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Borylene
A borylene is the boron analogue of a carbene. The general structure is R-B: with R an organic residue and B a boron atom with two unshared electrons. Borylenes are of academic interest in organoboron chemistry. A singlet ground state is predominant with boron having two vacant sp2 orbitals and one doubly occupied one. With just one additional substituent the boron is more electron deficient than the carbon atom in a carbene. For this reason stable borylenes are more uncommon than stable carbenes. Some borylenes such as boron monofluoride (BF) and boron monohydride (BH) the parent compound also known simply as borylene, have been detected in microwave spectroscopy and may exist in stars. Other borylenes exist as reactive intermediates and can only be inferred by chemical trapping. The first stable terminal borylene complex OC)5WBN(SiMe3)2was reported by Holger Braunschweig et al. in 1998. In this compound a borylene is coordinated to a transition metal. Borylenes are also sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holger Braunschweig
Holger Braunschweig is Head and Chair of Inorganic Chemistry at the Julius-Maximilians-University of Würzburg in Würzburg, Germany. He is best known for founding the field of transition metal-boron multiple bonding (transition metal borylenes), the synthesis of the first stable compounds containing boron-boron and boron-oxygen triple bonds, the isolation of the first non-carbon/nitrogen main-group dicarbonyl, and the first fixation of dinitrogen at an element of the p-block of the periodic table. By modifying a strategy pioneered by Prof. Gregory Robinson of the University of Georgia, Braunschweig also discovered the first rational and high-yield synthesis of neutral compounds containing boron-boron double bonds (diborenes). In 2016 Braunschweig isolated the first compounds of beryllium in the oxidation state of zero. Education and research career Braunschweig obtained his Ph.D. and Habilitation from RWTH Aachen with P. Paetzold and worked as a postdoctoral researche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typical Borylene '', an American Comedy Central television series
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Typical may refer to: * ''Typical'' (album), Peter Hammill * "Typical" (song), song by MuteMath *"Typical", song by Frazier Chorus from ''Sue'', 1987 *''Typical'', story collection by Padgett Powell, 1991 See also *''Typical Rick ''Typical Rick'' is an American television series produced by Comedy Central, created by Nicholaus Goossen and Nick Swardson. Comedy Central declined to renew the series for a third season. Cast * Nick Swardson as Gary * Simon Rex Simon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NHC Carbene
A persistent carbene (also known as stable carbene) is a type of carbene demonstrating particular stability. The best-known examples and by far largest subgroup are the ''N''-heterocyclic carbenes (NHC) (sometimes called Arduengo carbenes), for example diaminocarbenes with the general formula (R2N)2C:, where the four R moieties are typically alkyl and aryl groups. The groups can be linked to give heterocyclic carbenes, such as those derived from imidazole, imidazoline, thiazole or triazole. Traditionally carbenes are viewed as so reactive that were only studied indirectly, such as by trapping reactions. This situation has changed dramatically with the emergence of persistent carbenes. Although they are fairly reactive substances, undergoing dimerization, many can be isolated as pure substances. Persistent carbenes tend to exist in the singlet. Their stability is only partly due to steric hindrance by bulky groups. Some singlet carbenes are thermodynamically stable and can be iso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-block
A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in. The term appears to have been first used by Charles Janet. Each block is named after its characteristic orbital: s-block, p-block, d-block, and f-block. The block names (s, p, d, and f) are derived from the spectroscopic notation for the value of an electron's azimuthal quantum number: sharp (0), principal (1), diffuse (2), or fundamental (3). Succeeding notations proceed in alphabetical order, as g, h, etc., though elements that would belong in such blocks have not yet been found. Characteristics There is an ''approximate'' correspondence between this nomenclature of blocks, based on electronic configuration, and sets of elements based on chemical properties. The s-block and p-block together are usually considered main-group elements, the d-block corresponds to the transition metals, and the f-block corresponds to the inner trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Fixation
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmospheric nitrogen is molecular dinitrogen, a relatively nonreactive molecule that is metabolically useless to all but a few microorganisms. Biological nitrogen fixation or ''diazotrophy'' is an important microbials mediated process that converts dinitrogen (N2) gas to ammonia (NH3) using the nitrogenase protein complex (Nif). Nitrogen fixation is essential to life because fixed inorganic nitrogen compounds are required for the biosynthesis of all nitrogen-containing organic compounds, such as amino acids and proteins, nucleoside triphosphates and nucleic acids. As part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer. It is also, indirectly, relevant to the manufacture of all nitrogen chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B Lp NBO
B, or b, is the second letter of the Latin-script alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''bee'' (pronounced ), plural ''bees''. It represents the voiced bilabial stop in many languages, including English. In some other languages, it is used to represent other bilabial consonants. History Old English was originally written in runes, whose equivalent letter was beorc , meaning "birch". Beorc dates to at least the 2nd-century Elder Futhark, which is now thought to have derived from the Old Italic alphabets' either directly or via Latin . The uncial and half-uncial introduced by the Gregorian and Irish missions gradually developed into the Insular scripts' . These Old English Latin alphabets supplanted the earlier runes, whose use was fully banned under King Canute in the early 11th century. The Norman Conquest popularised the Carolingian half-uncial forms which la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron Dinitrogen Activation
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral sodium borate, and the ultra-hard crystals of boron carbide and boron nitride. Boron is synthesized entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, so it is a low-abundance element in the Solar System and in the Earth's crust. It constitutes about 0.001 percent by weight of Earth's crust. It is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known deposits are in Turkey, the largest producer of boron minerals. Elemental boron is a metalloid t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BB Sigma NBO
BB, Bb, or similar, may refer to: In arts and entertainment *BB, abbreviation for a catalogue of works by Béla Bartók * ''BB'' (album), by Mod Sun (2017) *"BB Talk", 2015 song by Miley Cyrus *BB (Transformers), a character in the franchise *BB, pseudonym of author and artist Denys Watkins-Pitchford *Les B.B., a Canadian band from Quebec *BattleBots, a robot combat TV show *Beast Boy, a comic book character *Beyond Birthday, a character from the novel '' Death Note Another Note: The Los Angeles BB Murder Cases'' * Big Brother (''Nineteen Eighty-Four'') or BB in Orwell's novel * ''Big Brother'' (TV series), home living reality TV popularity contest show *Billy Butcher, supporting character and final antagonist of the ''The Boys'' comic book series ** ''Butcher, Baker, Candlestickmaker'', spin-off comic miniseries of ''The Boys'', following Billy Butcher *** "Butcher, Baker, Candlestick Maker" (''The Boys''), television adaptation of the comic miniseries *BB, the production ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LUMO Diborene
In chemistry, HOMO and LUMO are types of molecular orbitals. The acronyms stand for ''highest occupied molecular orbital'' and ''lowest unoccupied molecular orbital'', respectively. HOMO and LUMO are sometimes collectively called the ''frontier orbitals'', such as in the frontier molecular orbital theory. Gap The energy difference between the HOMO and LUMO is ''the HOMO–LUMO gap''. Its size can be used to predict the strength and stability of transition metal complexes, as well as the colors they produce in solution.Griffith, J. S. and L. E. Orgel"Ligand Field Theory" ''Q. Rev. Chem. Soc.'' 1957, 11, 381–383. As a rule of thumb, the larger a compound's HOMO-LUMO gap, the more stable the compound. Semiconductors The HOMO level is to organic semiconductors roughly what the maximum valence band is to inorganic semiconductors and quantum dots. The same analogy can be made between the LUMO level and the conduction band minimum.Bredas, J,-L"Mind the gap!" ''Mater. Horiz.'' 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
