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A study clarified the relationship between geometry and electronic structure and the effects of hole and electron injection in tris(8-hydroxyquinolino)aluminum (Alq3) interacting with individual atoms of Li, Al and Ca. It also analyzed the similarities and differences between the two geometrical isomers of Alq3. Understanding the nature of the chemical bonding of the systems investigated in this experiment is essential for gaining a microscopic understanding of light emitting diodes based on Alq3 and its derivatives. Experimental results are discussed.

A report on the synthesis and structure of the first known aluminoarsenate D4R derivative (tBuAl(mu3-O3AsPH))4 (1) and the bicyclic galloarsenate ((super t)Bu(sub 2)Ga(mu2-O2AsPh))2O (2) is presented. Compound 1 crystallizes in the rhombohedral space group R3 with one-third of the molecule in the asymmetric unit. Compound 2 has a bicyclic Ga2As2O5 core made up of two mu2-OsAsPh groups bridging two distorted tetrahedral gallium centers.

The spectra and photochemistry of trans-azobenzene incorporated into the eight angstrom channels of AlPO4-5 have been studied. Uniform crystals of AlPO4-5 were prepared according to the procedure used by Finger. The dispersed aluminum oxide hydrate sol was prepared by adding 1.3889 g of boehmite to 40 mL of water in the presence of 0.8 mL of 1.4% HNO3 and stirred for 45 min. Results indicate the Bronsted acidity of AlPO4-5 can protonate the azo groups in azobenzene. Emission occurs at 518 nm at room temperature due to the protonated form of azobenzene.

A study was conducted to examine the reaction of aluminum hydrides with (Me2SiO)3 or (Me3-Si)2S which can be attributed to the formation of the Al-O9 and Al-S10 bonds with mild conditions. The synthesis, structure and thermolysis of the complexes were also analyzed. Aluminum hydride reactions were conducted under N2 through the use of the Schlenk techniques or the Vacuum Atmospheres He43-2 drybox. Results revealed that thermolysis resulted in the activation of the ortho t-Bu groups of the Mes substituent which led to the cyclized products.

High-resolution Fourier-transform infrared spectra of Al(BH4)3 and Al(BD4)3 were obtained for low-pressure samples at room temperature. Results indicated only wide vibrational bands with no resolved rotational structure. The BH bridge stretching and the BH2 deformation areas were also analyzed at 0.001/cm resolution through tunable infrared diode laser spectroscopy for samples cooled to about 10 K in a multipass, slit expansion. Results showed near continua, with much more crowding than predicted by nonrigid rotor simulations based on boron isotopic shifts.

The hydroxyl groups and 'physisorbed' water moieties of the pseudo-boehmite (Al2O3.2.05H2O) compound was analyzed via solid-state nuclear magnetic resonance (SSNMR) after successive dehydration treatments. SSNMR analysis of the high-surface-area boehmite during exposure to various heating temperatures indicated the loss of 'physisorbed' water protons in aluminum-coordinated hydroxyls in the clustered Al2OH sites. Furthermore, the less distorted nature of the 5-coordinated AlO4OH species favored the condensation of the isolated AlOH groups.

The lithiation of aluminum triamide [{Hn(t-Bu)CH2CH2N-t-Bu}Al{N(t-Bu)CH2}2] in hexane and diethyl ether led to the formation of lithium aluminum tetraamides. The reaction of the lithium aluminum tetraamides with a chelating nitrogen Lewis base afforded ionic complexes containing bischelated lithium cation and a secodnary complex as the uncoordinating anion. On the other hand, the reaction of lithium aluminum tetraamide with HgCl2 yielded a neutral paramagnetic aluminum tetraamide species.

The interactions of R2AlX with monodentate bases were analyzed to characterize the factors affecting the formation of alkylaluminum cations. The formation of R2AlX.base neutral adducts and cationic complexes from the reaction of the monodentate bases with R2AlX were dependent on the nature of the monodentate base such as primary amines and phosphine oxide. The resulting cationic complexes were also derived from the dissociation of the Al-X bond.

The ligand, N,N'bis(2-pyridylmethyl)enthylenediamine-N',N'-diacetic acid (H2bped) was synthesized via a one-pot method utilizing the secondary aliphatic amines of N,N'-bis(2-pyridylmethyl)ethylenediamine. The ligand bped2- coordinated to Co(III) in a distorted octahedral fashion with trans carboxylato groups. Binary complexes with [M(bped)]+ also exhibited high stability while Al(III) complexes were the least stable. Furthermore, Ga(III) formed the most stable hydroxo complex by displacing the carboxylate donor.

A two-step sol-gel process of cisCl(H)Ru(CO)(P-O)3 (P-O3 = eta1-P-coordinated ether-phosphine ligand) was utilized for the synthesis of poly(aluminosiloxane)-bound ruthenium complexes. The co-condensed ruthenium complexes exhibited numerous Si-O-Al linkages due to homogeneously distributed aluminum units within the polymers. The compounds also contain AlO4 and AlO6 units that are tetrahedrally and octahedrally coordinated with high ionic charges which are responsible for the high polarity of the matrices.

Ion exchange methods were utilized to produce pillared derivatives of Mg3Al layered double hydroxides with polyoxometalate (alpha-H2W12Osub4sup6-), (alpha-P2W18Osub62sup6-) and (CO4(H2O)2(PW9O34)sub2sup10-) anions. The Mg2+ of the Mg3Al layered double hydroxides (LDH) were depleted during the pillaring reactions of Mg3Al-LDH. However, the hexagonal geometry of the crystals were not altered by the pillaring reactions that led to the ion-exchange formation of the LDH derivatives.

Aluminun hydride and halide derivatives of 2,6-Mes2C6H3- and 2,6-Trip2C6H3- (Trip = 2,4,6-i-Pr3C6H2-) ligands were synthesized by the reaction of [2,6-Mes2C6H3Li]sub2sup21 with AlH3NMesub3sup22 in Et2O. The sterically encumbered terphenyl derivatives of the ligands did not inhibit the coordination of aluminum. Furthermore, the artho aryl groups of the terphenyl ligands exhibited minimal interaction with aluminum.

A new chain of aluminophosphate labeled, UT-7, and a new layered material, UT-8, were synthesized in a mixed cyclic amine system. The UT-7 is a non-framework aluminophosphate with a one-dimensional chain structure that undergoes solid state transformation under thermal conditions to form a layered material. UT-8 is a layered aluminophosphate with a molecular formula of [Al3PO4O16]3-. The layered aluminophosphate is also composed of two intermellar cyclic ammonium species.

Excess tertiary-butylamine reacts with R2AlX, where X = Br or I, to produce cationic aluminum complexes. Analyses of combinations of R2AlX.NH2tBu and (R2Al(NH2tBu)2)X with respect to varying ligand, base, and halide determine the factors affecting cation formation in organometallic aluminum complexes. Melting points, 1H NMR, IR, X-ray crystallography and elemental analysis allow characterization of the organometallic aluminum complexes.

Electroless-plated copper improves the surface morphology of the AIN substrate, initially increased and then decreased the adhesion strength of copper after 150 degrees centigrades thermal storage and introduced stress concentrations in the interface leading to decrease in adhesive strength of the interface of Sn/Pb solder and electroless copper-plated AIN substrate. The presence of intermetallic compound leads to cracks along the interface and reduced adhesive strength.

First and second energy derivative analysis methods help determine the stabilities of the newly discovered, six planar monobridged dihydrides, M2H2 (M = heavy atom of group IIIA or IVA). Though B2H2 and C2H2 do not have mono-bridged-type equilibrium structures, the stationary points of these systems are studied for comparative purposes, The structural stabilities of all the six systems are discussed with the energy derivative quantities in terms of M-H*-M-asymmetric stretching vibrations.

New synthetic methodologies enable the preparation of monomeric and dimeric azatranes. X-ray diffraction studies show that the dimeric azagallatrane and azaalumatranes have an unusual cis configuration of the substituents on the four-membered central (M-N)2 ring. When the substituted alkyl group is bulky, the azagallatrane is monomeric, and is dimeric when the alkyl group is methyl. Nitrogen atoms coordinate with the Al and Ga atoms of the azatranes to yield a distorted trigonal bipyramidal geometry.

