luminescence and luminol,cyalume and luciferin

1. Luminescence is emission of light by a
substance
Types
Chemiluminescence, a result of a chemical reaction
Bioluminescence, emission by a living organism
Sensitized Luminescence
One type of activator absorbs the exciting, transfer its energy to another
Substance.

2. CHEMILUMINESCENCE
A chemical reaction yields an electronically excited molecule
Chemoiluminescence is the production of light from chemical
substances without the aid of other energy sources.
A + B → C* + D
C* → C + light

3. A + B → C* + D
C* → C + light
Intensity depends on rate of reaction of production of C*
( )84 −

4. chemical reaction yields an electronically excited species that emit light as it returns to
ground state.
Examples of Chemical Systems giving off light:
C
NH
NH
C
NH2 O
O
O2/OH-
NH2
COO-
COO-
+ hν + N2 + H2O
- phenyl oxalate ester (glow sticks- phenyl oxalate ester (glow sticks)
LuminolLuminol (used to detect blood)(used to detect blood)

5. chemiluminescence of luminol:
NH
NH
O
O
NH2
Luminol
-
OH
N
N
O
O
NH2
N
N
O
O
NH2
-
OH, H2O2
K3Fe(CN)6
- N2
O
O
O
O
NH2
*O
O
O
O
NH2
*O
O
O
O
NH2
Triplet excited state
(3-aminophthalate
anion)
Singlet excited state
(3-aminophthalate
anion)hν
(light)
Here the triplet
excited state is
formed chemically
by the degradation
of this dianion

6. Energetically:
Energy
O2
+
Luminol dianion
Peroxide intermdediate
Intersystem
crossing Fluorescence
emission
- hν
T1 vibrational
energy levels
S1 vibrational
energy levels
3-Aminophthalate
dianion
S0 Ground state
N2
photon

7. Acridinium Compounds
The best-known chemiluminescent acridinium derivative is lucigenin
(10,10’-
dimethyl-9,90-biacridinium dinitrate
alkaline peroxide produces N-methylacridone, with emission of blue light at 442 nm
Dioxetanes
The pyrene vinyl ether reacts readily with singlet oxygen to generate an
unstable dioxetane , which decomposes to excited pyrene carbaldehyde .

8. Commercially available dioxetane AMPPD

9. Bioluminescence in biological systems, biological reactions
firefly, the sea pansy, certain jellyfish, bacteria, protozoa,
and crustacea (Luciferin, enzyme catalyse, luciferease)

10. Bioluminescence
Bioluminescence is the production and emission of light by a living
organism.
Bioluminescence is a naturally occurring form of chemiluminescence where
energy is
released by a chemical reaction in the form of light emission.
Fireflies, anglerfish, and other creatures produce the chemicals luciferin (a
pigment) and luciferase (an enzyme).
The luciferin reacts with oxygen to create light. The luciferase acts as a
catalyst to speed up the reaction, which is sometimes mediated by cofactors
such as calcium ions or ATP.

11. Luciferin (fireflies): Similar to cyalume in the formation and degradation of a
4-membered ring followed by phosphorescence
N
S
S
N
H
OH
O
HO
Luciferin
ATP
S
N
H
O
O
AMP
+ pyrophosphate
S
N
O
O
AMP- H+
O O
S
N
O
O
AMP
O
O
S
N
O
O
AMP
O
O
R
N
SHO
R
R
R
S
N O
+ AMP
O
O
R
S
N
R
O
S
N
R
O
+ CO2
*
= R
Oxyluciferin

12. Proposed applications of engineered
bioluminescence
■ Glowing trees to line highways to save government electricity bills
■ Christmas trees that do not need lights, reducing danger from
electrical fires
■ Agricultural crops and domestic plants that luminesce when they need
watering
■ New methods for detecting bacterial contamination of meats and other
foods
■ Bio-identifiers for escaped convicts and mental patients
■ Detecting bacterial species in suspicious corpses
■ Novelty pets that bioluminesce (rabbits, mice, fish etc.)
Bioluminescent organisms

13. All cells produce some form of bioluminescence within the
electromagnetic spectrum, but most are neither visible nor
noticeable to the naked eye.
Animals
Fungi
Fish
Marine invertebrates
Microorganisms

14. - phenyl oxalate ester (glow sticks- phenyl oxalate ester (glow sticks)
Sensitized Luminescence
One type of activator absorbs the exciting, transfer its energy to another
Substance.

15. Other Example: Light Sticks: Cyalume
Light sticks contains a thin glass vial that contains an alkaline (basic)
solution of hydrogen peroxide suspended in a solution of diphenyloxalate
and an organic dye.
When the inner vial is broken two successive nucleophilic substitution
reactions occur to form an unstable 4-membered ring.
This ring decomposes by a pathway that forms a excited triplet electronic
state on the oxygen of one of the two molecules of carbon dioxide
produced.
Normally, if this electron decayed to the ground state the photon released
would be in the UV region. In the presence of the dye, however,
photosensitization occurs (triplet to triplet).
T1 + A(S0)  S0 + A(T1)
The excited dye molecule undergoes phosphorescence to give a photon in
the visible region of the spectrum (dye dependant).

16. O C C O
O O
Cl
Cl
Cl
Cl
Cl
Cl
Cyalume
O C C O
O O
HO OH O OH + H2O
O C C O
O O
O
OH
O
C C O
O
O
O
OH
HO-
+
HO-
C C O
O
O
O
O + H2O
C C O
O
O
O O
C C O
O O
O O
+
+
C C
O O
O O
reverse [2 + 2]
cycloaddition
C
O
O
C
O
O
*
dye
C
O
O
+ dye* dye + hν (visible light)
Cyalume: