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Aromatic 8. What are chromophores?
Aromatic 8. What are chromophores?
Published: 2016/02/06
Channel: FranklyChemistry
What is CHROMOPHORE? What does CHROMOPHORE mean? CHROMOPHORE meaning, definition & explanation
What is CHROMOPHORE? What does CHROMOPHORE mean? CHROMOPHORE meaning, definition & explanation
Published: 2017/01/28
Channel: The Audiopedia
Chromophore Meaning
Chromophore Meaning
Published: 2015/04/25
Channel: ADictionary
Chromophore, Chromophore Definition, Explanation of Chromophores
Chromophore, Chromophore Definition, Explanation of Chromophores
Published: 2012/11/19
Channel: vedupro
Chromophore: The Two Brothers Director
Chromophore: The Two Brothers Director's Cut - Trailer - E3 2014
Published: 2014/06/10
Channel: GameSpot Trailers
The Chromophore Concept
The Chromophore Concept
Published: 2016/12/04
Channel: Learn With Anoo
spectroscopy:  chromophores and UV-vis Spectra
spectroscopy: chromophores and UV-vis Spectra
Published: 2017/01/19
Channel: Patricia Mabrouk
Conjugation and color | Spectroscopy | Organic chemistry | Khan Academy
Conjugation and color | Spectroscopy | Organic chemistry | Khan Academy
Published: 2014/07/15
Channel: Khan Academy Organic Chemistry
Pigments and Chromophores in Nature (3.7)
Pigments and Chromophores in Nature (3.7)
Published: 2010/01/21
Channel: jeffrey Moore
Chromophore-Chromophore Interactions (3.5)
Chromophore-Chromophore Interactions (3.5)
Published: 2010/01/20
Channel: jeffrey Moore
CGI Animated Audio-Visual Performance HD: "Chromophore" by - Paul Prudence
CGI Animated Audio-Visual Performance HD: "Chromophore" by - Paul Prudence
Published: 2013/07/17
Channel: The CGBros
Chromophore
Chromophore
Published: 2016/08/31
Channel: WikiWikiup
Chromophore, Chromophore Definition, Explanation of Chromophores
Chromophore, Chromophore Definition, Explanation of Chromophores
Published: 2016/07/20
Channel: IncTutorial Education
Farbstoffchemie - Grundlagen der Farbigkeit
Farbstoffchemie - Grundlagen der Farbigkeit
Published: 2012/05/14
Channel: spnConnection
CGI Animated Audio Visual Performance HD   Chromophore  by   Paul Prudence
CGI Animated Audio Visual Performance HD Chromophore by Paul Prudence
Published: 2014/01/05
Channel: MorePreviews
Spectra of Isolated Chromophores and Auxochromes
Spectra of Isolated Chromophores and Auxochromes
Published: 2016/10/01
Channel: TeachGlobal
chromophore and auxochrome determination
chromophore and auxochrome determination
Published: 2015/08/17
Channel: Newspirit 60
Video# 3 of 7 Chromophore what Exciting new experiments!
Video# 3 of 7 Chromophore what Exciting new experiments!
Published: 2016/03/12
Channel: Akina Bekasi
Chemistry of Colors
Chemistry of Colors
Published: 2012/11/09
Channel: Khedronium
Spectroscopie UV visible : les molécules colorées - Physique-Chimie - Terminale S - digiSchool
Spectroscopie UV visible : les molécules colorées - Physique-Chimie - Terminale S - digiSchool
Published: 2014/06/13
Channel: digiSchool
(38 of 50)  CARBONYL CHROMOPHORE - SYMMETRY SELECTION RULES  FOR  ELECTRONIC SPECTRUM
(38 of 50) CARBONYL CHROMOPHORE - SYMMETRY SELECTION RULES FOR ELECTRONIC SPECTRUM
Published: 2015/07/04
Channel: Chitra Thomas
Talk at Naimies Chromophores
Talk at Naimies Chromophores
Published: 2016/05/04
Channel: Ask Aliesh
Protein Methods 2010 - Dilutions with Chromophores (no audio)
Protein Methods 2010 - Dilutions with Chromophores (no audio)
Published: 2010/08/24
Channel: ProteinMethodsMSU
EGFP chromophore and local H-bond environment
EGFP chromophore and local H-bond environment
Published: 2014/09/19
Channel: Dafydd JOnes
Auxochromes, Auxochromes Definition
Auxochromes, Auxochromes Definition
