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Iminoborane
Iminoboranes comprise a group of organoboron compounds with the formula RB=NR'. They are electronically related to acetylenes but are usually more reactive due to the polarity. Structure and bonding The parent iminoborane, HB=NH, is produced by the photolysis of H3BNH3. Bonding in iminoboranes can be described by two resonance structures In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or ''forms'', also variously known as ''resonance structures'' or '' ...: :R-\overset\overset-R R-B=\ddot-R The stability is dramatically affected by bulky substituents. One isolable iminoborane is (''tert''-Bu)B=N(''tert''-Bu). Synthesis Elimination of fluoro- or chlorosilanes provides a well-tested route. Bulky substituents such as (Me3Si)3Si stabilize the iminoborane with respect to oligomerization: :(Me3Si)3SiB(F)-N(SiMe3)2 → (Me3Si)3Si-B=N-SiMe3 + F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia Borane
Ammonia borane (also systematically named amminetrihydridoboron), also called borazane, is the chemical compound with the formula H3NBH3. The colourless or white solid is the simplest molecular boron-nitrogen-hydride compound. It has attracted attention as a source of hydrogen fuel, but is otherwise primarily of academic interest. Synthesis Reaction of diborane with ammonia mainly gives the diammoniate salt 2B(NH3)2sup>+ (BH4)−. Ammonia borane is the main product when an adduct of borane is employed in place of diborane: :BH3(THF) + NH3 → BH3NH3 + THF Properties and structure The molecule adopts a structure similar to that of ethane, with which it is isoelectronic. The B−N distance is 1.58(2) Å. The B−H and N−H distances are 1.15 and 0.96 Å, respectively. Its similarity to ethane is tenuous since ammonia borane is a solid and ethane is a gas: their melting points differing by 284 °C. This difference is consistent with the highly polar natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine-borane
Ammonia borane (also systematically named amminetrihydridoboron), also called borazane, is the chemical compound with the formula H3NBH3. The colourless or white solid is the simplest molecular boron-nitrogen-hydride compound. It has attracted attention as a source of hydrogen fuel, but is otherwise primarily of academic interest. Synthesis Reaction of diborane with ammonia mainly gives the diammoniate salt + (BH4)−. Ammonia borane is the main product when an adduct of borane is employed in place of diborane: :BH3(THF) + NH3 → BH3NH3 + THF Properties and structure The molecule adopts a structure similar to that of ethane, with which it is isoelectronic. The B−N distance is 1.58(2) Å. The B−H and N−H distances are 1.15 and 0.96 Å, respectively. Its similarity to ethane is tenuous since ammonia borane is a solid and ethane is a gas: their melting points differing by 284 °C. This difference is consistent with the highly polar nature of ammonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borazine
Borazine, also known as borazole, is a non-polar inorganic compound with the chemical formula B3H6N3. In this cyclic compound, the three BH units and three NH units alternate. The compound is isoelectronic and isostructural with benzene. For this reason borazine is sometimes referred to as “inorganic benzene”. Like benzene, borazine is a colourless liquid with an aromatic smell. Synthesis The compound was reported in 1926 by the chemists Alfred Stock and Erich Pohland by a reaction of diborane with ammonia. Borazine can be synthesized by treating diborane and ammonia in a 1:2 ratio at 250–300 °C with a conversion of 50%. :3 B2H6 + 6 NH3 → 2 B3H6N3 + 12 H2 An alternative more efficient route begins with sodium borohydride and ammonium sulfate: :6 NaBH4 + 3 (NH4)2SO4 → 2 B3N3H6 + 3 Na2SO4 + 18 H2 In a two-step process to borazine, boron trichloride is first converted to trichloroborazine: :3 BCl3 + 3 NH4Cl → Cl3B3H3N3 + 9 HCl The B-Cl bonds are subsequently c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Figure Product Of Iminboboranes Oligomerization-1
Figure may refer to: General *A shape, drawing, depiction, or geometric configuration * Figure (wood), wood appearance * Figure (music), distinguished from musical motif * Noise figure, in telecommunication * Dance figure, an elementary dance pattern *A person's figure, human physical appearance Arts *Figurine, a miniature statuette representation of a creature *Action figure, a posable jointed solid plastic character figurine * Figure painting, realistic representation, especially of the human form * Figure drawing *Model figure, a scale model of a creature Writing *figure, in writing, a type of floating block (text, table, or graphic separate from the main text) *Figure of speech, also called a rhetorical figure * Christ figure, a type of character * in typesetting, text figures and lining figures Accounting *Figure, a synonym for number * Significant figures in a decimal number Science *Figure of the Earth, the size and shape of the Earth in geodesy Sports * Figure (hor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Dewar
Sir James Dewar (20 September 1842 – 27 March 1923) was a British chemist and physicist. He is best known for his invention of the vacuum flask, which he used in conjunction with research into the liquefaction of gases. He also studied atomic and molecular spectroscopy, working in these fields for more than 25 years. Early life James Dewar was born in Kincardine, Perthshire (now in Fife) in 1842, the youngest of six boys of Ann Dewar and Thomas Dewar, a vintner. He was educated at Kincardine Parish School and then Dollar Academy. His parents died when he was 15. He attended the University of Edinburgh where he studied chemistry under Lyon Playfair (later Baron Playfair), becoming Playfair's personal assistant. Dewar also studied under August Kekulé at Ghent. Career In 1875, Dewar was elected Jacksonian professor of natural experimental philosophy at the University of Cambridge, becoming a member of Peterhouse. He became a member of the Royal Institution and later, in 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tris(trimethylsilyl)silane
Tris(trimethylsilyl)silane is the organosilicon compound with the formula (Me3Si)3SiH (where Me = CH3). It is a colorless liquid that is classified as a hydrosilane since it contains an Si-H bond. The compound is notable as having a weak Si-H bond, with a bond dissociation energy estimated at 84 kcal/mol. For comparison, the Si-H bond in trimethylsilane is 94 kcal/mol. With such a weak bond, the compound is used as a reagent to deliver hydrogen atoms. The compound has been described as an environmentally benign analogue of tributyltin hydride Tributyltin hydride is an organotin compound with the formula (C4H9)3SnH. It is a colorless liquid that is soluble in organic solvents. The compound is used as a source of hydrogen atoms in organic synthesis. Synthesis and characterization The .... The compound can be prepared by protonation of tris(trimethylsilyl)silyl lithium, which is derived from tetrakis(trimethylsilyl)silane: :(Me3Si)4Si + MeLi → (Me3Si)3SiLi + Me4Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Spectroscopy
Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency, wavenumber or wavelength on the horizontal axis. Typical units of wavenumber used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers (formerly called "microns"), symbol μm, which are related to the wavenumber in a reciprocal way. A com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Spectroscopy
Rotational spectroscopy is concerned with the measurement of the energies of transitions between quantized rotational states of molecules in the gas phase. The spectra of polar molecules can be measured in absorption or emission by microwave spectroscopy or by far infrared spectroscopy. The rotational spectra of non-polar molecules cannot be observed by those methods, but can be observed and measured by Raman spectroscopy. Rotational spectroscopy is sometimes referred to as ''pure'' rotational spectroscopy to distinguish it from rotational-vibrational spectroscopy where changes in rotational energy occur together with changes in vibrational energy, and also from ro-vibronic spectroscopy (or just vibronic spectroscopy) where rotational, vibrational and electronic energy changes occur simultaneously. For rotational spectroscopy, molecules are classified according to symmetry into spherical top, linear and symmetric top; analytical expressions can be derived for the rotational ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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