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Conjugated system

Index Conjugated system

In chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in molecules which are conventionally represented as having alternating single and multiple bonds, which in general may lower the overall energy of the molecule and increase stability. [1]

88 relations: Annulene, Anthocyanidin, Antiaromaticity, Antibonding molecular orbital, Aromaticity, Atom, Atomic orbital, Azo compound, Benzene, Beta-Carotene, Carbenium ion, Carbon nanotube, Carbonyl group, Charge-transfer complex, Chemistry, Chlorin, Chlorophyll, Chlorophyll a, Chromophore, Cobalamin, Cobalt, Conductive polymer, Conformational isomerism, Conjugated microporous polymer, Coordination complex, Corrin, Covalent bond, Cross-conjugation, Cyclic compound, Cyclooctatetraene, Delocalized electron, Diazo, Double bond, Dye, Electromagnetic radiation, Enzyme, Food coloring, Functional group, Furan, Graphene, Graphite, Ground state, Hückel's rule, Heme, Hemoglobin, HOMO/LUMO, Hydrocarbon, Hyperconjugation, Imine, Ion, ..., Iron, IUPAC books, Johannes Thiele (chemist), Ligand, Light, List of conjugated polymers, Lone pair, Lycopene, Macrocycle, Magnesium, Molecular orbital, Nitrogen, Orbital overlap, Organic compound, Oxidation state, Oxygen, Particle in a box, Photochemistry, Photon, Photoreceptor cell, Phthalocyanine, Phthalocyanine Blue BN, Phthalocyanine Green G, Pi bond, Pigment, Polyene, Polymer, Porphyrin, Quantum mechanics, Radical (chemistry), Resonance (chemistry), Selection rule, Sigma bond, Ultraviolet–visible spectroscopy, Vinyl group, Vitamin B12, Wavelength, 1,3-Butadiene. Expand index (38 more) »


Annulenes are completely conjugated monocyclic hydrocarbons.

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Anthocyanidins are common plant pigments.

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Antiaromaticity is a characteristic of a cyclic molecule with a π electron system that has higher energy due to the presence of 4n electrons in it.

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Antibonding molecular orbital

In chemical bonding theory, an antibonding orbital is a type of molecular orbital (MO) that weakens the bond between two atoms and helps to raise the energy of the molecule relative to the separated atoms.

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In organic chemistry, the term aromaticity is used to describe a cyclic (ring-shaped), planar (flat) molecule with a ring of resonance bonds that exhibits more stability than other geometric or connective arrangements with the same set of atoms.

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An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.

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Atomic orbital

In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom.

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Azo compound

Azo compounds are compounds bearing the functional group R−N.

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Benzene is an important organic chemical compound with the chemical formula C6H6.

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β-Carotene is an organic, strongly colored red-orange pigment abundant in plants and fruits.

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Carbenium ion

A carbenium ion is a positive ion with the structure RR′R″C+, that is, a chemical species with a trivalent carbon that bears a +1 formal charge.

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Carbon nanotube

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure.

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Carbonyl group

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C.

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Charge-transfer complex

A charge-transfer complex (CT complex) or electron-donor-acceptor complex is an association of two or more molecules, or of different parts of one large molecule, in which a fraction of electronic charge is transferred between the molecular entities.

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Chemistry is the scientific discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds.

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In organic chemistry, a chlorin is a large heterocyclic aromatic ring consisting, at the core, of three pyrroles and one pyrroline coupled through four CH- linkages.

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Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and the chloroplasts of algae and plants.

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Chlorophyll a

Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. It also reflects green-yellow light, and as such contributes to the observed green color of most plants. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria and prochlorophytes because of its role as primary electron donor in the electron transport chain. Chlorophyll a also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located.

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A chromophore is the part of a molecule responsible for its color.

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Cobalamin (Cbl) is a general term that is referred to a number of compounds, that have cobalt ion in the middle, hence the name of the compound.

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Cobalt is a chemical element with symbol Co and atomic number 27.

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Conductive polymer

Conductive polymers or, more precisely, intrinsically conducting polymers (ICPs) are organic polymers that conduct electricity.

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Conformational isomerism

In chemistry, conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds (refer to figure on single bond rotation).

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Conjugated microporous polymer

Conjugated microporous polymers (CMPs) are a sub-class of porous materials that are related to structures such as zeolites, metal-organic frameworks, and covalent organic frameworks, but are amorphous in nature, rather than crystalline.

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Coordination complex

In chemistry, a coordination complex consists of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents.

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Corrin is a heterocyclic compound.

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Covalent bond

A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.

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Cross-conjugation is a special type of conjugation in a molecule, when in a set of three Pi bonds only two pi-bonds interact with each other by conjugation, the third one is excluded from interaction.

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Cyclic compound

A cyclic compound (ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring.

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1,3,5,7-Cyclooctatetraene (COT) is an unsaturated derivative of cyclooctane, with the formula C8H8.

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Delocalized electron

In chemistry, delocalized electrons are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent bond.

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Diazo refers to a type of organic compound called diazo compound that has two linked nitrogen atoms (azo) as a terminal functional group.

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Double bond

A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two.

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A dye is a colored substance that has an affinity to the substrate to which it is being applied.

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Electromagnetic radiation

In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.

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Enzymes are macromolecular biological catalysts.

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Food coloring

Food coloring, or color additive, is any dye, pigment or substance that imparts color when it is added to food or drink.

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Functional group

In organic chemistry, functional groups are specific substituents or moieties within molecules that are responsible for the characteristic chemical reactions of those molecules.

