Play Video
1
Chromophore-Chromophore Interactions (3.5)
Chromophore-Chromophore Interactions (3.5)
::2010/01/20::
Play Video
2
Chromophore, Chromophore Definition, Explanation of Chromophores
Chromophore, Chromophore Definition, Explanation of Chromophores
::2012/11/19::
Play Video
3
Pigments and Chromophores in Nature (3.7)
Pigments and Chromophores in Nature (3.7)
::2010/01/21::
Play Video
4
CGI Animated Audio-Visual Performance HD: "Chromophore" by - Paul Prudence
CGI Animated Audio-Visual Performance HD: "Chromophore" by - Paul Prudence
::2013/07/17::
Play Video
5
Synthesis of Polarity-Indicating Chromophore
Synthesis of Polarity-Indicating Chromophore
::2012/11/22::
Play Video
6
Chemistry of Colors
Chemistry of Colors
::2012/11/09::
Play Video
7
CHROMOPHORE
CHROMOPHORE
::2014/02/02::
Play Video
8
Chromophore Electro Plurality
Chromophore Electro Plurality
::2012/03/26::
Play Video
9
How to Pronounce Chromophore
How to Pronounce Chromophore
::2014/02/01::
Play Video
10
Chromophore [Blue Nebula]
Chromophore [Blue Nebula]
::2011/04/25::
Play Video
11
Chromophore: Color Blind Aid System DEMO
Chromophore: Color Blind Aid System DEMO
::2011/07/01::
Play Video
12
CHROMOPHORE
CHROMOPHORE
::2011/01/28::
Play Video
13
Chromophore [Red Nebula]
Chromophore [Red Nebula]
::2011/04/22::
Play Video
14
Happy Chromophore in Bacteriorhodopsin
Happy Chromophore in Bacteriorhodopsin
::2011/05/22::
Play Video
15
Chromophore [Imploding Star]
Chromophore [Imploding Star]
::2011/04/25::
Play Video
16
Alash Ensemble Track 2 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
Alash Ensemble Track 2 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
::2013/11/27::
Play Video
17
Alash Ensemble Track 3 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
Alash Ensemble Track 3 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
::2013/11/28::
Play Video
18
Alash Ensemble Track 6 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
Alash Ensemble Track 6 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
::2013/11/28::
Play Video
19
Alash Ensemble Track 1 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
Alash Ensemble Track 1 (Tuvan Throat Singing) at the University of Chicago (Nov. 2013)
::2013/11/27::
Play Video
20
Freeman Dyson: The seminar series: convincing Oppenheimer
Freeman Dyson: The seminar series: convincing Oppenheimer
::2014/01/13::
Play Video
21
Farbstoffe - Einführung | Chemie | Organische Verbindungen - Eigenschaften und Reaktionen
Farbstoffe - Einführung | Chemie | Organische Verbindungen - Eigenschaften und Reaktionen
::2014/03/28::
Play Video
22
20. Electronic and Vibrational Spectroscopy
20. Electronic and Vibrational Spectroscopy
::2012/04/05::
Play Video
23
Persian Percussion Instrument Daf
Persian Percussion Instrument Daf
::2007/03/08::
Play Video
24
Bangalore Highway Floods
Bangalore Highway Floods
::2007/03/02::
Play Video
25
Einführung in die Farbstoffe (GK) | Chemie | Organische Chemie
Einführung in die Farbstoffe (GK) | Chemie | Organische Chemie
::2012/06/15::
Play Video
26
Auxochromes, Auxochromes Definition
Auxochromes, Auxochromes Definition
::2012/11/17::
Play Video
27
We Are From the Future Let There Be Light
We Are From the Future Let There Be Light
::2014/03/27::
Play Video
28
New Technology to Control the Dispersion of Single-Wall CNT with Light
New Technology to Control the Dispersion of Single-Wall CNT with Light
::2011/09/07::
Play Video
29
GFPChromoforeUREKA.mov
GFPChromoforeUREKA.mov
::2010/08/03::
Play Video
30
The ATGCAT hexamer binds racemic [Ru(phen)2dppz]2+
The ATGCAT hexamer binds racemic [Ru(phen)2dppz]2+
::2013/07/24::
Play Video
31
We Are From The Future (3:14 version summary)
We Are From The Future (3:14 version summary)
::2014/04/04::
Play Video
32
James & Michelle
James & Michelle
::2010/09/10::
Play Video
33
Intercalation into DNA studied by X-ray crystallography
Intercalation into DNA studied by X-ray crystallography
::2012/06/30::
Play Video
34
LASER HAIR REMOVAL TREATMENT  IN CHANDIGARH
LASER HAIR REMOVAL TREATMENT IN CHANDIGARH
::2014/01/06::
Play Video
35
Paraiba tourmaline Blue and pink Brazil Batalha
Paraiba tourmaline Blue and pink Brazil Batalha
::2010/05/07::
Play Video
36
IPL vs LASER Hair Removal
IPL vs LASER Hair Removal
::2014/03/17::
Play Video
37
Human Eye: 04: Biochemistry
Human Eye: 04: Biochemistry
::2010/04/26::
Play Video
38
Molecular Orbitals of Butadiene (3.3)
Molecular Orbitals of Butadiene (3.3)
::2010/01/20::
Play Video
39
best hair removal Treatment in Chandigarh
best hair removal Treatment in Chandigarh
::2013/12/23::
Play Video
40
laser Treatment in Chandigarh
laser Treatment in Chandigarh
::2013/12/21::
Play Video
41
Bioluminescence in Aequorea victoria
Bioluminescence in Aequorea victoria
::2010/05/31::
Play Video
42
Structural Studies of Phycobiliproteins from Spirulina - Amrita University
Structural Studies of Phycobiliproteins from Spirulina - Amrita University
::2011/11/19::
Play Video
43
antibiotics-17-anti metabolites
antibiotics-17-anti metabolites
::2014/03/08::
Play Video
44
Detection of Bacteria Using Fluorogenic DNAzymes
Detection of Bacteria Using Fluorogenic DNAzymes
::2014/02/27::
Play Video
45
cen solar+spin 1920x1080
cen solar+spin 1920x1080
::2013/05/30::
Play Video
46
Aerosol Detector for any Nonvolatile or Semivolatile Analyte
Aerosol Detector for any Nonvolatile or Semivolatile Analyte
::2013/03/20::
Play Video
47
The intercalation of daunomycin
The intercalation of daunomycin
::2012/06/29::
Play Video
48
Corona ultra RS Detector
Corona ultra RS Detector
::2012/04/11::
Play Video
49
DNA intercalation by acridine-4-carboxamides
DNA intercalation by acridine-4-carboxamides
::2012/06/28::
Play Video
50
Xlase by Biotec Italia srl
Xlase by Biotec Italia srl
::2013/02/25::
NEXT >>
RESULTS [51 .. 101]
From Wikipedia, the free encyclopedia
Jump to: navigation, search

A chromophore is the part of a molecule responsible for its colour. [1] The colour arises when a molecule absorbs certain wavelengths of visible light and transmits or reflects others. The chromophore is a region in the molecule where the energy difference between two different 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 8.2−12.0
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]

External links[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
Wikipedia content is licensed under the GFDL License

Mashpedia enables any individual or company to promote their own Youtube-hosted videos or Youtube Channels, offering a simple and effective plan to get them in front of our engaged audience.

Want to learn more? Please contact us at: hello@mashpedia.com

Powered by YouTube
LEGAL
  • Mashpedia © 2014