System of connected p-orbitals with delocalized electrons in a molecule
Cinnamaldehyde is a naturally-occurring compound that has a conjugated systempenta-1,3-diene is a molecule with a conjugated systemDiazomethane conjugated pi-system
In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability. It is conventionally represented as having alternating single and multiple bonds. Lone pairs, radicals or carbenium ions may be part of the system, which may be cyclic, acyclic, linear or mixed. The term "conjugated" was coined in 1899 by the German chemist Johannes Thiele.[1]
Conjugation is the overlap of one p-orbital with another across an adjacent σ bond (in transition metals, d-orbitals can be involved).[2][a]
A conjugated system has a region of overlapping p-orbitals, bridging the interjacent locations that simple diagrams illustrate as not having a π bond. They allow a delocalization of π electrons across all the adjacent aligned p-orbitals.[3]
The π electrons do not belong to a single bond or atom, but rather to a group of atoms.
Molecules containing conjugated systems of orbitals and electrons are called conjugated molecules, which have overlapping p orbitals on three or more atoms. Some simple organic conjugated molecules are 1,3-butadiene, benzene, and allylic carbocations.[4] The largest conjugated systems are found in graphene, graphite, conductive polymers and carbon nanotubes.
^Thiele, Johannes (1899). "Zur Kenntnis der ungesättigten Verbindungen" [[Contribution] to our knowledge of unsaturated compounds]. Justus Liebig's Annalen der Chemie (in German). 306: 87–142. doi:10.1002/jlac.18993060107. On p. 90, Thiele coined the term "conjugated": "Ein solches System benachbarter Doppelbindungen mit ausgeglichenen inneren Partialvalenzen sei als 'conjugirt' bezeichnet." (Such a system of adjacent double bonds with equalized inner partial valences shall be termed "conjugated".)
^IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "conjugated system (conjugation)". doi:10.1351/goldbook.C01267
^March, Jerry (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, Inc. ISBN 0-471-85472-7.
^"16 Conjugation, Resonance, and Dienes". Organic Chemistry(PDF) (3rd ed.). Belonia, South Tripura, India: Iswar Chandra Vidyasagar College. Retrieved 19 April 2022.
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).
to a group of atoms. Molecules containing conjugatedsystems of orbitals and electrons are called conjugated molecules, which have overlapping p orbitals...
yellow light and more likely to absorb red light. ("Conjugatedsystems of fewer than eight conjugated double bonds absorb only in the ultraviolet region...
complete conjugated π-electron system within the ring. The molecule must have 4n π-electrons where n is any integer within the conjugated π-system. This...
beneficial effects on human health. CLA is conjugated, and in the United States, trans linkages in a conjugatedsystem are not counted as trans fats for the...
Mesomeric effect can be transmitted along any number of carbon atoms in a conjugatedsystem. This accounts for the resonance stabilization of the molecule due...
molecule Conjugate (acid-base theory), a system describing a conjugate acid-base pair Conjugatedsystem, a system of atoms covalently bonded with alternating...
least one lone pair of electrons which can be viewed as extending the conjugatedsystem by resonance. It increases the colour of any organic compound. For...
part of a macromolecular chain containing two positive charges in a conjugatedsystem. In physics, a bipolaron is a bound pair of two polarons. An electron...
structure is often described as aromatic. One result of the large conjugatedsystem is that porphyrins typically absorb strongly in the visible region...
generally dynamical systems, since, if the dynamics of one iterative function can be determined, then that for a topologically conjugate function follows...
(i.e., are conjugated). Electron delocalization enables the EWG to receive electron density through participation of the conjugatedsystem. A classic...
Indigo The spiro form of an oxazine is a colorless leuco dye; the conjugatedsystem of the oxazine and another aromatic part of the molecule is separated...
meningococcal vaccine), both of which are conjugated to protein carriers like those used in the Hib conjugate vaccine. Both Streptococcus pneumoniae and...
In mathematics, the conjugate gradient method is an algorithm for the numerical solution of particular systems of linear equations, namely those whose...
Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is...
electromagnetic spectrum from near IR to UV. Chemically, cyanines are a conjugatedsystem between two nitrogen atoms; in each resonance structure, exactly one...
prior. One can think of conditioning on conjugate priors as defining a kind of (discrete time) dynamical system: from a given set of hyperparameters, incoming...
A chromoprotein is a conjugated protein that contains a pigmented prosthetic group (or cofactor). A common example is haemoglobin, which contains a heme...
a Lewis conjugate may refer to: The conjugate acid of a Lewis base or the conjugate base of a Lewis acid A molecule having a conjugatedsystem of bonds...
in addition to amino acids and they are called conjugated proteins. The non-amino part of a conjugated protein is usually called its prosthetic group...
(Woodward-Hoffmann symbol ω), a conjugatedsystem (π) or even a sigma bond (σ). The relationship is antarafacial when opposite faces of the π system or isolated orbital...
chemical phenomenon. Phototoxins are molecules with a conjugatedsystem, often an aromatic system. They have a low-lying excited state that can be reached...
example, the spiro form of an oxazine is a colorless leuco dye; the conjugatedsystem of the oxazine and another aromatic part of the molecule is separated...
this state, bilirubin is soluble in water and it is called conjugated bilirubin. Conjugated bilirubin is excreted into the bile ducts and enters the duodenum...
objects that are not in proximity Conjugatedsystem (or nonlocalized bond), in chemistry, a conjugatedsystem is a system of connected p-orbitals with delocalized...
conjugated double bonds. A polyene antifungal is a macrocyclic polyene with a heavily hydroxylated region on the ring opposite the conjugatedsystem....
Kistiakowsky, a conjugative contribution of 3.5 kcal/mol was found based on the energetic comparison of hydrogenation between conjugated species and unconjugated...
different fields: In organic chemistry, it refers to resonance in conjugatedsystems and aromatic compounds. In solid-state physics, it refers to free...
Global Information
