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Hans-Werner Wanzlick
Hans-Werner Wanzlick (1917-1988) was a German chemist. A Professor of chemistry at the Berlin Technical University he is notable for work on persistent carbenes and for proposing the Wanzlick equilibrium between saturated imidazolin-2-ylidenes and their dimer Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * Julius Dimer ...s — which he called "''das doppelte Lottchen''", after a 1949 novel by Erich Kästner about a pair of mischievous twins. Anthony J. Arduengo, III (1999) ''Looking for Stable Carbenes: The Difficulty in Starting Anew''. Accounts of Chemical Research, volume 32, number 11, pages 913–921. References * Hans-Werner Wanzlick (1958), letter to Linus Pauling (in German). Linus Pauling's Correspondence, item #444.6. Technical University of Berlin faculty 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin
Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constituent states, Berlin is surrounded by the State of Brandenburg and contiguous with Potsdam, Brandenburg's capital. Berlin's urban area, which has a population of around 4.5 million, is the second most populous urban area in Germany after the Ruhr. The Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions. Berlin straddles the banks of the Spree, which flows into the Havel (a tributary of the Elbe) in the western borough of Spandau. Among the city's main topographical features are the many lakes in the western and southeastern boroughs formed by the Spree, Havel and Dahme, the largest of which is Lake Müggelsee. Due to its l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimer (chemistry)
A dimer () ('' di-'', "two" + ''-mer'', "parts") is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. Dimers also have significant implications in polymer chemistry, inorganic chemistry, and biochemistry. The term ''homodimer'' is used when the two molecules are identical (e.g. A–A) and ''heterodimer'' when they are not (e.g. A–B). The reverse of dimerization is often called dissociation. When two oppositely charged ions associate into dimers, they are referred to as ''Bjerrum pairs'', after Niels Bjerrum. Noncovalent dimers Anhydrous carboxylic acids form dimers by hydrogen bonding of the acidic hydrogen and the carbonyl oxygen. For example, acetic acid forms a dimer in the gas phase, where the monomer units are held together by hydrogen bonds. Under special conditions, most OH-containing molecules form dimers, e.g. the water dimer. Excimers and exciplexes are excited structures with a short lifetime. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1917 Births
Events Below, the events of World War I have the "WWI" prefix. January * January 9 – WWI – Battle of Rafa: The last substantial Ottoman Army garrison on the Sinai Peninsula is captured by the Egyptian Expeditionary Force's Desert Column. * January 10 – Imperial Trans-Antarctic Expedition: Seven survivors of the Ross Sea party were rescued after being stranded for several months. * January 11 – Unknown saboteurs set off the Kingsland Explosion at Kingsland (modern-day Lyndhurst, New Jersey), one of the events leading to United States involvement in WWI. * January 16 – The Danish West Indies is sold to the United States for $25 million. * January 22 – WWI: United States President Woodrow Wilson calls for "peace without victory" in Germany. * January 25 ** WWI: British armed merchantman is sunk by mines off Lough Swilly (Ireland), with the loss of 354 of the 475 aboard. ** An anti- prostitution drive in San Francisco occurs, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical University Of Berlin Faculty
Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is constructed or functions (also known as drafting) * Technical file, set of technical drawings * Technical death metal, a subgenre of death metal that focuses on complex rhythms, riffs, and song structures * Technical foul, an infraction of the rules in basketball usually concerning unsportsmanlike non-contact behavior * Technical rehearsal for a performance, often simply referred to as a technical * Technical support, a range of services providing assistance with technology products * Vocational education, often known as technical education * Legal technicality, an aspect of law See also * Lego Technic, a line of Lego toys * Tech (other) * Technicals (other) * Technics (other) * Technique (other) * Tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linus Pauling
Linus Carl Pauling (; February 28, 1901August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. ''New Scientist'' called him one of the 20 greatest scientists of all time, and as of 2000, he was rated the 16th most important scientist in history. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize (the others being Marie Curie, John Bardeen, Frederick Sanger and Karl Barry Sharpless). Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie. Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erich Kästner