Published: 2012/11/17
Channel: vedupro
Two Brothers Official Trailer No.2
Two Brothers Official Trailer No.2
Published: 2013/04/03
Channel: Ackk Studios
Chromophore
Chromophore
Published: 2014/04/27
Channel: Kropn
Chromophore: Color Blind Aid System DEMO
Chromophore: Color Blind Aid System DEMO
Published: 2011/07/01
Channel: Burhan Adi Wicaksana
Chromophore Electro Plurality
Chromophore Electro Plurality
Published: 2012/03/26
Channel: JeffreyPlaide
Molecular Chromophores for Next-Generation Solar Photon Harvesting, Andrew Ferguson - O+P 2013
Molecular Chromophores for Next-Generation Solar Photon Harvesting, Andrew Ferguson - O+P 2013
Published: 2013/09/06
Channel: SPIETV
YFP (Yellow Fluorescent Protein)  chromophore
YFP (Yellow Fluorescent Protein) chromophore
Published: 2014/09/19
Channel: Dafydd JOnes
Happy Chromophore in Bacteriorhodopsin
Happy Chromophore in Bacteriorhodopsin
Published: 2011/05/22
Channel: Emad Tajkhorshid
Photorelaxation of πσ∗ states in chromophore water clusters
Photorelaxation of πσ∗ states in chromophore water clusters
Published: 2015/04/01
Channel: Rafał Szabla
UV-induced Water-chromophore Electron Transfer in Cytosine and Cytidine
UV-induced Water-chromophore Electron Transfer in Cytosine and Cytidine
Published: 2017/06/21
Channel: Rafał Szabla
Andrea Chidichimo - Daouda - Frequencies - chromophore productions
Andrea Chidichimo - Daouda - Frequencies - chromophore productions
Published: 2015/09/01
Channel: chromophore
CHROMOPHORE
CHROMOPHORE
Published: 2014/02/02
Channel: Aliona MICHEL
How to Pronounce Chromophore
How to Pronounce Chromophore
Published: 2014/02/01
Channel: Emma Saying
CHROMOPHORE
CHROMOPHORE
Published: 2011/01/28
Channel: TheGuido2727
How to say "chromophore"! (High Quality Voices)
How to say "chromophore"! (High Quality Voices)
Published: 2017/01/29
Channel: WordBox
NCW 2015 and Organic chromophores, by Dr. Chris Mullins
NCW 2015 and Organic chromophores, by Dr. Chris Mullins
Published: 2015/10/14
Channel: Chris Mullins
How to say "chromophores"! (High Quality Voices)
How to say "chromophores"! (High Quality Voices)
Published: 2017/02/08
Channel: WordBox
What is an AUXOCHROME?
What is an AUXOCHROME?
Published: 2016/12/05
Channel: Learn With Anoo
How to Pronounce Chromophore
How to Pronounce Chromophore
Published: 2015/03/02
Channel: Pronunciation Guide
S.  Moreira - Clean or High [SL006]
S. Moreira - Clean or High [SL006]
Published: 2016/05/27
Channel: CMYK
Bryan Clark: Chromophore
Bryan Clark: Chromophore
Published: 2015/07/24
Channel: Bryan Clark
Chromophore.in new arrives for diwali fest
Chromophore.in new arrives for diwali fest
Published: 2016/10/31
Channel: Nilesh Hande
Somatic Responses - Chromophore (Land Speed Record)
Somatic Responses - Chromophore (Land Speed Record)
Published: 2017/04/04
Channel: Low Entropy
Learn how to say this word: "Chromophore"
Learn how to say this word: "Chromophore"
Published: 2017/02/09
Channel: The Butler Says
20. Electronic and Vibrational Spectroscopy
20. Electronic and Vibrational Spectroscopy
Published: 2012/04/05
Channel: YaleCourses
Woodward–Fieser rules-Part-3
Woodward–Fieser rules-Part-3
Published: 2015/06/16
Channel: PharmaToppers
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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A chromophore is the part of a molecule responsible for its color.[1] The color that is seen by our eyes is the one not absorbed within a certain wavelength spectrum of visible light. The chromophore is a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum. Visible light that hits the chromophore can thus be absorbed by exciting an electron from its ground state into an excited state.

In biological molecules that serve to capture or detect light energy, the chromophore is the moiety that causes a conformational change of the molecule when hit by light.

Chemical structure of beta-carotene. The eleven conjugated double bonds that form the chromophore of the molecule are highlighted in red.

Conjugated pi-bond system chromophores[edit]

Conjugated chromophore that straightens in response to a photon γ (light), of the correct wavelength: 11-cis-retinal becomes all-trans-retinal

In the conjugated chromophores, the electrons jump between energy levels that are extended pi orbitals, created by a series of alternating single and double bonds, often in aromatic systems. Common examples include retinal (used in the eye to detect light), various food colorings, fabric dyes (azo compounds), pH indicators, lycopene, β-carotene, and anthocyanins. Various factors in a chromophore's structure go into determining at what wavelength region in a spectrum the chromophore will absorb. Lengthening or extending a conjugated system with more unsaturated (multiple) bonds in a molecule will tend to shift absorption to longer wavelengths. Woodward-Fieser rules can be used to approximate ultraviolet-visible maximum absorption wavelength in organic compounds with conjugated pi-bond systems.

Some of these are metal complex chromophores, which contain a metal in a coordination complex with ligands. Examples are chlorophyll, which is used by plants for photosynthesis and hemoglobin, the oxygen transporter in the blood of vertebrate animals. In these two examples, a metal is complexed at the center of a tetrapyrrole macrocycle ring: the metal being iron in the heme group (iron in a porphyrin ring) of hemoglobin, or magnesium complexed in a chlorin-type ring in the case of chlorophyll. The highly conjugated pi-bonding system of the macrocycle ring absorbs visible light. The nature of the central metal can also influence the absorption spectrum of the metal-macrocycle complex or properties such as excited state lifetime.[2][3][4] The tetrapyrrole moiety in organic compounds which is not macrocyclic but still has a conjugated pi-bond system still acts as a chromophore. Examples of such compounds include bilirubin and urobilin, which exhibit a yellow color.

Auxochrome[edit]

An auxochrome is a functional group of atoms attached to the chromophore which modifies the ability of the chromophore to absorb light, altering the wavelength or intensity of the absorption.

Halochromism in chromophores[edit]

Halochromism occurs when a substance changes color as the pH changes. This is a property of pH indicators, whose molecular structure changes upon certain changes in the surrounding pH. This change in structure affects a chromophore in the pH indicator molecule. For example, phenolphthalein is a pH indicator whose structure changes as pH changes as shown in the following table:

Structure Phenolphthalein-low-pH-2D-skeletal.svg Phenolphthalein-mid-pH-2D-skeletal.svg
pH 0-8.2 8.2-12
Conditions acidic or near-neutral basic
Color name colorless pink to fuchsia
Color

In a pH range of about 0-8, the molecule has three aromatic rings all bonded to a tetrahedral sp3 hybridized carbon atom in the middle which does not make the π-bonding in the aromatic rings conjugate. Because of their limited extent, the aromatic rings only absorb light in the ultraviolet region, and so the compound appears colorless in the 0-8 pH range. However, as the pH increases beyond 8.2, that central carbon becomes part of a double bond becoming sp2 hybridized and leaving a p orbital to overlap with the π-bonding in the rings. This makes the three rings conjugate together to form an extended chromophore absorbing longer wavelength visible light to show a fuchsia color.[5] At pH ranges outside 0-12, other molecular structure changes result in other color changes; see Phenolphthalein for details.

See also[edit]

References[edit]

  1. ^ IUPAC Gold Book Chromophore
  2. ^ Gouterman, M. (1978) Optical spectra and electronic structure of porphyrins and related rings. In Dolphin, D. (ed.) The porphyrins. Academic Press, New York. Volume III, Part A, pp 1-165
  3. ^ Scheer, H. (2006) An overview of chlorophylls and bacteriochlorophylls: biochemistry, biophysics, functions and applications. Advances in Photosynthesis and Respiration, vol 25, pp 1-26
  4. ^ Shapley, P. (2012) Absorbing light with organic molecules. http://butane.chem.uiuc.edu/pshapley/GenChem2/B2/1.html
  5. ^ UV-Visible Absorption Spectra

External links[edit]

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