394 Mr. C. A. Schunck. A Photographic Investigation 



Phylloxanthin, Phyllocyanin and its Compounds. 



Phylloxanthin and phyllocyanin, the two leading chlorophyll 

 derivatives obtained by the action of hydrochloric acid (Schunck, 

 " Contributions to the Chemistry of Chlorophyll")* give in alcoholic 

 solutions in the violet region of the spectrum, in the former case two 

 bands, and in the latter one (Plate 5, figs. 3 and 4). As has already 

 been pointed out, the two phylloxanthin bands are identical in posi- 

 tion with the second and third of the chlorophyll ones in the violet, 

 the band in phyllocyanin being moved slightly towards the violet 

 end, this band being situated between the lines h and H 2 . In both 

 cases the solutions have to be exceedingly dilute before the bands 

 become visible on the photographic plate, the only band remaining 

 visible to the eye in the visible part of the spectrum being the first, 

 the characteristic one in the red, and that now only appears faint. 

 From the investigations of 8chunck,f phyllocyanin plays the part of 

 a weak base, and combines with strong acids, the compounds, how- 

 ever, being unstable and easily decomposed even by water, and, like 

 other bases, giving definite double compounds of great comparative 

 stability, into which metals and acids, especially organic acids, enter 

 as constituents. 



I have examined the compounds formed by dissolving phyllocyanin 

 in anhydrous acetic acid, hydrochloric acid, and sulphuric acid, and 

 find a more pronounced band in each than even in the case of an 

 alcoholic solution of phyllocyanin, but in each compound the band 

 is shifted slightly towards the red end of the spectrum compared to 

 the band in phyllocyanin itself (Plate 4, figs. 1, 2, 3, and 4). 



Of the compounds formed by phyllocyanin with metallic salts, the 

 one with zinc carbonate in alcohol, with zinc acetate in acetic acid, 

 and the one with cupric acetate in the same solvent were examined. 

 In each the characteristic absorption was noticeable in the same 

 region of the spectrum. In the zinc carbonate compound two very 

 distinct bands were found corresponding very nearly in position with 

 the two in phylloxanthin, the shifting being towards the violet end 

 (Plate 4, figs. 5 and 6), the zinc acetate compound, on the other hand, 

 gave only one band, corresponding in position with the band of the 

 anhydrous acetic acid compound of phyllocyanin (Plate 4, fig. 7), 

 whilst in the case of the cupric acetate compound two badly defined 

 dark bands were apparent, the division between the bands corre- 

 sponding about to the position of the phyllocyanin band (Plate 4, 

 fig. 8). In both these series of compounds, as in the case of phyll- 

 oxanthin and phyllocyanin, the solutions had to be very dilute before 

 the characteristic absorption became apparent on the photographic 



* 'Boy. Soc. Proc.,' vol. 39, p. 348; TO!. 50, p. 306. 

 t * Roy. Soc. Proc.,' vol. 39, pp. 354 and 356. 