Emil Erich Kästner (; 23 February 1899 – 29 July 1974) was a German writer, poet, screenwriter and satirist, known primarily for his humorous, socially astute poems and for children's books including '' Emil and the Detectives''. He received the international Hans Christian Andersen Medal in 1960 for his autobiography '. He was nominated for the Nobel Prize in Literature in six separate years. Biography Dresden 1899–1919 Kästner was born in Dresden, Saxony, and grew up on Königsbrücker Straße in Dresden's Äußere Neustadt. Close by, the Erich Kästner Museum was subsequently opened in the Villa Augustin that had belonged to Kästner's uncle Franz Augustin. Kästner's father, Emil Richard Kästner, was a master saddlemaker. His mother, Ida Amalia (née Augustin), had been a maidservant, but in her thirties she trained as a hairstylist in order to supplement her husband's income. Kästner had a particularly close relationship with his mother. When he was living ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lottie And Lisa
''Lisa and Lottie'' (original German title: ''Das doppelte Lottchen'', "The Double Lottie") (published since 2014 in the United Kingdom and Australia as ''The Parent Trap'') is a 1949 German novel by Erich Kästner, about twin girls separated in infancy who meet at summer camp. The book originally started out during World War II as an aborted movie scenario. In 1942, when for a brief time Kästner was allowed by the Nazi authorities to work as a screenwriter, he proposed it to Josef von Báky, under the title ''The Great Secret'', but the Nazis once again forbade him to work. After the war, Kästner worked the idea into the highly successful book. Subsequently, it has been adapted into film many times, most notably Disney's 1961 film '' The Parent Trap'' starring Hayley Mills, the subsequent film series, and their various translations. Plot summary Two nine-year-old girls, bold Lisa Palfy (orig. Luise Palfy) from Vienna and shy Lottie Horn (orig. Lotte Körner) from Munich meet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemische Berichte
''Chemische Berichte'' (usually abbreviated as ''Ber.'' or ''Chem. Ber.'') was a German-language scientific journal of all disciplines of chemistry founded in 1868. It was one of the oldest scientific journals in chemistry, until it merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Chemische Berichte/Recueil'' in 1997. ''Chemische Berichte/Recueil'' was then merged with other European journals in 1998 to form ''European Journal of Inorganic Chemistry''. History Founded in 1868 as ''Berichte der Deutschen Chemischen Gesellschaft'' (, CODEN BDCGAS), it operated under this title until 1928 (Vol. 61). The journal was then split into: * ''Berichte der Deutschen Chemischen Gesellschaft, A: Vereins-Nachrichten'' (, CODEN BDCAAS), and * ''Berichte der Deutschen Chemischen Gesellschaft, B: Abhandlungen'' (, CODEN BDCBAD). Vol. 78 and 79 (1945–1946) were omitted and not published due to World War II. The journal was renamed ''Chemische Berichte'' (, CODEN CHBEAM) in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the ''Journal Citation Reports'', the journal had a 2021 impact factor of 16.823. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'' ( (print), (online)), and a fully English-language edition, ''Angewandte Chemie International Edition'' ( (print), (online)). The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Business model ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroimidazol-2-ylidene
Dihydroimidazol-2-ylidene is a hypothetical organic compound with formula C3H6N2. It would be a heterocyclic compound, formally derived from imidazolidine with two hydrogen atoms removed from carbon number 2, leaving two vacant chemical bonds — which makes it a carbene. Although carbenes in general are extremely short-lived, some derivatives of this compound are surprisingly stable, and form an important class of the persistent carbenes. They include the first stable carbenes postulated (but not isolated) by Hans-Werner Wanzlick around 1960. They also include an example of the (saturated) imidazolin-2-ylidene (carbene In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms. The term "carbene" ma ...) reported by A.J. Arduengo in 1995. References Carbenes Imidazolines Hypothetical chemical compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wanzlick Equilibrium
The Wanzlick equilibrium is a chemical equilibrium between a relatively stable carbene compound and its dimer. The equilibrium was proposed to apply to certain electron-rich alkenes, such as tetraminoethylenes, which have been called "carbene dimers." Such equilibria occur, but the mechanism does not proceed simply, but requires catalysts. Original conjecture In 1960, Hans-Werner Wanzlick and E. Schikora proposed that carbenes derived from dihydroimidazol-2-ylidene were generated by vacuum pyrolysis of 2-trichloromethyl dihydroimidazole derivatives, with the loss of chloroform. Wanzlick and Schikora believed that once prepared these carbenes existed in an unfavourable equilibrium with their corresponding dimers. This assertion was based on reactivity studies which they believed showed that the free carbene reacted with electrophiles (E-X). The dimer (a substituted tetraaminoethylene) was believed to be inactive to the electrophiles (E-X), and thought to merely act as a stable c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
