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Paddlane
In organic chemistry, paddlane is any member of a class of polycyclic compound, tricyclic alkane, saturated hydrocarbons having two bridgehead carbon atoms joined by four bridge (chemical), bridges. The name derives from a supposed resemblance of the molecule to a paddle wheel: namely, the rings would be the propeller's blades, and the shared carbon atoms would be its axis. Systematically named tricyclo [''m''.''n''.''o''.''p''1,''m''+2]alkanes, these compounds have been referred to as [''m''.''n''.''o''.''p'']paddlanes. The notation [''m''.''n''.''o''.''p'']paddlane means the member of the family whose rings have ''m'', ''n'', ''o'', and ''p'' carbons, not counting the two bridgeheads; or ''m'' + 2, ''n'' + 2, ''o'' + 2, and ''p'' + 2 carbons, counting them. The chemical formula is therefore C2+''m''+''n''+''o''+''p''H2(''m''+''n''+''o''+''p''). When ''p'' = 0, the compounds are propellanes. Compounds The best known paddlane i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverted Tetrahedral Geometry
In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1(−) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane () as well as its heavier analogues. Methane and other perfectly symmetrical tetrahedral molecules belong to point group Td, but most tetrahedral molecules have lower symmetry. Tetrahedral molecules can be chiral. Tetrahedral bond angle The bond angle for a symmetric tetrahedral molecule such as CH4 may be calculated using the dot product of two vectors. As shown in the diagram, the molecule can be inscribed in a cube with the tetravalent atom (e.g. carbon) at the cube centre which is the origin of coordinates, O. The four monovalent atoms (e.g. hydrogens) are at four corners of the cube (A, B, C, D) chosen so that no two atoms are at adjacent corners linked by only one cube edge. If the edge length of the cube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Paddlane
A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". OED Online. March 2021. Oxford University Press. https://www.oed.com/view/Entry/77489?rskey=dCKrg4&result=1 (accessed May 11, 2021) The term ''general'' is used in two ways: as the generic title for all grades of general officer and as a specific rank. It originates in the 16th century, as a shortening of ''captain general'', which rank was taken from Middle French ''capitaine général''. The adjective ''general'' had been affixed to officer designations since the late medieval period to indicate relative superiority or an extended jurisdiction. Today, the title of ''general'' is known in some countries as a four-star rank. However, different countries use different systems of stars or other insignia for senior ranks. It has a NATO rank s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes Physical property, physical and Chemical property, chemical properties, and evaluation of Reactivity (chemistry), chemical reactivity to understand their behavior. The study of organic reactions includes the organic synthesis, chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Compound
In the field of organic chemistry, a polycyclic compound is an organic compound featuring several closed rings of atoms, primarily carbon. These ring substructures include cycloalkanes, aromatics, and other ring types. They come in sizes of three atoms and upward, and in combinations of linkages that include tethering (such as in biaryls), fusing (edge-to-edge, such as in anthracene and steroids), links via a single atom (such as in spiro compounds), bridged compounds, and longifolene. Though poly- literally means "many", there is some latitude in determining how many rings are required to be considered polycyclic; many smaller rings are described by specific prefixes (e.g., bicyclic, tricyclic, tetracyclic, etc.), and so while it can refer to these, the title term is used with most specificity when these alternative names and prefixes are unavailable. In general, the term polycyclic includes polycyclic aromatic compounds, including polycyclic aromatic hydrocarbons, as well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkane
In organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clay ..., an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula . The alkanes range in complexity from the simplest case of methane (), where ''n'' = 1 (sometimes called the parent molecule), to arbitrarily large and complex molecules, like Higher alkanes#Nonatetracontane to tetrapentacontane, pentacontane () or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an isomer of tetradecane (). The International Union of Pure and Applied Chemistry (IUPAC) defines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge (chemical)
In chemistry, a bicyclic molecule () is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic (all of the ring atoms are carbons), or heterocyclic (the rings' atoms consist of at least two elements), like DABCO. Moreover, the two rings can both be aliphatic (''e.g.'' decalin and norbornane), or can be aromatic (''e.g.'' naphthalene), or a combination of aliphatic and aromatic (''e.g.'' tetralin). Three modes of ring junction are possible for a bicyclic compound: * In spirocyclic compounds, the two rings share only one single atom, the spiro atom, which is usually a quaternary carbon. An example of a spirocyclic compound is the photochromic switch spiropyran. * In fused/condensed bicyclic compounds, two rings share two adjacent atoms. In other words, the rings share one covalent bond, ''i.e.'' the so-called bridgehead atoms are direc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paddle Wheel
