More on Chemiluminescence

[eXcidium]

Hi folks, I don't know if anyone is interested ot not, but I digged a book out and dipped into luminescence a bit longer.

It's not "hive" related, so sorry, just a bit of general chemistry knowledge (if anyone is interested)


The reaction

The reaction is a two step "one pot" one, and here's how it goes

1: Aryl Oxalate (e.g. bis(2,4,6-trichlorophenyl) oxalate) + Hydrogen peroxide + catalist -----> 1,2-dioxetane-3,4-dione + 2,4,6-trichlorophenol

2: 1,2-dioxetane-3,4-dione + Fluorophore

Dye

(http://www.semrock.com/Catalog/AllFluorophoresTable.htm)  -----> CO₂ + Fluorophore + Light

Now with some pictures....

1:

Molecule:

bis(2,4,6-trichlorophenyl) oxalate ("ClC(C=C(Cl)C=C1Cl)=C1OC(C(OC2=C(Cl)C=C(Cl)C=C2Cl)=O)=O")

 +

Molecule:

Hydrogen Peroxide ("[H]OO[H]")

 ----->

Molecule:

1,2-dioxetane-3,4-dione ("O=C1OOC1=O")

 +

Molecule:

2,4,6-trichlorophenol ("ClC1=CC(Cl)=CC(Cl)=C1O ")



2:

Molecule:

1,2-dioxetane-3,4-dione ("O=C1OOC1=O ")

+ Fluorophore ----->

Molecule:

Carbon Dioxide (" O=C=O ")

+ Fluorophore + Light


And how it's done :

A solution of ~0.3% H2O2  + a catalytic amount of NaOH in THF was added dropwise to approximately 8 mL of the diaryl oxalate + fluorophore in THF (~25ºC) in a test tube (open vial)

The emission is relatively short lived but since H2O2 is apparently limiting, a second and third dropwise addition of the oxidant yields additional bursts of light.

[eXcidium]

Same Goes with Luminol :

Luminol (2,3-dihydrophthalazine-1,4-dione) + Hydrogen Peroxide  + NaOH (^-OH) + Catalist ----->
3-aminophthalate + Light

H₂O₂ +

Molecule:

Luminol (" O=C2NNC(C1=C(N)C=CC=C12)=O ")

 AND (base ^-OH + catalyst) ----->

Molecule:

3-aminophthalate ("[O-]C(C1=C(N)C=CC=C1C([O-])=O)=O ")

+ Light

[hypo]

but i don't see the relevance to the subjects discussed here at all.

now if you're into 24h+ phosphorescence and make bright yellow glowing
pills, now _that_ would be cool.  

[armageddon]

Well although it's absolutely NOT drug related chemistry - don't you know these moments when the chemist begins staring at a flask like a child 'cause something wierd/fascinating happens inside it?  

- In case you would like to reproduce this "aah"-effect at any time: try the luminol reaction, preferably with a buffered basic solution and Cobalt(2)chloride or potassiumhexacyano(3)ferrate as catalyst (copper(2) salts work too), and you will be astonished by the beauty of this blue glowing light....

Greetz A

[hest]

In the oxalicester reation tre things is important. keep the mixture dry, use stronh H2O2 (90%) if you cant't get that use peroxide in ether (mix diethyletehr an hydrogenperoxide, shake, seperate the ether and dry it) Make it on demand, some etherperoxide will be generated over time, but they are not as dangeres as the literature indikate.
Iff yoy can get the original phenol (trifluro propy something) you can made lightsticks with are as good as them you buy in a shop (5L of this mixture looks damm god)

[armageddon]

I wouldn't store ethereal H202 for longer periods - believe me, as soon as the ether becomes discolored, it becomes VERY instabile..

(like Zwitterion said time ago: "One of the all-around party favourites.."   )

A

[eXcidium]

[armageddon]

The Luminol reaction

Two solutions are prepared:

A) 100mg Luminol are dissolved in 20ml 10% NaOH solution. This is then diluted to 200ml with water.

B) 500mg K₃[Fe(CN)₆] are dissolved in 20ml 5% hydrogen peroxide. (solution B should be prepared immediately before use)

In a dark room, pour the (freshly prepared) solution B into solution A - a green/blue glowing light is the result. The Chemoluminescence can be refreshed by adding small quantities of K3[Fe(CN)6]...

Greetz A