MadSci Network: Chemistry

Re: chemiluminescence reaction example written out scientifically

Date: Wed Mar 17 10:56:53 1999
Posted By: Uncle Al Schwartz, Organic synthetic chemist
Area of science: Chemistry
ID: 918449585.Ch

Start with a labile (good leaving groups) oxylate bis-ester.  React with 
alkaline hydrogen peroxide.  Peroxide mono-anion attacks the first ester 
group to give the ester (unaffected one side) peracid (the other) by 
nucleophilic displacement (amplified by the Alpha Effect).

The peracid ionizes and intramolecularly attacks, displacing the other 
leaving group and closing to a four-membered ring - two carbons, two 
oxygens, both carbons being carbonyls - a diketodioxetane.

The diketodioxetane undergoes spontaneous ring cleavage to give two 
molecules of carbon dioxide, one electronically excited.  Said excitation 
energy can be efficiently transferred to almost any fluorescent species, as 

Tetrakis(dimethylamino)ethylene spontaneously reacts with oxygen in the air 
to give 2+2 cycloaddition to 3,3,4,4-tetrakis(dimethylamino)dioxetane.  
That in turn spontaneously cleaves as above into two molecules of 
tetramethylurea, one electronically excited.  It gives a (faint) green glow 
all by itself.

Aldrichimica Acta 16(3) 59 (1983) Cyalume

A Multicolored Luminescence Demonstration, J. Chem. Ed. 69(10) 
827 (1992) (luminol; which is also enhanced by addition of a 
little 4,4'-dihydroxybiphenyl).

The H2O2 oxidation of lucigenin (bis-N-methylacridinium nitrate 
Aldrich B4,920-3) is modified to provide a slow color change 
across the visible spectrum.

Cyalume lightsticks contain dilute hydrogen peroxide (0.5%) in 
dioctylphthalate in a thin glass ampoule, and a DOP solution of 
oxalate ester and fluorochrome 9,10-bis(phenylethynyl)anthracene.

9,10-bis(phenylethynyl)anthracene (BPEA) (green)  [10075-85-1] Fluka 15146
9,10-diphenylanthracene (DPA)             (blue)   [1499-10-1] Fluka 42785
5,6,11,12-tetraphenylnaphthacene (rubrene) (orange) [517-51-1] Fluka 84027

bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate (CPPO) 
                                     [75203-51-9]  Aldrich 39,325-8
bis(2-ethylhexyl)phthalate (DOP) (solvent) [117-81-7]   Fluka 80032
sodium salicylate (catalyst)               [54-21-7]    Fluka 71945
35% hydrogen peroxide                      [7722-84-1]  Fluka 95299

Saturate solvent with dye and CPPO. Sonicate to help solvation. 
Start with about 50 mg dye (BPEA, DPA or rubrene) in 10 g solvent 
with 50 mg CPPO and 5 mg sodium salicylate.  CPPO is limiting 
reagent.  Put a ml in a small vial and add equal volume of 
hydrogen peroxide.  Mix vigorously. There will be two phases. 
Avoid skin contact! Don't cap tightly!  

Cyalume sticks use 1-chloro(BPEA) (30 min high intensity yellow-
green) and the 2-chloro isomer (12 hour green).  The yellow fluor 
is 1,8-dichloro(BPEA).  The red fluor is 2,4-di-t-butylphenyl 
substituted 1,4,5,8 tetracarboxynapthalene diamide - very deep 
red in organic solvents - mixed with dpa gives "white" light 
stick, or "hot pink" depending on concentrations.  Almost any 
fluorescent dye will give light in the oxlate system - rhodamine 
640 gives a good red, and BABN the most intense green fluor (not 
as stable as BPEA).

1- and 2-chloro(DPA)s are more efficient than DPA and slightly 
Stokes-shifted toward the blue-green.  Dihydro(DPA) is shifted 
towards the purple in emission - quite pretty.

Uncle Al Schwartz
 (Toxic URLs!  Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?"   The Net!

Current Queue | Current Queue for Chemistry | Chemistry archives

Try the links in the MadSci Library for more information on Chemistry.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1999. All rights reserved.