Showing papers on "Diborane published in 1980"

The optical band gap of hydrogenated amorphous‐boron thin films: The effect of thermal treatment

Abstract: Hydrogenated amorphous‐boron thin films produced by glow‐discharge decomposition of a gas mixture of 3.1 vol. % diborane and 96.9 vol. % hydrogen have been heat treated at 360 and 400 °C. The resulting absorption coefficients and optical band gaps have been measured as a function of heat‐treatment time and temperature. Both the absorption coefficients and the optical band gaps of these films can be drastically changed by such treatments. Thermal treatment at 400 °C for 200 h results in a systematic decrease in the optical band gap from 2.19 to 0.90 eV. From quantitative hydrogen analyses it is shown that hydrogen evolution during heating plays a strong role in reducing the apparent optical band gap. These results indicate that it might be possible to optimize theoretical amorphous‐boron thin films through the tailoring of the optical band gap by such thermal treatment.

Preparations and asymmetric, reducing abilities of chiral polymeric amine‐boranes

Abstract: Polymeric amine-boranes 2b, 4b, and 8c and their corresponding low-molecular-weight model compounds 3b, 5b, and 6b were obtained by reaction of chiral amines with diborane; these amines were poly(pyrrolidine-1,2-diylmethylene) (2a), poly(imino-1-isobutylethylene) (4a), poly{[1,2-bis(4-vinylphenyl)ethyl]amine} (8b), 1-methylpyrrolidin-2-yl-1-pyrrolidinyl-methane (3a), N1-isopentyl-N2-methyl-4-methyl-1,2-pentanediamine (5a), and α-phenylphenethylamine (6a). The polymeric amine-boranes are white powders, stable to be kept for several weeks at room temperature, whereas the low-molecular-weight model compounds are less stable syrup-like materials. The reduction of acetophenone to optically active 1-phenylethanol was carried out with the chiral amine-boranes in the presence of boron trifluoride etherate at various reaction temperatures. The product resulting from the reduction with 8c can easily be separated from the reaction mixture by filtration. The optical yield of the product obtained with 8c was 8,9% at −40°C. The highest optical yield (25,3%) was obtained with α-phenylphenethylamineborane 6b at 0°C.

Molecular orbital study of the bridge bonding in an electron deficient molecule [(CH3)2ALH]2

Abstract: The electronic distribution in the AlH2Al bridge of the dimethyl aluminium hybride dimer was computed through ab initio SCF calculation. Comparison with diborane shows an increased role of the ionic Al+H 2 2− Al+ structures with respect to the usual covalent three-center bonds.

Wire hold*guide member for use in wire dot printer

Abstract: PURPOSE:To improve wear resistance by forming a boron phosphide film on the inside surface of through-holes of a wire hold-guide member in which wires are loosely inserted. CONSTITUTION:Parts B1, B2, B3 constituting a substrate B are formed of a material available at relatively low cost such as aluminum oxide and copper by extrusion. The substrate B is formed with plural through-holes H large enough to loosely insert wires W therein, to constitute a wire hold/guide member G. The parts B1, B2 and B3 are heated in a heating furnace, and diborane and phosphine are introduced in the furnace using hydrogen gas as a carrier gas, with the concentration of diborane about 2X10 mole/min and the molar ratio of phosphine to diborane about 50. Thus, a boron phosphide film K is formed on the outside surface of the parts B1, B2 and B3 by gas phase growth. These parts formed thereon with the film K are integrally combined with the substrate B preferably mechanically.

Method for the epitaxial growth of boron phosphorous semiconductors

Abstract: The epitaxial growth of boron-phosphorous semiconductors can be accomplished by chemically reacting the gas materials diborane and phosphorous trichloride. The preferable temperature of the substrate in 880° C.-1,110° C. and the preferable ratio of the phosphorous trichloride to diborane in mol is 2-200. Use is made of a composite substrate.

Measuring method for volatile metal hydride

Abstract: PURPOSE:To make it possible to take a measurement in a short time through simple operation and also to measure even a fine quantity easily and accurately by measuring the density of mercury atoms generated from a mercury oxide by making a volatile metal hydride react on a mercury oxide CONSTITUTION:Inert gas of nitrogen, etc, and a volatile metal hydride such as a diborane, arsine, phosphine, stibine, hydrogen selenide, and monosilane in the air are made to react on a mercury oxide of more than stoichiometry quantity under the ordinary temperature so as to change the mercury oxide into mercury atoms Next, the density of mercury atoms generated is measured in an ultraviolet absorbing method, for example, and the density of a volatile metal hydride corresponding to it is found As a result, even a fine quantity of mercury atoms can be detected easily and mercury of 15-3mol per 1mol of hydride is generated, so that a detecting measurement of even a small quantity can be taken easily and accurately in a short time through simple operation

Borane-1,4-thioxane

Abstract: The novel borane-1,4-thioxane is synthesized by adding the calculated quantity of diborane to 1,4-thioxane. It is a stable liquid at 25° C. The neat liquid is approximately 8.0 M in borane. The product, in spite of the additional oxygen atom in the ring, exhibits the desirable hydroborating and reducing action of borane-methyl sulfide. However, it possesses a major advantage over the latter in that the donor component, 1,4-thioxane, in contrast to methyl sulfide, is readily soluble in water and can be washed out of typical reaction mixtures. This greatly facilitates the synthetic applications of borane-1,4-thioxane over borane-methyl sulfide.

Hydroxymethylcrown and its preparation

Abstract: NEW MATERIAL:N,N'-Dimethylhydroxymethyl-14-crown-N2O2 of formula I USE:An intermediate of fixed crown useful as interphase shifting catalyst and agent for capturing heavy metals, which is readily recovered and low toxicity PREPARATION:Methylenecrown is hydroborated with a diborane as alkylborane or chloroborane by usual method to form the objective compound of formula I The compound of formula II is prepared by reaction of 22'-[trimethylenebis (methylimino)]diethanol with 3-chloro-2-chloromethyl-1-propene in the presence of a base The resulting compound of formula I is made to react with a chloro- methylated and crosslinked polystyrene in the presence of a base to give the above fixed crown

Distribution of alkylboranes in the reaction of norbornene and cyclopentene with borane-thf

Abstract: Systematic studies of the partial alkylation of diborane with norbornene and cyclopentene were carried out in THF and the equilibrium distribution of the borane derivatives was determined. Di-exo-norbornylborane was obtained in 71% yield with no mono-exo-norbornylborane as a by-product, under the conditions: initial ratio of norbornene to borane 2 : 1, temperature 0 °C and reaction time 1 h. Mono-exo-norbornylborane was obtained in 72–75% yield under the conditions: initial ratio of norbornene to borane 1 : 1, temperature 25 °C, and reaction time 48 h. In the dialkylborane [R2BH]2, norbornene and cyclopentene exhibit very different behavior during the course of equilibration reaction.