Chemoluminescence
Akmal Firuz
C t t
Contents
 Historical background
 Luminescence
 Occurrence
O
in
i nature
t
 Chemiluminescence
- Requirements
- Factors
 Applications: luminol, glow sticks
 Bioluminescence
 References
Historical background
 Luminescence phenomena has been known since ancient times. Multiple
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written references in ancient Chinese literature – “emperor’s magic paint”
The first written acknowledgement of chemiluminescent reactions was
made by Aristotle who noted weak emission from some dead fungi and
fish.
1663: R.
R Boyle worked on oxygen which opened new doors for scientific
explanation of CL. Mentions the CL of phosphorus.
1877: B. Radziszewski studies the CL of Lophine
1888: The term “chemiluminescence”
chemiluminescence is coined by Eilhardt Weidemann
1901: R. Dubois publishes the first paper on BL and introduces the
phrases Luciferin and Luciferase
1905: M. Trautz publishes a review of known CL and BL reactions and
attributes them to active oxygen
1928: H. O. Albrecht is attributed with the discovery and characterisation
of the chemiluminescence of luminol
Luminescence phenomena has a very long historical development!
Luminescence
What?
 Emission
E i i off lilight
ht b
by a substance
b t
nott resulting
lti ffrom heat
h t
(cold light)
When?
 When electron in excited state falls back to ground
state.
state
Types?
 Chemiluminescence,
Chemiluminescence Bioluminescence
Bioluminescence,
Photoluminescence
Compare to incandescence and fluorescence.
Occurrence in nature (bioluminescence)
 Fireflies,, glow
g
worms
 90% of deep-sea creatures
 Bacteria
 Fungi
 Dinoflagellate
Chemiluminescence
 Emission of light (usually in visible and near infrared)
as a resultlt off a chem.
h
reaction.
ti
 [A] + [B] → [◊] → [Products] + light
A chemiluminescent
A:
h il i
t precursor
B: oxidant
◊: excited intermediate
 Sometimes in a presence of catalyst (reduce
activation energy)
energy), intermediate in electronically
excited state, subsequently relax to ground state by
the emission of photon.
photon
Requirements
 Reaction must be exothermic to produce sufficient
energy to form electronically excited state. For
visible
i ibl lilight:
ht 160 – 320 kJ/mol.
kJ/ l
 Reaction pathway must be favourable to channel the
energy for the formation of electronically excited
state.
 Photon emission must be a favourable deactivation
process of excited product (figure 3) in relation to
other
th competitive
titi nonradiative
di ti process th
thatt may
appear in low proportion.

For CL to occur, reaction must be sufficiently
exothermic such that:
: Free Energy
: wavelength limit for excitation of
luminescent species
Factors affecting chemiluminescence
emission
 Chemical structure of CL precursor
precursor, including side

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chain
Nature of other substrates affecting
g CL p
pathway
y
Selected catalyst
Presence of metal ions
Temperature
pH and ionic strength
Hydrophobicity of the solvent and solution
composition
p
Presence of energy transfer acceptor
Application: Luminol (forensics)
Reaction:
•Luminol must be activated by hydroxide salt forming a dianion.
• Iron
I
catalyzes
t l
hydrogen
h d
peroxide
id tto d
decompose and
d fform O
Oxygen
• The dianion reacts with oxygen producing the unstable organic peroxide intermediate:
• This intermediate decomposes
p
from higher
g
energy
gy states to the g
ground state,, emitting
ga
photon
• Floorboard treated with luminol
Application: Glow sticks
 First container contains Phenyl
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Oxalate and dye. Glass vial contains
Hydrogen Peroxide.
Reaction produces 2 molecules of
phenol and one molecule of
peroxyacid
p
y
ester.
Peroxyacid decompose to CO2 and
releases energy which excites the dye.
Dye
y relaxes byy releasing
gap
photon.
Wavelength is dye dependant!
Examples of dyes used:
Other applications
 Pharmaceutical Industry (analysis and quality
control)
 Clinical
Cli i l S
Science
i
 Detecting the photoactivity of water through its
H2O2 concentration
 Detecting Nitric Oxide in the breath of Asthma
Patients.
 HPLC ((High
g Performance Liquid
q
Chromatography)
Special
p
mention: Bioluminescence
 In general, involves 2 types
of substances: light
producing luciferin and
enzyme-based catalyst
luciferase.
 Often the process requires
the presence of other
substances, such as oxygen
or ATP
ATP.
 Luciferin is oxidized by
oxygen and reaction is
catalysed by luciferase and
light is emitted. Emission
continues until all light is
oxidised.
 Reaction mechanism,
luciferin and luciferase vary
from organism to organism.
organism
Example: Firefly
luciferin
luciferase
 luciferin + ATP → luciferyl adenylate+
adenylate Pyrophosphate
 luciferyl adenylate + O2 → Oxyluciferin + Adenosine monophosphate
+ light
 Light is emitted because the reaction forms oxyluciferin in an
electronically excited state. The reaction releases a photon of light as
oxyluciferin
y
returns to the ground
g
state.
R f
References
 Ana M. Garcia-Campana
p
((2001)) Chemiluminescence in
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Analytical Chemistry
http://en.wikipedia.org/wiki/Luminol
http://en wikipedia org/wiki/Luciferase
http://en.wikipedia.org/wiki/Luciferase
http://uvminerals.org/fms/luminescence
http://science.howstuffworks.com/innovation/everydayp
y y
innovations/light-stick2.htm
http://animals.howstuffworks.com/animalfacts/bioluminescence3.htm
acts/b o u
esce ce3 t
https://www.flickr.com/photos/jackofspades/1424860617/in/set72157602138715960/
http://www chemistry blog com/2013/07/30/chemsummer
http://www.chemistry-blog.com/2013/07/30/chemsummercarnival-glow-sticks-how-do-they-work/
Thank you for your attention!