194 



LIGHT AND LIFE 



reaction (Fig. 9) , based on bond energy values, indicate that ca. 

 90 kcal are available and that most of this energy is associated, in a 

 sense, with the formation of the nitrogen molecule. The latter possi- 

 bility suggests that the emitting species is excited during the ejection 

 of the nitrogen molecule and that the phthalate ion might be the 

 emitter (Fig. 10). Indeed, the evidence for this choice seems rather 

 good for the water systems (previous section) . The evidence is not 



TABLE 2 

 Chemiluminescf.nci: ami Fluorkscence Maxima in Various Solvents 



comi^elling for the reaction in organic solvents, however. We have 

 compared the chemiluminescence spectra in four solvents with the 

 fluorescence spectra of various possible emitters (Table 2). Although 

 a case might be made for the aminophthalate ion in water, and for 

 the anhydride in dimethyl formamide and in dimethyl sulfoxide, no 

 completely satisfying general correspondence has been found. It has 

 been recently observed, however, that immediately after the chemi- 

 luminescence is over in dimethyl sulfoxide, the solution fluoresces at 

 -180 ny, attcmjHs to isolate and identify the emitter are in progress. 



