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DISCUSSION 



Cations of Porphyrins and Their Spectra 



Orgel: I should like to ask Phillips why it is that in the detergent system it is possible 

 to measure the addition of a single proton to a metal-free porphyrin, while in the past 

 those measurements which have been done have suggested that two protons are 

 added simultaneously. 



Phillips: We believe the reason that the monocation is so readily obtained in anionic 

 detergent solution to be due to its stabilization at the negatively charged micelle-water 

 interface. It is of interest to note that no monocationic species can be detected in 

 non-ionic or cationic detergent solutions. 



Lemberg: It is reassuring that on the whole there seems to be a satisfactory agreement 

 between the conclusion as to basicity of porphyrins derived from the Willstiitter 



