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Moses Gomberg
Moses Gomberg (February 8, 1866 – February 12, 1947) was a chemistry professor at the University of Michigan. He was elected to the National Academy of Sciences and served as president of the American Chemical Society. Early life and education He was born in Yelisavetgrad, Russian Empire to a Jewish merchant family. His father was Hershko (Hirsh) Gomberg and his mother was Maryam-Ethel Reznikova. In 1884, the family emigrated to Chicago to escape the pogroms following the assassination of Czar Alexander II. In Chicago he worked at the Stock Yards while attending Lake High School. In 1886, Moses entered the University of Michigan, where he obtained his B.Sc. in 1890 and his doctorate in 1894 under the supervision of A. B. Prescott. His thesis, titled "''Trimethylxanthine and Some of its Derivatives''", dealt with the derivatization of caffeine. Career Appointed an instructor in 1893, Gomberg worked at the University of Michigan for the duration of his professional academic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yelizavetgrad
Kropyvnytskyi ( uk, Кропивницький, Kropyvnytskyi ) is a city in central Ukraine on the Inhul river with a population of . It is an administrative center of the Kirovohrad Oblast. Over its history, Kropyvnytskyi has changed its name several times. The settlement was known as Yelysavethrad ( uk, Єлисаветград, links=no ) after Empress Elizabeth of Russia () from 1752 to 1924 as well as simply Elysavet. In 1924 it became Zinovievsk ( uk, Зінов'євськ, links=no, ) in honour of the Bolshevik revolutionary and Politburo member Grigory Zinoviev (1883-1936), who was born there. Following the assassination of the First Secretary of the Leningrad City Committee of the All-Union Communist Party (Bolsheviks) Sergei Kirov (in office 1926–1934), the town was renamed Kirovo ( uk, Кірово, links=no ) in Kirov's honour on 7 December, 1934—a name-change similar to those of numerous other localities throughout the USSR (including present-day Kirov i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicago
(''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_type2 = Counties , subdivision_name1 = Illinois , subdivision_name2 = Cook and DuPage , established_title = Settled , established_date = , established_title2 = Incorporated (city) , established_date2 = , founder = Jean Baptiste Point du Sable , government_type = Mayor–council , governing_body = Chicago City Council , leader_title = Mayor , leader_name = Lori Lightfoot ( D) , leader_title1 = City Clerk , leader_name1 = Anna Valencia ( D) , unit_pref = Imperial , area_footnotes = , area_tot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexaphenylethane
Hexaphenylethane is a hypothetical organic compound consisting of an ethane core with six phenyl substituents. All attempts at its synthesis have been unsuccessful. The trityl free radical, Ph3C, was originally thought to dimerize to form hexaphenylethane. However, an inspection of the NMR spectrum of this dimer reveals that it is in fact a non-symmetrical species, Gomberg's dimer instead. A substituted derivative of hexaphenylethane, hexakis(3,5-di-''t''-butylphenyl)ethane, has however been prepared. It features a very long central C–C bond at 167 pm (compared to the typical bond length of 154 pm). Attractive London dispersion forces between the ''t''-butyl substituents are believed to be responsible for the stability of this very hindered molecule. See also * Tetraphenylmethane Tetraphenylmethane is an organic compound consisting of a methane core with four phenyl substituents. It was first synthesized by Moses Gomberg in 1898. Synthesis Gomberg's class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steric Effects
Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions and molecules. Steric effects complement electronic effects, which dictate the shape and reactivity of molecules. Steric repulsive forces between overlapping electron clouds result in structured groupings of molecules stabilized by the way that opposites attract and like charges repel. Steric hindrance Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in ''intermolecular reactions'', whereas discussion of steric effects often focus on ''intramolecular interactions''. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions. Steric hindrance between adjacent groups can also affect torsional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetraphenylmethane
Tetraphenylmethane is an organic compound consisting of a methane core with four phenyl substituents. It was first synthesized by Moses Gomberg in 1898. Synthesis Gomberg's classical organic synthesis shown below starts by reacting triphenylmethyl bromide 1 with phenylhydrazine 2 to the hydrazine 3. Oxidation with nitrous acid then produces the azo compound 4 from which on heating above the melting point, nitrogen gas evolves with formation of tetraphenylmethane 5.{{cite journal , title = On tetraphenylmethane , first= M. , last=Gomberg , journal = J. Am. Chem. Soc. , year = 1898 , volume = 20 , issue = 10 , pages = 773–780 , doi= 10.1021/ja02072a009, url= https://zenodo.org/record/1428930 : Gomberg was able to distinguish this compound from triphenylmethane ( elemental analysis was not an option given the small differences in the hydrogen fractions of 6.29% and 6.60%) by nitration of 5 with nitric acid to 6. A strong base would be able to abstract th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heidelberg
Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. Located about south of Frankfurt, Heidelberg is the List of cities in Baden-Württemberg by population, fifth-largest city in Baden-Württemberg. Heidelberg is part of the densely populated Rhine-Neckar, Rhine-Neckar Metropolitan Region. Heidelberg University, founded in 1386, is Germany's oldest and one of Europe's most reputable universities. Heidelberg is a Science, scientific hub in Germany and home to several internationally renowned #Research, research facilities adjacent to its university, including the European Molecular Biology Laboratory and four Max Planck Society, Max Planck Institutes. The city has also been a hub for the arts, especially literature, throughout the centurie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victor Meyer
Viktor Meyer (8 September 18488 August 1897) was a German chemist and significant contributor to both organic and inorganic chemistry. He is best known for inventing an apparatus for determining vapour densities, the Viktor Meyer apparatus, and for discovering thiophene, a heterocyclic compound. He is sometimes referred to as Victor Meyer, a name used in some of his publications. Early life Viktor Meyer was born in Berlin in 1848, the son of trader and cotton printer Jacques Meyer and mother, Bertha. His parents were Jewish, though he was not actively raised in the Jewish faith. Later, he was confirmed in a Reform Jewish congregation. He married a Christian woman, Hedwig Davidson, and raised his children as such. He entered the gymnasium at the age of ten in the same class as his two-year older brother Richard. Although he had excellent science skills his wish to become an actor was based on his love for poetry. At a visit from his brother Richard, who was studying chemistry at t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Thiele (chemist)
Friedrich Karl Johannes Thiele (May 13, 1865 – April 17, 1918) was a Germans, German chemist and a prominent professor at several universities, including those in Munich and Strasbourg. He developed many laboratory techniques related to isolation of organic compounds. In 1907 he described a device for the accurate determination of melting points, since named Thiele tube after him. Thiele was born in Ratibor, Prussia, now Racibórz, Poland. Thiele studied mathematics at the University of Breslau but later turned to chemistry, receiving his doctorate from University of Halle-Wittenberg, Halle in 1890 . He taught at the University of Munich from 1893 to 1902, when he was appointed professor of chemistry at Strasbourg. He developed the preparation of glyoxal bis(guanylhydrazone). After Friedrich August Kekulé von Stradonitz, Kekulé's proposal for Aromaticity, benzene structure in 1865, Thiele suggested a "Partial Valence Hypothesis", which concerned Covalent bond, double a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adolf Von Baeyer
Johann Friedrich Wilhelm Adolf von Baeyer (; 31 October 1835 – 20 August 1917) was a German chemist who synthesised indigo and developed a nomenclature for cyclic compounds (that was subsequently extended and adopted as part of the IUPAC organic nomenclature). He was ennobled in the Kingdom of Bavaria in 1885 and was the 1905 recipient of the Nobel Prize in Chemistry.''Adolf von Baeyer: Winner of the Nobel Prize for Chemistry 1905 '' Armin de Meijere Angewandte Chemie International Edition Volume 44, Issue 48, Pages 7836 – 7840 2005''Abstract/ref> Family and education Baeyer was born in Berlin as the son of the noted geodesist and captain of the Royal Prussian Army Johann Jacob Baeyer and his wife Eugenie Baeyer née Hitzig (1807–1843). Both his parents were Lutherans at the time of his birth and he was raised in the Lutheran religion. His mother was the daughter of Julius Eduard Hitzig and a member of the originally Jewish Itzig family, and had converted to Christianity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postdoctoral Researcher
A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). The ultimate goal of a postdoctoral research position is to pursue additional research, training, or teaching in order to have better skills to pursue a career in academia, research, or any other field. Postdocs often, but not always, have a temporary academic appointment, sometimes in preparation for an academic faculty position. They continue their studies or carry out research and further increase expertise in a specialist subject, including integrating a team and acquiring novel skills and research methods. Postdoctoral research is often considered essential while advancing the scholarly mission of the host institution; it is expected to produce relevant publications in peer-reviewed academic journals or conferences. In some countries, postdoctoral research may lead to further formal qualificati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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