196 LIGHT AND LIFE 



31. Yale, et al, J. Am. Chem. Soc, 75, 1933 (1953), prepared compound X, and 



XI was prepared and tested by \VegIer, /. prakt. Chem., 148, 135 (1937). 



32. Zellner, C. N., and Dougherty, G., /. Am. Chem. Soc, 59, 2580 (1937). These 



authors isolated benzil-2,2'-dicarboxylic acid from the reaction of phthalic 

 hydrazide with sodium hypochlorite. The chemiluminescence under these 

 conditions is extremely weak. 



DISCUSSION 



Dr. Ka.sha: I would like to direct a question to Dr. Linschitz. I am 

 impressed by what a mute harp the porphyrin ring makes when the chemi- 

 luminescence arises as "one twangs tlie porphyrin ring." It is the low 

 quantum yield to which I am referring, which makes a very interesting 

 comparison to the second reaction of yours. This suggests that in both 

 ca.ses the emitting molecule is in a different environment. The point is that 

 I think that the porphyrin spectra characteristically show vibrational struc- 

 ture and yet I see you attribute the second band in the porphyrin base to 

 some impurity. I think that this may not be correct. But, if not, the 

 question is why does the second band disappear in the chemiluminescent 

 reaction? 



Dr. Lin.sc;hitz: Professor Dorough has also measured the fluorescence of 

 the same prophyrin at low temperatures. His spectrum does not have the 

 side band in it, and his spectrum checks exactly with our luminescence 

 spectrum. To be sure we measured our fluorescence spectrum at the same 

 elevated temperatures as our chemiluminescent reaction, and I think our 

 explanation makes sense for this reason. As far as overall chemiluminescence 

 quantum yields are concerned, it is hard to say. They are probably very, 

 very low. If you calculate the number of molecules which are going through 

 this system and if the yields were 100%, you would expect an output of 

 something like 10" to 10'* photons per second. I would expect our yields 

 to l)e below 0.1%. This represents, of course, the primary yield of excited 

 molecules produced in the reaction, multiplied by the fluorescence yield. 

 The point is that the chemiluminescence corresponds to the fluorescence of 

 the original dye. 1 hus, it is hard to see how this can be excited in any 

 breakdown processes involving the dye. The point is that the one unam- 

 biguous fact which I am really sure of is that the chemiluminescence cor- 

 responds to tiie fluorescence of tlie original dye. 1 hus, it is hard to see how 

 this can i)e excited in the breakdown processes. 



Dr. Calvin: I have a question for Dr. Linschitz. Is there any evidence for 

 tlic kind of complexes with wiiich you start the reaction if you examine the 

 .spectrum carefully of porphyrins at low temperatures in the presence of 

 peroxides? 



Dr. LiNSCiirrz: No. we ha\e not been aljle to find any evidence for that. 



Dr. Calvin: It's a rather sharp spectrum. 



Dr. Linsc;hit/.: I would think so, and we have looked for it. 



Dr. McKiro^ : I woidd like to ask a (|uestion on the inhibitor product 



