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Hückel's rule can also be applied to molecules containing other atoms such as nitrogen or oxygen. For example, pyridine (C 5 H 5 N) has a ring structure similar to benzene, except that one -CH- group is replaced by a nitrogen atom with no hydrogen. There are still six π electrons and the pyridine molecule is also aromatic and known for its ...
The model for benzene consists of two resonance forms, which corresponds to the double and single bonds superimposing to produce six one-and-a-half bonds. Benzene is a more stable molecule than would be expected without accounting for charge delocalization. [citation needed]
A common method for expanding a ring involves opening cyclopropane-containing bicyclic intermediate. The strategy can start with a Simmons-Smith-like cyclopropanation of a cyclic alkene. [8] A related cyclopropane-based ring expansion is the Buchner ring expansion. The Buchner ring expansion is used to convert arenes to cycloheptatrienes. The ...
A diagram of an aromatic ring current. B 0 is the applied magnetic field, the red arrow indicating its direction. The orange ring shows the direction of the ring current, and the purple rings show the direction of the induced magnetic field. An aromatic ring current is an effect observed in aromatic molecules such as benzene and naphthalene.
Benzoxazines are a group of isomeric bicyclic heterocyclic chemical compounds that consist of a benzene ring fused to an oxazine ring. [1] The different isomers depend on the relative positions of the oxygen and nitrogen atoms in the oxazine ring, on the location of ring fusion, and on the position of the double bond in the oxazine ring. [1]
Benzene ring contractions are the last two mechanisms that have been suggested, and they are currently the preferred mechanisms. These reaction mechanisms proceed through the lowest free energy transition states compared to the diradical and dyotropic mechanisms. The difference between the two ring contractions is minute however, so it has not ...
The following other wikis use this file: Usage on de.wikibooks.org Organische Chemie für Schüler/ Aromatische Kohlenwasserstoffe; Organische Chemie für Schüler/ Druckversion
Its structure is one-atom-thick planar sheets of sp and sp 2-bonded carbon atoms arranged in crystal lattice. It can be seen as a lattice of benzene rings connected by acetylene bonds. The material is called graphyne- n when benzene rings are connected by n sequential acetylene molecules, and graphdiyne for a particular case of n = 2 ...