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In this paper, we report a turn-on fluorescence sensing of Al.sup.3+ ion using a new fluorenone derivative. The imino derivative of 2-amino-9-fluorenone and mercapto-2-butanone is synthesized and characterized using IR, NMR, and mass spectral techniques. The fluorescence of the compound shows a large enhancement at the addition of Al.sup.3+ ions, and other metal ions show insignificant changes of the fluorescence. The stoichiometry and the binding constant of the complex are reported. The detection limit of the Al.sup.3+ determination by the fluorenone derivative is 5 x 10.sup.-8 M. A visible enhancement of color occurs on illumination of the fluorescent compound - Al.sup.3+ ion complex., Author(s): S. E. Thangaraj [sup.1] , E. J. Antony [sup.1] , G. T. Selvan [sup.2] , P. M. Selvakumar [sup.2] , I. V. M. V. Enoch [sup.1] [sup.2] Author Affiliations: [...]

Electron-induced electron yields of high-resistivity high-yield materials--ceramic polycrystalline aluminum oxide and polymer polyimide (Kapton HN)--were made by using a low-fluence pulsed incident electron beam and charge neutralization electron source to minimize charge accumulation. Large changes in the energy-dependent total yield curves and yield decay curves were observed, even for incident electron fluences of < 3 fC/[mm.sup.2]. The evolution of the electron yield as charge accumulates in the material is modeled in terms of electron recapture based on an extended Chung--Everhart model of the electron emission spectrum. This model is used to explain the anomalies measured in highly insulating high-yield materials and to provide a method for determining the limiting yield spectra of uncharged dielectrics. The relevance of these results to spacecraft charging is also discussed. Index Terms--Charging, dielectrics, electron, emission.

Synthesis of a series of aluminum complexes containing ketiminate ligands is discussed. Results reveal that the complexes are active towrd the ring-opening polymerization of epsilon-caprolactone. Furthermore, a higher molecular weight polymer results from the aluminum alkyl complexes, whereas the aluminum halide complex forms a lower molecular weight oligomer.

The new fluoroaluminophosphate chain compound is synthesized from isopropylamine units in the presence of hydrogen fluoride. The compound is a one-dimensional aluminophosphate chain exhibiting an Al/P ratio of 1/1.

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.

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.

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.

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.

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 intermetallic compounds R7+(sub x)Os(sub 12)Al(sub 61+y)(R=Y, Nd, Sm, Gd-Tb) crystallize with a hexagonal structure, which is recognized as belonging to a relatively new structural family with layered topology. Different structures showing atomic layers are presented.

A novel aluminum complex was formed by the reaction of {MeC(NPr)2}AlMe2 with B(C6F5)3 in CD2Cl2. The synthetic process was characterized by the initial generation of a three-coordinate {MeC(NPr)2}AlMe+ cation that was rapidly trapped by adduct formation with {MeC(NPr)2}AlMe2. The reaction of process for the formation of ({MeC(NiPr)2}AlMe)2(mu-Me)+ was mediated by alkyl abstraction from {RC(NR')2}AlMe2 and {RC(NR')2}AlR+ cations which acted as active species for ethylene polymerization.

The spontaneous dimerization of multiply-bonded Al-N hydrides requires a zero activation energy with dative-bond dimerization energies that are similar to Al-N adducts. The Al-N analogs of acetylene and ethylene exhibited a planar geometry with a trans-bending distortion to the bent HAlNH structure as indicated by Moller-Plesset perturbation theory. Analysis of the Al-N bond in the H2AlNH2 analog indicated the presence of a slightly strained structure while Al2N2 exhibited a planar ring with a puckered conformation.

Clear, colorless crystals of [(tBu)2Al(mu2-O)2P(OSiMe3)2]2 were produced by the reaction of (Me3SiO)3P=O with Bu2AlCl in tetrahydrofuran. The alkylaluminophosphate complex is a cyclic dimer that is composed of an eight-membered Al2P2O4 rings. The distorted tetrahedral aluminum centers of the Alk2P2O4 rings are composed of two mu2-eta2-O2P-(OSiMe3)2 bridges. The complex can be hydrolyzed in the presence of moisture but it is stable in a solution of dry oxygen and benzene-d6.

New carbon-carbon bonds can be synthesized by using ketal Claisen rearrangement and the major aspect of this Claisen variant is the regioselectivity of enol ether formation, followed by rearrangement. A study of the synthesis of enol ethers using cleavage of acetals induced by triiosobutyl aluminium shows that 1-methyl-1-methoxyethyl ether of geraniol splits into enol ether followed by Claisen rearrangement of enol ether. The reaction mechanism of the synthesis is discussed.

Aluminum chloride-amine complexes increase the rate of the transamidation reactions of primary, secondary and tertiary amides. This aluminum-chloride promotion method, in association with the activating effect of an electron-withdrawing moiety on the amide nitrogen, facilitates transamidation reactions of hindered and aromatic amines.

Amphiphilic reagents such as organoaluminum amides can be used for Fischer indole synthesis. Diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP) is the best reagent in the case of regioselective Fischer indole synthesis. 3-sec-butyl-2-ethyl-1-methylindole is formed as the only isolable product from the treatment of the (E)-N-methyl-N-phenylhydrazone of 5-methyl-3-heptanone with DATMP.