From Chromic Phenomena: Technological Applications of Colour Chemistry

3.6 Chemiluminescence

Chemiluminescence is the production of light by chemical substances without the help from other energy sources; in effect it is the conversion of energy stored in chemical bonds into light. Mechanistically, chemiluminescence involves several consecutive processes. The first step is the chemical reaction to form a product, which can undergo further highly exothermic transformations of sufficient energy to emit light in the visible region (400 700 nm) of the spectrum. For this to occur the reaction enthalpy must be in excess of 40 kcal mol ?1. In the second step, chemical potential energy is transformed into electron excitation energy by a reaction intermediate entering an electronically excited state. The final step is the loss of energy from this excited state, as fluorescence or phosphorescence depending on whether the orientation of the spin in the excited intermediate is singlet or triplet (see Figure 3.1). This is called direct Chemiluminescence as opposed to indirect Chemiluminescence in which the electronically excited state transfers energy to a suitable acceptor which itself emits light.

3.6.1 Chemiluminescent Reactions

The most useful chemiluminescent reactions fall into three categories.1 ,48

  • Reactions involving electron transfer. Reaction of free ion radicals, oxidation of anion radicals of aromatic and heteroaromatic hydrocarbons. Usually an energy acceptor is required to be present

  • Reactions of singlet oxygen. Singlet oxygen, e.g. generated by the action of chlorine on alkaline hydrogen peroxide, transfers its energy to a fluorophore acceptor, which emits light

  • Peroxide decomposition. Singlet oxygen can also...

Copyright The Royal Society of Chemistry 2001 under license agreement with Books24x7

Products & Services
Microplate Readers
Microplate readers are designed to scan, analyze and obtain numerical results from chemical reactions conducted within microplates.
Light Sticks
Light Sticks are self contained, short-term light source, generally consisting of a translucent plastic tube containing isolated substances that, when combined, produce light through chemiluminescence. Light sticks are sometimes called glow sticks.
Inorganic Chemicals and Compounds
Inorganic chemicals, inorganic salts and inorganic compounds are substances of mineral origin that do not contain carbon in their molecular structure.
Lasers
Lasers are devices that produce intense beams of monochromatic, coherent radiation. The word "laser" is an acronym for Light Amplification by Stimulated Emission of Radiation.

Topics of Interest

3.7 Bioluminescence Bioluminescence is the production of light by living systems. The best-known example of this phenomenon is the characteristic glow of the firefly, but other luminous species...

Chemiluminescent detection with 1,2-dioxetane substrates Substrates for alkaline phosphatase can be variously enhanced so as to provide highly sensitive detection with many assay formats and...

15.1 Historical Introduction It has long been a matter of dispute in biology whether magnetic fields can give appreciable influence to biological reactions or organisms. Although there has been no...

4.1 Introduction The excited state produced by the interaction of a molecule with light can lose or transfer its energy in various ways.1 Return to the ground state can be accompanied by the emission...

3.1 Introduction Those phenomena that involve absorption of energy and subsequent emission of light are classified genetically under the term luminescence. This phenomenon is observed when a...

Product Announcements
IDEX Health & Science
ichromatography/Analtech, Inc.
IDEX Health & Science