An analysis of SCS-22, an aluminophosphate compound with tetrahedral coordination, reveals characteristics homologous to ALPO-based molecular sieves and layered zirconium phosphates. Aluminophosphate molecular sieves permit isomorphous substitution, while the compound's layered structure causes the reaction of P-OH at the surface with monolayered amines. However, (P+Si):(Al+Co) ratio in SCS-22 is 4:3, unlike the element ratio in molecular sieves, which is less than unity.

The oligomeric behavior of alumatrane, Al(OCH2CH2)3N (1), was investigated. Both 1(sub 2) and 1(sub 4) have been observed in the gas phase by mass spectroscopy. Solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectral data are consistent with the tetrameric solid-state structure and with the tetrameric structure found in solution by 27Al, 1H and 13C NMR studies.

Powder X-ray diffraction and solid-state and solution spectroscopies show that the structure of the GaO4Al12(OH)24(H20)12(super 7+) polyoxocation (GaAl12) is analogous to that of AlO4Al12(OH)24(H2O)12(super 7+) (Al13). The Ga atom forms the core of a tetrahedral sphere that is less distorted than that in Al13. The solution spectra reveal similar broadening of line widths. The infrared shifts that accompany both the change from Al13 to GaAl12 and their deuteration enable the assignment of the Al-O stretching vibrations. These spectral fingerprints are useful in probing into other MAl12 systems.

A new class of anionic aluminum complexes, ({SalpanAl}Li{THF}2)2 and ({SalomphanAl}-Li{THF}2)2 was synthesized using SalanH4 ligands. The amine used determines the geometry of the subsequent aluminum complex. The compounds are prepared by the reaction of LiAlH4 with the appropriate SalanH4 ligands.

A newly designed chemical purification technique isolates C60 from crude fullerene extracts based on preferentially complexing of C60 and C70 with AlCl3 in CS2 solution. The method provides a C70 and C60 mixture concentrated with C70 as a by-product. Effective complexation of C60 and C70 occurs with the conjugate acid of AlCl3, and AlCl3 provides high purification as it forms a heterogeneous system with the CS2 solution of the fullerene.

X-ray diffraction analyses of two synthetic monomeric aluminum phosphide show that, in both compounds, phosphorus exhibits a pyramidal coordination and has an Al-P bond length of 2.342 angstroms. Aluminum and phosphorus show steric hindrance, leading to rotational barrier, while minimum overlap is observed between phosphorus lone pairs and vacant aluminum. p-orbital-variable-temperature NMR reveals the dynamic behavior of these compounds.

Omega-substituted carboxylic acid derivatives are produced by ring opening reaction of lactams due to nucleophilic attack. The reaction requires the presence of an electron withdrawing group on the lactam nitrogen, as the reactivity of the endocyclic carbonyl compounds is very low.

The free hole concentration and the low-field transport properties of Al-doped 4H-SiC epilayers with many acceptor concentrations grown on semi-insulating substrates are examined by using Hall-effect measurements. A Caughey-Thomas mobility model with temperature dependent parameters is used for describing the dependence of the hole mobilities on the acceptor concentration.

Photoluminescence (PL) properties of GaAs/AlAs multiple quantum wells are examined at 10 K under high density excitation conditions at excitation energies in the region of the fundamental excitons. The exciton-exciton scattering process has prevented the formation of biexcitons and the studies have confirmed the existence of optical gain leading to stimulated emission due to the exciton-exciton scattering process with use of a variable-stripe-length method.

Byline: Mao-xiang Jing, Xiang-qian Shen, Wang-xing Li, Dong-hong Li Alumina-based cermets with Ni doping modes of intergranular, intragranular and mixture of both were prepared by hot press-sintering Ni-coated alumina, alumina-coated Ni and co-precipitate powders respectively. The densification process of the cermets from these three Ni/alumina powders was mainly influenced by Ni contents, sintering temperature, and precipitation process of precursor powders. The Ni phase at low contents with small particles located on the interfaces promoted the densification process due to a high reactivity and at high contents to some extent restrained the densification rate while reduced coarsening of alumina grains at high sintering temperatures. The Ni-doping modes could lead to a change in the fracture approach of alumina matrix and improvements of mechanical properties.