Reduction of Derivatives of α-Arylidene-α-(2-Thiazolyl)acetonitrile with Lithium Aluminum Hydride

The action of lithium aluminum hydride on derivatives of -arylidene--(2-thiazolyl)acetonitrile in absolute ether leads to reduction of the nitrile group without affecting the double bond conjugated with it. The reaction products are the corresponding substituted allylamines.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 221–224, February, 2005.     

Coordination Structure of Aluminum in Magnesium Aluminum Hydroxide Studied by ^27Al NMR

The coordination structure of aluminum in magnesium aluminum hydroxide was studied by ^27Al NMR.The result showed that tetrahedral aluminum (Al^IV) existed in magnesium aluminum hydroxide,and the contents of Al^TV increased with the increase of the ratio of Al/Mg and with the peptizing temperature.Al^IV originated from the so-called Al13 polymer with the structure of one Al tetrahedron surrounded by twelve Al octahedrons.     

Fragmentation Behavior and Ionization Potentials of Aluminum Clusters Al_n(n≤40)

Al2-Al40 clusters were studied by means of the all-electron DFT method.The properties of the aluminum clusters including binding energy,the second difference in energy,HOMO-LUMO gap,especially fragmentation energies and ionization potentials,were analyzed.The main products from the dissociations of aluminum cluster ions are shown to be Al+Al+n-1 for the larger clusters,and Al++Aln-1 for the smaller ones.And,the calculated ionization potentials are consistent with the experiment data.     

Luminescence of Eu~(2 ) in Strontium Aluminum Oxide System with Long Decay Property

Luminescentmaterialshavinglongdecayperi0dhaveat-IIactedmuchinterestduetotheirpotentialwidespreadaPplicati0ns.Recently,alongdecayluminescentp0wderhavingthecomPositionofSrAl2O4activatedwithEu' wasreportedandregardedasthebestcandidateforpracticalaPPlicationbecauseofitsuniqueadVantages0veritsprecursors.l'2Inthispaper,wereportthesynthesisofthelongdecayluminescentpowderandtheinnuence0fthemolarratioofAlt0sr0ntheethessioncolor.Toproducethelundnescentp0wder,amixtureofSrCO3,Al2O3,Eu2O3andsomesol…     

Electronic and Chemical Characterization of Aluminum–Nitrogen (AlN) Substituted Fullerenes: C58AlN to C24Al12N12

Density functional theory calculations (B3LYP/6-311G*) are applied to devise a series of AlN-substituted C₆₀ fullerenes, avoiding weak homonuclear Al–Al and N–N bonds. The substitutional structures, energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, ionization potentials, binding energies, as well as dipole moments have been systematically investigated. The band gap (HOMO–LUMO gap) is larger for all the AlN-substituted fullerenes than C₆₀. The properties of heterofullerenes, especially, the HOMO–LUMO strongly depend on the number of AlN units. Natural charge analyses indicate that doping of fullerene with AlN units exerts electronic environment diversity to the cage. High charge transfer on the surfaces of our heterofullerenes provokes more studies on their possible application for hydrogen storage.     

Mechanism and Dynamics of the Addition of Lithium Hydride to Acetylene

Reaction ergodography for the addition of lithium hydride to acetylene indicates that the lithium hydride, in both monomeric and dimeric forms, reacts with the acetylene via two similar and competitive pathways. Hence, we have obtained the pseudo-first-order rate constant of this reaction.     

Conductivity of Al2(WO4)3–WO3 and Al2(WO4)3–Al2O3 Composites

Russian Journal of Electrochemistry - Composites of (1 – x)Al2(WO4)3–xWO3 and (1 – x)Al2(WO4)3–xAl2O3 are synthesized and their conductivity is studied as dependent on the...     

Unusual Reaction of β-Hydroxy α-Diazo Carbonyl Compounds with Trichloroacetonitrile (CI3CCN) and Sodium Hydride

In the process of preparing α-diazo carbonyl compound 2 by imidation of 1, we unexpectedly observed a direct conversion of the hydroxyl group into trichloroacetylamino group. In this presentation, we report this unprecedented reaction, as well as the Rh2(OAc)4-catalyzed reaction of the resulting β-(trichloroacetyl)amino β-diazo carbonylcompounds 3. [ 1]     

Determination of Sb(III) and Total Sb in Antileishmanial Drugs by Spectrophotometric Flow‐Injection Hydride Generation

