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Phosphaalkene
Phosphaalkenes ( IUPAC name: alkylidenephosphanes) are organophosphorus compounds with double bonds between carbon and phosphorus(III) with the formula R2C=PR. In the compound phosphorine one carbon atom in benzene is replaced by phosphorus. The reactivity of phosphaalkenes is often compared to that of alkenes and not to that of imines because the HOMO of phosphaalkenes is not the phosphorus lone pair (as in imines the amine lone pair) but the double bond. Therefore like alkenes, phosphaalkenes engage in Wittig reactions, Peterson reactions, Cope rearrangements and Diels-Alder reactions. The first phosphaalkene discovered was a phosphabenzene, by Mërkl in 1969. The first localized phosphaalkene was reported in 1976 by Gerd Becker as a keto-enol tautomerism akin a Brook rearrangement: :: In the same year Harold Kroto established spectroscopically that thermolysis of Me2PH generates CH2=PMe. A general method for the synthesis of phosphaalkenes is by 1,2-elimination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stable Phosphorus Radicals
Stable and persistent phosphorus radicals are phosphorus-centred radicals that are isolable and can exist for at least short periods of time. Radicals consisting of main group elements are often very reactive and undergo uncontrollable reactions, notably dimerization and polymerization. The common strategies for stabilising these phosphorus radicals usually include the delocalisation of the unpaired electron over a pi system or nearby electronegative atoms, and kinetic stabilisation with bulky ligands. Stable and persistent phosphorus radicals can be classified into three categories: neutral, cationic, and anionic radicals. Each of these classes involve various sub-classes, with neutral phosphorus radicals being the most extensively studied. Phosphorus exists as one isotope 31P (''I'' = 1/2) with large hyperfine couplings relative to other spin active nuclei, making phosphorus radicals particularly attractive for spin-labelling experiments. Neutral phosphorus radicals Neu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphorus Compound
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus, like nitrogen, is in group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need contain only an organic substituent, but need not have a direct phosphorus-carbon (P-C) bond. Thus a large proportion of pesticides (e.g., malathion), are often included in this class of compounds. Phosphorus can adopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Kroto
Sir Harold Walter Kroto (born Harold Walter Krotoschiner; 7 October 1939 – 30 April 2016), known as Harry Kroto, was an English chemist. He shared the 1996 Nobel Prize in Chemistry with Robert Curl and Richard Smalley for their discovery of fullerenes. He was the recipient of many other honors and awards. Kroto ended his career as the Francis Eppes Professor of Chemistry at Florida State University, which he joined in 2004. Prior to this, he spent approximately 40 years at the University of Sussex. Kroto promoted science education and was a critic of religious faith. Early years Kroto was born in Wisbech, Isle of Ely, Cambridgeshire, England, to Edith and Heinz Krotoschiner, his name being of Silesian origin. His father's family came from Bojanowo, Poland, and his mother's from Berlin. Both of his parents were born in Berlin and fled to Great Britain in the 1930s as refugees from Nazi Germany; his father was Jewish. Harry was raised in Bolton while the British authoriti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerd Becker (chemist)
Gerd Becker (3 May 1940 in Eschwege, Germany – 10 January 2017) was a German chemist. He held a chair of inorganic chemistry at the University of Stuttgart. In 1974 he synthesized the first localized phosphaalkene Phosphaalkenes ( IUPAC name: alkylidenephosphanes) are organophosphorus compounds with double bonds between carbon and phosphorus(III) with the formula R2C=PR. In the compound phosphorine one carbon atom in benzene is replaced by phosphorus. The .... SourcesEntry on Becker's death External links {{DEFAULTSORT:Becker, Gerd 1940 births 2017 deaths People from Eschwege 20th-century German chemists Academic staff of the University of Stuttgart 21st-century German chemists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorine
Phosphorine ( IUPAC name: phosphinine) is a heavier element analog of pyridine, containing a phosphorus atom instead of an aza- moiety. It is also called phosphabenzene and belongs to the phosphaalkene class. It is a colorless liquid that is mainly of interest in research. Phosphorine is an air-sensitive oil but is otherwise stable when handled using air-free techniques (however, substituted derivatives can often be handled under air without risk of decomposition). In contrast, silabenzene, a related heavy-element analogue of benzene, is not only air- and moisture-sensitive but also thermally unstable without extensive steric protection. History The first phosphorine to be isolated is 2,4,6-triphenylphosphorine. It was synthesized by Gottfried Märkl in 1966 by condensation of the corresponding pyrylium salt and phosphine or its equivalent ( P(CH2OH)3 and P(SiMe3)3).''G. Märkl'', 2,4,6-Triphenylphosphabenzol iAngewandte Chemie 78, 907–908 (1966)/ref> 500px, Synthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphabenzene
