An asterisk denotes the excited species.  Here h is Planck's constant and v (Greek "nu") is the frequency of the emitted photon.  In some reactions the excited species may transfer its electronic energy to another compound not involved in the initial reaction ( e.g., the  fluorescent dye in the case of the light stick).

Lophine¹ (2:4:5-triphenyliminazole) can be prepared by heating hydrobenzamide (tribenzaldiamine, (C₆H₅CH)₃N₂) to about 300 C.  The reaction involves ring closure to form an intermediate heterocyclic compound, amarine (2:4:5-triphenyldihydroiminazole) at about 130 C.  On further heating this dehydrogenates to form lophine.  The reaction during this step is still not well understood.  The conversion of amarine to lophine is an oxidation in the general sense. Possibly a portion of the amarine is reduced to "balance the books" so to speak .  Figure 1 (below) shows the structural rearrangements that take place.  As a historical sidelight, these reactions were investigated by the Russian organic chemist, Alexander Borodin (1833-1887) in his first scientific paper.  Today Borodin is better known as a composer than a chemist, although he always regarded chemistry as his vocation and music as his hobby.

Figure 1

Despite the formidable-looking structures shown in Figure 1, lophine is relatively easy to synthesize in the home laboratory.  The starting material, hydrobenzamide can be prepared by reacting benzaldehyde with concentrated ammonium hydroxide.  Place 10 mL benzaldehyde in a 250 mL flask and add 40 mL conc. ammonium hydroxide.  Shake until thoroughly mixed and pour into a beaker.  Cover the beaker with a watch glass and allow it to stand for three days at room temperature At the end of this time the ingredients will have reacted to form a cake of hydrobenzamide (Eq. 1):

               
Pour off the liquid in the beaker, break up the cake and wash twice with water and once with alcohol.  Let stand for a day or two until dry.

Place the hydrobenzamide in an evaporating dish.  Heat gradually with constant stirring.   The hydrobenzamide will melt to form a light honey-colored liquid. Continue heating until the liquid suddenly turns a molasses brown and starts to emit acrid fumes.  At this point the product consists of crude lophine.  Continue heating a second or two longer and then allow it to cool.  When cold the lophine forms a brown translucent glass.  Use a spatula or knife blade to chip it out of the dish.  The yield should be about 5 to 6 grams.

To demonstrate the chemiluminescence of lophine prepare the following solutions:

A: Dissolve 2 g crude lophine in 100 mL alcohol.

B.  Dissolve 2.5 mL 3% hydrogen peroxide in 22.5 ml alcohol,

C: Dissolve 1 g potassium hydroxide² in 15 mL water and add 5 mL alcohol.

D: Mix 2.5 mL household bleaching water (contains about 4 % NaOCl) with 22.5 mL water.

In a darkened room mix 10 mL of solution A into the whole of solutions B and C.  Pour the mixture into solution D contained in a cylinder or tall bottle.  A fairly bright lemon-yellow luninescence will result.  The liquid will glow brightly for a minute or so and then gradually die away.  Several additions of undiluted bleach will repeatedly renew the luminescence until finally all the lophine is consumed.  Bubbles of gas (presumably O₂) are released during the reaction and the mixture becomes warm following the later additions of bleach, suggestive of further exothermic reactions of the crude material.

Notes:

1.  A chemist with whom I once discussed lophine punned that he preferred it to "workine"   

2.  Sodium hydroxide (sometimes available at a supermarket as "concentrated lye") may also be used.