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Olympiadane
Olympiadane is a mechanically interlocked molecule composed of five interlocking macrocycles that resembles the Olympic rings. The molecule is a linear pentacatenane or a atenane. It was synthesized and named by Fraser Stoddart Sir James Fraser Stoddart, (24 May 1942 – 30 December 2024) was a British-American chemist who was Chair Professor in Chemistry at the University of Hong Kong. He was the Board of Trustees Professor of Chemistry and head of the Stoddart ... and coworkers in 1994. The molecule was designed without any practical use in mind, although other catenanes may have possible application to the construction of a molecular computer. See also * Olympicene References {{heterocyclic-stub Molecular topology Hexafluorophosphates Supramolecular chemistry Pyridinium compounds Substances discovered in the 1990s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanically Interlocked Molecular Architectures
In chemistry, mechanically interlocked molecular architectures (MIMAs) are molecules that are connected as a consequence of their topology. This connection of molecules is analogous to keys on a keychain loop. The keys are not directly connected to the keychain loop but they cannot be separated without breaking the loop. On the molecular level, the interlocked molecules cannot be separated without the breaking of the covalent bonds that comprise the conjoined molecules; this is referred to as a mechanical bond. Examples of mechanically interlocked molecular architectures include catenanes, rotaxanes, molecular knots, and molecular Borromean rings. Work in this area was recognized with the 2016 Nobel Prize in Chemistry to Bernard L. Feringa, Jean-Pierre Sauvage, and J. Fraser Stoddart. The synthesis of such entangled architectures has been made efficient by combining supramolecular chemistry with traditional covalent synthesis, however mechanically interlocked molecular archite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympic Symbols
The International Olympic Committee (IOC) uses icons, flags, and symbols to represent and enhance the Olympic Games. These symbols include those commonly used during Olympic competitions such as the flame, fanfare, and theme as well as those used both during and outside competition, such as the Olympic flag. The Olympic flag was created in 1913 under the guidance of Pierre de Coubertin, Baron de Coubertin of France. It was first hoisted in Alexandria, Egypt in Old Shatby Stadium which is now located in Al Ittihad Alexandria Club , at the 1914 Pan-Egyptian Games. The five rings on the flag represent the inhabited continents of the world (the Americas were considered as one continent and Europe was treated as distinct from Asia). It contains the colours blue, black, red, yellow, and green, which are common on national flags globally. Motto and creed The original Olympic motto is the hendiatris "" which is Latin for "Faster, Higher, Stronger". The motto was proposed by Pierre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catenane
In macromolecular chemistry, a catenane () is a mechanically interlocked molecular architecture consisting of two or more interlocked macrocycles, i.e. a molecule containing two or more intertwined rings. The interlocked rings cannot be separated without breaking the covalent bonds of the macrocycles. They are conceptually related to other mechanically interlocked molecular architectures, such as rotaxanes, molecular knots or molecular Borromean rings. Recently the terminology " mechanical bond" has been coined that describes the connection between the macrocycles of a catenane. Catenanes have been synthesised in two different ways: statistical synthesis and template-directed synthesis. Synthesis There are two primary approaches to the organic synthesis of catenanes. The first is to simply perform a ring-closing reaction with the hope that some of the rings will form around other rings giving the desired catenane product. This so-called "statistical approach" led to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympicene
Olympicene is an organic carbon-based molecule formed of five rings, of which four are benzene rings, joined in the shape of the Olympic rings. The molecule was conceived in March 2010 as a way to celebrate the 2012 London Olympics by Graham Richards of University of Oxford and Antony Williams. It was first synthesized by researchers Anish Mistry and David Fox of the University of Warwick in the UK. Relative energies of olympicene and its isomers were first predicted from quantum electronic-structure computations by Andrew Valentine and David Mazziotti of the University of Chicago. Electron counting Olympicene has 18 pi electrons in its ring system; as it is a flat molecule, this makes it an aromatic molecule. The central ring is not an aromatic ring. Related compounds A very similar molecule ( benzo 'c''henanthrene) which lacks the −CH2− spacer between the two sides of the molecule has been known for many years. This earlier molecule has been studied by X-ray crystallog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraser Stoddart