Abstract

A spectrophotometric procedure based on hydride generation and flow analysis is proposed for determination of antimony (III) [Sb(III)] and total antimony (Sb) in pharmaceutical samples. Firstly, Sb(III) reacts with hydrogen species generated in the system, forming antimony hydride. The reaction leads to a decrease in the permanganate concentration and, hence, in the intensity of the color of this specie, which is spectrophotometrically measured at 528 nm. Total Sb is determined as Sb(III) after Sb(V) reduction using 0.02% (m/v) KI. Some parameters, such as the number of channels of the gas phase separator, injection volume, coil length, and KBH₄ concentration, are investigated. The system presents a frequency of ca. 100 h^?1 and precision <3.0% [expressed as relative standard deviation (RSD) of 30 measurements using a 3.0 mg L^?1 Sb(III) solution]. The analytical curve ranging from 0.5 mg L^?1 to 5.0 mg L^?1 (r>0.998; n=5) permits limit of detection (LOD) and limit of quantification (LOQ) of 83 and 250 µg L^?1. For total Sb, the accuracy is checked by atomic absorption spectrometry applying the t test and the results are in accordance at the 95% confidence level. Recovery tests are used to check the accuracy for Sb(III) determination, and the recoveries are between 95% and 105%.     

Nanostructures’ study of chemisorptions of O2 molecule on Al (100) surface

In this study, oxygen molecule adsorption on the surface of aluminum at various positions (top, bridge, and central sites) was studied, and the binding energies of oxygen species adsorbed on aluminum were calculated using density functional theory (DFT) within the generalized gradient approximation (GGA). The potential of the adsorption of oxygen on aluminum was examined as a function of both surface coverage and adsorption site. The relative stabilities of oxygen chemisorptions were independent of both the transition metal surface and surface coverage. That is, oxygen exhibited insignificant selectivity with respect to positions on the metal surface. Our data O₂/Al surface chemisorptions revealed that the stables model for oxygen adsorption was that on the top site. The top site approach is important for the chemisorption processes because the adsorption energy for this model was lower than for the other sites. The paper presents the results of quantum chemical calculations using density functional theory method for adsorption of O₂ molecules on Al (100) surface at cubic structure with LANL2DZ, SDD and 6-31G¹ basis sets. We can extract energetic information about the stability of adsorption O₂ on aluminum surface and calculation adsorption energy.     

Correlating Physical and Chemical Degradation in the Performance of Aluminum tris(8‐Hydroxyquinoline) (Alq3)‐Based OLEDs

Abstract

Aluminum tris(8‐hydroxyquinoline) (Alq₃), which is utilized as an electron transport layer (ETL) in organic light emitting diodes (OLEDs) is known to form crystalline domains over time. This morphological instability plays an important role in OLED degradation. In this study, crystallization was suppressed via entropic stabilization by blending Alq₃ with a close adduct of the same i.e., aluminum tris(4 methyl, 8‐hydroxyquinoline) (4m‐Alq₃). X‐ray diffraction studies at elevated temperatures indicate that the blend remains amorphous even after 96 hr of annealing at 160°C. OLED devices were fabricated and investigated for Alq₃, 4m‐Alq₃, and a co‐evaporated 50/50% mixture (blend) of Alq₃ and 4m‐Alq₃. As expected, the blend device possessed both the highest resistance and quantum efficiency over the entire current density range. Devices made with 4m‐Alq₃ showed the highest current density, yet their quantum efficiency and lifetime were significantly lower than that of Alq₃. In spite of the morphological stability of the blend, the intrinsic instability of 4m‐Alq₃ was found to play a more important role in device degradation. This study indicates that while entropic stabilization is an effective way of obtaining brighter and more efficient OLEDs, care must be taken to ensure electrochemical stability and interfacial energy‐level optimization for both components.     

Binuclear Aluminum Complexes Supported by Linked Bis(β-diketiminate) Ligands for Ring-Opening Polymerization of Cyclic Esters

Binuclear aluminum alkyl complexes 2a–4g supported by linked bis(β-diketiminate) ligands were synthesized via the reaction of AlEt_3 or AlMe_3 and the corresponding proligand in a 2:1 molar ratio with moderate yields. The isolated complexes were well-characterized by ~1H-NMR, ~(13)C-NMR and elemental analysis. The binuclear nature of aluminum complex 2b was further confirmed by an X-ray diffraction study. All complexes 2a–4g could efficiently initiate the ring-opening polymerization(ROP) of ε-caprolactone in toluene. The substituents at the aromatic rings and the linker unit in the auxiliary ligands exerted significant influence on the catalytic behavior of the investigated aluminum complexes. Complex 4g(R~1 = R~2 = Cl) containing propylenyl bridging unit exhibited the highest catalytic activity among these complexes, which might be attributed to the increased electrophilicity of the metal center as well as more opened coordination sphere. The molecular weights of obtained poly(ε-caprolactone)s deviating considerably from the theoretical values indicated that the ROP of ε-caprolactone by complexes 2a–4g was not well-controlled, which was also judged from the broad molecular weight distributions(MWD = 1.47-2.47) of produced poly(ε-caprolactone)s. These complexes proved to be inactive toward the polymerization of rac-lactide alone. In the presence of alcohol the polymerization occurred, which was actually initiated by the decomposition species of the aluminum complex upon the treatment with isopropanol.     