Phosphorine ( IUPAC name: phosphinine) is a heavier element analog of pyridine, containing a phosphorus atom instead of an aza- moiety. It is also called phosphabenzene and belongs to the phosphaalkene class. It is a colorless liquid that is mainly of interest in research. Phosphorine is an air-sensitive oil but is otherwise stable when handled using air-free techniques (however, substituted derivatives can often be handled under air without risk of decomposition). In contrast, silabenzene, a related heavy-element analogue of benzene, is not only air- and moisture-sensitive but also thermally unstable without extensive steric protection. History The first phosphorine to be isolated is 2,4,6-triphenylphosphorine. It was synthesized by Gottfried Märkl in 1966 by condensation of the corresponding pyrylium salt and phosphine or its equivalent ( P(CH2OH)3 and P(SiMe3)3).''G. Märkl'', 2,4,6-Triphenylphosphabenzol iAngewandte Chemie 78, 907–908 (1966)/ref> 500px, Synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Becker Reaction
Becker () is one of the German-language surnames, along with Bäcker and Baecker, that derive from the root, which refers to baking. The surname began as a name for a baker (and thus his family). In northern Germany it can also derive from the word ''Beck'' for ''Bach'' ("creek" or "brook") to denote origin. Geographical distribution As of 2014, 55.3% of all known bearers of the surname ''Becker'' were residents of Germany (frequency 1:287), 24.7% of the United States (1:2,891), 8.0% of Brazil (1:5,052), 2.7% of France (1:4,987), 2.0% of South Africa (1:5,431) and 1.2% of Canada (1:6,120). In Germany, the frequency of the surname was higher than the national average (1:287) in the following states: * 1. Saarland (1:84) * 2. Rhineland-Palatinate (1:123) * 3. Hesse (1:159) * 4. North Rhine-Westphalia (1:226) * 5. Saxony-Anhalt (1:248) People Surname * Alan Becker (born 1989), U.S. animator, YouTuber *Alan S. Becker (1946–2020), American lawyer and politician * Albert Bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(p-phenylenephosphaalkene)
Poly, from the Greek πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong incorporated Chinese property developer ** Poly Real Estate, a Chinese real estate developer ** Poly Technologies, a defense manufacturing company * Poly (company), formerly Polycom, an American communications technology company People * Poly (footballer) (1906-1986), full name Policarpo Ribeiro de Oliveira, Brazilian footballer * Natasha Poly (born 1985), stage name of Russian supermodel Natalya Sergeyevna Polevshchikova * Poly Styrene (1957–2011), stage name of British musician Marianne Joan Elliott-Said Other uses * Hong Kong Polytechnic University The Hong Kong Polytechnic University (PolyU) is a public research university located in Hung Hom, Hong Kong near Hung Hom station. The University is one of the eight government-funded degree-granting tertiary institutions in H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(p-phenylene Vinylene)
Poly(''p''-phenylene vinylene) (PPV, or polyphenylene vinylene) is a conducting polymer of the rigid-rod polymer family. PPV is the only polymer of this type that can be processed into a highly ordered crystalline thin film. PPV and its derivatives are electrically conducting upon doping. Although insoluble in water, its precursors can be manipulated in aqueous solution. The small optical band gap and its bright yellow fluorescence makes PPV a candidate in applications such as light-emitting diodes (LED) and photovoltaic devices. Moreover, PPV can be doped to form electrically conductive materials. Its physical and electronic properties can be altered by the inclusion of functional side groups. Preparation PPVs can be synthesized by a variety of methods, the details of which determine purity and molecular weight. The most popular methods proceed via p- xylylene intermediates after a base induced elimination from α,α'-disubstituted para-xylenes. : Other methods Although xyly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triethylamine
Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA is also a common abbreviation. It is a colourless volatile liquid with a strong fishy odor reminiscent of ammonia. Like diisopropylethylamine (Hünig's base), triethylamine is commonly employed in organic synthesis, usually as a base. Synthesis and properties Triethylamine is prepared by the alkylation of ammonia with ethanol: :NH3 + 3 C2H5OH → N(C2H5)3 + 3 H2O The pKa of protonated triethylamine is 10.75,David Evans Research Group and it can be used to prepare buffer solutions at that pH. The |