Sir James Fraser Stoddart, (24 May 1942 – 30 December 2024) was a British-American chemist who was Chair Professor in Chemistry at the University of Hong Kong. He was the Board of Trustees Professor of Chemistry and head of the Stoddart Mechanostereochemistry Group in the Department of Chemistry at Northwestern University in the United States. He worked in the area of supramolecular chemistry and nanotechnology. Stoddart developed highly efficient syntheses of mechanically-interlocked molecular architectures such as molecular Borromean rings, catenanes and rotaxanes utilising molecular recognition and molecular self-assembly processes. He demonstrated that these topologies can be employed as molecular switches. His group has even applied these structures in the fabrication of nanoelectronic devices and nanoelectromechanical systems (NEMS). His efforts were recognized by numerous awards, including the 2007 King Faisal International Prize in Science. He shared the Nobel P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie International Edition In English
''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 2023 impact factor of 16.1. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'', and a fully English-language edition, ''Angewandte Chemie International Edition''. The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Publication history In 1887, Ferdinand Fischer established the ''Zei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of the longest-running newspapers in the United States, the ''Times'' serves as one of the country's Newspaper of record, newspapers of record. , ''The New York Times'' had 9.13 million total and 8.83 million online subscribers, both by significant margins the List of newspapers in the United States, highest numbers for any newspaper in the United States; the total also included 296,330 print subscribers, making the ''Times'' the second-largest newspaper by print circulation in the United States, following ''The Wall Street Journal'', also based in New York City. ''The New York Times'' is published by the New York Times Company; since 1896, the company has been chaired by the Ochs-Sulzberger family, whose current chairman and the paper's publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Computer
DNA computing is an emerging branch of unconventional computing which uses DNA, biochemistry, and molecular biology hardware, instead of the traditional electronic computing. Research and development in this area concerns theory, experiments, and applications of DNA computing. Although the field originally started with the demonstration of a computing application by Len Adleman in 1994, it has now been expanded to several other avenues such as the development of storage technologies, nanoscale imaging modalities, synthetic controllers and reaction networks, etc. History Leonard Adleman of the University of Southern California initially developed this field in 1994. — The first DNA computing paper. Describes a solution for the directed Hamiltonian path problem. Also available here: Adleman demonstrated a proof-of-concept use of DNA as a form of computation which solved the seven-point Hamiltonian path problem. Since the initial Adleman experiments, advances have occurred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Topology
A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supramolecular Chemistry
Supramolecular chemistry refers to the branch of chemistry concerning Chemical species, chemical systems composed of a integer, discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from weak intermolecular forces, electrostatics, electrostatic charge, or hydrogen bonding to strong covalent bonding, provided that the electronic coupling strength remains small relative to the energy parameters of the component. While traditional chemistry concentrates on the covalent bond, supramolecular chemistry examines the weaker and reversible non-covalent interactions between molecules. These forces include hydrogen bonding, coordination complex, metal coordination, hydrophobic effect, hydrophobic forces, van der Waals forces, pi–pi interactions and electrostatic effects. Important concepts advanced by supramolecular chemistry include molecular self-assembly, folding (chemistry), molecular folding, molecular recognition, host–gues ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridinium Compounds
Pyridinium refers to the cation . It is the conjugate acid of pyridine. Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines. They are prepared by treating pyridine with acids. As pyridine is often used as an organic base in chemical reactions, pyridinium salts are produced in many acid-base reactions. Its Salt (chemistry), salts are often insoluble in the organic solvent, so Precipitation (chemistry), precipitation of the pyridinium leaving group complex is an indication of the progress of the reaction. Pyridinium cations are aromatic, as determined through Hückel's rule. They are isoelectronic with benzene. ''N''-Alkylpyridinium cations When the acidic proton is replaced by alkyl, the compounds are called ''N''-alkylpyridinium. A simple representative is Methylpyridinium, ''N''-methylpyridinium (). These pyridinium intermediates have been used as electrophiles in synthetic organic chemistry to build dearomatized congeners calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
