimino)isoindolin-1-ones as convenient starting materials for the preparation of vic-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)aromatic acids and subsequently related compounds, in particular isomeric vic-carbamimidoyl(hetero)aromatic carboxylic acids, which cannot be obtained by other currently known methods. All the compounds obtained during the development of the method were studied by means of NMR spectroscopy.

scholarly journals Behavior of Viscous Liquid Byproduct Formed in Exhaust Tube by Silicon Carbide Epitaxial Growth

2019 ◽  
Vol 8 (12) ◽  
pp. P805-P810
Author(s):  
Ichiro Mizushima ◽  
Hitoshi Habuka
Keyword(s):  
Silicon Carbide ◽  
Epitaxial Growth ◽  
Viscous Liquid ◽  
Growth Process ◽  
Room Temperature ◽  
Product Layer ◽  
Layer Formation ◽  
Low Concentrations ◽  
Related Compounds ◽  
By Products

The behavior of the by-product produced in an exhaust tube by the semiconductor silicon carbide epitaxial growth process was evaluated. The by-product layer was a dark-colored viscous liquid; it captured precursor gases and gaseous by-products, such as hydrogen, monosilane, propane, hydrogen chloride and chlorosilanes. These captured gases were spontaneously emitted in ambient nitrogen at room temperature. By an etching process using a chlorine trifluoride gas at low concentrations in ambient nitrogen, the by-product layer could be safely decomposed to gaseous fluorides of silicon and carbon. After finishing the etching, there remained a small amount of residue which included particles of carbon, silicon carbide and related compounds. Based on these results, the by-product layer formation process was discussed.

Synthesis of N-methyl-N-(2,2,2-trichloro-1-arylaminoethyl)formamides and related compounds as potential fungicides

1980 ◽  
Vol 33 (3) ◽  
pp. 613 ◽  
Author(s):  
HG Grant ◽  
LA Summers
Keyword(s):  
Room Temperature ◽  
Amide Bond ◽  
Restricted Rotation ◽  
Related Compounds

The synthesis of several analogues of the chloralformamide fungicides is reported. The compounds, which comprise N-methyl-N-(2,2,2-trichloro- 1-arylaminoethyl)formamides and related alkoxyethyl and aryloxyethyl derivatives, exist at room temperature as two isomers due to restricted rotation about the C-N amide bond. The results of their evaluation as fungicides are reported.

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