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Abstract: A series of glasses [(Te[O.sub.2]).sub.x] [([B.sub.2][O.sub.3]).sub.1-x] with x = 0.6, 0.63, 0.65, 0.70, 0.73, 0.75, 0.78 and 0.80 were synthesized by rapid quenching. Longitudinal and shear ultrasonic velocity were [...]

The formation of planar waveguide in lithium tetraborate crystal using 2 MeV helium implantation, is discussed.

Nonlinear optical response in borate glasses with gold nanoparticles was studied to determine relaxation behavior.

A study concerning the stereoselective synthesis of leukotriene B (sub)4 compounds is presented. The use of the nickel-catalyzed coupling reaction is discussed.

Results show that in aqueous solutions a 1:1 replacement of hydroxide ion by aluminate and borate occurs with release of bound water.

Mononuclear and dinuclear lanthanide(III) complexes of multidentate podand ligands based on poly(pyrazolyl)borates are discussed relative to their structural and photophysical properties. Four series of lanthanide complexes of the ligands, all based on bis- or tris(pyrazolylborate) cores, were studied. Photophysical behavior can be rationalized on the basis of structural, electronic, and solvent-induced effects. A wide range of ways to tune absorption and luminescence properties of lanthanide complexes exists.

It has been established that electron transfer between -BPh3R and MV2+ is effectively induced by photoexcitation of C60. Electron transfer from -BPh3R to MV2+ takes place efficiently through the sensitization and electron mediation by C60.

The synthesis and characterization of the novel complexes that have been obtained by reacting trans-[ReO (sub)2 (py) (sub)4]Cl with K[H (sub)2 B(pz*) (sub)2]. The synthesis and characterization of the oxo-siloxy derivatives is described.

Research has been conducted on the cesium hypochlorite or hypobromite. The formation of N,N-dichloroamino- or N,N-dibromoamino-tris(trifluoromethyl)borates has been examined.

Research was conducted to examine the synthesis and structures of salen-supported borates containing siloxides. The ligand N,n'-bis(2-hydroxybenzylidene)diethylenetriamine (SalenN3H3) was utilized in the preparation of the compound SalenN3H(B(OMe2))2 which could be used for the formation of SalenN3H(B(OSiPh3)2)2. Results suggest coordination number expansion for ReO4- but not for TcO4-, consistent with previous findings on the differences in behavior between TcO4- and ReO4- when they would not have been expected on structure alone.

A study showed that tetramethoxyborate anions are potentially versatile general synthons for one-dimensional compounds. Self-assembly of lanthanide(III), salicylaldehyde, sodium and tetramethoxyborate species resulted in a novel ionically linked sinusoidal chain. Tight crest-in-trough packing of the sinusoidal chains caused a multidimensional energy transport while positional switching of Eu and Na cations produced intriguing luminescence characteristics.

Research was conducted to examine the preparation of a family of saturated beta-stabilized carbocations that are stable under ambient conditions in solution. The carbocations were prepared at room temperature with benzene acting as solvent and tetrakis(pentafluorophenyl)borate (TPFPB) as anion through the addition of solvated triethylsilylium TPFPB. Results demonstrate that the cations are open and not bridged.

Radical trapping experiments were performed on several new 4-benzoylbenzylammonium borates to investigate their photochemical properties. Results showed that alpha-aminoalkyl radical and other radicals can be successfully formed from 4-benzoylbenzylammonium tetraphenylborates, suggesting that the alpha-aminoalkyl radical in not the only initiating species. However, the radical was found to be the most active initiating specie.

A fractal analysis of the nitrogen adsorption isotherms of alumina and aluminum borate samples was conducted to study the effects of calcination temperature on the surface roughness of the samples. The surface fractal dimension values for samples calcined from 500 to 1100 degrees Centigrade were found to be constant despite a large reduction of the BET surface area and pore volume. The alpha-alumina crystalline phase began to sinter and a slightly larger change in the surface fractal dimension was observed only after a 1250 degrees Centigrade calcination.

As far as we know this is the first report on picosecond green-light generation from an actively mode-locked diode-pumped self-doubling neodymium yttrium aluminum borate (NYAB) laser. The pulse width is approximately 100 ps and is limited by imperfect antireflection coating and the intracavity doubling effect. The green average output power of this laser for mode-locked operation was more than 12 tunes higher than that for the continuous wave NYAB laser. The polarization state of the laser can be switched from ordinary to extraordinary rays by displacement of the pump spot. The polarization ratio can be better than 200 without any intracavity polarization element.

Research was conducted to reexamine previous calculations of B9H10- using higher computational levels. IGLO12 chemical shift calculations provide additional information. Thus, a combined ab initio/IGLO/NMR method was used on the structural elucidation of electron deficient boron compounds, protonated closoboranes and carbocations. Other members of the BnHn+1- set were also studied in relation to their proton affinities and stabilities. Results indicate that a tricapped trigonal prism with Dd3h symmetry is the most stable B9H92- dianion structure.

Four dinuclear V(IV) complexes were prepared and characterized with respect to the relationship between their crystal structure and magnetic behavior. The four are (LVO(mu-(Ph)2PO2)LVO, (LVO(mu-Ph)HPO2)2LVO), (LVO(mu-OH)2LVO), (LVO(mu-OH)(mu-OAc)LVO) where L = hydrotis(pyrazolyl)borate. The results demonstrated differences in the V---V distances of the four dimers due to variances in the geometries of their eight-membered V(OPO)2V rings.

A new sulfur-rich tridentate ligand, tetrakis(2-thienyl)borate (1-) was synthesized. Its reactivity and other characteristics were by molecular orbital analysis of its coordination to a metal center. Unlike the analogous tetrakis((methylthio)methyl)borate (2-), 1- does not coordinate Mo(CO)3 when reacted with (C7H8)Mo(CO)3. The sulfur atoms in both ligands are oriented to coordinate the metal in a pyramidal eta1 sulfur-bound mode. Approximate molecular orbital computations were employed to compare the metal-ligand interactions in these related species. Findings indicated that the magnitude and polarizability of the electronic charge density of the lone pairs on the sulfur atoms determine the coordination strength of the ligands.

The dynamics of the complexes ((eta5-C6H7)Fe(CO)3)BF4 and ((eta5-C7H9)Fe(CO)3)BF4 are analyzed by nuclear magnetic resonance spectroscopy in solid state. Both complexes exhibit dynamic processes at elevated temperatures by going through a phase transition. The phase transition temperature is higher for the cycloheptadienyl than the cyclohexadienyl. Such observation implies greater hindrance to the motion for the more sterically hindered cation. The motion consists of a fast and complete reorientation of the molecule.

The viability of borates to act as reagents or catalysts in the nickel-catalyzed coupling of 1,3-disubstituted secondary allylic carbonates with lithium aryl- and alkenylborates was investigated. Specifically, the reactivity and selectivity of the methoxyborates, MeLi-derived alkenyl borates, and borates obtained from MeLI and cyclic boronates were evaluated. The experiments demonstrated that the borates induce substrate-controlled regioselection under mild or neutral conditions.