96 



RADIATION BIOLOGY 



5 - 



o> 4 

 o 



SORET • 



f \ 



PORPHIN IN ACID 

 ETIOPORPHIN IN ACID 



PORPHIN (PHYLLO) 

 ETIOPORPHIN (ETIO) 



•RHODOPORPHYRIN X2 

 ( RHODO) 



_L 



_L 



_L 



2000 



3000 



4000 



7000 



8000 



9000 



5000 6000 



WAVE LENGTH, A 



Fig. 2-15. Absorption of porphyrins. {Etioporphyrin spectra from Erdman and 

 Corwin, 1946; others from Stern and Wenderlein, 1935, and Pruckner and Stern, 1936.) 



CHLORIN / 



RHODIN gTj 



CHLOROPHYLL Q 



CHLOROPHYLL b 



2000 



3000 



4000 



7000 



8000 



9000 



5000 6000 



WAVE LENGTH, A 



Fig. 2-16. Absorption of ehlorins. (Chlorin from Stern and Wenderlein, 1935; rhodin 

 from Pruckner and Stern, 1936; chlorophylls adapted from Zscheile and Comar, 1941.) 



2000 3000 4000 5000 6000 7000 8000 9000 



WAVE LENGTH, A 



Fig. 2-17. Absorption of bacteriochlorins. (Adapted from French, 1937.) 



longer than the naphthyl group itself, the long-wave-length spectra will 

 begin to have predominantly polyene character. 



PORPHYRINS 



After the polyenes, the porphyrins open up new vistas of sophistication 

 and interest. These compounds comprise 



1. The true porphyrins, which are derivatives of porphin (Fig. 2-14); 