Direct Observation of Various Al Sites in SAPO-34by ^27Al Multiquantum(MQ) Magic Angle Spinning (MAS)NMR

The elegant 2D multiquantum (MQ) MAS NMR has been applied to investigate the coordination of Al atoms in SAPO-34.The results show that the effects of the template and /or water on the coordination of Al atoms are significant,which lead to the formation of various Al species.Up to four kinds of Al species are distinctly resolved.     

Hydride addition to Ru3(CO)12. Synthesis and characterization of the transient formyl cluster complex Ru3(CO)11(CHO)−

The reaction of Ru₃(CO)₁₂ (1) with LiEt₃BH at −78°C affords the transient cluster formyl complex Ru₃(CO)₁₁(CHO)⁻ (2) which is observed to decompose by CO loss to give the known hydride cluster Ru₃(CO)₁₁(H)⁻ (3) rapidly at temperatures above −50°C. The formyl cluster has been characterized by low temperature FT-IR, ¹H and ¹³C NMR measurements. Formyl trapping experiments and the effect of Bu₃SnH on the rate of formyl decomposition are briefly described.     

Solid Phase Interaction of the Recondensed Finely Dispersed Mixture (VC0.40O0.53–C) with Titanium Hydride

Russian Journal of Applied Chemistry - The processing of industrial waste and highly hazardous substances using extreme techniques of formation, in addition to else, of nanocrystalline materials,...     

Study on Isoelectric Point of Magnesium Aluminum Hydroxide

Isoelectricpoint(IEP)valuesareInaiulyforbytheprOpeniesandcomposihonOfmetalions,thcyindicaethemagnitudeofrmnityofmetalionsf0releCtrn.TheeffodofIEPofmagncsiumabonumhydroaldeonthepropeniesandcomposihonofmetalionsarediscussedinthispaPer.Experimentall.PreparationofmagnesiumaltalnumhydrokidePOsihvesol.ThepreParationmethodreferredtoref[41.2.MeasurementS0ftheelmphoreticmobilityTheelectrophorehcmobilihesweredetetrinedwithDXD-IIm0delInieroelCCtfophoresisapparatUs.at1hei0nicstrengthof0.OOland…     

Metastable Aluminum(I) Compounds: Experimental and Quantum Chemical Investigations on Aluminum(I) Phosphanides—An Alternative Channel to the Disproportionation Reaction?

The well known thermodynamic instability of Al and Ga monohalides is caused by the favored disproportionation process to the bulk metal and the trihalides. During this highly complex process, a number of metalloid clusters that are intermediates on the way to the metal have been trapped. Therefore, all observations in the field of metalloid Al/Ga clusters have been traced to this favored disproportionation process. The failure to form phosphanide‐substituted Al clusters, in contrast to the generation of similar Ga clusters and analogous Al amide clusters, was the starting point of this contribution. For aluminum(I) phosphanides, there exists a different decomposition route in which the salt‐like bulk material AlP and not Al metal is the final product. The synthesis of two molecular “AlP” intermediate species, together with supporting DFT calculations, provide plausible arguments for this decomposition route, which is thermodynamically favored for many AlR/GaR species and which, surprisingly, has not been discussed before.     

Catalytic Dehydration of α-Phenylethanol on the Surface of Aluminum Oxides

The relationship between the acid–base properties of commercial and test samples of aluminum oxides and their catalytic activity in the dehydration of -phenylethanol was studied. It was found that, in the dehydration of -phenylethanol, the conversion of the alcohol and the yield of styrene on a catalyst depend on the concentrations of both Brønsted and Lewis acid sites. A hypothetical mechanism of the dehydration with the participation of coordinatively unsaturated aluminum atoms and bridging oxygen ions on the alumina surface was proposed.     

Studies on ζ-Potential of Positive Sol of Magnesium Aluminum Hydroxide

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