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Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen.

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Graphene is a semi-metal with a small overlap between the valence and the conduction bands (zero bandgap material).

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Graphite, archaically referred to as plumbago, is a crystalline allotrope of carbon, a semimetal, a native element mineral, and a form of coal.

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Ground state

The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system.

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Hückel's rule

In organic chemistry, Hückel's rule estimates whether a planar ring molecule will have aromatic properties.

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Heme or haem is a coordination complex "consisting of an iron ion coordinated to a porphyrin acting as a tetradentate ligand, and to one or two axial ligands." The definition is loose, and many depictions omit the axial ligands.

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Hemoglobin (American) or haemoglobin (British); abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates (with the exception of the fish family Channichthyidae) as well as the tissues of some invertebrates.

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In chemistry, HOMO and LUMO are types of molecular orbitals.

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In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.

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In organic chemistry, hyperconjugation is the interaction of the electrons in a sigma orbital (e.g. C–H or C–C) with an adjacent empty (or partially filled) non-bonding orbital, antibonding σ or π orbital, to give an extended molecular orbital.

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An imine is a functional group or chemical compound containing a carbon–nitrogen double bond.

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An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).

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Iron is a chemical element with symbol Fe (from ferrum) and atomic number 26.

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IUPAC books

The International Union of Pure and Applied Chemistry publishes many books, which contain its complete list of definitions.

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Johannes Thiele (chemist)

Friedrich Karl Johannes Thiele (May 13, 1865 – April 17, 1918) was a German chemist and a prominent professor at several universities, including those in Munich and Strasbourg.

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In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex.

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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.

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List of conjugated polymers

No description.

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Lone pair

In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atomIUPAC Gold Book definition: and is sometimes called a non-bonding pair.

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Lycopene (from the neo-Latin Lycopersicum, the tomato species) is a bright red carotene and carotenoid pigment and phytochemical found in tomatoes and other red fruits and vegetables, such as red carrots, watermelons, gac, and papayas, but it is not in strawberries or cherries.

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Macrocycles are often described as a molecule containing twelve or more atoms with at least one large ring.

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Magnesium is a chemical element with symbol Mg and atomic number 12.

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Molecular orbital

In chemistry, a molecular orbital (MO) is a mathematical function describing the wave-like behavior of an electron in a molecule.

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Nitrogen is a chemical element with symbol N and atomic number 7.

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Orbital overlap

In chemical bonds, an orbital overlap is the concentration of orbitals on adjacent atoms in the same regions of space.

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Organic compound

In chemistry, an organic compound is generally any chemical compound that contains carbon.

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Oxidation state

The oxidation state, sometimes referred to as oxidation number, describes degree of oxidation (loss of electrons) of an atom in a chemical compound.

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Oxygen is a chemical element with symbol O and atomic number 8.

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Particle in a box

In quantum mechanics, the particle in a box model (also known as the infinite potential well or the infinite square well) describes a particle free to move in a small space surrounded by impenetrable barriers.

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Photochemistry is the branch of chemistry concerned with the chemical effects of light.

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The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).

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Photoreceptor cell

A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction.

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Phthalocyanine (H2Pc) is a large, aromatic, macrocyclic, organic compound with the formula (C8H4N2)4H2 and is of theoretical or specialized interest.

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Phthalocyanine Blue BN

Phthalocyanine Blue BN, also called by many names (EINECS 205-685-1), is a bright, crystalline, synthetic blue pigment from the group of phthalocyanine dyes.

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Phthalocyanine Green G

Phthalocyanine green G, which has many commercial names, is a synthetic green pigment from the group of phthalocyanine dyes, a complex of copper(II) with chlorinated phthalocyanine.

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Pi bond

In chemistry, pi bonds (π bonds) are covalent chemical bonds where two lobes of an orbital on one atom overlap two lobes of an orbital on another atom.

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A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption.

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Polyenes are poly-unsaturated organic compounds that contain at least three alternating double and single carbon–carbon bonds.

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A polymer (Greek poly-, "many" + -mer, "part") is a large molecule, or macromolecule, composed of many repeated subunits.

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Porphyrins (/phɔɹfɚɪn/ ''POUR-fer-in'') are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (.

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Quantum mechanics

Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.

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Radical (chemistry)

In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has an unpaired valence electron.

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Resonance (chemistry)

In chemistry, resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis structure.

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Selection rule

In physics and chemistry, a selection rule, or transition rule, formally constrains the possible transitions of a system from one quantum state to another.

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Sigma bond

In chemistry, sigma bonds (σ bonds) are the strongest type of covalent chemical bond.

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Ultraviolet–visible spectroscopy

Ultraviolet–visible spectroscopy or ultraviolet–visible spectrophotometry (UV–Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region.

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Vinyl group

In chemistry, vinyl or ethenyl is the functional group with the formula −CH.

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Vitamin B12

Vitamin B12, also called cobalamin, is a water-soluble vitamin that is involved in the metabolism of every cell of the human body: it is a cofactor in DNA synthesis, and in both fatty acid and amino acid metabolism.

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In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.

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1,3-Butadiene is the organic compound with the formula (CH2.

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Conjugated double bond, Conjugated double bonds, Conjugated molecule, Conjugated polymer, Conjugated polymers, Conjugation (chemistry), Conjugation (organic chemistry), Delocalized bond, Delocalized bonds, Non-conjugated, Nonlocalized bond.


[1] https://en.wikipedia.org/wiki/Conjugated_system

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