A paddle wheel is a form of waterwheel or impeller in which a number of paddles are set around the periphery of the wheel. It has several uses, of which some are: * Very low-lift water pumping, such as flooding paddy fields at no more than about height above the water source. * To move and mix algae culture in the raceway ponds used for algaculture. * Propulsion of watercraft (as a paddlewheel) * Low head hydro power (as a waterwheel) * Flow sensors * Aerators The paddle wheel is an ancient invention but is still used today in a wide range of industrial and agriculture applications. Ship propulsion Paddle wheels would enable ships to travel without needing wind or oars. They were made obsolete by propellers, which had greater propulsion with lower weight and fuel usage. This was demonstrated by an 1845 tug-of-war competition between and with the screw-driven ''Rattler'' pulling the paddle steamer ''Alecto'' backward at . [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propellane
In organic chemistry, propellane is any member of a class of polycyclic hydrocarbons, whose carbon skeleton consists of three rings of carbon atoms sharing a common carbon–carbon covalent bond. The concept was introduced in 1966 by D. Ginsburg Propellanes with small cycles are highly strained and unstable, and are easily turned into polymers with interesting structures, such as staffanes. Partly for these reasons, they have been the object of much research. Nomenclature The name derives from a supposed resemblance of the molecule to a propeller: namely, the rings would be the propeller's blades, and the shared C–C bond would be its axis. The bond shared by the three cycles is usually called the "bridge"; the shared carbon atoms are then the "bridgeheads". The IUPAC nomenclature of the homologue series of all-carbon propellanes would be called tricyclo .y.z.01,(x+2)lkane. More common in literature is the notation means the member of the family whose rings have ''x'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platonic Hydrocarbon
In organic chemistry, a Platonic hydrocarbon is a hydrocarbon (molecule) whose structure matches one of the five Platonic solids, with carbon atoms replacing its vertices, carbon–carbon bonds replacing its edges, and hydrogen atoms as needed. Not all Platonic solids have molecular hydrocarbon counterparts; those that do are the tetrahedron (tetrahedrane), the cube ( cubane), and the dodecahedron (dodecahedrane). Tetrahedrane Tetrahedrane (C4H4) is a hypothetical compound. It has not yet been synthesized without substituents, but it is predicted to be kinetically stable in spite of its angle strain. Some stable derivatives, including tetra( ''tert''-butyl)tetrahedrane (a hydrocarbon) and tetra(trimethylsilyl)tetrahedrane, have been produced. Cubane Cubane (C8H8) has been synthesized. Although it has high angle strain, cubane is kinetically stable, due to a lack of readily available decomposition paths. Octahedrane Angle strain would make an octahedron highly unstable due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philip Eaton
Philip E. Eaton (born 1936) is a Professor Emeritus of Chemistry at the University of Chicago. He and his fellow researchers were the first to synthesize the "impossible" cubane molecule in 1964.P. Eaton and T. W. Cole, The Cubane System, J. Am. Chem. Soc., 86 (1964) 962.doi:10.1021/ja01059a072/ref>P. Eaton and T. W. Cole, Cubane, J. Am. Chem. Soc., 86 (1964) 3157doi:10.1021/ja01069a041/ref> Working with Mao-Xi Zhang he is reported as having been the first to make octanitrocubane (their paper was published in the year 2003) Because of its eight nitro groups and highly strained C-C bonds - octanitrocubane is a very powerful high explosive. Early years Philip E. Eaton was born in 1936 in Brooklyn, New York. When Eaton was seven his family relocated to Budd Lake, New Jersey. Here he began attending Roxbury Grammar School and later Roxbury High School. It was during these high school years that he began to find his passion for science. It was the support of his parents and teache ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubane
Cubane () is a synthetic hydrocarbon compound that consists of eight carbon atoms arranged at the corners of a Cube (geometry), cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane is one of the Platonic hydrocarbons and a member of the prismanes. It was first synthesized in 1964 by Philip Eaton and Thomas Cole. Before this work, Eaton believed that cubane would be impossible to synthesize due to the "required 90 degree molecular geometry, bond angles". The cubic shape requires the carbon atoms to adopt an unusually sharp 90° bonding angle, which would be highly strain (chemistry), strained as compared to the 109.45° angle of a tetrahedral geometry, tetrahedral carbon. Once formed, cubane is quite kinetic stability, kinetically stable, due to a lack of readily available decomposition paths. It is the simplest hydrocarbon with octahedral symmetry. Having high potential energy but kinetic stability makes cubane and its derivative compoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
