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In chemistry, pyramidal inversion (also umbrella inversion) is a fluxional process in compounds with a pyramidal molecule, such as ammonia (NH 3) "turns inside out". [1] [2] It is a rapid oscillation of the atom and substituents, the molecule or ion passing through a planar transition state. [3]
In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. [1] The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually restricted to small ligands such as pseudohalides or to ligands that are specifically designed to ...
In bridged bicyclic compounds, the two rings share three or more atoms, separating the two bridgehead atoms by a bridge containing at least one atom. For example, norbornane , also known as bicyclo[2.2.1]heptane, can be viewed as a pair of cyclopentane rings each sharing three of their five carbon atoms.
The methylene bridge (methanediyl group) In organic chemistry, a methylene bridge, methylene spacer, or methanediyl group is any part of a molecule with formula −CH 2 −; namely, a carbon atom bound to two hydrogen atoms and connected by single bonds to two other distinct atoms in the rest of the molecule.
A spiro compound, or spirane, from the Latin spīra, meaning a twist or coil, [22] [5]: 1138 [23] is a chemical compound, typically an organic compound, that presents a twisted structure of two or more rings (a ring system), in which 2 or 3 rings are linked together by one common atom, [2]: SP-0
As stated above, a chair flip is a ring inversion specifically of cyclohexane (and its derivatives) from one chair conformer to another, often to reduce steric strain.The term, "flip" is misleading, because the direction of each carbon remains the same; what changes is the orientation.
According to one definition, a turn is a structural motif where the C α atoms of two residues separated by a few (usually 1 to 5) peptide bonds are close (less than 7 Å [0.70 nm]). [1] The proximity of the terminal C α atoms often correlates with formation of an inter main chain hydrogen bond between the corresponding residues.
In chemistry, a disulfide (or disulphide in British English) is a compound containing a R−S−S−R′ functional group or the S 2− 2 anion.The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups.